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Anti-tumor necrosis factor (TNF) antibodies play a major role in treating inflammatory bowel disease (IBD), both in adult and pediatric patients. While there is a large number of studies on efficacy and safety of infliximab in treating children and adolescents with ulcerative colitis (UC), data on adalimumab (ADA) are scarce.Here, we review published case reports, cohort and real-time data, as well as the first randomized trial, ENVISION I, using ADA for treating pediatric UC. Available evidence confirms good efficacy in inducing and maintaining remission in children and adolescents with UC, with even higher response rates compared to adult UC. ENVISION I showed that in UC patients responding to ADA induction therapy, almost half of the patients remained in remission after 52 weeks of therapy on high-dosing ADA (weekly administration). As already well experienced with other biologics, dosing schemes are different between pediatric and adult patients, with children often requiring higher dosing.Further data are required to better understand how to optimize ADA therapy. The present and still-growing evidence places subcutaneous (sc.) anti-TNF-medication as alternative first-line therapy also for pediatric UC. This is also reflected by the preference for sc. medication of adolescent patients allowing less frequent and autonomous drug administration.

Dedicator of cytokinesis (DOCK) proteins play a central role in actin cytoskeleton regulation. This is highlighted by the DOCK2 and DOCK8 deficiencies leading to actinopathies and immune deficiencies. DOCK8 and DOCK11 activate CDC42, a RHO-GTPase involved in actin cytoskeleton dynamics, among many cellular functions. The role of DOCK11 in human immune disease has been long suspected but has never been described so far. We studied eight male patients, from seven unrelated families, with hemizygous DOCK11 missense variants leading to reduced DOCK11 expression. The patients were presenting with early-onset autoimmunity, including cytopenia, systemic lupus erythematosus, skin, and digestive manifestations. Patients' platelets exhibited abnormal ultrastructural morphology and spreading as well as impaired CDC42 activity. In vitro activated T cells and B lymphoblastoid cell lines (B-LCL) of patients exhibited aberrant protrusions and abnormal migration speed in confined channels concomitant with altered actin polymerization during migration. A DOCK11 knock-down recapitulated these abnormal cellular phenotypes in monocytes-derived dendritic cells (MDDC) and primary activated T cells from healthy controls. Lastly, in line with the patients' autoimmune manifestations, we also observed abnormal regulatory T cells (Tregs) phenotype with profoundly reduced FOXP3 and IKZF2 expression. Moreover, we found a reduced T cell proliferation and an impaired STAT5B phosphorylation upon IL2 stimulation of the patients' lymphocytes. In conclusion, DOCK11 deficiency is a new X-linked immune-related actinopathy leading to impaired CDC42 activity and STAT5 activation, and associated with abnormal actin cytoskeleton remodeling as well as Tregs phenotype culminating in immune dysregulation and severe early-onset autoimmunity.

Background and Aims Despite recent approvals for new drugs to treat adults with Crohn’s disease or ulcerative colitis, there are only two approved advanced treatment options [infliximab and adalimumab] for children with inflammatory bowel disease [IBD]. There are many potential new therapies being developed for adult and paediatric IBD. Moreover, regulatory agencies in both the European Union and USA have processes in place to support the early planning and initiation of paediatric studies. Nevertheless, unacceptable delays in approvals for use of drugs in children persist, with an average 7-year gap, or longer, between authorization of new IBD drugs for adults and children. Methods A 2-day virtual meeting was held during April 14–15, 2021 for multi-stakeholders [clinical academics, patient community, pharmaceutical companies and regulators] to discuss their perspectives on paediatric drug development for IBD. Results The multi-stakeholder group presented, discussed and proposed actions to achieve expediting the approval of new drugs in development for paediatric IBD. Conclusions Collaborative action points for all stakeholders are required to make progress and facilitate new drug development for children with IBD.

Mevalonate kinase deficiency should be considered in patients with severe very-early-onset inflammatory bowel disease (IBD), especially in patients with a history of recurrent or chronic fever, peritoneal adhesions, and atypical IBD pathology. Anti-interleukin-1 therapy may be efficacious in these patients with monogenic very-early-onset IBD.

The mechanisms that maintain intestinal homeostasis despite constant exposure of the gut surface to multiple environmental antigens and to billions of microbes have been scrutinized over the past 20 years with the goals to gain basic knowledge, but also to elucidate the pathogenesis of inflammatory bowel diseases (IBD) and to identify therapeutic targets for these severe diseases. Considerable insight has been obtained from studies based on gene inactivation in mice as well as from genome wide screens for genetic variants predisposing to human IBD. These studies are, however, not sufficient to delineate which pathways play key nonredundant role in the human intestinal barrier and to hierarchize their respective contribution. Here, we intend to illustrate how such insight can be derived from the study of human Mendelian diseases, in which severe intestinal pathology results from single gene defects that impair epithelial and or hematopoietic immune cell functions. We suggest that these diseases offer the unique opportunity to study in depth the pathogenic mechanisms leading to perturbation of intestinal homeostasis in humans. Furthermore, molecular dissection of monogenic intestinal diseases highlights key pathways that might be druggable and therapeutically targeted in common forms of IBD.

European Crohn's Colitis Organization (ECCO) and the European Society of Pediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN) guidelines recommend the early use of anti-TNF biologicals in pediatric Crohn disease (CD) patients with positive predictors for poor outcome.The objective of the present study was to compare early "Top-Down" use of Adalimumab (ADA) immunomodulator/biologics-naïve patients to conventional "Step-Up" management.One hundred and twenty consecutive patients with a confirmed diagnosis of CD and treated with Adalimumab (ADA) between 2008 and 2019 were included and allocated to the ADA-Top Down (n=59) or ADA-Step Up group (n=61). The primary endpoint was prolonged steroid-/enteral nutrition-free clinical remission at 24 months, defined by a wPCDAI12.5. Clinical and biological data were collected at 12 and 24 months.At start of ADA, disease activity was comparable between the ADA-Top Down group and the ADA-Step Up group (wPCDAI=31 ± 16 versus 31.3 ± 15.2 respectively, p=0.84). At 24 months, the remission rate was significantly higher in the ADA-Top Down group (73% versus 51%, p0.01). After propensity score, the Top-Down strategy is still more effective than the Step-Up strategy in maintaining remission at 24 months (HR=0.36, 95%CI[0.15-0.87], p=0.02). Patients in the ADA-Top Down group were mainly on monotherapy compared to patients in the ADA-Step Up group (53/55 versus 28/55 respectively, p0.001). Serum levels of Adalimumab were higher in the ADA-Top Down group than in the ADA-Step Up group (12.8µg/ml±4.3 versus 10.4µg/ml±3.9 respectively, p0.01).There were no serious adverse events.Early use of ADA appears to be more effective in maintaining relapse-free remission at 2 years, while using it as monotherapy. These findings further favor the recommendation of early anti-TNF use in high-risk CD patients.

BACKGROUND: It is important to identify patients with monogenic IBD as management may differ from classical IBD. In this position statement we formulate recommendations for the use of genomics in evaluating potential monogenic causes of IBD across age groups. METHODS: The consensus included paediatric IBD specialists from the Paediatric IBD Porto group of the European Society of Paediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN) and specialists from several monogenic IBD research consortia. We defined key topics and performed a systematic literature review to cover indications, technologies (targeted panel, exome and genome sequencing), gene panel setup, cost-effectiveness of genetic screening, and requirements for the clinical care setting. We developed recommendations that were voted upon by all authors and Porto group members (32 voting specialists). RESULTS: We recommend next-generation DNA-sequencing technologies to diagnose monogenic causes of IBD in routine clinical practice embedded in a setting of multidisciplinary patient care. Routine genetic screening is not recommended for all IBD patients. Genetic testing should be considered depending on age of IBD-onset (infantile IBD, very early-onset IBD, paediatric or young adult IBD), and further criteria, such as family history, relevant comorbidities, and extraintestinal manifestations. Genetic testing is also recommended in advance of hematopoietic stem cell transplantation. We developed a diagnostic algorithm that includes a gene panel of 75 monogenic IBD genes. Considerations are provided also for low resource countries. CONCLUSIONS: Genomic technologies should be considered an integral part of patient care to investigate patients at risk for monogenic forms of IBD.

ObjectiveWe aimed to provide an evidence-supported update of the ECCO-ESPGHAN guideline on the medical management of paediatric Crohn’s disease [CD].MethodsWe formed 10 working groups and formulated 17 PICO-structured clinical questions [Patients, Intervention, Comparator, and Outcome]. A systematic literature search from January 1, 1991 to March 19, 2019 was conducted by a medical librarian using MEDLINE, EMBASE, and Cochrane Central databases. A shortlist of 30 provisional statements were further refined during a consensus meeting in Barcelona in October 2019 and subjected to a vote. In total 22 statements reached ≥ 80% agreement and were retained.ResultsWe established that it was key to identify patients at high risk of a complicated disease course at the earliest opportunity, to reduce bowel damage. Patients with perianal disease, stricturing or penetrating behaviour, or severe growth retardation should be considered for up-front anti-tumour necrosis factor [TNF] agents in combination with an immunomodulator. Therapeutic drug monitoring to guide treatment changes is recommended over empirically escalating anti-TNF dose or switching therapies. Patients with low-risk luminal CD should be induced with exclusive enteral nutrition [EEN], or with corticosteroids when EEN is not an option, and require immunomodulator-based maintenance therapy. Favourable outcomes rely on close monitoring of treatment response, with timely adjustments in therapy when treatment targets are not met. Serial faecal calprotectin measurements or small bowel imaging [ultrasound or magnetic resonance enterography] are more reliable markers of treatment response than clinical scores alone.ConclusionsWe present state-of-the-art guidance on the medical treatment and long-term management of children and adolescents with CD.

Management of inflammatory complications of chronic granulomatous disease (CGD) is challenging. The aim of this study was to assess safety, with a focus on infections, and effectiveness of tumor necrosis factor alpha (TNF-α) blockers in CGD patients. A retrospective, single-center cohort study of CGD patients treated by anti-TNF-α agents at Necker-Enfants Malades University Hospital (Paris, France) and registered at the French National Reference Center for Primary Immunodeficiencies (CEREDIH). Between 2006 and 2019, 14 (X-linked: n = 10, 71.4%; autosomal-recessive: n = 4, 28.6%) CGD patients with gastrointestinal (n = 12, 85.7%), pulmonary (n = 10, 71.4%), cutaneous (n = 3, 21.4%), and/or genitourinary (n = 2, 14.3%) inflammatory manifestations received one or more doses of infliximab because of steroid-dependent (n = 7, 50%), refractory (n = 4, 28.6%) inflammatory disease or as first-line drug (n = 2, 14.3%; missing data, n = 1). All patients received adequate antimicrobial prophylaxis. Infliximab achieved complete (n = 2, 14.3%) or partial (n = 9, 64.3%) response in 11 (78.6%) patients. Seven (50%) patients were switched to adalimumab. During anti-TNF-α treatment, 11 infections (pneumonia, adenitis, invasive candidiasis, each n = 2; intra-abdominal abscess, bacteremic salmonellosis, Pseudomonas aeruginosa–related folliculitis, cat-scratch disease, proven pulmonary mucormycosis, each n = 1) occurred in 7 (50%) patients. All infectious complications had a favorable outcome. Anti-TNF-α treatment was definitively stopped because of infection in two patients. Nine (64.3%) patients finally underwent hematopoietic stem cell transplantation. No death occurred during follow-up. Anti-TNF-α treatment could improve the outcome of severe inflammatory complications in CGD patients, but increases their risk of infections. We suggest that anti-TNF-α treatment might be of short-term benefit in selected CGD patients with severe inflammatory complications awaiting hematopoietic stem cell transplantation.

The first ECCO-ESPGHAN guidelines for the medical management of pediatric Crohn disease (CD) were published in 2014. Whether their implementation, and the consequent increased use of an upfront anti-tumor necrosis factor therapy, have changed the course of the disease has not been investigated yet. We aimed at comparing the evolution of pediatric CD patients diagnosed and treated before and after 2014.Single-center retrospective study including all children diagnosed with CD from January 2010 to December 2018. Patients diagnosed between 2010 and 2014 (group 1) were compared to those diagnosed after 2014 (group 2). For each patient, at baseline and every 6-month, number of relapses, the occurrence of complication, therapy received and biological parameters were noted, as well as any endoscopic or radiologic evaluation.One hundred and fifty-four patients were included in the analysis, 78 (51%) diagnosed after 2014. The cumulative probability of a relapse-free and surgery-free course was significantly higher for patients treated according to the guidelines (log rank hazard ratio [HR] = 1,818, P = 0.003 and HR = 3,15, 95% confidence interval, P = 0.04, respectively). Mucosal healing rate was significantly higher among patients of group 2 at 1 and 2 years (P = 0.04 and P = 0.05, respectively), while no significant difference was observed for transmural healing rates, as well as for the risk of complications.The implementation of the 2014 CD guidelines appears to have a significant impact on disease outcomes, with a significantly lower risk for relapse and surgery, while no effect could be observed on the risk of developing complications.

To describe the ambulatory proton pump inhibitor (PPI) prescription in French children, its trends, and the impact of French (2014) and international (2018) clinical guidelines.We described PPI prescription rates based on national dispensation data in French children (IQVIA's Xponent database, 2009-2019). Using a segmented linear regression, we assessed the impact of clinical guidelines on PPI prescription rates. Analyses were performed for the overall pediatric population and by age subgroups (infants2 years old, children 2-11 years old, adolescents 12-17 years old).During the study period, 8 060 288 pediatric PPI prescriptions were filled, with a mean PPI prescription rate of 52.5 per 1000 inhabitants per year. Between 2009 and 2019, the PPI prescription rate increased by 41% in the overall pediatric population (+110% in infants). The PPI prescription rate showed seasonal patterns with peaks in winter. After the release of French guidelines, significant decreases in trends of prescription rates occurred overall (change in trend -0.28, 95% CI -0.34;-0.23) and across all age groups. In infants, this change in trend was not sufficient to reverse the PPI prescription rate that was still increasing over time. In children, the PPI prescription rate slightly decreased and in adolescents, it was stable. After the release of international guidelines, a significant decrease in trend occurred in adolescents only (change in trend -0.26, 95% CI -0.47; -0.04).The pediatric PPI prescription rate in France was high, displayed a major increase over the last decade, mainly among infants, and was modestly affected by clinical guidelines.

International audience; Dysregulated transforming growth factor TGF-beta signaling underlies the pathogenesis of genetic disorders affecting the connective tissue such as Loeys-Dietz syndrome. Here, we report 12 individuals with bi-allelic loss-of-function variants in IPO8 who presented with a syndromic association characterized by cardio-vascular anomalies, joint hyperlaxity, and various degree of dysmorphic features and developmental delay as well as immune dysregulation; the individuals were from nine unrelated families. Importin 8 belongs to the karyopherin family of nuclear transport receptors and was previously shown to mediate TGF-beta-dependent SMADs trafficking to the nucleus in vitro. The important in vivo role of IPO8 in pSMAD nuclear translocation was demonstrated by CRISPR/Cas9-mediated inactivation in zebrafish. Consistent with IPO8's role in BMP/TGF-beta signaling, ipo8(-/-) zebrafish presented mild to severe dorso-ventral patterning defects during early embryonic development. Moreover, ipo8(-/-) zebrafish displayed severe cardiovascular and skeletal defects that mirrored the human phenotype. Our work thus provides evidence that IPO8 plays a critical and non-redundant role in TGF-beta signaling during development and reinforces the existing link between TGF-beta signaling and connective tissue defects.

Summary Background & aims Intestinal rehabilitation is the preferred treatment for children with short bowel syndrome (SBS) whatever the residual bowel length, and depends on the accurate management of long-term parenteral nutrition (PN). If nutritional failure develops, intestinal transplantation (ITx) should be discussed and may be life-saving. This study aimed to evaluate survival, PN dependency and nutritional status in children with neonatal very SBS on PN or after ITx, in order to define indications and timing of both treatments. Patients and methods This retrospective cross-sectional study enrolled 36 children with very SBS ( Results All the children on long-term PN (n = 16) survived with a follow-up of 17 years (9–20). Six of them were eventually weaned off PN. Twenty children underwent ITx: eight children died (40%) 29 months (0–127) after Tx. The others 12 patients were weaned off PN 73 days (13–330) after Tx. Follow-up after transplantation was 14 years (6–28). Seven out of 8 (88%) patients with a history of gastroschisis required ITx. Patients who required ITx had longer stoma duration. Conclusion Survival rate of children with very short bowel was excellent if no life-threatening complications requiring transplantation developed. Gastroschisis and delayed ostomy closure are confirmed as risk factor for nutritional failure. Intestinal rehabilitation may allow a total weaning of PN before adulthood. A follow-up by a multidisciplinary team is necessary to avoid PN complications in order to minimize indications for ITx.

Objectives: To evaluate the longitudinal evolution of work productivity loss and activity impairment in caregivers of children with inflammatory bowel disease (IBD). We also evaluated the associations between these impairments, IBD-related factors, and caregivers’ health-related quality of life (HRQOL) and estimated the indirect costs related to work absenteeism. Study design: Since January 2017, children with newly diagnosed IBD were enrolled prospectively in the Pediatric Inflammatory Bowel Disease Network for Safety, Efficacy, Treatment and Quality improvement of care study. The impact of pediatric-onset IBD on caregivers' socioeconomic functioning (work and daily activities) and HRQOL was assessed using the Work Productivity and Activity Impairment for caregivers questionnaire and the European Quality of Life Five Dimension Five Level questionnaire, at diagnosis and 3 and 12 months of age. Generalized estimating equation models were applied to evaluate outcomes longitudinally, adjusted for IBD type, disease activity, and child's age at diagnosis. Results: Up to July 2021, 491 children with IBD were eligible for analysis of caregivers' Work Productivity and Activity Impairment questionnaire. At diagnosis, the mean caregivers' employment rate was 78.4%; the adjusted mean work productivity loss was 44.6% (95% CI, 40.2%-49.0%), and the adjusted mean activity impairment was 34.3% (95% CI, 30.8%-37.7%). Work productivity loss and activity impairment significantly decreased over time and were associated with disease activity, but not with IBD type or child's age. Caregivers' HRQOL was associated with both impairments. Costs related to work absenteeism were at least €6272 ($7276) per patient during the first year after diagnosis. Conclusions: Caregivers of children with IBD experience significant impairments in work and daily activities, especially at diagnosis. The impact decreases thereafter and is associated with disease activity and caregivers’ HRQOL. Work absenteeism results in high indirect costs.

AimsExclusive enteral nutrition [EEN] is as efficacious as corticosteroids [CS] to induce remission in Crohn’s disease [CD], without their adverse effects. EEN seems to be more efficient than steroids to induce mucosal healing, but the underlying molecular mechanisms are only sparsely understood. We aimed in the present work to study the anti-inflammatory effects of EEN with Modulen IBD® vs CS in active paediatric CD, and to assess its modulatory effects on the intestinal microbiota as compared with steroids.Materials and MethodsNineteen patients with new-onset active CD (Harvey-Bradshaw index [HBI] >5), aged from 6 to 17 years, were included in this prospective randomised induction trial with CS [n = 6] or EEN [n = 13]. Patients were assessed at Weeks 0 and 8 using clinical parameters HBI, endoscopic findings (Crohn’s Disease Endoscopic Index of Severity [CDEIS] score) and analysis of faecal microbiota composition.ResultsAt 8 weeks, clinical remission [HBI ConclusionsBoth steroid and EEN induced clinical remission. However, patients with EEN-induced remission showed a higher rate of mucosal healing and this was associated with a different gut microbiota compositional shift in these children.

FOXP3 deficiency in mice and in patients with immune dysregulation polyendocrinopathy enteropathy X-linked (IPEX) syndrome results in fatal autoimmunity by altering regulatory T (T-reg) cells. CD4(+) T cells in patients with IPEX syndrome and Foxp3-deficient mice were analyzed by single-cell cytometry and RNA-sequencing, revealing heterogeneous T-reg-like cells, some very similar to normal T-reg cells, others more distant. Conventional T cells showed no widespread activation or helper T cell bias, but a monomorphic disease signature affected all CD4(+) T cells. This signature proved to be cell extrinsic since it was extinguished in mixed bone marrow chimeric mice and heterozygous mothers of patients with IPEX syndrome. Normal T-reg cells exerted dominant suppression, quenching the disease signature and revealing in mutant T-reg-like cells a small cluster of genes regulated cell-intrinsically by FOXP3, including key homeostatic regulators. We propose a two-step pathogenesis model: cell-intrinsic downregulation of core FOXP3-dependent genes destabilizes T-reg cells, de-repressing systemic mediators that imprint the disease signature on all T cells, furthering T-reg cell dysfunction. Accordingly, interleukin-2 treatment improved the T-reg-like compartment and survival. FOXP3 deficiency leads to dramatic loss of immune homeostasis. This multicenter collaborative group finds that loss of FOXP3 function only disrupts a few core genes, but this unmasks a degree of systemic inflammation, and it is this environment that then strongly perturbs T-reg cells.

Background Congenital chloride diarrhoea [CLD] is a rare autosomal recessive disease caused by mutations in the solute family carrier 26 member 3 [SLC26A3] gene. Patients suffer from life-long watery diarrhoea and chloride loss. Inflammatory bowel disease [IBD] has been reported in individual patients with CLD and in scl26a3-deficient mice. Methods We performed an international multicentre analysis to build a CLD cohort and to identify cases with IBD. We assessed clinical and genetic characteristics of subjects and studied the cumulative incidence of CLD-associated IBD. Results In a cohort of 72 patients with CLD caused by 17 different SLC26A3 mutations, we identified 12 patients [17%] diagnosed with IBD. Nine patients had Crohn’s disease, two ulcerative colitis and one IBD-unclassified [IBD-U]. The prevalence of IBD in our cohort of CLD was higher than the highest prevalence of IBD in Europe [p < 0.0001]. The age of onset was variable [13.5 years, interquartile range: 8.5–23.5 years]. Patients with CLD and IBD had lower z-score for height than those without IBD. Four of 12 patients had required surgery [ileostomy formation n = 2, ileocaecal resection due to ileocaecal valve stenosis n = 1 and colectomy due to stage II transverse colon cancer n = 1]. At last follow-up, 5/12 were on biologics [adalimumab, infliximab or vedolizumab], 5/12 on immunosuppressants [azathioprine or mercaptopurine], one on 5-ASA and one off-treatment. Conclusions A substantial proportion of patients with CLD develop IBD. This suggests the potential involvement of SL26A3-mediated anion transport in IBD pathogenesis. Patients with CLD-associated IBD may require surgery for treatment failure or colon cancer.

Biologic treatment options are limited for children with ulcerative colitis. The aim of this study was to assess the safety and efficacy of adalimumab in children with moderate-to-severe ulcerative colitis.The double-blind ENVISION I study was done at 24 hospitals in ten countries. Children (4-17 years) with moderate-to-severe ulcerative colitis despite stable doses of concurrent treatment with oral corticosteroids or immunosuppressants were enrolled. Per the original study design, patients were randomly assigned with an Interactive Voice Response System (IVRS) to receive either high-dose induction adalimumab (2·4 mg/kg [maximum 160 mg] at weeks 0 and 1) or standard-dose induction adalimumab (2·4 mg/kg at week 0 and placebo at week 1); both groups received 1·2 mg/kg (maximum 80 mg) at week 2 and 0·6 mg/kg (maximum 40 mg) at weeks 4 and 6. Patients with partial Mayo score (PMS) response at week 8 (defined as a decrease of two or more points and a decrease of ≥30% from baseline in PMS) were randomly assigned (2:2:1)-using IVRS-to receive either high-dose maintenance adalimumab (0·6 mg/kg weekly), standard-dose maintenance adalimumab (0·6 mg/kg every other week), or placebo up to week 52 (random assignment to the placebo group was ceased mid-trial, as was randomisation in the induction phase with all subsequent patients receiving open-label high-dose induction adalimumab). Coprimary endpoints were the proportion of patients with PMS remission at week 8 (intent-to-treat [ITT]-E population, not including those patients who were not randomised in the induction phase) and full Mayo score (FMS) remission at week 52 in week 8 PMS responders (maintenance ITT-E [mITT-E] population), for which the pooled adalimumab group (patients who received high-dose or standard-dose adalimumab) and the individual dose groups were compared against external adult placebo rates. We report results of the final confirmatory analysis. This trial is registered with ClinicalTrials.gov, NCT02065557.93 children were recruited between Oct 13, 2014, and Sept 5, 2018, to the main study (77 [83%] were randomly assigned [double-blind] to receive high-dose or standard-dose induction adalimumab; 16 [17%] received open-label high-dose induction adalimumab after study design change). At week 8, 74 (80%) children who were PMS responders continued to the maintenance period. 62 (84%) patients were randomly assigned to receive high-dose or standard-dose maintenance adalimumab treatment; 12 (16%) patients received placebo. In patients in the ITT-E population who were randomly assigned to receive high-dose induction adalimumab, a significantly higher proportion of patients were in PMS remission at week 8 (28 [60%] of 47) compared with external placebo (19·8%; p=0·0001). 13 (43%) of 30 patients in the standard-dose induction adalimumab group were in PMS remission at week 8 versus an external placebo rate of 19·8%, but this difference was not significant (p=0·38). Similarly, FMS remission at week 52 in children who were week 8 PMS responders was reported in a significantly higher proportion of patients in mITT-E population who received high-dose maintenance adalimumab (14 [45%] of 31 patients) versus external placebo at week 52 (18·4%; p=0·0001). Nine (29%) of 31 patients in the standard-dose maintenance adalimumab group were in FMS remission at week 52 versus an external placebo rate of 18·4%, but this difference was not significant (p=0·38). Remission rates in the pooled adalimumab groups were significantly better compared with external placebo (PMS remission at week 8: 41 [53%] of 77 patients; p0·0001; FMS remission at week 52: 23 [37%] of 62 patients; p=0·0001). 21 (23%) of 93 patients in the main study had one or more treatment-emergent serious adverse events during any adalimumab exposure. The most common adverse events were headache, anaemia, and ulcerative colitis flare during the induction period and ulcerative colitis flare, headache, and nasopharyngitis during the maintenance period.Clinically meaningful rates of remission and response were reported in children who received adalimumab in this study. No new safety signals were observed, suggesting that adalimumab is an efficacious and safe treatment option for children with moderate-to-severe ulcerative colitis.AbbVie.

Myosin Vb (MYO5B) is a motor protein that facilitates protein trafficking and recycling in polarized cells by RAB11- and RAB8-dependent mechanisms. Biallelic MYO5B mutations are identified in the majority of patients with microvillus inclusion disease (MVID). MVID is an intractable diarrhea of infantile onset with characteristic histopathologic findings that requires life-long parenteral nutrition or intestinal transplantation. A large number of such patients eventually develop cholestatic liver disease. Bi-allelic MYO5B mutations are also identified in a subset of patients with predominant early-onset cholestatic liver disease. We present here the compilation of 114 patients with disease-causing MYO5B genotypes, including 44 novel patients as well as 35 novel MYO5B mutations, and an analysis of MYO5B mutations with regard to functional consequences. Our data support the concept that (1) a complete lack of MYO5B protein or early MYO5B truncation causes predominant intestinal disease (MYO5B-MVID), (2) the expression of full-length mutant MYO5B proteins with residual function causes predominant cholestatic liver disease (MYO5B-PFIC), and (3) the expression of mutant MYO5B proteins without residual function causes both intestinal and hepatic disease (MYO5B-MIXED). Genotype-phenotype data are deposited in the existing open MYO5B database in order to improve disease diagnosis, prognosis, and genetic counseling., publishedVersion

OBJECTIVES Crohn disease (CD) can affect patient's quality of life (QOL) with physical, social, and psychological impacts. This study aimed to investigate the QOL of children with CD and its relationship with patient and disease characteristics. METHODS Children ages from 10 to 17 years with diagnosed CD for more than 6 months were eligible to this cross-sectional study conducted in 35 French pediatric centers. QOL was assessed by the IMPACT-III questionnaire. Patient and disease characteristics were collected. RESULTS A total of 218 children (42% of girls) were included at a median age of 14 years (interquartile range [IQR]: 13--16). Median duration of CD was 3.2 years (IQR: 1.7-5.1) and 63% of children were in clinical remission assessed by wPCDAI. Total IMPACT-III score was 62.8 (±11.0). The lowest score was in "emotional functioning" subdomain (mean: 42.8 ± 11.2). Clinical remission was the main independent factor associated with QOL of children with CD (5.74 points higher compared with those "with active disease", 95% confidence interval [CI] 2.77--8.70, P

FOXP3 deficiency in mice and IPEX syndrome patients results in fatal autoimmunity by altering T regulatory cells (Treg). CD4+ T cells in IPEX patients and Foxp3-deficient mice were analyzed by single-cell cytometry and RNAseq, revealing heterogeneous Treg-like cells, some very similar to normal Tregs, others more distant. Conventional T cells showed no widespread activation or Th bias, but a monomorphic disease signature affected all CD4+ T cells, cell-extrinsic signature since extinguished in mixed bone marrow chimeric mice and heterozygous mothers of IPEX patients. Normal Tregs exerted dominant suppression, extinguishing the disease signature, and revealing in mutant Treg-like cells a small cluster of genes regulated cell-intrinsically by FOXP3, including key homeostatic regulators. We propose a two-step pathogenesis model: cell-intrinsic downregulation of core genes destabilizes Tregs, de-repressing systemic mediators which imprint the disease signature on all T cells, furthering Treg dysfunction. Accordingly, IL2 treatment improved the Treg-like compartment and survival.

Management of inflammatory complications of chronic granulomatous disease (CGD) is challenging. The aim of this study was to assess safety, with a focus on infections, and effectiveness of tumor necrosis factor alpha (TNF-α) blockers in CGD patients.A retrospective, single-center cohort study of CGD patients treated by anti-TNF-α agents at Necker-Enfants Malades University Hospital (Paris, France) and registered at the French National Reference Center for Primary Immunodeficiencies (CEREDIH).Between 2006 and 2019, 14 (X-linked: n = 10, 71.4%; autosomal-recessive: n = 4, 28.6%) CGD patients with gastrointestinal (n = 12, 85.7%), pulmonary (n = 10, 71.4%), cutaneous (n = 3, 21.4%), and/or genitourinary (n = 2, 14.3%) inflammatory manifestations received one or more doses of infliximab because of steroid-dependent (n = 7, 50%), refractory (n = 4, 28.6%) inflammatory disease or as first-line drug (n = 2, 14.3%; missing data, n = 1). All patients received adequate antimicrobial prophylaxis. Infliximab achieved complete (n = 2, 14.3%) or partial (n = 9, 64.3%) response in 11 (78.6%) patients. Seven (50%) patients were switched to adalimumab. During anti-TNF-α treatment, 11 infections (pneumonia, adenitis, invasive candidiasis, each n = 2; intra-abdominal abscess, bacteremic salmonellosis, Pseudomonas aeruginosa-related folliculitis, cat-scratch disease, proven pulmonary mucormycosis, each n = 1) occurred in 7 (50%) patients. All infectious complications had a favorable outcome. Anti-TNF-α treatment was definitively stopped because of infection in two patients. Nine (64.3%) patients finally underwent hematopoietic stem cell transplantation. No death occurred during follow-up.Anti-TNF-α treatment could improve the outcome of severe inflammatory complications in CGD patients, but increases their risk of infections. We suggest that anti-TNF-α treatment might be of short-term benefit in selected CGD patients with severe inflammatory complications awaiting hematopoietic stem cell transplantation.

IntroductionPatients with paediatric-onset inflammatory bowel disease (PIBD) may develop a complicated disease course, including growth failure, bowel resection at young age and treatment-related adverse events, all of which can have significant and lasting effects on the patient’s development and quality of life. Unfortunately, we are still not able to fully explain the heterogeneity between patients and their disease course and predict which patients will respond to certain therapies or are most at risk of developing a more complicated disease course. To investigate this, large prospective studies with long-term follow-up are needed. Currently, no such European or Asian international cohorts exist. In this international cohort, we aim to evaluate disease course and which patients are most at risk of therapy non-response or development of complicated disease based on patient and disease characteristics, immune pathology and environmental and socioeconomic factors.Methods and analysisIn this international prospective observational study, which is part of the PIBD Network for Safety, Efficacy, Treatment and Quality improvement of care (PIBD-SETQuality), children diagnosed with inflammatory bowel disease Ethics and disseminationMedical ethical approval has been obtained prior to patient recruitment for all sites. The results will be disseminated through peer-reviewed scientific publications.Trial registration numberNCT03571373.

Objectives Neurological adverse effects (NAEs) induced by biotherapies have been reported in the literature mainly in adult patients with inflammatory bowel disease (IBD), rheumatic diseases, or psoriasis. There are scant data in children. Aims of this study are to report and describe noninfective NAE associated with anti-TNFα antibodies in pediatric IBD, and to evaluate their incidence. Methods We retrospectively collected all reports of NAE in pediatric IBD treated with anti-TNFα antibodies recorded in the French Pharmacovigilance Database. To estimate the national incidence of NAEs, we extrapolated data from the French regional inception population-based cohort EPIMAD. Results Between 2000 and 2018, 231 adverse events in pediatric IBD exposed to anti-TNFα antibodies were reported to this Database. Seventeen NAEs (7.36%) were collected: 8 severe NAE (1 demyelinating neuropathy, 1 optic neuritis, 1 acute transverse myelitis, 1 polyradiculoneuritis, 1 sensorineural hearing loss, 1 seizure, 1 stroke, and 1 glioma), 7 moderate NAE (headaches), and 2 neuropsychic events. The median delay between anti-TNFα start and NAE occurrence was 6 months (range: 13 days to 26 months). In 10 of 17 patients, anti-TNFα antibodies were stopped. Nine of 17 patients had a complete resolution (including 2 severe NAE) and 8 of 17 a partial resolution (including 6 severe NAE). We estimate the incidence of severe NAE in pediatric IBD treated with anti-TNFα antibodies at 1 case for 10,000 patients-year in France. Conclusions NAE associated with anti-TNFα antibodies in pediatric IBD are rare. In severe NAE, we recommend to discontinue anti-TNFα therapy and to consider alternative treatment.

BACKGROUND & AIMS: A better understanding of prognostic factors in ulcerative colitis (UC) could improve patient management and reduce complications. We aimed to identify evidence-based predictors for outcomes in pediatric UC, which may be used to optimize treatment algorithms. METHODS: Potential outcomes worthy of prediction in UC were determined by surveying 202 experts in pediatric UC. A systematic review of the literature, with selected meta-analysis, was performed to identify studies that investigated predictors for these outcomes. Multiple national and international meetings were held to reach consensus on evidence-based statements. RESULTS: Consensus was reached on 31 statements regarding predictors of colectomy, acute severe colitis (ASC), chronically active pediatric UC, cancer and mortality. At diagnosis, disease extent (6 studies, N = 627; P = .035), Pediatric Ulcerative Colitis Activity Index score (4 studies, n = 318; P < .001), hemoglobin, hematocrit, and albumin may predict colectomy. In addition, family history of UC (2 studies, n = 557; P = .0004), extraintestinal manifestations (4 studies, n = 526; P = .048), and disease extension over time may predict colectomy, whereas primary sclerosing cholangitis (PSC) may be protective. Acute severe colitis may be predicted by disease severity at onset and hypoalbuminemia. Higher Pediatric Ulcerative Colitis Activity Index score and C-reactive protein on days 3 and 5 of hospital admission predict failure of intravenous steroids. Risk factors for malignancy included concomitant diagnosis of primary sclerosing cholangitis, longstanding colitis (>10 years), male sex, and younger age at diagnosis. CONCLUSIONS: These evidence-based consensus statements offer predictions to be considered for a personalized medicine approach in treating pediatric UC.

BACKGROUND & AIMS: A better understanding of prognostic factors within the heterogeneous spectrum of pediatric Crohn's disease (CD) should improve patient management and reduce complications. We aimed to identify evidence-based predictors of outcomes with the goal of optimizing individual patient management. METHODS: A survey of 202 experts in pediatric CD identified and prioritized adverse outcomes to be avoided. A systematic review of the literature with meta-analysis, when possible, was performed to identify clinical studies that investigated predictors of these outcomes. Multiple national and international face-to-face meetings were held to draft consensus statements based on the published evidence. RESULTS: Consensus was reached on 27 statements regarding prognostic factors for surgery, complications, chronically active pediatric CD, and hospitalization. Prognostic factors for surgery included CD diagnosis during adolescence, growth impairment, NOD2/CARD15 polymorphisms, disease behavior, and positive anti-Saccharomyces cerevisiae antibody status. Isolated colonic disease was associated with fewer surgeries. Older age at presentation, small bowel disease, serology (anti-Saccharomyces cerevisiae antibody, antiflagellin, and OmpC), NOD2/CARD15 polymorphisms, perianal disease, and ethnicity were risk factors for penetrating (B3) and/or stenotic disease (B2). Male sex, young age at onset, small bowel disease, more active disease, and diagnostic delay may be associated with growth impairment. Malnutrition and higher disease activity were associated with reduced bone density. CONCLUSIONS: These evidence-based consensus statements offer insight into predictors of poor outcomes in pediatric CD and are valuable when developing treatment algorithms and planning future studies. Targeted longitudinal studies are needed to further characterize prognostic factors in pediatric CD and to evaluate the impact of treatment algorithms tailored to individual patient risk.

Background and Aims An expanding number of monogenic defects have been identified as causative of severe forms of very early-onset inflammatory bowel diseases [VEO-IBD]. The present study aimed at defining how next-generation sequencing [NGS] methods can be used to improve identification of known molecular diagnosis and to adapt treatment. Methods A total of 207 children were recruited in 45 paediatric centres through an international collaborative network [ESPGHAN GENIUS working group] with a clinical presentation of severe VEO-IBD [n = 185] or an anamnesis suggestive of a monogenic disorder [n = 22]. Patients were divided at inclusion into three phenotypic subsets: predominantly small bowel inflammation, colitis with perianal lesions, and colitis only. Methods to obtain molecular diagnosis included functional tests followed by specific Sanger sequencing, custom-made targeted NGS, and in selected cases whole exome sequencing [WES] of parents-child trios. Genetic findings were validated clinically and/or functionally. Results Molecular diagnosis was achieved in 66/207 children [32%]: 61% with small bowel inflammation, 39% with colitis and perianal lesions, and 18% with colitis only. Targeted NGS pinpointed gene mutations causative of atypical presentations, and identified large exonic copy number variations previously missed by WES. Conclusions Our results lead us to propose an optimised diagnostic strategy to identify known monogenic causes of severe IBD.

Background and Aims Adalimumab has been shown to be more effective than placebo in healing fistulae in adults with moderately to severely active Crohn’s disease. The efficacy and safety of adalimumab in healing fistulae in children/adolescents with Crohn’s disease from the 52-week IMAgINE 1 clinical trial, and its open-label extension IMAgINE 2, are reported. Methods Children/adolescents with perianal fistulae at baseline of IMAgINE 1 were assessed for fistula closure and improvement during IMAgINE 1 [Weeks 0–52] and from Week 0 of IMAgINE 2 [Week 52 of IMAgINE 1] through to Week 240 of IMAgINE 2 using non-responder imputation. Results A total of 36 children/adolescents had fistulae at baseline of IMAgINE 1 and were included in the analysis. Fistula closure and improvement were observed in 44.4% and 52.8%, respectively, at Week 12. Rates of closure and improvement were maintained throughout the analysis period to Week 292. No new safety signals were identified. Conclusions In children/adolescents with moderately to severely active, fistulizing Crohn’s disease, adalimumab induced perianal fistula closure and improvement within 12 weeks of treatment, with rates that were sustained for more than 5 years. The safety profile of adalimumab in patients with fistulae at baseline was similar to that of the overall population in IMAgINE 1/2. ClinicalTrials.gov identifiers: IMAgINE 1 (NCT00409682); IMAgINE 2 (NCT00686374).

Background: The contemporary management of ambulatory ulcerative colitis (UC) continues to be challenging with similar to 20% of children needing a colectomy within childhood years. We thus aimed to standardize daily treatment of pediatric UC and inflammatory bowel diseases (IBD)-unclassified through detailed recommendations and practice points. Methods: These guidelines are a joint effort of the European Crohn's and Colitis Organization (ECCO) and the Paediatric IBD Porto group of European Society of Paediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN). An extensive literature search with subsequent evidence appraisal using robust methodology was performed before 2 face-to-face meetings. All 40 included recommendations and 86 practice points were endorsed by 43 experts in Paediatric IBD with at least an 88% consensus rate. Results: These guidelines discuss how to optimize the use of mesalamine (including topical), systemic and locally active steroids, thiopurines and, for more severe disease, biologics. The use of other emerging therapies and the role of surgery are also covered. Algorithms are provided to aid therapeutic decision-making based on clinical assessment and the Paediatric UC Activity Index (PUCAI). Advice on contemporary therapeutic targets incorporating the use of calprotectin and the role of therapeutic drug monitoring are presented, as well as other management considerations around pouchitis, extraintestinal manifestations, nutrition, growth, psychology, and transition. A brief section on disease classification using the PIBD-classes criteria and IBD-unclassified is also part of these guidelines. Conclusions: These guidelines provide a guide to clinicians managing children with UC and IBD-unclassified management to provide modem management strategies while maintaining vigilance around appropriate outcomes and safety issues.

Growth failure is common in children with Crohn's disease. The effect of adalimumab (ADA), a fully human antitumor necrosis factor antagonist, on height velocity in pediatric patients with baseline (BL) linear growth impairment in the IMAgINE 1 trial is presented.This analysis included female and male patients with growth potential (bone age ≤13 and ≤14 yr, respectively), with BL Pediatric Crohn's disease Activity Index30, and who failed or were intolerant to conventional therapy. Patients received open-label induction ADA at weeks 0 and 2 by body weight (≥40 kg, 160 and 80 mg and40 kg, 80 and 40 mg). At week 4, patients were randomized to double-blind high (40 or 20 mg for ≥40 kg or40 kg) or low dose (20 or 10 mg for ≥40 kg or40 kg) every other week ADA to week 52. Height velocity z-score was summarized at BL, week 26, and week 52 by patients with BL growth impairment (z-score ≤-1.0) or normal growth (z-score-1.0).ADA therapy significantly improved and normalized growth rate at weeks 26 and 52 in patients with BL growth impairment (median z-score, BL, -3.25; week 26, -0.34; and week 52, 0.21; P0.001 versus BL for both), but not in patients with normal growth. Growth improvement was significantly greater at week 26 in week 4 responders to induction therapy compared with nonresponders (median z-score 0.09 versus -2.92; P = 0.02).ADA treatment resulted in growth rate normalization as early as week 26 in children with moderately to severely active Crohn's disease and growth impairment.

Article first published online 26 January 2017. Supplemental Digital Content is Available in the Text, Background: IMAgINE 1 assessed 52-week efficacy and safety of adalimumab in children with moderate to severe Crohn's disease. Long-term efficacy and safety of adalimumab for patients who entered the IMAgINE 2 extension are reported. Methods: Patients who completed IMAgINE 1 could enroll in IMAgINE 2. Endpoints assessed from weeks 0 to 240 of IMAgINE 2 were Pediatric Crohn's Disease Activity Index remission (Pediatric Crohn's Disease Activity Index ≤ 10) and response (Pediatric Crohn's Disease Activity Index decrease ≥15 from IMAgINE 1 baseline) using observed analysis and hybrid nonresponder imputation (hNRI). For hNRI, discontinued patients were imputed as failures unless they transitioned to commercial adalimumab (with study site closure) or adult care, where last observation was carried forward. Corticosteroid-free remission in patients receiving corticosteroids at IMAgINE 1 baseline, discontinuation of immunomodulators (IMMs) in patients receiving IMMs at IMAgINE 2 baseline, and linear growth improvement were reported as observed. Adverse events were assessed for patients receiving ≥1 adalimumab dose in IMAgINE 1 and 2 through January 2015. Results: Of 100 patients enrolled in IMAgINE 2, 41% and 48% achieved remission and response (hNRI) at IMAgINE 2 week 240. Remission rates were maintained by 45% (30/67, hNRI) of patients who entered IMAgINE 2 in remission. At IMAgINE 2 week 240, 63% (12/19) of patients receiving corticosteroids at IMAgINE 1 baseline achieved corticosteroid-free remission and 30% (6/20) of patients receiving IMMs at IMAgINE 2 baseline discontinued IMMs. Adalimumab treatment led to growth velocity normalization. No new safety signals were identified. Conclusions: Efficacy and safety profiles of prolonged adalimumab treatment in children with Crohn's disease were consistent with IMAgINE 1 and adult Crohn's disease adalimumab trials.

Background: Vedolizumab, an anti-integrin antibody, has proven to be effective in adults with inflammatory bowel disease [IBD], but the data in paediatrics are limited. We describe the short-term effectiveness and safety of vedolizumab in a European multi-centre paediatric IBD cohort. Method: Retrospective review of children [aged 2–18 years] treated with vedolizumab from 19 centres affiliated with the Paediatric IBD Porto group of ESPGHAN. Primary outcome was Week 14 corticosteroid-free remission [CFR]. Results: In all, 64 children were included (32 [50%] male, mean age 14.5 ± 2.8 years, with a median follow-up 24 weeks [interquartile range 14–38; range 6–116]); 41 [64%] cases of ulcerative colitis/inflammatory bowel disease unclassified [UC/IBD-U] and 23 [36%] Crohn’s disease [CD]. All were previously treated with anti-tumour necrosis factor [TNF] [28% primary failure, 53% secondary failure]. Week 14 CFR was 37% in UC, and 14% in CD [P = 0.06]. CFR by last follow-up was 39% in UC and 24% in CD [p = 0.24]. Ten [17%] children required surgery, six of whom had colectomy for UC. Concomitant immunomodulatory drugs did not affect remission rate [42% vs 35%; p = 0.35 at Week 22]. There were three minor drug-related adverse events. Only 3 of 16 children who underwent endoscopic evaluation had mucosal healing after treatment (19%). Conclusions: Vedolizumab was safe and effective in this cohort of paediatric refractory IBD. These data support previous findings of slow induction rate of vedolizumab in CD and a trend to be less effective compared with patients with UC.

BACKGROUND & AIMSGenome-wide association studies (GWAS) have uncovered multiple loci associated with inflammatory bowel disease (IBD), yet delineating functional consequences is complex. We used a network-based approach to uncover traits common to monogenic and polygenic forms of IBD in order to reconstruct disease relevant pathways and prioritize causal genes.METHODSWe have used an iterative random walk with restart to explore network neighborhood around the core monogenic IBD cluster and disease-module cohesion to identify functionally relevant GWAS genes. Whole exome sequencing was used to screen a cohort of monogenic IBD for germline mutations in top GWAS genes. One mutation was identified and validated by a combination of biochemical approaches.RESULTSMonogenic IBD genes clustered siginificantly on the molecular networks and had central roles in network topology. Iterative random walk from these genes allowed to rank the GWAS genes, among which 14 had high disease-module cohesion and were selected as putative causal genes. As a proof of concept, a germline loss of function mutation was identified in PTPN2, one of the top candidates, as a novel genetic etiology of early-onset intestinal autoimmunity. The mutation abolished the catalytic activity of the enzyme, resulting in haploinsufficiency and hyper-activation of the JAK/STAT pathway in lymphocytes.CONCLUSIONSOur network-based approach bridges the gap between large-scale network medicine prediction and single-gene defects and underscores the crucial need of fine tuning the JAK/STAT pathway to preserve intestinal immune homeostasis. Our data provide genetic-based rationale for using drugs targeting the JAK/STAT pathway in IBD.

BACKGROUND The REDUCE-RISK trial was set up to compare the effectiveness of weekly subcutaneously administered methotrexate with daily oral azathioprine or 6-mercaptopurine in low-risk Crohn disease (CD) or subcutaneously administered adalimumab (ADA) in high-risk CD in a pediatric population (age 6-17 years). OBJECTIVE The aim of this study is to perform a systematic review to provide input into the research protocol to gather the necessary information to improve the performance of an evidence-based economic evaluation when the trial is finished. METHODS The Centre for Reviews and Dissemination (CRD) Health Technology Assessment (HTA) database, websites of HTA institutes, CRD’s National Health Service Economic Evaluation Database, MEDLINE (OVID), and Embase databases were consulted to retrieve (reviews of) relevant economic evaluations. Studies were eligible if they included a pediatric or adult population with inflammatory bowel diseases (CD and ulcerative colitis [UC]) treated with ADA (Humira). There were no restrictions on the comparator. Only economic evaluations expressing outcomes in life years gained or quality-adjusted life years gained were selected. RESULTS A total of 12 primary studies were identified. None of these studies included a pediatric population because of a lack of supporting trials. The economic evaluations identified in our systematic review indicate that ADA is an appropriate intervention for inclusion in such a trial. From a health economic point of view, it is important to make an incremental analysis comparing such an intervention with standard care and not immediately versus another (expensive) biological treatment. Information on the impact of children’s school attendance and parents’ productivity is currently lacking in economic evaluations, and none of the underlying trials measured quality of life (QoL) using a generic utility instrument. CONCLUSIONS The review of the economic literature on ADA for the treatment of patients with CD supports the performance of a trial with biologicals in pediatric patients, including making a distinction according to disease severity. Conducting an economic literature review enabled us to decide which variables should be added to the research protocol from an economic point of view. Measurements for children’s and parents’ QoL (EuroQol 5-Dimension questionnaires), children’s school attendance, and parents’ productivity (WPAI-CD-CG questionnaire) were added to the research protocol. This will provide support for the calculation of the cost-effectiveness of the interventions evaluated in the REDUCE-RISK trial. CLINICALTRIAL ClinicalTrials.gov NCT02852694; https://clinicaltrials.gov/ct2/show/NCT02852694

IntroductionThe optimal trial design for assessing novel therapies in paediatric IBD (PIBD) is a subject of intense ongoing global discussions and debate among the different stakeholders. However, there is a consensus that the current situation in which most medications used in children with IBD are prescribed as off-label without sufficient paediatric data is unacceptable. Shortening the time lag between adult and paediatric approval of drugs is of the upmost importance. In this position paper we aimed to provide guidance from the global clinical research network (Pediatric Inflammatory Bowel Disease Network, PIBDnet) for designing clinical trials in PIBD in order to facilitate drug approval for children.MethodsA writing group has been established by PIBDnet and topics were assigned to different members. After an iterative process of revisions among the writing group and one face-to-face meeting, all statements have reached consensus of >80% as defined a priori. Next, all core members of PIBDnet voted on the statements, reaching consensus of >80% on all statements. Comments from the members were incorporated in the text.ResultsThe commentary includes 18 statements for guiding data extrapolation from adults, eligibility criteria to PIBD trials, use of placebo, dosing, endpoints and recommendations for feasible trials. Controversial issues have been highlighted in the text.ConclusionThe viewpoints expressed in this paper could assist planning clinical trials in PIBD which are both of high quality and ethical, while remaining pragmatic.

Several disorders related to the ingestion of gluten are well recognized despite overlapping clinical presentations: celiac disease, an autoimmune enteropathy triggered by gluten ingestions in susceptible individuals, allergy to wheat, and more recently non-celiac gluten sensitivity (NCGS). While celiac disease and wheat allergy are well-known disorders with a clear-cut diagnosis based on clinical tests and biological parameters, NCGS is a more difficult diagnosis, especially in children with functional gastrointestinal (GI) complaints. NCGS is considered a syndrome of intestinal but also extraintestinal symptoms occurring within hours, but sometimes even after several days of gluten ingestion. In children, the leading symptoms of NCGS are abdominal pain and diarrhea, while extraintestinal symptoms are rare, in contrast to adult patients. No precise diagnostic test nor specific biomarkers exist, except a rather cumbersome three-phase gluten-exposure, gluten-free diet, followed by a blinded placebo-controlled gluten challenge with crossover to provoke symptoms elicited by gluten in a reproducible manner that disappear on gluten-free alimentation. Recent data indicate that the peptide part of wheat proteins is not necessarily the sole trigger of clinical symptoms. Mono- or oligosaccharides, such as fructan and other constituents of wheat, were able to provoke GI symptoms in clinical trials. These new findings indicate that the term gluten sensitivity is probably too restrictive. The incidence of NCGS was reported in the range of 1–10% in the general population and to increase steadily; however, most data are based on patients’ self-reported gluten intolerance or avoidance without a medically confirmed diagnosis. Treatment consists of gluten avoidance for at least several weeks or months. Patients with NCGS require regular reassessment for gluten tolerance allowing with time the reintroduction of increasing amounts of gluten.

International audience; The gut microbiota plays a key role 63 in host physiology and is an actor in inflammatory bowel disease pathogenesis. Patients with primary immunodeficiency causing intestinal inflammation have disease-specific dysbiosis.

Specific features of childhood-onset inflammatory bowel diseases. The incidence of pediatric-onset inflammatory bowel diseases (PIBD) is increasing in developed countries for several decades. Pediatric-onset of the disease is a factor of severity, due to a higher activity and a longer evolution of the disease. IBD presents as two major forms, Crohn's disease (CD) potentially affecting all parts of the gastrointestinal tract, and ulcerative colitis (UC), which is restricted to the colon and rectum. Exclusive enteral nutrition is the recommended first-choice induction therapy in luminal CD, allowing symptoms remission, mucosal healing and catch-up growth. The use of an immunosuppressive maintenance therapy is frequently required. Biological therapies may be used as first-line therapy in severe cases, or in case of failure of thiopurines. In mild to moderate forms of UC, salicylates retain an important role while the use of thiopurines or biological should be considered in severe forms of disease. The use of surgery is sometimes required, usually earlier in PIBD than in adult IBD patients.Particularités des maladies inflammatoires chroniques intestinales chez l’enfant. L’incidence des maladies inflammatoires chroniques intestinales (MICI) à début pédiatrique augmente de façon importante dans les pays développés depuis plusieurs décennies. Le début pendant l’enfance est un facteur de gravité, en raison d’une plus grande activité de la maladie et d’une durée d’évolution plus longue. Il existe deux formes principales de MICI, la maladie de Crohn qui peut atteindre toutes les parties du tube digestif et la rectocolite hémorragique qui est restreinte au côlon et au rectum. La nutrition entérale exclusive est le traitement d’induction de premier choix de la maladie de Crohn, permettant en dehors de la résolution des symptômes digestifs et de la cicatrisation muqueuse d’obtenir une croissance de rattrapage, le retard de croissance étant parfois sévère. Le recours à un traitement d’entretien par immunosuppresseurs est le plus souvent nécessaire. L’utilisation des biothérapies se fait, soit en première intention dans les formes sévères, soit en cas d’échec des thiopurines. Dans la rectocolite hémorragique de forme mineure à modérée, les salicylés gardent un rôle important tandis que le recours aux thiopurines ou aux biothérapies est réservé aux formes plus sévères. La tolérance de ces traitements doit être surveillée au long cours. Le recours à une intervention chirurgicale est parfois nécessaire, de façon plus précoce chez l’enfant que chez l’adulte.

Background Inflammatory bowel disease (IBD), including Crohn’s disease (CD) and ulcerative colitis (UC), is a T cell driven intestinal inflammation. Current T cell suppressive therapeutic regimens are moderately successful due to a large clinical heterogeneity amongst patients. Detailed understanding of aberrant inflammatory and inhibitory T-cell responses in individual patients is lacking. Previously, we have shown that, in healthy individuals, 40% of peripheral blood CD38+ (CD62LnegCD4+) effector T cells, which are enriched for intestinal antigen specificity, express the inhibitory molecule T cell immunoglobulin and ITIM domain (TIGIT). TIGIT+CD38+ effector T cells have a regulatory function, produce IL-10 and express multiple co-inhibitory receptors. Conversely, TIGITnegCD38+ effector T cells are enriched in inflammatory IFN-γ producing cells. In a small cohort of pediatric-onset IBD patients, low frequencies of TIGIT+CD38+ effector T cells were associated with a reduced duration of clinical remission. We hypothesize that a subgroup of IBD patients has reduced frequencies of circulating inhibitory TIGIT+CD38+ effector T cells, reflecting a distinct pathogenesis associated with a more severe disease course. Methods In the Rotterdam PIBD-SETQuality cohort of newly diagnosed pediatric IBD patients (CD: n=37; UC: n=16), patients with suspicion of IBD but negative diagnosis (n=12) and age-matched healthy controls (n=22), we monitored TIGIT+ and TIGITnegCD38+ effector T cells in peripheral blood and collected plasma at diagnosis and during immunosuppressive therapy. Results At diagnosis, approximately 50% of CD patients had strongly reduced frequencies of inhibitory TIGIT+CD38+ effector T cells compared to UC patients and age-matched controls. CD patients with low frequencies of TIGIT+CD38+ effector T cells at diagnosis needed earlier anti-TNF treatment with 73% of patients receiving anti-TNF treatment within 1 year versus 38% for patients with normal frequencies of TIGIT+CD38+ effector T cells. Inflammatory TIGITnegCD38+ effector T cells were enriched in Ki67, reflecting recent proliferation, and expressed chemokine receptors associated with inflammatory non-classical T-helper-1 IFN-γ hiIL-17lo producing cells. High frequencies of TIGITnegCD38+ effector T cells correlated with high plasma IFN-γ concentrations. Conclusion These results demonstrate that reduced frequencies of circulating inhibitory TIGIT+CD38+ effector T cells discriminate a subgroup of pediatric CD patients with high frequencies of inflammatory IFN-γ hiIL-17lo producing cells, high plasma IFN-γ concentrations, and in need of early anti-TNF treatment, possibly indicative of a distinct pathogenesis with a more severe disease course.