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DNA damage is a constant event in every cell caused by exogenous factors such as ultraviolet and ionizing radiation (UVR/IR) and intercalating drugs, or endogenous metabolic and replicative stress. Proteins of the DNA damage response (DDR) network sense DNA lesions and induce cell cycle arrest, DNA repair, and apoptosis. Genetic defects of DDR or DNA repair proteins can be associated with immunodeficiency, bone marrow failure syndromes, and cancer susceptibility. Although various diagnostic tools are available to evaluate DNA damage, their quality to identify DNA repair deficiencies differs enormously and depends on affected pathways. In this study, we investigated the DDR biomarkers γH2AX (Ser139), p-ATM (Ser1981), and p-CHK2 (Thr68) using flow cytometry on peripheral blood cells obtained from patients with combined immunodeficiencies due to non-homologous end-joining (NHEJ) defects and ataxia telangiectasia (AT) in response to low-dose IR. Significantly reduced induction of all three markers was observed in AT patients compared to controls. However, delayed downregulation of γH2AX was found in patients with NHEJ defects. In contrast to previous reports of DDR in cellular models, these biomarkers were not sensitive enough to identify ARTEMIS deficiency with sufficient reliability. In summary, DDR biomarkers are suitable for diagnosing NHEJ defects and AT, which can be useful in neonates with abnormal TREC levels (T cell receptor excision circles) identified by newborn screening. We conclude that DDR biomarkers have benefits and some limitations depending on the underlying DNA repair deficiency., publishedVersion

Although chest radiograph (CXR) is commonly used in diagnosing pediatric community acquired pneumonia (pCAP), limited data on interobserver agreement among radiologists exist. PedCAPNETZ is a prospective, observational, and multicenter study on pCAP. N = 233 CXR from patients with clinical diagnosis of pCAP were retrieved and n = 12 CXR without pathological findings were added. All CXR were interpreted by a radiologist at the site of recruitment and by two external, blinded pediatric radiologists. To evaluate interobserver agreement, the reporting of presence or absence of pCAP in CXR was analyzed, and prevalence and bias‐adjusted kappa (PABAK) statistical testing was applied. Overall, n = 190 (82%) of CXR were confirmed as pCAP by two external pediatric radiologists. Compared with patients with pCAP negative CXR, patients with CXR‐confirmed pCAP displayed higher C‐reactive protein levels and a longer duration of symptoms before enrollment (p

Introduction Hypersensitivity pneumonitis (HP) in children is a severe interstitial lung disease and potentially, a chronic condition, if not treated appropriately. No evidence-based guidelines are available; in particular, the role of systemic glucocorticoid therapy is unclear. Methods The aim of this randomized, double-blind, placebo-controlled, parallel-group, multi-center, phase II trial in pediatric HP was to assess the outcome of HP in children after 6 months of treatment and to compare 3 months of treatment with oral prednisolone or placebo. Results After 1.5 years and the inclusion of only four children, we terminated the study prematurely. Two of the children randomized to prednisolone did not achieve the predefined response of FVC to normal. One child treated with placebo recovered to normal, similar to another child treated with prednisolone. All children treated with steroids developed drug-related side effects. Discussion This uncompleted study illustrates the urgent medical need for evidence-based treatment protocols for this condition. We discuss the hurdles which were specific for completion of this trial in a rare condition. Among other options, we suggest the inclusion of children into an all-age study of HP, as in adults the same questions are unanswered.

Background: Investigating the role of children in the COVID-19 pandemic is pivotal to prevent the virus spreading. In most cases, children infected with Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) develop non-specific symptoms or are asymptomatic. Therefore, the infection rate among this age group remains unclear. Seroprevalence studies, including clinical questionnaires, may contribute to our understanding of the time course and clinical manifestations of SARS-CoV-2 infections. Methods: SARS-CoV-2-KIDS is a longitudinal, hospital-based, multicentre study in Germany on the seroprevalence of anti-SARS-CoV-2 immunoglobulin G, as determined by an Enzyme-Linked Immunosorbent Assay in children (aged ≤17 years). A study-specific questionnaire provided additional information on clinical aspects. Findings: This analysis included 10,358 participants recruited from June 2020 to May 2021. The estimated anti-SARS-CoV-2 seroprevalence increased from 2·0% (95% confidence interval (95% CI) 1·6, 2·5) to 10·8% (95% CI 8·7, 12·9) in March 2021, without major change afterwards and was higher in children with migrant background (on average 6·6% vs. 2·8%). In the pandemic early stages, children under three years were 3·5 (95% CI 2·2, 5·6) times more likely to be seropositive than older children, with the levels equalising in later observations. History of self-reported respiratory tract infections or pneumonia was associated with seropositivity (OR 1·8 (95% CI 1·4, 2·3);2·7 (95% CI 1·7, 4·1)). Interpretation: The majority of children in Germany do not have detectable SARS-CoV-2 IgG. To some extent, this may reflect the effect of differing containment measures implemented in the federal states. Detection levels might have been greater in certain age groups or migrant background. Lifting containment measurements is likely to cause a general increase in respiratory tract infections, which already pose a challenge to paediatric medical care during regular winter seasons. This challenge might become critical with additional infections caused by SARS-CoV-2.

Introduction: chILD comprises various rare respiratory conditions and partially overlaps with adult ILD. Lung fibrosis is the most common disease entity in adults; however, there are no data on the prevalence, clinical, radiological and histopathological presentation of pulmonary fibrosis in chILD. Aim: To assess the prevalence of fibrosis in lung biopsies from the international management platform, the European chILD registry (NCT02852928), and to correlate paediatric lung fibrosis with radiological findings. Methods: Features of fibrosis in biopsies were defined by the presence of any of the following: description of interstitial fibrosis, fibroblastic foci or honeycombing. A histological diagnosis of chronic pneumonitis of infancy (CPI) was also included. Fibrosis by chest computed tomography (CT) scans was defined by the presence of linear or reticular opacities, honeycombing, traction bronchiectasis or architectural distortion. Results: Lung biopsies were available for 149/825 chILD cases (18%); 46 biopsies (31%) had features of fibrosis and 11 were identified by CPI pattern alone. Mean age at biopsy was 6.4 years (range 0–26). Thirty cases were related to alveolar surfactant region (ABCA3: n=11; SFTPC: n=3), five to systemic disease processes (e.g. connective tissue disease: n=2) and three to immunodeficiency. Individual cases accounted for the other categories. Only 21/46 cases (46%) with biopsy-proven features of fibrosis had fibrosis features by CT. Conclusions: Features of fibrosis were already present in 31% of cases with a diagnostic lung biopsy. Concordance between biopsy- and CT-diagnosed fibrosis was lower than expected and requires further evaluation.

We performed a prospective, observational, cohort study of children newly diagnosed with children’s interstitial lung disease (ChILD), with structured follow-up at 4, 8, 12 weeks and 6 and 12 months. 127 children, median age 0.9 (IQR 0.3–7.9) years had dyspnoea (68%, 69/102), tachypnoea (75%, 77/103) and low oxygen saturation (SpO2) median 92% (IQR 88–96). Death (n=20, 16%) was the most common in those 2

Background Pediatric community acquired pneumonia (pedCAP) is one of the leading causes for childhood morbidity accounting for up to 20% of pediatric hospital admissions in high income countries. In spite of its high morbidity, updated epidemiological and pathogen data after introduction of preventive vaccination and novel pathogen screening strategies are limited. Moreover, there is a need for validated recommendations on diagnostic and treatment regimens in pedCAP. Through collection of patient data and analysis of pathogen and host factors in a large sample of unselected pedCAP patients in Germany, we aim to address and substantially improve this situation. Methods pedCAPNETZ is an observational, multi-center study on pedCAP. Thus far, nine study centers in hospitals, outpatient clinics and practices have been initiated and more than 400 patients with radiologically confirmed pneumonia have been enrolled, aiming at a total of 1000 study participants. Employing an online data base, information on disease course, treatment as well as demographical and socioeconomical data is recorded. Patients are followed up until day 90 after enrollment; Comprehensive biosample collection and a central pedCAPNETZ biobank allow for in-depth analyses of pathogen and host factors. Standardized workflows to assure sample logistics and data management in more than fifteen future study centers have been established. Discussion Through comprehensive epidemiological, clinical and biological analyses, pedCAPNETZ fills an important gap in pediatric and infection research. To secure dissemination of the registry, we will raise clinical and scientific awareness at all levels. We aim at participating in decision making processes for guidelines and prevention strategies. Ultimately, we hope the results of the pedCAPNETZ registry will help to improve care and quality of life in pedCAP patients in the future.

Background Respiratory syncytial virus (RSV) is responsible for upper and lower respiratory tract infection in adults and children. Especially immunocompromised patients are at high risk for a severe course of infection, and mortality is increased. Moreover RSV can spread in healthcare settings and can cause outbreaks. Herein we demonstrate the successful control and characteristics of a RSV outbreak that included 8 patients in our Department of Pediatric Hematology and Oncology. Methods We performed an epidemiologic investigation and a molecular analysis of the outbreak strains. Moreover we present the outbreak control bundle and our concept for RSV screening in the winter season. Results RSV A and B strains caused the outbreak. RSV B strains affected 3 patients, 2 of whom were co-infected with RSV A. Exactly this RSV A strain was detected in another 5 patients. Our multimodal infection control bundle including prophylactic RSV screening was able to rapidly stop the outbreak. Conclusion An infection control bundle in RSV outbreaks should address all potential transmission pathways. In pediatric settings the restriction of social activities might have a temporal negative impact on quality of life but helps to limit transmission opportunities. Molecular analysis allows better understanding of RSV outbreaks and, if done in a timely manner, might be helpful for guidance of infection control measures.

Introduction The current extent of migration to the European continent is associated with exceptional humanitarian challenges. In 2015, Western Europe faced an enormous immigration of refugees with largely unknown protection status against communicable diseases. To adapt vaccination strategies, we aimed at assessing seroprevalences against three of the most relevant vaccine preventable diseases (VPD) in a large representative cohort. Methods IgG seroprevalences for rubella, varicella (n = 554) and measles (n = 552) were analyzed in inhabitants of a Northern German refugee camp in the summer of 2015. Results Of the refugees, 77.9% were male (mean age 27.4 years for male and 26.8 years for female migrants). Most refugees came from the Eastern Mediterranean region (83.4%), followed by immigrants from Eastern Europe (7.4%), Africa (4.6%), or other regions (4.5%). The vast majority of migrants were protected against the three VPD: overall IgG seropositivity was 88.5% for measles, 77.9% for rubella and 95.9% for varicella. However, seroprevalences showed age- and origin-dependent differences. Varicella immunity, for example, was lowest in the youngest age group of both genders (10.1% of male/4.5% of female seronegative refugees 49 years of age), and Sudanese migrants displayed particularly low rates of protection against varicella. Conclusion In accordance with previous studies, our analyses show an overall satisfactory seropositivity against measles, rubella, and varicella in refugees entering Europe during the current exodus. However, this rate is not sufficient for preventing transmission. For example, the rate of 12.9–17.9% female refugees at reproductive age unprotected against measles and the low protection levels against varicella in minors observed in our cohort emphasizes the need for stringent vaccination strategies in refugees coming to Europe during the current crisis.

INTRODUCTION Foreign body (FB) aspiration is a frequent and preventable source of morbidity and mortality, especially in children under 4 years of age. Few comprehensive studies exist on presentation and outcome of apple aspirations in children. METHODS In a retrospective analysis of bronchoscopy records of a tertiary medical care center from January 2007 to August 2019, we identified pediatric cases of suspected apple aspirations. RESULTS A total of 11 suspected apple aspirations were identified (observation time 12.7 years, n = 5858 bronchoscopies, n = 226 interventions due to suspected FB aspirations in total). The mean age of patients was 24 months (standard error mean, 7 months; range, 8-83 months), and 6 out of 11 cases (55%) were male. Bronchoscopy confirmed apple aspiration in n = 6/11 cases (55%). In n = 2/11 cases (18%), a bite of the apple was located in the esophagus causing significant tracheal narrowing, and in n = 3/11 cases (27%), no FB was found. In all cases of airway FB identification, extraction was successful. Hypersalivation was associated with esophageal FB location, whereas persistent cough, stridor, or dyspnea were associated with airway FB location. Outcomes ranged from complete reconstitution 1 day after bronchoscopy in most cases to hypoxemia with severe brain damage in one patient. DISCUSSION This analysis shows that apple aspirations are not entirely uncommon in children and may lead to disastrous complications. Typical signs of airway location are persistent cough, stridor or dyspnea, whereas hypersalivation may point toward an esophageal location. In each case of suspected apple aspiration, timely bronchoscopy with possible FB extraction should be performed by an experienced team.

Background: Pulmonary interstitial glycogenosis (PIG) is a rare interstitial lung disease in children. The clinical hallmark is a rapid onset with respiratory distress and hypoxemia shortly after birth in the absence of an infectious cause or a surfactant dysfunction syndrome. The diagnosis can only be made by lung biopsy. The histopathological pattern defining PIG can exist in diffuse or patchy distribution. Only few cases have been reported. Not much is known on clinical features, outcomes, CT imaging and histopathology. Methods: The clinical course, CT-scans and tissue samples of children diagnosed with PIG were collected and systematically re-analysed by clinicians, radiologists and pathologists all specialized in interstitial lung diseases in children. All data were uploaded into the Kidslungregister for follow up. Results: 11 children diagnosed with PIG were included in this study. All presented with respiratory distress shortly after birth. More than half of the children were diagnosed with additional abnormalities, especially congenital heart defects. The CT-scan of the lungs showed mainly groundglass opacities, consolidations and septal thickening. Of interest each tissue sample had signs of reduced alveolarization. The prognosis was favourable in almost all cases. When systemic glucocorticosteroids were given a fast improvement was noticed. Conclusion: PIG is a interstitial lung disease in infants with mostly favourable outcome. As alveolar growth retardation was present in all subjects this can support a theory of an underlying maturation delay. In all infants with congenital heart defects and unexplained respiratory distress an interstitial lung disease due to PIG should be considered.

Background: Immigration into Europe has reached an all-time high. Provision of coordinated healthcare, especially to refugee women that are at increased risk for adverse pregnancy outcomes, is a challenge for receiving health care systems. Methods: We assessed pregnancy rates and associated primary healthcare needs in three refugee cohorts in Northern Germany during the current crisis. Results: Out of n = 2911 refugees, 18.0% were women of reproductive age, and 9.1% of these were pregnant. Pregnancy was associated with a significant, 3.7-fold increase in primary health care utilization. Language barrier and cultural customs impeded healthcare to some refugee pregnant women. The most common complaints were demand for pregnancy checkup without specific symptoms (48.6%), followed by abdominal pain or urinary tract infections (in 11.4% of cases each). In 4.2% of pregnancies, severe complications such as syphilis or suicide attempts occurred. Discussion: We present data on pregnancy rates and pregnancy associated medical need in three current refugee cohorts upon arrival in Germany. Healthcare providers should be particularly aware of the requirements of pregnant migrants and should adapt primary caretaking strategies accordingly.

BACKGROUND: Pulmonary interstitial glycogenosis (PIG) is a rare paediatric interstitial lung disease of unknown cause. The diagnosis can only be made by lung biopsy. Less than 100 cases have been reported. Clinical features, treatment and outcomes have rarely been assessed systematically in decent cohorts of patients.METHODS: In this retrospective multicentre study, the clinical presentation, radiologic findings, pattern of lung biopsy, extrapulmonary comorbidities, treatment and outcome of eleven children with PIG were collected systematically.RESULTS: 10/11 children presented with respiratory distress immediatly after birth and 8/11 needed invasive ventilation. In 8/11 children extrapulmonary comorbidities were present, congenital heart defects being the most common. 7/11 children received systemic glucocorticoids and of these four showed a clear favorable response. During a median follow-up of 3.0 years (range 0.42-12.0) one child died, while 10 patients improved. Chest CT-scans showed ground-glass opacities (7/10), consolidations (6/10), linear opacities (5/10) and mosaic attenuation (4/10) without uniform pattern. Besides interstitial thickening related to undifferentiated glycogen positive mesenchymal cells all tissue samples showed growth abnormalities with reduced alveolarization.CONCLUSIONS: PIG is associated with alveolar growth abnormalities and has to be considered in all newborns with unexplained respiratory distress. Apparent treatment benefit of glucocorticosteroids needs to be evaluated systematically.

Background: In 2015, a high number of refugees with largely unknown health statuses immigrated to Western Europe. To improve caretaking strategies, we assessed the prevalence of latent tuberculosis infection (LTBI) in a refugee cohort. Methods: Interferon-Gamma release assays (IGRA, Quantiferon) were performed in n = 232 inhabitants of four German refugee centers in the summer of 2015. Results: Most refugees were young, male adults. Overall, IGRA testing was positive in 17.9% (95% CI = 13.2&ndash, 23.5%) of subjects. Positivity rates increased with age (0% &lt, 18 years versus 46.2% &gt, 50 years). Age was the only factor significantly associated with a positive IGRA in multiple regression analysis including gender, C reactive protein, hemoglobin, leukocyte, and thrombocyte count and lymphocyte, monocyte, neutrophil, basophil, and eosinophil fraction. For one year change in age, the odds are expected to be 1.06 times larger, holding all other variables constant (p = 0.015). Conclusion: Observed LTBI frequencies are lower than previously reported in similar refugee cohorts. However, as elderly people are at higher risk for developing active tuberculosis, the observed high rate of LTBI in senior refugees emphasizes the need for new policies on the detection and treatment regimens in this group.

Currently, vast numbers of migrants with largely unknown health statuses have been entering Europe. To improve care taking strategies, prevalence, severity and types of anemia in a large refugee cohort were assessed. Blood counts were performed in n = 787 inhabitants from six German refugee centers. Most included migrants were young, male adults. Anemia was present in 22.5% of subjects with an age-dependent prevalence increase (7.9% > 18 years vs. 30.8% > 50 years). More females than males were anemic (27.1% vs. 20.4%). The majority of affected migrants had mild anemia (86.2%) of either normocytic/normochromic (55.9%) or microcytic/hypochromic (20.9%) type. Observed anemia frequencies are in accordance with global anemia prevalence recently estimated by the WHO. However, the observed high rates of anemia particularly in female and older refugees emphasize the need for adapted care taking strategies in refugee medicine. Further evaluation of causes of anemia in the migrating population is needed.

Interstitial lung disease in children (chILD) is rare, and most centres will only see a few cases/year. There are numerous possible underlying diagnoses, with specific and non-specific treatment possibilities. The chILD-EU collaboration has brought together centres from across Europe to advance understanding of these considerations, and as part of this process, has created standard operating procedures and protocols for the investigation of chILD. Where established consensus documents exist already, for example, for the performance of bronchoalveolar lavage and processing of lung biopsies, these have been adopted. This manuscript reports our proposals for a staged investigation of chILD, starting from when the condition is suspected to defining the diagnosis, using pathways dependent on the clinical condition and the degree of illness of the child. These include the performance of genetic testing, echocardiography, high-resolution CT, bronchoscopy when appropriate and the definitive investigation of lung biopsy, in order to establish a precise diagnosis. Since no randomised controlled trials of treatment have ever been performed, we also report a Delphi consensus process to try to harmonise treatment protocols such as the use of intravenous and oral corticosteroids, and add-on therapies such as hydroxychloroquine and azithromycin. The aim is not to dictate to clinicians when a therapeutic trial should be performed, but to offer the possibility to collaborators of having a unified approach when a decision to treat has been made.

INTRODUCTION Histopathological assessment of lung biopsies does play an important diagnostic role in children's interstitial lung disease (ChILD). Thoracoscopic lung biopsy has been shown to be safe and effective. The aim of this study was to evaluate the diagnostic accuracy of thoracoscopic lung biopsies in children with ChILD. Furthermore, therapeutic relevance of the procedure, operative details, and perioperative complications of our series were investigated. METHODS We retrospectively reviewed all consecutive thoracoscopic lung biopsies taken from children with suspected ChILD in our institution over an 11-year period. Feasibility and complications were evaluated as well as histopathological diagnoses according to the recent ChILD classification and relevance of the procedure for medical treatment. RESULTS Fifty-nine patients (54.2% male, median age 7 years [8 d-18 y]) underwent 112 thoracoscopic lung biopsies. An endostapler (27%), endoloop ligature (63%), or cut and suture technique (10%) were used. A chest tube was placed in 54% of the cases. Complications occurred in 15% of cases and mainly consisted of pneumothoraces or bleedings. Adequate tissue was obtained in all but one case and the biopsy led to a specific diagnosis according to the ChILD classification in 98%. Medical treatment of the underlying disease was changed due to the results of the biopsy in 86%. CONCLUSIONS The diagnostic accuracy of thoracoscopic lung biopsies in children with suspected ChILD is high. The histopathologic results lead to a disease-specific treatment in the majority of the cases. Thoracoscopic lung biopsy is a safe and effective procedure with a low complication rate.

Introduction: Children’s interstitial lung disease (chILD) comprises a heterogeneous group of over 200 different entities of diffuse lung diseases with symptom onset in childhood. Only 1-3 of one million children are affected per year. No evidence based treatment guidelines exist. Aim: First analysis of the distribution of chILD disease entities using a classification system also including cases without lung biopsy (Orphanet J Rare Dis 2015 10:122), as well as respiratory medications prescribed. Methods: Patients with chILD reported to the European Management Platform for Childhood Interstitial Lung Diseases between December 2012 and November 2016 were included. Baseline and follow up visits including information on disease course and respiratory treatments used in the whole cohort and specific subcategories were analysed. Results: 366 peer-reviewed patients received a final diagnosis: the most common was chILD related to alveolar surfactant region (category A4, n=194), followed by chILD related to systemic disease (B1, n=60), specific conditions of undefined etiology (A3, n=59) and chILD of the immune intact host (B2, n=46). The most commonly used drugs at baseline were glucocorticosteroids in 175 cases (48%), especially in the subcategories A4 and B1. Azithromycin was used in 24% and hydroxychloroquine in 14%. Conclusion: The knowledge of most frequently diagnosed subcategories of chILD and most commonly used medication in these groups will inform controlled studies in the future, especially for glucocorticosteroids and azithromycin in the subcategories A4 and B1.

Macrophages harbor great plasticity and adapt effectively to specific environmental factors. Here, we analyzed the adaptation of induced pluripotent stem cell (iPSC) derived macrophages to the lung environment. Human iPSC derived macrophages were transplanted intrapulmonary to humanized Pulmonary Alveolar Proteinosis (PAP) mice which display high pulmonary levels of surfactant and human GM-CSF. PAP is a life-threatening lung disease caused by GM-CSF receptor mutations and a differentiation block of alveolar macrophages (AM). Mice were transplanted four times in four consecutive weeks, and iPSC macrophages were re-isolated and analyzed two months after the first treatment. Pulmonary transplantation of iPSC macrophages led to pulmonary engraftment and in situ differentiation of iPSC macrophages which displayed the typical morphology of primary human AM and were red-Oil-O positive illustrating functional surfactant uptake. The surface marker profile of re-isolated macrophages was similar to that of primary human AM and was clearly distinct to that of iPSC macrophages before transplantation. The transcriptome of the iPSC macrophages after re-isolation had clearly changed compared to that of iPSC macrophages before transplantation and was most similar to that of hematopoietic stem cell derived AM like cells or primary human AM. Our data show that human iPSC derived macrophages can adapt to the lung environment in a humanized lung disease model. Future studies include the characterization of specific genes central for the adaptation and proliferation of iPSC macrophages in the lung.

HLA-G is a non-classical MHC class Ib molecule predominantly expressed in cytotrophoblasts and under pathological conditions also in chronically inflamed and in malignant tissues. Recently an increased expression of HLA-G was found in ulcerative colitis (UC), but not in Crohn's disease (CD). The HLA-G gene is located in IBD3, a linkage region for inflammatory bowel disease (IBD). A 14-bp deletion polymorphism (Del+/Del-) within exon 8 of the HLA-G gene might influence transcription activity and is therefore of potential functional relevance. To investigate whether the 14-bp deletion polymorphism is associated with IBD, 371 patients with CD, 257 patients with UC and 739 controls were genotyped. The heterozygous genotype (P = 0.031) and the Del+ phenotype (P = 0.038) were significantly increased, whereas the homozygous Del- phenotype (P = 0.038) was significantly decreased in UC when compared with CD. Thus, the 14-bp deletion polymorphism within the HLA-G gene displayed significant differences between UC and CD. Moreover, a significant increase of the Del+ allele (P = 0.002) and the Del+/Del+ genotype (P = 0.013) and a consecutive decrease of the Del-/- genotype (P = 0.024) were observed in those CD cases positive for ileocecal resection. Thus, a potential effect of the HLA-G gene in IBD may affect both UC and CD. Other polymorphisms linked to the 14-bp deletion polymorphism might also contribute to immunopathogenesis. As there are several partly functional polymorphisms within the promoter region potentially influencing HLA-G expression, further studies in IBD are necessary in the context of differential expression of HLA-G between UC and CD.

Hereditary pulmonary alveolar proteinosis (hPAP) caused by granulocyte-macrophage colony-stimulating factor (GM-CSF) receptor α-chain (CSF2RA) deficiency is a rare, life-threatening lung disease characterized by accumulation of proteins and phospholipids in the alveolar spaces. The disease is caused by a functional insufficiency of alveolar macrophages, which require GM-CSF signaling for terminal differentiation and effective degradation of alveolar proteins and phospholipids. Therapeutic options are extremely limited, and the pathophysiology underlying the defective protein degradation in hPAP alveolar macrophages remains poorly understood.To further elucidate the cellular mechanisms underlying hPAP and evaluate novel therapeutic strategies, we here investigated the potential of hPAP patient-derived induced pluripotent stem cell (PAP-iPSCs) derived monocytes and macrophages.Patient-specific PAP-iPSCs were generated from CD34(+) bone marrow cells of a CSF2RA-deficient patient with PAP. We assessed pluripotency, chromosomal integrity, and genetic correction of established iPSC lines. On hematopoietic differentiation, genetically corrected or noncorrected monocytes and macrophages were investigated in GM-CSF-dependent assays.Although monocytes and macrophages differentiated from noncorrected PAP-iPSCs exhibited distinct defects in GM-CSF-dependent functions, such as perturbed CD11b activation, phagocytic activity, and STAT5 phosphorylation after GM-CSF exposure and lack of GM-CSF uptake, these defects were fully repaired on lentiviral gene transfer of a codon-optimized CSF2RA-cDNA.These data establish PAP-iPSC-derived monocytes and macrophages as a valid in vitro disease model of CSF2RA-deficient PAP, and introduce gene-corrected iPSC-derived monocytes and macrophages as a potential autologous cell source for innovative therapeutic strategies. Transplantation of such cells to patients with hPAP could serve as a paradigmatic proof for the potential of iPSC-derived cells in clinical gene therapy.

Recently, mutations in CCNO (encoding cyclin O) have been described as a novel genetic cause for primary ciliary dyskinesia (PCD). CCNO mutations are associated with reduced generation of motile cilia in the airways [1]. We here present the case of a two year old Syrian boy presenting with typical symptoms of PCD including recurrent respiratory infections, chronic cough and rhinitis and a history of neonatal RDS. In spite of the clinically suspected diagnosis of PCD, we could not detect any ciliar cells in repeated nasal brushings. Thus, we were unable to confirm PCD by evaluation of the ciliar motility. However, genetic screening of the CCNO gene yielded a homozygote loss of function mutation (c.248_252dup, p.Gly85Cysfs*11). This confirmed the diagnosis of CCNO associated PCD with „reduced generation of multiple motile cilia“. In conclusion, this case illustrates that in case of lack of ciliar cells in nasal brushings, CCNO genetics can confirm the PCD diagnosis. 1 Wallmeier et al. 2014 Nat Genet 46(6):646-51.

Asthma can be controlled well in most patients by inhaled β-adrenoreceptor (β2 AR) agonists and steroids. Poor response to β2 AR agonists is difficult to predict, especially in young children and by lung function testing, which may be affected by multiple influences. As an alternative approach, we analyzed ex vivo neutrophilic superoxide inhibition in response to β2 AR stimulation. In 60 healthy volunteers, this assay was unaffected by sex, age, smoking, atopy or asthma status. Furthermore, we assessed effects of genetic variants in β2 AR by sequencing the ADRB2 gene in our cohort and relating genotypes to β2 AR-mediated neutrophilic superoxide inhibition. Gly16Arg genotypes correlated with minor decrease in overall adrenoresponse in this small study population. Taken together, ex vivo testing of the β2 AR response in human neutrophils represents a robust tool with good signal-to-noise ratio at physiological β2 AR agonist concentrations, and this assay may be useful to complement future pharmacogenetic studies in asthma.

Recently, a genome-wide association study showed that single-nucleotide polymorphisms (SNPs) in the chromosome 4q27 region containing IL2 and IL21 are associated with celiac disease. Given the increased prevalence of inflammatory bowel disease (IBD) among celiac disease patients, we investigated the possible involvement of these SNPs in IBD.Five SNPs strongly associated with celiac disease within the KIAA1109/TENR/IL2/IL21 linkage disequilibrium block on chromosome 4q27 and one coding SNP within the IL21 gene were analyzed in a large German IBD cohort. The study population comprised a total of 2,948 Caucasian individuals, including 1,461 IBD patients (ulcerative colitis (UC): n=514, Crohn's disease (CD): n=947) and 1,487 healthy unrelated controls.Three of the five celiac disease risk markers had a protective effect on UC susceptibility, and this effect remained significant after correcting for multiple testing: rs6840978: P=0.0082, P(corr)=0.049, odds ratio (OR) 0.77, 95% confidence interval (CI) 0.63-0.93; rs6822844: P=0.0028, P(corr)=0.017, OR 0.73, 95% CI 0.59-0.90; rs13119723: P=0.0058, P(corr)=0.035, OR 0.75, 95% CI 0.61-0.92. A haplotype consisting of the six SNPs tested was markedly associated with UC susceptibility (P=0.0025, P(corr)=0.015, OR 0.72, 95% CI 0.58-0.89). Moreover, in UC, epistasis was observed between the IL23R SNP rs1004819 and three SNPs in the KIAA1109/TENR/IL2/IL21 block (rs13151961, rs13119723, and rs6822844).Similar to other autoimmune diseases such as celiac disease, rheumatoid arthritis, type 1 diabetes, Graves' disease, and psoriatic arthritis, genetic variation in the chromosome 4q27 region predisposes to UC, suggesting a common genetic background for these diseases.

Recent data suggest functional interactions between NOD2 and other receptors of the innate immune system modulating inflammatory responses. Here we analyzed the role of Toll-like receptor 9 (TLR-9) gene variants with respect to susceptibility to inflammatory bowel disease (IBD) and tested for genetic interactions with NOD2 and other susceptibility genes for Crohn's disease (CD).The single-nucleotide polymorphisms (SNPs) -1237T/C (rs5743836) and 2848A/G (rs352140=p.Pro545Pro) in TLR9, the main CD-associated variants within the genes for NOD2, IL23R, ATG16L1, and variants in the IBD5 locus and in the DLG5 gene were assessed in 956 patients with IBD (606 CD and 350 ulcerative colitis) and in 792 healthy controls. The associations with disease susceptibility and phenotype, and epistatic gene-gene interactions, were analyzed.The TLR9 -1237T/C polymorphism showed significant interactions with NOD2 mutations. The frequency of -1237C was significantly higher in CD patients with at least one NOD2 mutation (P=0.004 vs. controls, odds ratio (OR) 1.60, 95% confidence interval (CI) (1.15-2.21)) and further increased in CD patients with two mutated NOD2 alleles (P=0.002 vs. controls, OR 2.37, 95% CI (1.35-4.15)). Significant gene-gene interactions were also observed for the TLR9 polymorphism -1237T/C with IL23R variants (most significantly with rs1004819, P=0.0007), with a particular high frequency of -1237C in CD patients carrying CD-protective IL23R variants. Epistatic interactions of the TLR9 -1237T/C SNP were also noted with the DLG5 113G/A variant (P=0.0007).Our results provide evidence for genetic interactions between polymorphisms in TLR9 and CD-associated variants in NOD2, IL23R, and DLG5, differentially modulating CD susceptibility.

BACKGROUND Lipocalin-2 (LCN2) is a potent bacteriostatic protein. We aimed to investigate its role as a disease activity marker in patients with inflammatory bowel disease (IBD) and its induction by the Th17 cytokines IL-17A, IL-22, and TNF-α in colonic epithelial cells. Moreover, we analyzed the influence of IBD-associated IL23R alleles on LCN2 serum levels in IBD patients. METHODS LCN2 serum levels were determined in 131 IBD patients (71 with Crohn's disease [CD], 60 with ulcerative colitis [UC]) and 63 healthy controls. IBD patients were genotyped for 10 IBD-associated IL23R polymorphisms. LCN2 expression after stimulation with IL-17A, IL-22, and TNF-α was measured in human colonic epithelial cell lines. RESULTS A significant upregulation of serum LCN2 in active IBD (median [IQR], 36.84 [21.17-73.74] ng/mL; P = 0.01) compared with healthy controls (24.22 [17.76-35.25] ng/mL) was confined to active UC (42.21 [28.97-73.74] ng/mL; P = 0.0006). LCN2 proved to be a marker of UC disease activity (area under the curve 0.75, sensitivity 0.83, specificity 0.63; P = 0.0002). IL-17A showed a synergistic effect with IL-22 and TNF-α in inducing colonic epithelial expression of LCN2 and its essential transcription factor IKBZ. In CD, LCN2 concentrations were significantly modulated by IL23R genotype status with homozygous carriers of IBD risk-increasing alleles showing particularly low LCN2 levels. CONCLUSIONS Serum LCN2 proves to be a biomarker of active UC. Lower LCN2 levels in CD patients carrying IBD risk-increasing IL23R variants may result from a restricted upregulation of LCN2 due to an impaired Th17 immune response.

Hereditary pulmonary alveolar proteinosis (herPAP) is a rare lung disease caused by mutations in the granulocyte-macrophage colony-stimulating factor (GM-CSF) receptor genes, resulting in disturbed alveolar macrophage differentiation, massive alveolar proteinosis, and life-threatening respiratory insufficiency. So far, the only effective treatment for herPAP is repetitive whole-lung lavage, a merely symptomatic and highly invasive procedure. We introduce pulmonary transplantation of macrophage progenitors as effective and long-lasting therapy for herPAP. In a murine disease model, intrapulmonary transplanted macrophage progenitors displayed selective, long-term pulmonary engraftment and differentiation into functional alveolar macrophages. A single transplantation ameliorated the herPAP phenotype for at least 9 months, resulting in significantly reduced alveolar proteinosis, normalized lung densities in chest computed tomography, and improved lung function. A significant and sustained disease resolution was also observed in a second, humanized herPAP model after intrapulmonary transplantation of human macrophage progenitors. The therapeutic effect was mediated by long-lived, lung-resident macrophages, which displayed functional and phenotypical characteristics of primary human alveolar macrophages. Our findings present the concept of organotopic transplantation of macrophage progenitors as an effective and long-lasting therapy of herPAP and may also serve as a proof of principle for other diseases, expanding current stem cell-based strategies toward potent concepts using the transplantation of differentiated cells.

Background We analysed incidence, predictors, histological features and specific treatment options of anti-tumour necrosis factor α (TNF-α) antibody-induced psoriasiform skin lesions in patients with inflammatory bowel diseases (IBD). Design Patients with IBD were prospectively screened for anti-TNF-induced psoriasiform skin lesions. Patients were genotyped for IL23R and IL12B variants. Skin lesions were examined for infiltrating Th1 and Th17 cells. Patients with severe lesions were treated with the anti-interleukin (IL)-12/IL-23 p40 antibody ustekinumab. Results Among 434 anti-TNF-treated patients with IBD, 21 (4.8%) developed psoriasiform skin lesions. Multiple logistic regression revealed smoking (p=0.007; OR 4.24, 95% CI 1.55 to 13.60) and an increased body mass index (p=0.029; OR 1.12, 95% CI 1.01 to 1.24) as main predictors for these lesions. Nine patients with Crohn9s disease and with severe psoriasiform lesions and/or anti-TNF antibody-induced alopecia were successfully treated with the anti-p40-IL-12/IL-23 antibody ustekinumab (response rate 100%). Skin lesions were histologically characterised by infiltrates of IL-17A/IL-22-secreting T helper 17 (Th17) cells and interferon (IFN)-γ-secreting Th1 cells and IFN-α-expressing cells. IL-17A expression was significantly stronger in patients requiring ustekinumab than in patients responding to topical therapy (p=0.001). IL23R genotyping suggests disease-modifying effects of rs11209026 (p.Arg381Gln) and rs7530511 (p.Leu310Pro) in patients requiring ustekinumab. Conclusions New onset psoriasiform skin lesions develop in nearly 5% of anti-TNF-treated patients with IBD. We identified smoking as a main risk factor for developing these lesions. Anti-TNF-induced psoriasiform skin lesions are characterised by Th17 and Th1 cell infiltrates. The number of IL-17A-expressing T cells correlates with the severity of skin lesions. Anti-IL-12/IL-23 antibody therapy is a highly effective therapy for these lesions.

Background Genome-wide association studies identified a PTGER4 expression-modulating region on chromosome 5p13.1 as Crohn's disease (CD) susceptibility region. The study aim was to test this association in a large cohort of patients with inflammatory bowel disease (IBD) and to elucidate genotypic and phenotypic interactions with other IBD genes. Methodology/Principal Findings A total of 7073 patients and controls were genotyped: 844 CD and 471 patients with ulcerative colitis and 1488 controls were analyzed for the single nucleotide polymorphisms (SNPs) rs4495224 and rs7720838 on chromosome 5p13.1. The study included two replication cohorts of North American (CD: n = 684; controls: n = 1440) and of German origin (CD: n = 1098; controls: n = 1048). Genotype-phenotype, epistasis and transcription factor binding analyses were performed. In the discovery cohort, an association of rs4495224 (p = 4.10×10−5; 0.76 [0.67–0.87]) and of rs7720838 (p = 6.91×10−4; 0.81 [0.71–0.91]) with susceptibility to CD was demonstrated. These associations were confirmed in both replication cohorts. In silico analysis predicted rs4495224 and rs7720838 as essential parts of binding sites for the transcription factors NF-κB and XBP1 with higher binding scores for carriers of the CD risk alleles, providing an explanation of how these SNPs might contribute to increased PTGER4 expression. There was no association of the PTGER4 SNPs with IBD phenotypes. Epistasis detected between 5p13.1 and ATG16L1 for CD susceptibility in the discovery cohort (p = 5.99×10−7 for rs7720838 and rs2241880) could not be replicated in both replication cohorts arguing against a major role of this gene-gene interaction in the susceptibility to CD. Conclusions/Significance We confirmed 5p13.1 as a major CD susceptibility locus and demonstrate by in silico analysis rs4495224 and rs7720838 as part of binding sites for NF-κB and XBP1. Further functional studies are necessary to confirm the results of our in silico analysis and to analyze if changes in PTGER4 expression modulate CD susceptibility.

BACKGROUND: IL12B encodes the p40 subunit of IL-12, which is also part of IL-23. Recent genome-wide association studies identified IL12B and IL23R as susceptibility genes for inflammatory bowel disease (IBD). However, the phenotypic effects and potential gene-gene interactions of IL12B variants are largely unknown. METHODOLOGY/PRINCIPAL FINDINGS: We analyzed IL12B gene variants regarding association with Crohn's disease (CD) and ulcerative colitis (UC). Genomic DNA from 2196 individuals including 913 CD patients, 318 UC patients and 965 healthy, unrelated controls was analyzed for four SNPs in the IL12B gene region (rs3212227, rs17860508, rs10045431, rs6887695). Our analysis revealed an association of the IL12B SNP rs6887695 with susceptibility to IBD (p = 0.035; OR 1.15 [95% CI 1.01-1.31] including a trend for rs6887695 for association with CD (OR 1.41; [0.99-1.31], p = 0.066) and UC (OR 1.18 [0.97-1.43], p = 0.092). CD patients, who were homozygous C/C carriers of this SNP, had significantly more often non-stricturing, non-penetrating disease than carriers of the G allele (p = 6.8×10(-5); OR = 2.84, 95% CI 1.66-4.84), while C/C homozygous UC patients had less often extensive colitis than G allele carriers (p = 0.029; OR = 0.36, 95% CI 0.14-0.92). In silico analysis predicted stronger binding of the minor C allele of rs6887695 to the transcription factor RORα which is involved in Th17 differentiation. Differences regarding the binding to the major and minor allele sequence of rs6887695 were also predicted for the transcription factors HSF1, HSF2, MZF1 and Oct-1. Epistasis analysis revealed weak epistasis of the IL12B SNP rs6887695 with several SNPs (rs11889341, rs7574865, rs7568275, rs8179673, rs10181656, rs7582694) in the STAT4 gene which encodes the major IL-12 downstream transcription factor STAT4 (p

BACKGROUND: Osteopontin represents a multifunctional molecule playing a pivotal role in chronic inflammatory and autoimmune diseases. Its expression is increased in inflammatory bowel disease (IBD). The aim of our study was to analyze the association of osteopontin (OPN/SPP1) gene variants in a large cohort of IBD patients. METHODOLOGY/PRINCIPAL FINDINGS: Genomic DNA from 2819 Caucasian individuals (n = 841 patients with Crohn's disease (CD), n = 473 patients with ulcerative colitis (UC), and n = 1505 healthy unrelated controls) was analyzed for nine OPN SNPs (rs2728127, rs2853744, rs11730582, rs11739060, rs28357094, rs4754 = p.Asp80Asp, rs1126616 = p.Ala236Ala, rs1126772 and rs9138). Considering the important role of osteopontin in Th17-mediated diseases, we performed analysis for epistasis with IBD-associated IL23R variants and analyzed serum levels of the Th17 cytokine IL-22. For four OPN SNPs (rs4754, rs1126616, rs1126772 and rs9138), we observed significantly different distributions between male and female CD patients. rs4754 was protective in male CD patients (p = 0.0004, OR = 0.69). None of the other investigated OPN SNPs was associated with CD or UC susceptibility. However, several OPN haplotypes showed significant associations with CD susceptibility. The strongest association was found for a haplotype consisting of the 8 OPN SNPs rs2728127-rs2853744-rs11730582-rs11439060-rs28357094-rs112661-rs1126772-rs9138 (omnibus p-value = 2.07×10⁻⁸). Overall, the mean IL-22 secretion in the combined group of OPN minor allele carriers with CD was significantly lower than that of CD patients with OPN wildtype alleles (p = 3.66×10⁻⁵). There was evidence for weak epistasis between the OPN SNP rs28357094 with the IL23R SNP rs10489629 (p = 4.18×10⁻²) and between OPN SNP rs1126616 and IL23R SNP rs2201841 (p = 4.18×10⁻²) but none of these associations remained significant after Bonferroni correction. CONCLUSIONS/SIGNIFICANCE: Our study identified OPN haplotypes as modifiers of CD susceptibility, while the combined effects of certain OPN variants may modulate IL-22 secretion.

Background: The pregnane X receptor (PXR/NR1I2) is an important regulator of xenobiotic metabolism and intestinal integrity. However, there are controversial studies on the role of PXR/NR1I2 in inflammatory bowel disease (IBD). We therefore initiated the largest analysis to date on PXR/NR1I2 gene variants in IBD patients. Methods: Genomic DNA from 2823 individuals of Caucasian origin including 859 patients with Crohn's disease (CD), 464 patients with ulcerative colitis (UC), and 1500 healthy, unrelated controls was analyzed for eight PXR/NR1I2 single nucleotide polymorphisms (SNPs) (rs12721602 (−25564), rs3814055 (−25385), rs1523128 (−24756), rs1523127 (−24381), rs45610735 = p.Gly36Arg (+106), rs6785049 (+7635), rs2276707 (+8055), and rs3814057 (+11156)). In addition, detailed haplotype and genotype–phenotype analyses were performed. Results: The PXR/NR1I2 SNP rs2276707 was weakly associated with UC susceptibility (P = 0.01; odds ratio [OR] 1.27 [1.06–1.52]). None of the other PXR/NR1I2 SNPs were associated with UC or CD susceptibility. However, several rare PXR/NR1I2 haplotypes were highly associated with CD susceptibility. In CD, the strongest disease association was found for a haplotype consisting of the SNPs rs12721602-rs3814055-rs1523128-rs1523127-rs12721607-rs6785049-rs2276707-rs3814057 (omnibus P-value: 6.50 × 10−15) which was found in two separate cohorts (cohort I = discovery cohort: CD: n = 492, controls: n = 793; P = 4.51 × 10−17; Bonferroni corrected: P = 1.27 × 10−15; cohort II = replication cohort: CD: n = 367, controls: n = 707; P = 7.12 × 10−4; Pcorr = 1.99 × 10−2). Conclusions: Several PXR/NR1I2 haplotypes contribute to CD susceptibility, suggesting a role for PXR in the IBD pathogenesis of a certain patient subcohort. Given the accumulating evidence for an important role of PXR in intestinal inflammation, further analyses are required to investigate the functional and pharmacogenetic implications of these PXR/NR1I2 gene variants in IBD. (Inflamm Bowel Dis 2010)

We analyzed the efficacy and safety of the antitumor necrosis factor-alpha antibody infliximab (IFX) for induction therapy in patients with moderate-to-severe ulcerative colitis (UC) in a large single-center cohort.A total of 90 UC patients treated with IFX for 14 weeks were analyzed retrospectively. Colitis activity index (CAI) and markers of inflammation were measured during IFX induction therapy. Genotyping for UC-associated variants in the IL23R gene and in the IL2/IL21 region was performed.At week 2 (after the first IFX infusion), 64.1% of IFX-treated patients had clinical response to IFX and 52.6% were in remission. At week 14 (after three infusions), 61.0% showed clinical response and 52.5% were in remission. The mean CAI decreased significantly from 10.4 points at week 0 to 5.1 at week 2 (P0.001), to 4.4 at week 6 (P0.001), and to 5.0 at week 14 (P0.001). Similarly, IFX therapy significantly decreased C-reactive protein levels and leukocyte counts (P=0.01 and P=0.001 at week 2 and week 0, respectively). Multivariate regression analysis identified high CAI before IFX therapy (P=0.01) and negative antineutrophil cytoplasmatic autoantibody (ANCA) status (P=0.01) as independent positive predictors for response to IFX. Homozygous carriers of inflammatory bowel disease (IBD) risk-increasing IL23R variants were more likely to respond to IFX than were homozygous carriers of IBD risk-decreasing IL23R variants (74.1 vs. 34.6%; P=0.001). No serious adverse IFX-related events requiring hospitalization were recorded.Our findings suggest that IFX therapy is safe and effective in patients with moderate-to-severe UC. A high CAI before IFX therapy, ANCA seronegativity, and the IL23R genotype were predictors of early response to IFX.

We analyzed ATG16L1, a recently identified Crohn's disease (CD) susceptibility gene, in a large cohort with inflammatory bowel disease (IBD) including potential interactions with other IBD genes as well as factors regulating its gene expression.Genomic DNA from 2,890 Caucasians including 768 patients with CD, 507 patients with ulcerative colitis (UC), and 1,615 healthy controls was analyzed for 9 different ATG16L1 single nucleotide polymorphisms (SNPs). Genotyping included CARD15/NOD2 variants p.Arg702Trp, p.Gly908Arg, and p.Leu1007fsX1008 and polymorphisms in SLC22A4/OCTN1 (1672 C--T) and SLC22A5/OCTN2 (-207 G--C) as well as 10 CD-associated IL23R variants. The transcriptional regulation of ATG16L1 was studied in intestinal epithelial cells following stimulation with Toll-like receptor (TLR) ligands and proinflammatory cytokines and in a murine ileitis model and CD biopsies.All nine ATG16L1 gene variants analyzed displayed highly significant associations with CD demonstrating a CD-protective effect for the minor allele. The strongest associations were found for rs2241879 and the coding SNP rs2241880 (T300A); P= 3.6 x 10(-6) and 3.7 x 10(-6), respectively (OR 0.74, 95% CI 0.65-0.84 for both variants). The genotype-phenotype analysis revealed no significant associations. In UC, only rs6431660 was weakly disease-associated. There was no evidence for epistasis between the ATG16L1 gene and other susceptibility genes (IL23R, CARD15, SLC22A4/5). ATG16L1 mRNA expression was not upregulated in CD and murine ileitis, and was less than threefold increased in cells stimulated with proinflammatory cytokines and TLR ligands.ATG16L1 is a CD susceptibility gene without epistatic interaction with other CD susceptibility genes and is not upregulated in intestinal inflammation.

Background: We analyzed the influence of Crohn's disease (CD)-associated IL23R gene variants on IL-22 that is expressed in IL-23R+ Th17 cells. Methods: IL-22 serum levels were measured in 242 CD patients and in 31 healthy controls. Subanalyses included serum levels of IL-6, TNF-α, IL-17A, IL-17F, C-reactive protein (CRP), and leukocyte count. In all patients, genotyping for 10 CD-associated IL23R single nucleotide polymorphisms (SNPs) and the 3 main CD-associated CARD15 variants was performed. Results: There was a highly significant increase in IL-22 serum expression in CD patients compared to healthy controls (P = 2.53 × 10−9). IL-22 serum levels correlated with disease activity: IL-22 levels in patients with a Crohn's disease activity index (CDAI) >150 were significantly higher than in patients with a CDAI

BACKGROUND: The IL23R gene has been identified as a susceptibility gene for inflammatory bowel disease (IBD) in the North American population. The aim of our study was to test this association in a large German IBD cohort and to elucidate potential interactions with other IBD genes as well as phenotypic consequences of IL23R variants. METHODS: Genomic DNA from 2670 Caucasian individuals including 833 patients with Crohn's disease (CD), 456 patients with ulcerative colitis (UC), and 1381 healthy unrelated controls was analyzed for 10 IL23R SNPs. Genotyping included the NOD2 variants p.Arg702Trp, p.Gly908Arg, and p.Leu1007fsX1008 and polymorphisms in SLC22A4/OCTN1 (1672 C-->T) and SLC22A5/OCTN2 (-207 G-->C). RESULTS: All IL23R gene variants analyzed displayed highly significant associations with CD. The strongest association was found for the SNP rs1004819 [P = 1.92x10(-11); OR 1.56; 95 % CI (1.37-1.78)]. 93.2% of the rs1004819 TT homozygous carriers as compared to 78% of CC wildtype carriers had ileal involvement [P = 0.004; OR 4.24; CI (1.46-12.34)]. The coding SNP rs11209026 (p.Arg381Gln) was protective for CD [P = 8.04x10(-8); OR 0.43; CI (0.31-0.59)]. Similar, but weaker associations were found in UC. There was no evidence for epistasis between the IL23R gene and the CD susceptibility genes CARD15 and SLC22A4/5. CONCLUSION: IL23R is an IBD susceptibility gene, but has no epistatic interaction with CARD15 and SLC22A4/5. rs1004819 is the major IL23R variant associated with CD in the German population, while the p.Arg381Gln IL23R variant is a protective marker for CD and UC.

BACKGROUND: Recently, an association of the NFKB1 polymorphism -94ins/delATTG with ulcerative colitis (UC) has been reported. This 4-bp insertion/deletion polymorphism is localized in the promoter region of the NFKB1 gene and appears to be functionally relevant. The aim of the present study was to confirm the association of the -94ins/delATTG (W/D) NFKB1 promoter polymorphism with UC in a population of German origin and to test for a potential association with Crohn's disease (CD). Furthermore, potential interactions of the -94ins/delATTG polymorphism with the IKBL and the IL-1RN genes should be determined. MATERIALS AND METHODS: The study population comprised 630 patients with CD, 365 patients with UC, and 974 healthy controls. Genotyping was performed using polymerase chain reaction and restriction fragment length polymorphism analysis. For statistical evaluation, the chi-square test and the Fisher exact test were used. RESULTS: No significant association of the W/D NFKB1 polymorphism with CD or UC was detected. In addition, no significant interactions between the -94ins/delATTG NFKB1 polymorphism and polymorphisms within the IKBL and the IL-1RN genes, respectively, were found in CD or UC. Also, no significant interactions of the NFKB1 polymorphism with mutations of the CARD15/NOD2 gene and with clinical phenotypes were detected in CD. Moreover, no associations of the NFKB1 polymorphism were found in UC depending on disease localization. CONCLUSIONS: The present study could not confirm the reported association of the -94ins/delATTG NFKB1 polymorphism with UC and also found no evidence for a role of this polymorphism in CD. The results do not give evidence for a role of this NFKB1 polymorphism in the pathogenesis of UC and CD.

BACKGROUND: Genome-wide association studies identified PTPN2 (protein tyrosine phosphatase, non-receptor type 2) as susceptibility gene for inflammatory bowel diseases (IBD). However, the exact role of PTPN2 in Crohn's disease (CD) and ulcerative colitis (UC) and its phenotypic effect are unclear. We therefore performed a detailed genotype-phenotype and epistasis analysis of PTPN2 gene variants. METHODOLOGY/PRINCIPAL FINDINGS: Genomic DNA from 2131 individuals of Caucasian origin (905 patients with CD, 318 patients with UC, and 908 healthy, unrelated controls) was analyzed for two SNPs in the PTPN2 region (rs2542151, rs7234029) for which associations with IBD were found in previous studies in other cohorts. Our analysis revealed a significant association of PTPN2 SNP rs2542151 with both susceptibility to CD (p = 1.95×10⁻⁵; OR 1.49 [1.34-1.79]) and UC (p = 3.87×10⁻², OR 1.31 [1.02-1.68]). Moreover, PTPN2 SNP rs7234029 demonstrated a significant association with susceptibility to CD (p = 1.30×10⁻³; OR 1.35 [1.13-1.62]) and a trend towards association with UC (p = 7.53×10⁻²; OR 1.26 [0.98-1.62]). Genotype-phenotype analysis revealed an association of PTPN2 SNP rs7234029 with a stricturing disease phenotype (B2) in CD patients (p = 6.62×10⁻³). Epistasis analysis showed weak epistasis between the ATG16L1 SNP rs2241879 and PTPN2 SNP rs2542151 (p = 0.024) in CD and between ATG16L1 SNP rs4663396 and PTPN2 SNP rs7234029 (p = 4.68×10⁻³) in UC. There was no evidence of epistasis between PTPN2 and NOD2 and PTPN2 and IL23R. In silico analysis revealed that the SNP rs7234029 modulates potentially the binding sites of several transcription factors involved in inflammation including GATA-3, NF-κB, C/EBP, and E4BP4. CONCLUSIONS/SIGNIFICANCE: Our data confirm the association of PTPN2 variants with susceptibility to both CD and UC, suggesting a common disease pathomechanism for these diseases. Given recent evidence that PTPN2 regulates autophagosome formation in intestinal epithelial cells, the potential link between PTPN2 and ATG16L1 should be further investigated.