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Introduction: Characterised by chronic inflammation of the gastrointestinal tract, inflammatory bowel disease (IBD) symptoms including diarrhoea, abdominal pain and fatigue can significantly impact patient's quality of life. Therapeutic developments in the last 20 years have revolutionised treatment. However, clinical trials and real-world data show primary non-response rates up to 40%. A significant challenge is an inability to predict which treatment will benefit individual patients.Current understanding of IBD pathogenesis implicates complex interactions between host genetics and the gut microbiome. Most cohorts studying the gut microbiota to date have been underpowered, examined single treatments and produced heterogeneous results. Lack of cross-treatment comparisons and well-powered independent replication cohorts hampers the ability to infer real-world utility of predictive signatures.IBD-RESPONSE will use multi-omic data to create a predictive tool for treatment response. Future patient benefit may include development of biomarker-based treatment stratification or manipulation of intestinal microbial targets. IBD-RESPONSE and downstream studies have the potential to improve quality of life, reduce patient risk and reduce expenditure on ineffective treatments., Methods and Analysis: This prospective, multicentre, observational study will identify and validate a predictive model for response to advanced IBD therapies, incorporating gut microbiome, metabolome, single-cell transcriptome, human genome, dietary and clinical data. 1325 participants commencing advanced therapies will be recruited from ~40 UK sites. Data will be collected at baseline, week 14 and week 54. The primary outcome is week 14 clinical response. Secondary outcomes include clinical remission, loss of response in week 14 responders, corticosteroid-free response/remission, time to treatment escalation and change in patient-reported outcome measures., Ethics and Dissemination: Ethical approval was obtained from the Wales Research Ethics Committee 5 (ref: 21/WA/0228). Recruitment is ongoing. Following study completion, results will be submitted for publication in peer-reviewed journals and presented at scientific meetings. Publications will be summarised at www.ibd-response.co.uk., Trial Registration Number: ISRCTN96296121., Competing Interests: Competing interests: TA reports personal grants from F. Hoffmann-La Roche, Biogen, AbbVie, Janssen, Celltrion, Galapagos, Immunodiagnostik and Takeda, outside the submitted work; personal fees for educational development/delivery from Pfizer, payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events from Pfizer, Takeda and F. Hoffman-La Roche; support for attending meetings from Celltrion, Tillotts and Pfizer. CAA reports grants from the Wellcome Sanger Institute Quinquennial Review 2021–2026, Crohn’s and Colitis Foundation (USA), the Medical Research Council, Open Targets UK and the Helmsley Charitable Trust; consulting fees from BridgeBio, Genomics and Brigham & Women’s Hospital Boston; payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events from GlaxoSmithKline; support for attending meetings and/or travel membership from the Wellcome Sanger Institute Quinquennial Review 2021–2026; (Chair) of the Board of Trustees for the Sanger Prize; other interests as Director of Anderson Genomics Consultancy. MB reports partial personal salary funding from the Medical Research Council. ALH reports personal consulting fees from AbbVie, BMS, Celltrion, Falk, Galapagos, Janssen, Pfizer, Takeda and Roche; payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events from BMS, Celltrion, Falk, Galapagos, Janssen, Pfizer, Takeda, Roche and AbbVie; support for attending meetings and/or travel from BMS, Celltrion, Falk, Galapagos, Janssen, Pfizer, Takeda, Roche and AbbVie. PI reports personal grants from Celltrion, Galapagos and Pfizer, outside the submitted work; personal consulting fees from AbbVie, Takeda, BMS, Janssen, Arena, Pfizer, Galapagos, Lilly, Boehringer-Ingelheim and Celgene; payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events from AbbVie, Takeda, Janssen, Lilly, BMS, Pfizer and Galapagos; support for attending meetings and/or travel from AbbVie and Tillotts. LJ-D reports grants from the Wellcome Trust, the Royal Society, the Kennedy Trust for Rheumatology Research, the Helmsley Charitable Trust and the Medical Research Council; grants from Novartis Pharmaceutical, outside the submitted work; consulting fees from Nightingale Health and Genomics. CK reports partial salary funding from the Medical Research Council. NAK reports grants from AbbVie, Biogen, Celltrion, Galapagos and Immunodiagnostik; consulting fees from AbbVie, Bristol-Meyers Squibb and Dr Falk; payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events from AbbVie, Dr Falk, Tillotts, Galapagos and Takeda; support for attending meetings and/or travel from Tillotts; participation (Chair) on the Board of the British Society of Gastroenterology IBD Clinical Research Group. CAL reports grants from and/or consultancy for Janssen, Takeda, AbbVie, AstraZeneca, Eli Lilly, Orion, Pfizer, Roche, Sanofi Aventis, UCB, Biogen, GSK, Bristol-Myers Squibb and Genentech; payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events from Ferring, Takeda, Janssen, Nordic Pharma and Dr Falk; participation (Secretary) on the British Society of Gastroenterology IBD Section; participation on the Steering Committee of IBD UK. CWL reports grants from UKRI Future Leaders Fellowship; personal consulting fees from AbbVie, Pfizer, Janssen, Takeda, Galapagos, Fresnius Kabi, Novartis/Sandoz, BMS and Celltrion; payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events from AbbVie, Pfizer, Janssen, Takeda, Galapagos, Fresnius Kabi, Novartis/Sandoz, BMS, Ferring, Dr Falk and Celltrion. JOL reports grants from AbbVie, and Gilead; personal consulting fees from Allergan, AbbVie, Bristol-Myers Squibb, Celgene, Cornerstones US, Galapagos, Gilead, GSK, Lilly, MSD UK, Shire UK, Shire International, Ferring UK, Ferring International, Celltrion, Takeda, Pfizer and Janssen; payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events from AbbVie, Bristol-Myers Squibb, Cornerstones US, Galapagos, Ferring UK, Ferring International, Celltrion, Takeda, Pfizer and Janssen; support to attend meetings and/or travel from AbbVie and Janssen. RHM reports that she is an independent membership on the Trial Steering Committee for the National Institute for Health and Care Research funded ALLEGRO trial. JRM reports personal consulting fees from EnteroBiotix and Cultech; patent held (without financial gain) on Clostridium difficile therapy (WO2019197836A1), participation (Chair) on the IDMC Board. NMcG reports partial (10%) salary funding from the Medical Research Council. REM reports personal salary funding from the Wellcome Sanger Institute. JO reports stock held in Novartis. MP reports grants from Pfizer and Gilead; personal consulting fees from Galapagos; payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events from Janssen. NP reports grants from Bristol-Myers Squibb, Takeda and Pfizer; consulting fees from AbbVie, Allergan, AstraZeneca, Bristol-Myers Squibb, Celgene, Celltrion, Galapagos, GSK, Takeda and Vifor; payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events from AbbVie, Bristol-Myers Squibb, Ferring, Galapagos, Janssen, Roche, Pfizer, Takeda and Tillotts; support for attending meetings and/or travel from AbbVie, Allergan, Celltrion, Janssen and Takeda; participation on a data safety monitoring board or advisory board for AbbVie, Allergan, AstraZeneca, Bristol-Myers Squibb, Celgene, Celltrion, Galapagos, GSK, Takeda and Vifor. TR reports personal grants from AbbVie; personal consulting fees from AbbVie, Arena, Aslan, AstraZeneca, Boehringer-Ingelheim, BMS, Celgene, Ferring, Galapagos, Gilead, GSK, Heptares, LabGenius, Janssen, Mylan, MSD, Novartis, Pfizer, Roche, Sandoz, Takeda, UCB and XAP therapeutics; participation on the board of UCB, membership (Chair) of the ECCO Guidelines Committee, membership of the UEG Scientific Committee. JS reports grants from Crohn’s and Colitis UK, the Helmsley Charitable Trust, ECCO, the European Commission, CCFA and Action Medical Research; payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events from Roche; participation on a Data Safety Monitoring Board or Advisory Board for the MODULATE trial and the TRIBUTE trial; leadership or fiduciary role as the Director of the Royal College of Physicians IBD Registry, and Governing Body Fellow at Green Templeton College. AS reports personal consulting fees from GSK; payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events from Falk, and AbbVie; payment of conference fees to attend the British Society of Gastroenterology Annual Conference 2022 from Celltrion; participation on a Data Safety Monitoring Board or Advisory Board for the IBD-RESPONSE study (unpaid), and AbbVie; participation on the British Society of Gastroenterology IBD Section Committee. CJS reports personal consultancy fees from Astarte Medical; payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events from Nestle Nutrition Institute. JW reports grants from Intercept; consulting fees from Worg and UCB; payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events from Janssen; participation on a Data Safety Monitoring Board or Advisory Board for Roche. KW reports grants from the Helsmsley Charitable Trust, Crohn’s and Colitis UK, Almond Board of California, Danone, International Dried Fruit and Nut Council, Medical Research Council, National Institute for Health and care Research; royalty or license payments for Volatile organic compounds in the diagnosis and management of irritable bowel syndrome, and Wiley BDA Advances in Nutrition & Dietetics book series; personal consulting fees from Danone; payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events from Janssen; support for attending meetings and/or travel from Yakult; participation on a Data Safety Monitoring Board or Advisory Board for the MODULATE trial (unpaid)., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY. Published by BMJ.)

Background & Aims: Clinical trials evaluating biologics and small molecules in patients with ulcerative colitis are predominantly excluding ulcerative proctitis. The objective of the Definition and endpoints for ulcerative PROCtitis in clinical TRIALs initiative was to develop consensus statements for definitions, inclusion criteria, and endpoints for the evaluation of ulcerative proctitis in adults., Methods: Thirty-five international experts held a consensus meeting to define ulcerative proctitis, and the endpoints to use in clinical trials. Based on a systematic review of the literature, statements were generated, discussed, and approved by the working group participants using a modified Delphi method. Consensus was defined as at least 75% agreement among voters., Results: The group agreed that the diagnosis of ulcerative proctitis should be made by ileocolonoscopy and confirmed by histopathology, with the exclusion of infections, drug-induced causes, radiation, trauma, and Crohn's disease. Ulcerative proctitis was defined as macroscopic extent of lesions limited to 15 cm distance from the anal verge in adults. Primary and secondary endpoints were identified to capture response of ulcerative proctitis to therapy. A combined clinical and endoscopic primary endpoint for the evaluation of ulcerative proctitis disease activity was proposed. Secondary endpoints that should be evaluated include endoscopic remission, histologic remission, mucosal healing, histologic endoscopic mucosal improvement, disability, fecal incontinence, urgency, constipation, and health-related quality of life., Conclusions: In response to the need for guidance on the design of clinical trials in patients with ulcerative proctitis, the Definition and end points for ulcerative PROCtitis in clinical TRIALs consensus provides recommendations on the definition and endpoints for ulcerative proctitis clinical trials., (Copyright © 2022 AGA Institute. Published by Elsevier Inc. All rights reserved.)

Introduction: Crohn's disease (CD) is characterised by discontinuous, relapsing enteric inflammation. Instituting advanced therapies at an early stage to suppress inflammation aims to prevent future complications such as stricturing or penetrating disease, and subsequent surgical resection. Therapeutics are effective but associated with certain side-effects and relatively expensive. There is therefore an urgent need for robust methods to predict which newly diagnosed patients will develop disabling disease, to identify patients who are most likely to benefit from early, advanced therapies. We aim to determine if magnetic resonance enterography (MRE) features at diagnosis improve prediction of disabling CD within 5 years of diagnosis., Methods and Analysis: We describe the protocol for a multicentre, non-randomised, single-arm, prospective study of adult patients with newly diagnosed CD. We will use patients already recruited to the METRIC study and extend their clinical follow-up, as well as a separate group of newly diagnosed patients who were not part of the METRIC trial (MRE within 3 months of diagnosis), to ensure an adequate sample size. Follow-up will extend for at least 4 years. The primary outcome is to evaluate the comparative predictive ability of prognostic models incorporating MRE severity scores (Magnetic resonance Enterography Global Score (MEGS), simplified MAgnetic Resonance Index of Activity (sMaRIA) and Lémann Index) versus models using standard characteristics alone to predict disabling CD (modified Beaugerie definition) within 5 years of new diagnosis., Ethics and Dissemination: This study protocol achieved National Health Service Research Ethics Committee (NHS REC), London-Hampstead Research Ethics Committee approval (IRAS 217422). Our findings will be disseminated via conference presentations and peer-reviewed publications., Trial Registration Number: ISRCTN76899103., Competing Interests: Competing interests: SK—nothing to declare. AP—NIHR HTA, grants from NIHR Fellowships programme; and personal fees from Acelity, Actavis, Dr Falk, Janssen-Cilag and Takeda. SM, GB, SB, CSC, JH, ALH, IJ and RV—none. STr—Grants/Research Support: AbbVie, Buhlmann, Celgene, ECCO, Helmsley Trust, IOIBD, Janssen, Lilly, Pfizer, Takeda, UCB, UKIERI, Vifor and Norman Collisson Foundation. Consulting Fees: Abacus; AbbVie; Actial; ai4gi; Alcimed; Allergan; Amgen; Apexian; Aptel; Arena; Asahi; Aspen; Astellas; Atlantic; AstraZeneca; Barco; Biocare; Biogen; BLPharma; Boehringer Ingelheim; BMS; Buhlmann; Calcico; Celgene; Cellerix; Cerimon; ChemoCentryx; Chiesi; CisBio; ComCast; Coronado; Cosmo; Ducentis; Dynavax; Elan; Enterome; EQrX; Equillium; Falk; Ferring; FPRT Bio; Galapagos; Genentech/Roche; Genzyme; Gilead; Glenmark; Grunenthal; GSK; GW Pharmaceuticals; Immunocore; Immunometabolism; Indigo; Janssen; Lexicon; Lilly; Medarex; Medtrix; Merck; Merrimack; Mestag; Millenium; Neovacs; Novartis; Novo Nordisk; NPS-Nycomed; Ocera; Optima; Origin; Otsuka; Palau; Pentax; Pfizer; Pharmaventure; Phesi; Phillips; P&G; Pronota; Protagonist; Proximagen; Resolute; Robarts; Sandoz; Santarus; Satisfai; Sensyne Health; Shire; SigmoidPharma; Sorriso; Souffinez; Syndermix; Synthon; Takeda; Theravance; Tigenix; Tillotts; Topivert; Trino Therapeutics with Wellcome Trust; TxCell; UCB Pharma; Vertex; VHsquared; Vifor; Warner Chilcott and Zeria. Speaker fees: AbbVie, Amgen, Biogen, Falk; Ferring, Janssen, Pfizer, Shire, Takeda, UCB. No stocks or share options. SH—grants from the NIHR. SAT—personal fees from Robarts, shareholding in Motilent and grants from the NIHR., (© Author(s) (or their employer(s)) 2022. Re-use permitted under CC BY. Published by BMJ.)

Introduction: Few studies have investigated perianal fistula etiopathogenesis, and although the cryptoglandular theory is widely accepted in idiopathic cases, in Crohn's disease, it is thought to involve the interplay between microbiological, immunological and genetic factors. A pilot study was conducted to assess for metabolic variations in Crohn's perianal fistula tissue that might differ from that of idiopathic (cryptoglandular) perianal fistula tissue as a comparator. The goal was to identify any potential biomarkers of disease, which may improve the understanding of pathogenesis., Aims and Methods: Fistula tract biopsies were obtained from 30 patients with idiopathic perianal fistula and 20 patients with Crohn's anal fistula. Two different assays were used in an ultra-high-performance liquid chromatography system coupled with a mass spectrometric detector to achieve broad metabolome coverage. Univariate and multivariate statistical data analyses were used to identify differentiating metabolic features corresponding to the perianal fistula phenotype (i.e. Crohn's disease vs. idiopathic)., Results: Significant orthogonal partial least squares discriminant analysis predictive models (validated with cross-validated-analysis of variance P value <0.05) differentiated metabolites from tissue samples from Crohn's vs. idiopathic anal fistula patients using both metabolic profiling platforms. A total of 41 metabolites were identified, suggesting alterations in pathways, including amino acid, carnitine and lipid metabolism., Conclusion: Metabonomics may reveal biomarkers of Crohn's perianal fistula. Further work in larger numbers is required to validate the findings of these studies as well as cross-correlation with microbiome work to better understand the impact of host-gut/environment interactions in the pathophysiology of Crohn's and idiopathic perianal fistulas and identify novel therapeutic targets., (Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.)

Introduction: Crohn's perianal fistulas are challenging for patients and clinicians. Many do not respond to available treatments and despite recommendations by a global consensus, there are currently no specific patient-derived quality of life tools to measure response to treatment. We present a new validated patient-reported outcome measure (PROM) for this complicated disease phenotype., Methods: A draft questionnaire was generated using unstructured qualitative patient interviews on the experience of living with Crohn's perianal fistula, a nationwide multidisciplinary consensus exercise, a systematic review of outcomes assessing medical/surgical/combined treatment and a patient and public involvement day. Psychometric properties were assessed including construct validity (by comparison with the Hospital Anxiety and Depression Scale (HADS) and the UK Inflammatory Bowel Disease Questionnaire (UK-IBDQ)), and reliability and responsiveness was assessed by test-retest analysis., Results: Data from 211 patients contributed to development of a final 28-item questionnaire. The Crohn's Anal Fistula Quality of Life (CAF-QoL) demonstrated good internal consistency (Cronbach's alpha 0.88), excellent stability (intraclass correlation 0.98) and good responsiveness and construct validity, with positive correlation with the UK-IBDQ and HADS., Conclusion: The CAF-QoL scale is ready for use as a PROM in research and clinical practice. It complements objective clinical evaluation of fistula by capturing impact on the patient., Competing Interests: Competing interests: KS, PJT and SOA have received honoraria from Takeda for sitting on an advisory board. PJT has received honoraria from Takeda for speaking at a symposium. LD: speaker fees from Janssen and AbbVie; consultancy fees from GL Assessments. CN: speaker’s fees from Takeda, Tillots Pharma and Ferring Pharmaceuticals. ALH has served as a consultant, advisory board member or speaker for AbbVie, Atlantic, Bristol Myers Squibb, Celltrion, Falk, Ferring, Janssen, MSD, Napp Pharmaceuticals, Pfizer, Pharmacosmos, Shire and Takeda. She also serves on the global steering committee for Genentech., (© Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Aim: The aim of this work was to determine the factors associated with poor wound healing in patients with perianal Crohn's disease (pCD) who had undergone proctectomy in the era of biologic therapies., Method: Case record review was performed on 103 patients with pCD who underwent proctectomy at St Mark's Hospital, Harrow and the Western General Hospital, Edinburgh between 2005 and 2017. Healing rates at 6 and 12 months post-proctectomy were considered; univariate analysis was performed., Results: Sixty out of 103 patients (58.3%) had failure of wound healing at 6 months and 41/103 (39.8%) at 12 months. In total, 63.1% (65/103) patients received biologic therapies prior to proctectomy; however, exposure to biologics was not a significant factor in predicting failure of wound healing at 12 months (infliximab p = 0.255; adalimumab p = 0.889; vedolizumab p = 0.153). Male gender was the only variable associated with poor wound healing at 12 months on univariate analysis (p = 0.017). A lower pre-operative C-reactive protein was associated with early wound healing at 6 months compared with at 12 months (p = 0.041) on univariate analysis. Other parameters not associated with rates of wound healing included smoking status, corticosteroid exposure, thiopurine exposure, number of previous biologics, perianal sepsis on MRI within the last 12 months, duration of CD prior to proctectomy and pre-operative albumin., Conclusion: More than a third of patients had unhealed wounds 12 months after proctectomy. We report that unhealed wounds are more common in male patients. Importantly, our results also suggest that exposure to biologics does not affect rates of wound healing., (© 2021 The Association of Coloproctology of Great Britain and Ireland.)

Few cases of pouch-related cancers have been reported in inflammatory bowel disease, and squamous cell carcinoma (SCC) is very rare. We have reviewed the published literature searching the online databases PubMed and Medline. Since 1979, there have been eight cases of SCC developing after restorative proctocolectomy in ulcerative colitis. To date, there have been no reported cases of SCC of the ileo-anal pouch in Crohn's disease. We present the case of a 59-year-old woman who underwent colectomy with ileal pouch-anal anastomosis for Crohn's disease during the 1990s. The patient was noted to be anaemic and was experiencing significant weight loss with poor pouch function in 2019. Endoscopy with histology and radiological investigation revealed the presence of SCC of the pouch. This was subsequently treated with surgical therapy and chemoradiotherapy., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2021. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Perianal fistulas are a challenging manifestation of Crohn's disease. Best medical and surgical therapy results in only about a third of patients remaining in remission at one year on maintenance treatment and sustained healing is often elusive. There is little published data on patient perspective of living with the condition or coping strategies in the face of non-curative/non-definitive treatment. We aimed to understand the experience of living with perianal fistula(s) and their impact on quality of life and routine functioning., Methods: This exploratory qualitative study used purposive sampling to recruit participants with current / previous diagnosis of Crohn's anal fistulas, from national IBD / bowel disease charities. The "standards for reporting qualitative research" (SRQR) recommendations were followed. Unstructured individual face-to-face interviews were audio recorded, transcribed and analysed thematically. Early themes were reviewed by the study team including patient advocates, clinicians and qualitative researchers., Results: Twelve interviews were conducted, achieving apparent data saturation. Three broad themes were uncovered: Burden of symptoms; Burden of treatment; and Impact on emotional, physical and social well-being. Each included several sub-themes, with considerable interplay between these. The impact of perianal fistula(s) on patients with CD is intense and wide reaching, negatively affecting intimate, close and social relationships. Fistulas cause losses in life and work-related opportunities, and treatments can be difficult to tolerate., Conclusion: Crohn's perianal fistulas exert a heavy negative physical and emotional impact on patients. These findings will inform development of a patient reported outcome measure to assess treatment effectiveness and quality of life for patients living with this challenging condition.

Background: The gastrointestinal microbiota has an important role in mucosal immune homoeostasis and may contribute to maintaining mucosal healing in Crohn's disease (CD)., Aim: To identify changes in the microbiota, metabolome and protease activity associated with mucosal healing in established paediatric CD METHODS: Twenty-five participants aged 3-18 years with CD, disease duration of over 6 months, and maintenance treatment with biological therapy were recruited. They were divided into a low calprotectin group (faecal calprotectin <100 μg/g, "mucosal healing," n = 11), and a high calprotectin group (faecal calprotectin >100 μg/g, "mucosal inflammation," n = 11). 16S gene-based metataxonomics, 1 H-NMR spectroscopy-based metabolic profiling and protease activity assays were performed on stool samples., Results: Relative abundance of Dialister species was six-times greater in the low calprotectin group (q = 0.00999). Alpha and beta diversity, total protease activity and inferred metagenomic profiles did not differ between groups. Pentanoate (valerate) and lysine were principal discriminators in a machine-learning model which differentiated high and low calprotectin samples using NMR spectra (R 2 0.87, Q 2 0.41). Mean relative concentration of pentanoate was 1.35-times greater in the low calprotectin group (95% CI 1.03-1.68, P = 0.036) and was positively correlated with Dialister. Mean relative concentration of lysine was 1.54-times greater in the high calprotectin group (95% CI 1.05-2.03, P = 0.028)., Conclusions: This multiomic study identified an increase in Dialister species and pentanoate, and a decrease in lysine, in patients with "mucosal healing." It supports further investigation of these as potential novel therapeutic targets in CD., (© 2020 The Authors. Alimentary Pharmacology & Therapeutics published by John Wiley & Sons Ltd.)

Background and Aims: Anti-tumour necrosis factor [anti-TNF] therapy is indicated for treatment of moderate to severe inflammatory bowel disease [IBD], but has a primary non-response rate of around 30%. We aim to use metabonomic and metataxonomic profiling to identify predictive biomarkers of anti-TNF response in Crohn's disease., Methods: Patients with luminal Crohn's disease, commencing anti-TNF therapy, were recruited with urine, faeces, and serum samples being collected at baseline and 3-monthly. Primary response was defined according to a combination of clinical and objective markers of inflammation. Samples were measured using three UPLC-MS assays: lipid, bile acid, and Hydrophillic Interaction Liquid Chromatography [HILIC] profiling with 16S rRNA gene sequencing of faeces., Results: Samples were collected from 76 Crohn's disease patients who were anti-TNF naïve and from 13 healthy controls. There were 11 responders, 37 non-responders, and 28 partial responders in anti-TNF-treated Crohn's patients. Histidine and cysteine were identified as biomarkers of response from polar metabolite profiling [HILIC] of serum and urine. Lipid profiling of serum and faeces found phosphocholines, ceramides, sphingomyelins, and triglycerides, and bile acid profiling identified primary bile acids to be associated with non-response to anti-TNF therapy, with higher levels of phase 2 conjugates in non-responders. Receiver operating curves for treatment response demonstrated 0.94 +/ -0.10 [faecal lipid], 0.81 +/- 0.17 [faecal bile acid], and 0.74 +/- 0.15 [serum bile acid] predictive ability for anti-TNF response in Crohn's disease., Conclusions: This prospective, longitudinal cohort study of metabonomic and 16S rRNA gene sequencing analysis demonstrates that a range of metabolic biomarkers involving lipid, bile acid, and amino acid pathways may contribute to prediction of response to anti-TNF therapy in Crohn's disease., Podcast: This article has an associated podcast which can be accessed at https://academic.oup.com/ecco-jcc/pages/podcast., (© The Author(s) 2020. Published by Oxford University Press on behalf of European Crohn’s and Colitis Organisation. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Background: Magnetic resonance enterography and enteric ultrasonography are used to image Crohn's disease patients. Their diagnostic accuracy for presence, extent and activity of enteric Crohn's disease was compared., Objective: To compare diagnostic accuracy, observer variability, acceptability, diagnostic impact and cost-effectiveness of magnetic resonance enterography and ultrasonography in newly diagnosed or relapsing Crohn's disease., Design: Prospective multicentre cohort study., Setting: Eight NHS hospitals., Participants: Consecutive participants aged ≥ 16 years, newly diagnosed with Crohn's disease or with established Crohn's disease and suspected relapse., Interventions: Magnetic resonance enterography and ultrasonography., Main Outcome Measures: The primary outcome was per-participant sensitivity difference between magnetic resonance enterography and ultrasonography for small bowel Crohn's disease extent. Secondary outcomes included sensitivity and specificity for small bowel Crohn's disease and colonic Crohn's disease extent, and sensitivity and specificity for small bowel Crohn's disease and colonic Crohn's disease presence; identification of active disease; interobserver variation; participant acceptability; diagnostic impact; and cost-effectiveness., Results: Out of the 518 participants assessed, 335 entered the trial, with 51 excluded, giving a final cohort of 284 (133 and 151 in new diagnosis and suspected relapse cohorts, respectively). Across the whole cohort, for small bowel Crohn's disease extent, magnetic resonance enterography sensitivity [80%, 95% confidence interval (CI) 72% to 86%] was significantly greater than ultrasonography sensitivity (70%, 95% CI 62% to 78%), with a 10% difference (95% CI 1% to 18%; p  = 0.027). For small bowel Crohn's disease extent, magnetic resonance enterography specificity (95%, 95% CI 85% to 98%) was significantly greater than ultrasonography specificity (81%, 95% CI 64% to 91%), with a 14% difference (95% CI 1% to 27%). For small bowel Crohn's disease presence, magnetic resonance enterography sensitivity (97%, 95% CI 91% to 99%) was significantly greater than ultrasonography sensitivity (92%, 95% CI 84% to 96%), with a 5% difference (95% CI 1% to 9%). For small bowel Crohn's disease presence, magnetic resonance enterography specificity was 96% (95% CI 86% to 99%) and ultrasonography specificity was 84% (95% CI 65% to 94%), with a 12% difference (95% CI 0% to 25%). Test sensitivities for small bowel Crohn's disease presence and extent were similar in the two cohorts. For colonic Crohn's disease presence in newly diagnosed participants, ultrasonography sensitivity (67%, 95% CI 49% to 81%) was significantly greater than magnetic resonance enterography sensitivity (47%, 95% CI 31% to 64%), with a 20% difference (95% CI 1% to 39%). For active small bowel Crohn's disease, magnetic resonance enterography sensitivity (96%, 95% CI 92% to 99%) was significantly greater than ultrasonography sensitivity (90%, 95% CI 82% to 95%), with a 6% difference (95% CI 2% to 11%). There was some disagreement between readers for both tests. A total of 88% of participants rated magnetic resonance enterography as very or fairly acceptable, which is significantly lower than the percentage (99%) of participants who did so for ultrasonography. Therapeutic decisions based on magnetic resonance enterography alone and ultrasonography alone agreed with the final decision in 122 out of 158 (77%) cases and 124 out of 158 (78%) cases, respectively. There were no differences in costs or quality-adjusted life-years between tests., Limitations: Magnetic resonance enterography and ultrasonography scans were interpreted by practitioners blinded to clinical data (but not participant cohort), which does not reflect use in clinical practice., Conclusions: Magnetic resonance enterography has higher accuracy for detecting the presence, extent and activity of small bowel Crohn's disease than ultrasonography does. Both tests have variable interobserver agreement and are broadly acceptable to participants, although ultrasonography produces less participant burden. Diagnostic impact and cost-effectiveness are similar. Recommendations for future work include investigation of the comparative utility of magnetic resonance enterography and ultrasonography for treatment response assessment and investigation of non-specific abdominal symptoms to confirm or refute Crohn's disease., Trial Registration: Current Controlled Trials ISRCTN03982913., Funding: This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment ; Vol. 23, No. 42. See the NIHR Journals Library website for further project information., Competing Interests: Stuart A Taylor reports personal fees from Robarts Clinical Trials Inc. (London, ON, Canada) outside the submitted work. Simon Travis reports receiving fees for consultancy work and/or speaking engagements from the following: AbbVie Inc. (Chicago, IL, USA), Centocor Inc. (Horsham, PA, USA), Schering-Plough (Kenilworth, NJ, USA), Bristol-Myers Squibb (New York, NY, USA), Chemocentryx Inc. (Mountain View, CA, USA), Cosmo Pharmaceuticals (Dublin, Ireland), Elan Pharma Inc. (Dublin, Ireland), Genentech Inc. (San Francisco, CA, USA), Giuliani SpA (Milan, Italy), Merck & Co. Inc. (Kenilworth, NJ, USA), Takeda UK Ltd (Woodburn Green, Buckinghamshire, UK), Otsuka Pharmaceuticals (Tokyo, Japan), PDL BioPharma (Nevada, NV, USA), Pfizer Inc. (San Francisco, CA, USA), Shire Pharmaceuticals UK (St Helier, Jersey), Glenmark Pharmaceuticals (Maharashtra, India), Synthon Biopharmaceuticals (Nijmegen, the Netherlands), NPS Pharmaceuticals (Bedminster, NJ, USA), Eli Lilly and Company (Indiana, IN, USA), Warner Chilcott Ltd, Proximagen Group Ltd (London, UK), VHsquared Ltd (Cambridge, UK), Topivert Pharma Ltd (London, UK), Ferring Pharmaceuticals (Saint-Prex, Switzerland), Celgene Corporation (Summit, NJ, USA), GlaxoSmithKline plc (Brentford, UK), Amgen Inc. (Thousand Oaks, CA, USA), Biogen Inc. (Cambridge, MA, USA), Enterome SA (Paris, France), Immunocore Ltd (Oxford, UK), Immunometabolism/Third Rock Ventures (Boston, MA, USA), Bioclinica Inc. (Newtown, PA, USA), Boehringer Ingelheim GmBH (Ingelheim am Rhein, Germany), Gilead Sciences Inc. (Foster City, CA, USA), Grunenthal Ltd (Aachen, Germany), Janssen Pharmaceutica (Beerse, Belgium), Novartis AG (Basel, Switzerland), Receptos Inc. (San Diego, CA, USA), Pharm-Olam International UK Ltd (Bracknell, UK), Sigmoid Pharma (Dublin, Ireland), Theravance Biopharma Inc. (Dublin, Ireland), Given Imaging Ltd (Yokneam Illit, Israel), UCB Pharma SA (Brussels, Belgium), Tillotts Pharma AG (Rheinfelden, Switzerland), Sanofi Aventis SA (Paris, France), Vifor Pharma (St Gallen, Switzerland), Abbott Laboratories Ltd (Chicago, IL, USA) and Procter and Gamble Ltd (Cincinnati, OH, USA). Simon Travis reports directorships of charities IBD2020 (Barnet, UK; UK 09762150), Cure Crohn’s Colitis (Sydney, Australia; ABN 85 154 588 717) and the Truelove Foundation (London, UK; UK 11056711). Simon Travis also reports receiving fees from the following for expert testimony work and/or royalties: Santarus Inc. (San Diego, CA, USA), Cosmo Technologies Ltd (Dublin, Ireland), Tillotts Pharma AG, Wiley-Blackwell Inc. (Hoboken, NJ, USA), Elsevier Ltd (Amsterdam, the Netherlands) and Oxford University Press (Oxford, UK). Simon Travis has received research grants from the following: AbbVie Inc., the International Organization for the Study of Inflammatory Bowel Disease, Eli Lilly and Company, UCB Inc. (Brussels, Belgium), Vifor Pharma, Norman Collisson Foundation (Bicester, UK), Ferring Pharmaceuticals, Schering-Plough, Merck Sharpe & Dohme Corp. (Kenilworth, NJ, USA), Procter and Gamble Ltd, Warner Chilcott Ltd, Abbott Laboratories Ltd, PDL BioPharma Inc. (Incline Village, NV, USA), Takeda UK Ltd and the International Consortium for Health Care Outcomes Measurement. Ailsa Hart reports personal fees from AbbVie Inc., Atlantic Healthcare Ltd (Saffron Walden, UK), Bristol-Myers Squibb, Celltrion Inc. (Incheon, South Korea), Dr Falk Pharma UK Ltd (Bourne End, UK), Ferring Pharmaceuticals, Janssen Pharmaceuticals, Merck Sharpe & Dohme Corp., Napp Pharmaceuticals Ltd (Cambridge, UK), Pfizer Inc., Pharmacosmos A/S (Holbæk, Denmark), Shire Pharmaceuticals UK and Takeda UK Ltd, and non-financial support from Genentech Inc. Alastair Windsor reports personal fees from Takeda, grants from Allergan Inc. (Dublin, Ireland), personal fees from Allergan, personal fees from Cook Medical Inc. (Bloomington, IN, USA) and grants and personal fees from Bard Ltd (Crawley, UK) outside the submitted work. Andrew Plumb reports grants from the National Institute for Health Research (NIHR) Health Technology Assessment (HTA) programme outside the submitted work, grants from the NIHR Fellowships programme during the conduct of the study and honoraria for educational lectures delivered at events arranged by Acelity Inc. (Crawley, UK), Actavis Pharma Inc. (Parsippany-Troy Hills, NJ, USA), Dr Falk Pharma UK Ltd, Janssen-Cilag Ltd (High Wycombe, UK) and Takeda UK Ltd on the subject of inflammatory bowel disease. Ilan Jacobs reports share ownership in General Electric Company (Boston, MA, USA), which manufacturers and sells magnetic resonance imaging equipment. Charles D Murray reports personal fees from AbbVie Inc., Merck Sharpe & Dohme Corp. and Janssen Pharmaceutica outside the submitted work. Antony Higginson reports personal fees from Toshiba Corporation (Tokyo, Japan) outside the submitted work. Steve Halligan reports non-financial support from iCAD Inc. (Nashua, NH, USA) outside the submitted work, and sat on the HTA commissioning board (2008–14). Stephen Morris reports Health Services and Delivery Research (HSDR) Board membership (2014–18), HSDR Evidence Synthesis Sub Board membership (2016), HTA Commissioning Board membership (2009–13) and Public Health Research Board membership (2011–17).

Background: Anti-TNF drugs are effective treatments for the management of Crohn's disease but treatment failure is common. We aimed to identify clinical and pharmacokinetic factors that predict primary non-response at week 14 after starting treatment, non-remission at week 54, and adverse events leading to drug withdrawal., Methods: The personalised anti-TNF therapy in Crohn's disease study (PANTS) is a prospective observational UK-wide study. We enrolled anti-TNF-naive patients (aged ≥6 years) with active luminal Crohn's disease at the time of first exposure to infliximab or adalimumab between March 7, 2013, and July 15, 2016. Patients were evaluated for 12 months or until drug withdrawal. Demographic data, smoking status, age at diagnosis, disease duration, location, and behaviour, previous medical and drug history, and previous Crohn's disease-related surgeries were recorded at baseline. At every visit, disease activity score, weight, therapy, and adverse events were recorded; drug and total anti-drug antibody concentrations were also measured. Treatment failure endpoints were primary non-response at week 14, non-remission at week 54, and adverse events leading to drug withdrawal. We used regression analyses to identify which factors were associated with treatment failure., Findings: We enrolled 955 patients treated with infliximab (753 with originator; 202 with biosimilar) and 655 treated with adalimumab. Primary non-response occurred in 295 (23·8%, 95% CI 21·4-26·2) of 1241 patients who were assessable at week 14. Non-remission at week 54 occurred in 764 (63·1%, 60·3-65·8) of 1211 patients who were assessable, and adverse events curtailed treatment in 126 (7·8%, 6·6-9·2) of 1610 patients. In multivariable analysis, the only factor independently associated with primary non-response was low drug concentration at week 14 (infliximab: odds ratio 0·35 [95% CI 0·20-0·62], p=0·00038; adalimumab: 0·13 [0·06-0·28], p<0·0001); the optimal week 14 drug concentrations associated with remission at both week 14 and week 54 were 7 mg/L for infliximab and 12 mg/L for adalimumab. Continuing standard dosing regimens after primary non-response was rarely helpful; only 14 (12·4% [95% CI 6·9-19·9]) of 113 patients entered remission by week 54. Similarly, week 14 drug concentration was also independently associated with non-remission at week 54 (0·29 [0·16-0·52] for infliximab; 0·03 [0·01-0·12] for adalimumab; p<0·0001 for both). The proportion of patients who developed anti-drug antibodies (immunogenicity) was 62·8% (95% CI 59·0-66·3) for infliximab and 28·5% (24·0-32·7) for adalimumab. For both drugs, suboptimal week 14 drug concentrations predicted immunogenicity, and the development of anti-drug antibodies predicted subsequent low drug concentrations. Combination immunomodulator (thiopurine or methotrexate) therapy mitigated the risk of developing anti-drug antibodies (hazard ratio 0·39 [95% CI 0·32-0·46] for infliximab; 0·44 [0·31-0·64] for adalimumab; p<0·0001 for both). For infliximab, multivariable analysis of immunododulator use, and week 14 drug and anti-drug antibody concentrations showed an independent effect of immunomodulator use on week 54 non-remission (odds ratio 0·56 [95% CI 0·38-0·83], p=0·004)., Interpretation: Anti-TNF treatment failure is common and is predicted by low drug concentrations, mediated in part by immunogenicity. Clinical trials are required to investigate whether personalised induction regimens and treatment-to-target dose intensification improve outcomes., Funding: Guts UK, Crohn's and Colitis UK, Cure Crohn's Colitis, AbbVie, Merck Sharp and Dohme, Napp Pharmaceuticals, Pfizer, and Celltrion., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Importance: Use of thiopurines may be limited by myelosuppression. TPMT pharmacogenetic testing identifies only 25% of at-risk patients of European ancestry. Among patients of East Asian ancestry, NUDT15 variants are associated with thiopurine-induced myelosuppression (TIM)., Objective: To identify genetic variants associated with TIM among patients of European ancestry with inflammatory bowel disease (IBD)., Design, Setting, and Participants: Case-control study of 491 patients affected by TIM and 679 thiopurine-tolerant unaffected patients who were recruited from 89 international sites between March 2012 and November 2015. Genome-wide association studies (GWAS) and exome-wide association studies (EWAS) were conducted in patients of European ancestry. The replication cohort comprised 73 patients affected by TIM and 840 thiopurine-tolerant unaffected patients., Exposures: Genetic variants associated with TIM., Main Outcomes and Measures: Thiopurine-induced myelosuppression, defined as a decline in absolute white blood cell count to 2.5 × 109/L or less or a decline in absolute neutrophil cell count to 1.0 × 109/L or less leading to a dose reduction or drug withdrawal., Results: Among 1077 patients (398 affected and 679 unaffected; median age at IBD diagnosis, 31.0 years [interquartile range, 21.2 to 44.1 years]; 540 [50%] women; 602 [56%] diagnosed as having Crohn disease), 919 (311 affected and 608 unaffected) were included in the GWAS analysis and 961 (328 affected and 633 unaffected) in the EWAS analysis. The GWAS analysis confirmed association of TPMT (chromosome 6, rs11969064) with TIM (30.5% [95/311] affected vs 16.4% [100/608] unaffected patients; odds ratio [OR], 2.3 [95% CI, 1.7 to 3.1], P = 5.2 × 10-9). The EWAS analysis demonstrated an association with an in-frame deletion in NUDT15 (chromosome 13, rs746071566) and TIM (5.8% [19/328] affected vs 0.2% [1/633] unaffected patients; OR, 38.2 [95% CI, 5.1 to 286.1], P = 1.3 × 10-8), which was replicated in a different cohort (2.7% [2/73] affected vs 0.2% [2/840] unaffected patients; OR, 11.8 [95% CI, 1.6 to 85.0], P = .03). Carriage of any of 3 coding NUDT15 variants was associated with an increased risk (OR, 27.3 [95% CI, 9.3 to 116.7], P = 1.1 × 10-7) of TIM, independent of TPMT genotype and thiopurine dose., Conclusions and Relevance: Among patients of European ancestry with IBD, variants in NUDT15 were associated with increased risk of TIM. These findings suggest that NUDT15 genotyping may be considered prior to initiation of thiopurine therapy; however, further study including additional validation in independent cohorts is required.

Objective: Lack of standardised outcomes hampers effective analysis and comparison of data when comparing treatments in fistulising perianal Crohn's disease (pCD). Development of a standardised set of outcomes would resolve these issues. This study provides the definitive core outcome set (COS) for fistulising pCD., Design: Candidate outcomes were generated through a systematic review and patient interviews. Consensus was established via a three-round Delphi process using a 9-point Likert scale based on how important they felt it was in determining treatment success culminating in a final consensus meeting. Stakeholders were recruited nationally and grouped into three panels (surgeons and radiologists, gastroenterologists and IBD specialist nurses, and patients). Participants received feedback from their panel (in the second round) and all participants (in the third round) to allow refinement of their scores., Results: A total of 295 outcomes were identified from systematic reviews and interviews that were categorised into 92 domains. 187 stakeholders (response rate 78.5%) prioritised 49 outcomes through a three-round Delphi study. The final consensus meeting of 41 experts and patients generated agreement on an eight domain COS. The COS comprised three patient-reported outcome domains (quality of life, incontinence and a combined score of patient priorities) and five clinician-reported outcome domains (perianal disease activity, development of new perianal abscess/sepsis, new/recurrent fistula, unplanned surgery and faecal diversion)., Conclusion: A fistulising pCD COS has been produced by all key stakeholders. Application of the COS will reduce heterogeneity in outcome reporting, thereby facilitating more meaningful comparisons between treatments, data synthesis and ultimately benefit patient care., Competing Interests: Competing interests: KS and SOA have received honoraria from Takeda for sitting on an advisory board. PJT has received honoraria from Takeda for sitting on an advisory board and for speaking at a symposium. AJL is an advisory board member or received lecture fees from Takeda Pharma, AbbVie, Vifor Pharma, Dr Falk and Shield Therapeutics. ALH has served as a consultant, advisory board member or speaker for AbbVie, Atlantic, Bristol-Myers Squibb, Celltrion, Falk, Ferring, Janssen, MSD, Napp Pharmaceuticals, Pfizer, Pharmacosmos, Shire and Takeda. She also serves on the Global Steering Committee for Genentech. NSF has received travel grants from Obsidian Health and Strategen to deliver invited lectures., (© Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2019. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

Background: Treatment paradigms for Crohn's disease with perianal fistulae (CD-pAF) are evolving., Aims: To study the impact of multimodality treatment in CD-pAF on recurrence rates and the need for re-interventions and to identify predictive factors for these outcomes., Methods: This was a multinational multicentre retrospective cohort study. Multimodality approach was defined as using a combination of medical treatments (anti-TNFs ± immunomodulators ± antibiotics) along with surgical approach (examination under anaesthesia (EUA) ± seton drainage) at diagnosis of CD-pAF. Univariable and multivariable analyses were performed for variables indicative of the need for reintervention., Results: A total of 253 patients were included. 65% of patients received multimodality approach. Multimodality treatment resulted in complete fistula healing in 52% of patients. Re-intervention was needed in 27% of patients with simple and in 40.3% of those with complex fistula. On multivariable analysis multimodality treatment (OR: 0.35, 95% CI: 0.17-0.57, P = 0.001), seton removal (OR: 0.090, 95% CI: 0.027-0.30, P = 0.0001, therapy with infliximab (OR: 0.19, 95% CI: 0.06-0.64, P = 0.007), and therapy with adalimumab (OR: 0.12, "95% CI: 0.026-0.56, P = 0.007) were predictive of avoiding repeat surgery. Proctitis (OR: 3.76, 95% CI: 1.09-12.96, P = 0.03) was predictive of the need for radical surgery (proctectomy, diverting stoma) while multimodality treatment reduced the need for radical surgery (OR: 0.21, 95% CI: 0.05-0.81, P = 0.02)., Conclusions: Multimodality treatment, anti-TNFs use, and removal of setons after multimodality treatment can result in improved outcomes in CD patients with perianal fistulae and reduce the need for repeat surgery and radical surgery., (© 2018 John Wiley & Sons Ltd.)

Background and Aims: A third of patients with Crohn's disease develop perianal fistulas. These are associated with a significant burden of symptoms and negative impact on quality of life. This study reports the use of video-assisted anal fistula treatment [VAAFT] as a means of symptom improvement; this is a minimally invasive technique to access fistula track, and diagnose/facilitate drainage of deep/complex secondary extensions with cauterization of excess inflammatory tissue., Methods: Consecutive patients with complex Crohn's fistula undergoing VAAFT for symptomatic Crohn's anal fistula were included. They were identified from a prospectively maintained database, which was interrogated from June 2015 to November 2017. Patients underwent diagnostic fistuloscopy and fulguration of tracts/secondary extensions. Setons were sited/replaced after the procedure to maintain postoperative drainage. The primary endpoint was completion of the 'Measure your medical outcome profile' [MYMOP2] quality of life [QoL] questionnaire at 6 weeks postoperatively. Secondary outcome measures were a decisional regret scale [DRS], postoperative complications and the 30-day re-operation rate., Results: Twenty-five patients underwent the procedure during the study period. In total, 21/25 patients [84%] provided MYMOP2 QoL data demonstrating a statistically significant improvement in both pain and discharge scores. Eighty-one per cent of patients who completed the questionnaire agreed/strongly agreed that the procedure was the right decision and no patient regretted undergoing the procedure. There was one re-operation but otherwise no complications., Conclusions: This study demonstrates the feasibility, safety and importantly an improvement in patient-reported outcomes in a series of patients undergoing VAAFT for complex Crohn's anal fistula. VAAFT reduces the main symptoms [pain and discharge] in patients with complex refractory anal fistulas., (Copyright © 2018 European Crohn’s and Colitis Organisation (ECCO). Published by Oxford University Press. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Background: Evidence from groups who have studied fistula aetiology and extrapolation from interventional studies supports a multifactorial hypothesis of Crohn's perianal fistula, with several pathophysiological elements that may contribute to fistula formation, persistence and resistance to treatment., Aim: An evidence synthesis of current understanding of pathophysiological factors underlying Crohn's perianal fistula is presented, exploring the fundamental reasons why some treatments succeed and others fail, as a means of focussing clinical knowledge on improving treatment of Crohn's perianal fistula., Methods: Evidence to support this review was gathered via the Pubmed database. Studies discussing pathophysiological factors underpinning perianal fistula, particularly in Crohn's disease, were reviewed and cross-referenced for additional reports., Results: Pathophysiological factors that impact on success or failure of interventions for Crohn's perianal fistulae include the high-pressure zone, obliterating the dead space, disconnecting the track from the anus, removing epithelialisation, eradicating sepsis and by-products of bacterial colonisation, correcting abnormalities in wound repair and removing the pro-inflammatory environment which allows fistula persistence. Most current interventions for Crohn's perianal fistulae tend to focus on a single, or at best two, aspects of the pathophysiology of Crohn's anal fistulae; as a result, failure to heal fully is common., Conclusions: For an intervention or combination of interventions to succeed, multiple factors must be addressed. We hypothesise that correct, timely and complete attention to all of these factors in a multimodal approach represents a new direction that may enable the creation of an effective treatment algorithm for Crohn's anal fistula., (© 2018 John Wiley & Sons Ltd.)

Background: Magnetic resonance enterography (MRE) and ultrasound are used to image Crohn's disease, but their comparative accuracy for assessing disease extent and activity is not known with certainty. Therefore, we did a multicentre trial to address this issue., Methods: We recruited patients from eight UK hospitals. Eligible patients were 16 years or older, with newly diagnosed Crohn's disease or with established disease and suspected relapse. Consecutive patients had MRE and ultrasound in addition to standard investigations. Discrepancy between MRE and ultrasound for the presence of small bowel disease triggered an additional investigation, if not already available. The primary outcome was difference in per-patient sensitivity for small bowel disease extent (correct identification and segmental localisation) against a construct reference standard (panel diagnosis). This trial is registered with the International Standard Randomised Controlled Trial, number ISRCTN03982913, and has been completed., Findings: 284 patients completed the trial (133 in the newly diagnosed group, 151 in the relapse group). Based on the reference standard, 233 (82%) patients had small bowel Crohn's disease. The sensitivity of MRE for small bowel disease extent (80% [95% CI 72-86]) and presence (97% [91-99]) were significantly greater than that of ultrasound (70% [62-78] for disease extent, 92% [84-96] for disease presence); a 10% (95% CI 1-18; p=0·027) difference for extent, and 5% (1-9; p=0·025) difference for presence. The specificity of MRE for small bowel disease extent (95% [85-98]) was significantly greater than that of ultrasound (81% [64-91]); a difference of 14% (1-27; p=0·039). The specificity for small bowel disease presence was 96% (95% CI 86-99) with MRE and 84% (65-94) with ultrasound (difference 12% [0-25]; p=0·054). There were no serious adverse events., Interpretation: Both MRE and ultrasound have high sensitivity for detecting small bowel disease presence and both are valid first-line investigations, and viable alternatives to ileocolonoscopy. However, in a national health service setting, MRE is generally the preferred radiological investigation when available because its sensitivity and specificity exceed ultrasound significantly., Funding: National Institute of Health and Research Health Technology Assessment., (Copyright © 2018 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license. Published by Elsevier Ltd.. All rights reserved.)

Inflammatory bowel diseases are characterised by inflammation that compromises the integrity of the epithelial barrier. The intestinal epithelium is not only a static barrier but has evolved complex mechanisms to control and regulate bacterial interactions with the mucosal surface. Apical tight junction proteins are critical in the maintenance of epithelial barrier function and control of paracellular permeability. The characterisation of alterations in tight junction proteins as key players in epithelial barrier function in inflammatory bowel diseases is rapidly enhancing our understanding of critical mechanisms in disease pathogenesis as well as novel therapeutic opportunities. Here we give an overview of recent literature focusing on the role of tight junction proteins, in particular claudins, in inflammatory bowel diseases and inflammatory bowel disease associated colorectal cancer.

Background and Aims: Prebiotic inulin-type fructans are widely consumed in the diet and may have contrasting effects in Crohn's disease by stimulating gut microbiota and/or by generating functional gastrointestinal symptoms. The aim of this study was to measure fructan and oligofructose intakes in patients with active and inactive Crohn's disease compared with healthy controls., Methods: Patients with active Crohn's disease (n = 98), inactive Crohn's (n = 99) and healthy controls (n = 106) were recruited to a case-control study. Dietary intake of inulin-type fructans was measured using a specific food frequency questionnaire and was compared between the three groups and between patients with different disease phenotypes (Montreal classification). Associations between intakes and disease activity (Harvey-Bradshaw Index, HBI) were also undertaken., Results: Patients with active Crohn's disease had lower fructan intakes (median 2.9 g/d, interquartile range [IQR] 1.8) than those with inactive Crohn's (3.6 g/d, 2.1, p = 0.036) or controls (3.9 g/d, 2.1, p = 0.003) and lower oligofructose intakes (2.8 g/d, 1.8) than those with inactive Crohn's (3.5 g/d, 2.2, p = 0.048) or controls (3.8 g/d, 2.1, p = 0.003). There were no differences in intakes related to disease site or behaviour. There were negative correlations between HBI well-being score and fructan intake (ρ = -0.154, p = 0.03) and oligofructose intake (ρ = -0.156, p = 0.028) and for the HBI abdominal pain score and fructan (ρ = -0.164, p = 0.021) and oligofructose intake (ρ = -0.157, p = 0.027)., Conclusions: Patients with active Crohn's disease consume lower quantities of fructans and oligofructose than their inactive counterparts and healthy controls. The impact of lower intakes of prebiotic fructans on gut microbiota is unknown and warrants further research., (Copyright © 2015 European Crohn’s and Colitis Organisation (ECCO). Published by Oxford University Press. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Background: Temporary faecal diversion is sometimes used for management of refractory perianal Crohn's disease (CD) with variable success., Aims: To perform a systematic review with meta-analysis to evaluate the effectiveness, long-term outcomes and factors associated with success of temporary faecal diversion for perianal CD., Methods: Through a systematic literature review through 15 July 2015, we identified 16 cohort studies (556 patients) reporting outcomes after temporary faecal diversion. We estimated pooled rates [with 95% confidence interval (CI)] of early clinical response, attempted and successful restoration of bowel continuity after temporary faecal diversion (without symptomatic relapse), and rates of re-diversion (in patients with attempted restoration) and proctectomy (with or without colectomy and end-ileostomy). We identified factors associated with successful restoration of bowel continuity., Results: On meta-analysis, 63.8% (95% CI: 54.1-72.5) of patients had early clinical response after faecal diversion for refractory perianal CD. Restoration of bowel continuity was attempted in 34.5% (95% CI: 27.0-42.8) of patients, and was successful in only 16.6% (95% CI: 11.8-22.9). Of those in whom restoration was attempted, 26.5% (95% CI: 14.1-44.2) required re-diversion because of severe relapse. Overall, 41.6% (95% CI: 32.6-51.2) of patients required proctectomy after failure of temporary faecal diversion. There was no difference in the successful restoration of bowel continuity after temporary faecal diversion in the pre-biological or biological era (13.7% vs. 17.6%, P = 0.60), in part due to selection bias. Absence of rectal involvement was the most consistent factor associated with restoration of bowel continuity., Conclusions: Temporary faecal diversion may improve symptoms in approximately two-thirds of patients with refractory perianal Crohn's disease, but bowel restoration is successful in only 17% of patients., (© 2015 John Wiley & Sons Ltd.)

Background and Aims: Intra-abdominal septic complications [IASC] following ileocolonic resection for Crohn's disease are common. Determining risk factors for these complications can aid pre-operative and peri-operative strategies to reduced morbidity. This study aims to determine the incidence and predictors of intra-abdominal septic complications following ileocolonic resection for Crohn's disease., Methods: A single-centre, retrospective study was conducted. The clinical case notes of patients with histopathologically proven Crohn's disease, who underwent an ileocolonic resection as a one-stage or two-stage procedure, were reviewed. The primary endpoint was the formation of intra-abdominal septic complications within a 30-day post-operative time frame., Results: Overall 163 patients underwent 175 ileocolonic procedures. Post-operative intra-abdominal septic complications were demonstrated in 9% [13/142] of one-stage procedures and 12% [4/33] of two-stage procedures [p = 0.2]. Post-operative IASCs following a one-stage procedure demonstrated associations with smokers [p = 0.004], intraoperative abdominal sepsis [p = 0.005], concomitant upper gastrointestinal Crohn's [p = 0.015], the presence of peri-operative anaemia [p = 0.037], hypoalbuminaemia [< 25g/l] [p = 0.04], and histologically involved margins [p = 0.001]. Multivariate analysis demonstrated the presence of intra-abdominal sepsis (hazard ratio [HR] 8.6, 95% confidence interval [CI]: 1.2 60.1] and the use of peri-operative biologicals [HR 24.6, 95% CI: 2.0-298] as independent predictors of post-operative intra-abdominal septic complications., Conclusions: This study highlights specific variables that may be contributory to poor outcome. These findings may be important when optimising patients for surgery, as well as planning an appropriate operative strategy. Further prospective studies and a larger sample size are required to validate these findings., (Copyright © 2015 European Crohn’s and Colitis Organisation (ECCO). Published by Oxford University Press. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Aim: The aetiology of Crohn's disease-related anal fistula remains obscure. Microbiological, genetic and immunological factors are thought to play a role but are not well understood. The microbiota within anal fistula tracts has never been examined using molecular techniques. The present study aimed to characterize the microbiota in the tracts of patients with Crohn's and idiopathic anal fistula., Method: Samples from the fistula tract and rectum of patients with Crohn's and idiopathic anal fistula were analysed using fluorescent in situ hybridization, Gram staining and scanning electron microscopy were performed to identify and quantify the bacteria present., Results: Fifty-one patients, including 20 with Crohn's anal fistula, 18 with idiopathic anal fistula and 13 with luminal Crohn's disease and no anal fistula, were recruited. Bacteria were not found in close association with the luminal surface of any of the anal fistula tracts., Conclusion: Anal fistula tracts generally do not harbour high levels of mucosa-associated microbiota. Crohn's anal fistulas do not seem to harbour specific bacteria. Alternative explanations for the persistence of anal fistula are needed., (Colorectal Disease © 2014 The Association of Coloproctology of Great Britain and Ireland.)

Background: The management of perianal Crohn's fistulas represents a significant challenge. A combination of medical and surgical therapy, guided by radiology, is often required., Aim: To review systematically the literature to assess fistula healing rates with medical treatment (anti-TNF-α therapies ± immunomodulators) or surgical treatment alone, compared with combined medical and surgical treatment in fistulising perianal Crohn's disease (CD)., Methods: The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were used. Two independent reviewers searched the literature., Results: Twenty-four articles were included. The total population was 1139 patients; 460 (40%) received single treatment with either medical or surgical therapy, and 679 (60%) received combined medical and surgical therapy. Eight studies compared single and combination therapy, with a total population of 797 patients (single therapy: n = 448, combination therapy: n = 349). In the single therapy group, 191/448 were in complete remission (43%). This was lower than the healing rate of the combination therapy group 180/349 (52%). No response to therapy was noted in 34% (153/448) of the single therapy group compared with 23% (80/349) of the combination group., Conclusions: Combined surgical and medical (anti-TNF-α ± immunomodulators) therapy may have additional beneficial effects on perianal fistula healing in patients with Crohn's disease, compared with surgery or medical therapy alone. A well-designed Crohn's perianal fistula clinical trial is required in a multidisciplinary medical and surgical setting, with clearly defined end points of clinical (and likely patient reported outcomes) and radiological healing., (© 2014 John Wiley & Sons Ltd.)

Crohn's disease (CD) is characterized by inflammation that can affect any part of the gastrointestinal tract. It is a chronic destructive condition that follows a relapsing-remitting course and can lead to disability and a poor quality of life. Lifelong pharmacotherapy with systemic immunomodulator therapies remains the cornerstone of CD management. Advances in understanding of the immunopathogenic mechanisms underlying chronic gut inflammation in CD have led to the development of effective biological therapies for patients with CD. Tumor necrosis factor α (TNF-α) is a potent proinflammatory cytokine that plays a pivotal role in the development of Crohn's inflammation. Therapies designed to target this cytokine have revolutionized treatment of CD since their introduction in the late 1990s, thanks to their ability to induce and maintain remission, heal mucosa, reduce hospital admissions and surgical procedures, and restore quality of life. Despite widespread use of these therapies in CD, their precise mechanism of action remains unclear, although several different mechanisms have been proposed. This review summarizes the biology of the TNF-α cytokine and the development of biological therapies targeting TNF-α, and updates our current understanding of mechanisms of action of the commercially available anti-TNF-α therapies used in the treatment of CD.

Background and Aim: Intestinal failure (IF) is a rare but devastating complication of Crohn's disease (CD). The clinical and surgical factors that predispose to IF are poorly understood. The aim of this study was to define clinical factors that predispose to IF., Methods: A retrospective case-control study was performed using consecutive CD patients with IF who were identified from a prospective database. Local population-based controls were selected with which to compare demographic, phenotypic, and clinical outcomes., Results: Eighty-two CD patients requiring long-term intravenous fluids or nutrition were studied. Diagnosis at age 16 years or less (P = 0.01) and a family history of inflammatory bowel disease (P = 0.02) were associated with a significantly higher risk for developing IF. Among the IF group, 53% had perioperative complications from intestinal resections contributing to long-term IF. Furthermore, these patients had more abdominal surgeries (P = 0.05) and stricturing disease was less common than in patients with primary active CD (P = 0.01). IF due to primary active CD was associated with penetrating behavior (P = 0.02) and early age at first surgery (P = 0.004). The need for intravenous nutrition as opposed to intravenous fluids correlated inversely with small intestine length (P < 0.001)., Conclusions: CD resulting in IF relates to earlier age at diagnosis, family history of inflammatory bowel disease, stricturing disease, younger age at first surgery, and operative complications. These factors deserve consideration when planning therapy for CD patients., (© 2013 Journal of Gastroenterology and Hepatology Foundation and Wiley Publishing Asia Pty Ltd.)

Changes in phenotype and function of γδ T cells have been reported in inflammatory bowel disease (IBD), including Crohn's disease (CD) and ulcerative colitis (UC). Dysregulation of lymphocyte migration plays a key role in IBD pathogenesis; however, data on migratory properties of γδ T cells are scarce. Human circulating γδ T cells from healthy controls (n = 27), patients with active CD (n = 15), active UC (n = 14) or cutaneous manifestations of IBD (n = 2) were characterized by flow cytometry. Circulating γδ T cells in healthy controls were CD3(hi) and expressed CD45RO. They expressed gut-homing molecule β7 but not gut-homing molecule corresponding chemokine receptors (CCR)9, or skin-homing molecules cutaneous lymphocyte-associated antigen (CLA) and CCR4, despite conventional T cells containing populations expressing these molecules. CCR9 expression was increased on γδ T cells in CD and UC, while skin-homing CLA was expressed aberrantly on γδ T cells in patients with cutaneous manifestations of IBD. Lower levels of CD3 expression were found on γδ T cells in CD but not in UC, and a lower proportion of γδ T cells expressed CD45RO in CD and UC. Enhanced expression of gut-homing molecules on circulating γδ T cells in IBD and skin-homing molecules in cutaneous manifestations of IBD may be of clinical relevance., (© 2012 The Authors. Clinical and Experimental Immunology © 2012 British Society for Immunology.)

Background: Patients with Crohn's disease (CD) have an intestinal dysbiosis with components of the microbiota exerting differential immune effects. Smoking is associated with an increased incidence of CD, more frequent relapse, and greater burden of surgery. This study aimed to investigate the association between smoking and the intestinal microbiota in patients with active CD., Methods: Patients with active CD (n = 103) and healthy controls (n = 66) were recruited and demographic and clinical data recorded including current smoking behavior. Fecal samples were collected and analyzed by fluorescent in situ hybridization using probes targeting 16S rRNA of bacteria previously shown to be altered in active CD (bifidobacteria, bacteroides, Clostridium coccoides-Eubacterium rectale, Escherichia coli, and Faecalibacterium prausnitzii)., Results: In total, 29/101 (29%) patients with CD and 8/58 (14%) controls were current smokers (P = 0.032). Following multivariate analysis, smoking was found to have a significant and independent effect on the microbiota of patients with CD, with higher Bacteroides-Prevotella in smokers (38.4%) compared with nonsmokers (28.1%) (F((1,93)) = 12.6, P = 0.001). Healthy controls who smoked also had higher Bacteroides-Prevotella (34.8%) than nonsmokers (24.1%) (F((1,55)) = 4.5, P = 0.038). In the pooled multivariate analysis, patients with CD had higher bifidobacteria (F((1,156)) = 30.5, P < 0.001), higher Bacteroides-Prevotella (F((1,156)) = 6.5, P = 0.012), and lower F. prausnitzii (F((1,156)) = 3.8, P = 0.052) compared with healthy controls., Conclusions: Smokers have luminal microbiota that consist of significantly higher bacteroides. Investigation of whether this is one mechanism through which the negative effects of smoking on CD are mediated is warranted., (Copyright © 2011 Crohn's & Colitis Foundation of America, Inc.)

Background: Altered intestinal dendritic cell (DC) function underlies dysregulated T-cell responses to bacteria in Crohn's disease (CD) but it is unclear whether composition of the intestinal microbiota impacts local DC function. We assessed the relationship between DC function with disease activity and intestinal microbiota in patients with CD., Methods: Surface expression of Toll-like receptor (TLR)-2, TLR-4, and spontaneous intracellular interleukin (IL)-10, IL-12p40, IL-6 production by freshly isolated DC were analyzed by multicolor flow cytometry of cells extracted from rectal tissue of 10 controls and 28 CD patients. Myeloid DC were identified as CD11c(+) HLA-DR(+lin-/dim) cells (lin = anti-CD3, CD14, CD16, CD19, CD34). Intestinal microbiota were analyzed by fluorescent in situ hybridization of fecal samples with oligonucleotide probes targeting 16S rRNA of bifidobacteria, bacteroides-prevotella, C. coccoides-E. rectale, and Faecalibacterium prausnitzii., Results: DC from CD produced higher amounts of IL-12p40 and IL-6 than control DC. IL-6(+) DC were associated with the CD Activity Index (r = 0.425; P = 0.024) and serum C-reactive protein (CRP) (r = 0.643; P = 0.004). DC expression of TLR-4 correlated with disease activity. IL-12p40(+) DC correlated with ratio of bacteroides: bifidobacteria (r = 0.535, P = 0.003). IL-10(+) DC correlated with bifidobacteria, and IL-6(+) DC correlated negatively with F. prausnitzii (r = -0.50; P = 0.008). The amount of TLR-4 on DC correlated negatively with the concentration of F. prausnitzii., Conclusions: IL-6 production by intestinal DC is increased in CD and correlates with disease activity and CRP. Bacterially driven local IL-6 production by intestinal DC may overcome regulatory activity, resulting in unopposed effector function and tissue damage. Intestinal DC function may be influenced by the composition of the commensal microbiota., (Copyright © 2010 Crohn's & Colitis Foundation of America, Inc.)

Introduction: The commensal intestinal microbiota drive the inflammation associated with Crohn's disease. However, bacteria such as bifidobacteria and Faecalibacterium prausnitzii appear to be immunoregulatory. In healthy subjects the intestinal microbiota are influenced by prebiotic carbohydrates such as fructo-oligosaccharides (FOS). Preliminary data suggest that FOS increase faecal bifidobacteria, induce immunoregulatory dendritic cell (DC) responses and reduce disease activity in patients with Crohn's disease., Aims and Methods: To assess the impact of FOS in patients with active Crohn's disease using an adequately powered randomised double-blind placebo-controlled trial with predefined clinical, microbiological and immunological end points. Patients with active Crohn's disease were randomised to 15 g/day FOS or non-prebiotic placebo for 4 weeks. The primary end point was clinical response at week 4 (fall in Crohn's Disease Activity Index of ≥ 70 points) in the intention-to-treat (ITT) population., Results: 103 patients were randomised to receive FOS (n = 54) or placebo (n = 49). More patients receiving FOS (14 (26%) vs 4 (8%); p = 0.018) withdrew before the 4-week end point. There was no significant difference in the number of patients achieving a clinical response between the FOS and placebo groups in the ITT analysis (12 (22%) vs 19 (39%), p = 0.067). Patients receiving FOS had reduced proportions of interleukin (IL)-6-positive lamina propria DC and increased DC staining of IL-10 (p < 0.05) but no change in IL-12p40 production. There were no significant differences in the faecal concentration of bifidobacteria and F prausnitzii between the groups at baseline or after the 4-week intervention., Conclusion: An adequately powered placebo-controlled trial of FOS showed no clinical benefit in patients with active Crohn's disease, despite impacting on DC function. ISRCTN50422530.

Objectives: The incidence and prevalence of inflammatory bowel disease (IBD) is increasing throughout Asia. Since the 1950s, there has been substantial migration from South Asia (India, Pakistan, and Bangladesh) to the United Kingdom. The aim of this study was to define the clinical phenotype of IBD in UK South Asians living in North West London, and to compare the results with a white Northern European IBD cohort., Methods: The phenotypic details of 367 South Asian IBD patients (273 ulcerative colitis (UC) and 94 Crohn's disease (CD)), undergoing active follow-up in five North West London hospitals, were compared with those of 403 consecutively collected white Northern European IBD patients (188 UC and 215 CD)., Results: The phenotype of IBD differed significantly between the two populations. 63.0% of South Asian UC patients had extensive colitis compared with 42.5% of the Northern European cohort (P < 0.0001). Proctitis was uncommon in South Asian UC patients (9.9 vs. 26.1% in Northern European patients, P<0.0001). In the South Asian CD cohort, disease location was predominantly colonic (46.8%). CD behavior differed significantly between the groups, with less penetrating disease compared with Northern Europeans (P=0.01) and a reduced need for surgery (P=0.003)., Conclusions: The phenotype of IBD in South Asians living in North West London is significantly different from that of a white Northern European IBD cohort. Knowledge of ethnic variations in disease phenotype may help to identify key genetic, environmental, and behavioral factors contributing to the development of IBD.

Background: Crohn's anal fistulas are common and cause considerable morbidity. Their management is often difficult; medical and surgical treatments rarely lead to true healing with frequent recurrence and complications., Aim: To examine medical treatments previously and currently used, surgical techniques and the important role of optimal imaging., Methods: We conducted a literature search in the Pub Med database using Crohn's, Anal Fistula, Surgery, Imaging and Medical Treatment as search terms., Results: Antibiotics and immunosuppressants have a role, but slow initial response, side effects and relatively low remission rates of up to around a third with frequent recurrence limit their value. Long-term infliximab produces clinical remission in 36-58% of patients with combined medical and surgical management achieving optimal outcomes. Traditional and newer surgical procedures often have a high rate of recurrence with a significant risk of temporary or, in up to 10% of cases, permanent stomas, incontinence and unhealed or slowly healing wounds in 30%., Conclusions: Management of Crohn's anal fistulas remains challenging. Established principles are to drain infection, use setons as required, aggressively manage active proctitis, give antibiotics, immunosuppressants and employ anti-TNFα therapy, and they demand significant co-operation between gastroenterologists and surgeons., (© 2010 Blackwell Publishing Ltd.)

Perianal fistulation is a common complication of Crohn's disease (CD). Fistulating perianal CD appears to represent a distinct phenotype of CD, separate from luminal fistulating disease, with differing disease behavior and which often requires different therapeutic strategies. The etiology of Crohn's perianal fistulae appears to have genetic, microbiological, and immunological components. Relationships with IBD5, which codes for the organic/cation transporter and IRGM, important in the autophagy pathway, have been identified but further genetic associations remain elusive. The partially efficacious use of antibiotics and fecal diversion imply a microbiological component and, similarly, the partial efficacy of immunosuppressants and anti-tumor necrosis factor alpha (TNFalpha) treatments suggest not only that an immunological process is taking place, but also that microbiota alone cannot account for the pathogenesis. Recent work implicates failures in the tissue injury/repair process with myofibroblasts, matrix metalloproteinases, and an epithelial-to-mesenchymal transition being possible culprits. We examine these areas in a review of the current understanding of the etiology of Crohn's perianal fistulae.

Background: The aim of this study is to evaluate the efficacy of topical tacrolimus in treating perianal Crohn's disease., Methods: Nineteen patients, stratified into 7 with ulcerating, and 12 with fistulizing, perianal Crohn's disease were randomized to topical tacrolimus 1 mg/g (1 g ointment twice a day [bid]) or placebo for 12 weeks. Sixteen patients had been on, or were currently taking, azathioprine/6-MP, and 6 had received infliximab. The primary outcome in ulcerating disease was global improvement in perianal/anal lesions, as assessed by the attending physician; for fistulas, it was reduction of > or =50% of actively draining fistulas on 2 consecutive visits. Blood tacrolimus levels and adverse events were assessed., Results: Three of 4 patients treated with topical tacrolimus for ulcerating disease improved compared with none of 3 in the placebo group. Complete healing was not achieved. In fistulizing disease, topical tacrolimus was not beneficial. Two tacrolimus-treated patients developed perianal abscesses, 1 after improvement in fistula drainage. Adverse events were otherwise infrequent and mild. Whole blood tacrolimus levels were detectable in only 2 patients and were low., Conclusions: These preliminary data suggest that topical tacrolimus is effective and safe in the treatment of perianal or anal ulcerating Crohn's disease. This therapy is unlikely to be beneficial in fistulizing perianal Crohn's disease, although a larger study is required to confirm this.

Background & Aims: Dendritic cells (DCs) recognize and respond to microbial structures using pattern recognition receptors, including Toll-like receptors (TLRs). In the intestine, DCs are pivotal in tolerance induction and direct the differentiation of T cells. We aimed to identify changes in intestinal DCs that may underlie the dysregulated immune response to enteric bacteria that occurs in patients with inflammatory bowel disease (IBD)., Methods: DCs were identified in freshly isolated lamina propria mononuclear cells by multicolor flow cytometry in patients with IBD and controls. Expression of TLR2, TLR4, and the activation/maturation marker CD40 was assessed by cell surface labeling. Production of cytokines (interleukin [IL]-12, IL-6, and IL-10) was assessed in the absence of exogenous stimulation by intracellular staining of permeabilized cells., Results: In healthy controls, few intestinal DCs expressed TLR2 or TLR4, in contrast to blood DCs. DC expression of both TLRs was significantly enhanced in Crohn's disease and ulcerative colitis. DCs from inflamed tissue of patients with Crohn's disease expressed significantly higher levels of the maturation/activation marker CD40. Elevated levels of CD40 on DCs were decreased after treating patients with anti-tumor necrosis factor alpha. In Crohn's disease, but not ulcerative colitis, more colonic DCs produced IL-12 and IL-6. The number of IL-10-producing DCs did not differ significantly between patients with IBD and controls., Conclusions: In IBD, DCs are activated, their expression of microbial recognition receptors is up-regulated, and more DCs produce pathologically relevant cytokines. Intestinal DCs are likely to be key initiators or perpetuators of the inflammatory response that characterizes IBD.

Background: Forty per cent of patients with inflammatory bowel disease fail to respond to standard dose azathioprine (2 mg/kg/day)., Aims: To evaluate the efficacy and safety of increasing the azathioprine dose according to a fixed schedule and guided by clinical response and adverse effects., Methods: We reviewed the records of all patients with inflammatory bowel disease treated by a single clinician over 6 years, unresponsive to at least 3 months treatment with standard dose azathioprine, and whose dose was subsequently increased., Results: Forty patients (27 male; 24 Crohn's, 16 ulcerative colitis) with chronic active disease or recurrent flares despite standard dose azathioprine for a median 8 months (range 3-114) increased their dose from a median 2.02 (1.61-3.19) mg/kg/day to 2.72 (2.37-3.99) mg/kg/day in one to four increments of 0.5 mg/kg/day, and were followed over a median 6 (0.5-54) months. Eleven of the 40 patients (seven Crohn's, four ulcerative colitis) responded or had reduced frequency of flare-ups at the end of follow-up, while 17 of the 40 patients had no benefit. Response was more likely for maximum doses < or =2.5 mg/kg/day (six of 11 patients) than for doses >2.5 mg/kg/day (five of 29 patients) (P = 0.042). Twelve patients (11 of whom received maximum doses >2.5 mg/kg/day) were unable to maintain an increased azathioprine dose because of leukopenia in eight, nausea in three, and raised liver enzymes in one (all transient and reversible)., Conclusions: Increasing the azathioprine dose up to 2.5 mg/kg/day appears beneficial in patients who have not responded to 2 mg/kg/day. Further increase above 2.5 mg/kg/day is less likely to be efficacious, and is associated with a substantial risk of adverse reactions.

Circulating memory T cells can be subdivided on the basis of beta7 integrin expression. The beta7+ population contains cells primed in the intestine capable of homing back to the gut. We hypothesized that cytokine production by beta7+ memory T cells reflects the specialized mucosal compartment in which they were primed. Flow cytometry of whole blood was used to assess numbers of beta7+ (beta7hi and beta7int) and beta7- memory T cells and their production of Th1 and regulatory cytokines in healthy controls and Crohn's disease patients. In controls, beta7+ and beta7- memory T cells displayed a similar qualitative profile of cytokine production but the beta7+ population was enriched for cytokine-producing effector cells. In addition, the beta7hi population contained more cytokine-producing cells than the beta7int population, suggesting a gradient of cytokine production based on beta7 integrin expression. In active Crohn's disease, there was altered expression of beta7 integrin with a decrease in intestinal-homing memory T cells and an increase in systemic memory T cells. Furthermore, there was a selective loss of IL-10 and increase in TGF-beta in both beta7+ and beta7- memory T cell subsets which may contribute to the pathogenesis of the inflammatory process in Crohn's disease.