Pediatric Inflammatory Bowel Disease Cohort Research Articles

Pharmacogenomic Assessment of Genes Implicated in Thiopurine Metabolism and Toxicity in a UK Cohort of Pediatric Patients With Inflammatory Bowel Disease.

Thiopurine drugs are effective treatment options in inflammatory bowel disease and other conditions but discontinued in some patients due to toxicity. We investigated thiopurine-induced toxicity in a pediatric inflammatory bowel disease cohort by utilizing exome sequencing data across a panel of 46 genes, including TPMT and NUDT15. The cohort included 487 patients with a median age of 13.1 years. Of the 396 patients exposed to thiopurines, myelosuppression was observed in 11%, gastroenterological intolerance in 11%, hepatotoxicity in 4.5%, pancreatitis in 1.8%, and "other" adverse effects in 2.8%. TPMT (thiopurine S-methyltransferase) enzyme activity was normal in 87.4%, intermediate 12.3%, and deficient in 0.2%; 26% of patients with intermediate activity developed toxicity to thiopurines. Routinely genotyped TPMT alleles associated with defective enzyme activity were identified in 28 (7%) patients: TPMT*3A in 4.5%, *3B in 1%, and *3C in 1.5%. Of these, only 6 (21%) patients developed toxic responses. Three rare TPMT alleles (*3D, *39, and *40) not assessed on routine genotyping were identified in 3 patients, who all developed toxic responses. The missense variant p.R139C (NUDT15*3 allele) was identified in 4 patients (azathioprine 1.6mg/kg/d), but only 1 developed toxicity. One patient with an in-frame deletion variant p.G13del in NUDT15 developed myelosuppression at low doses. Per-gene deleteriousness score GenePy identified a significant association for toxicity in the AOX1 and DHFR genes. A significant association for toxicity was observed in the AOX1 and DHFR genes in individuals negative for the TPMT and NUDT15 variants. Patients harboring the NUDT15*3 allele, which is associated with myelosuppression, did not show an increased risk of toxicity.

Racial and ethnic differences in diagnosis age and blood biomarkers in a pediatric inflammatory bowel disease cohort.

Prompt diagnosis of pediatric-onset inflammatory bowel disease (IBD) is crucial for preventing a complicated disease course; however, it is not well understood how social determinants of health might affect pediatric IBD diagnosis. This study examined differences in diagnosis age, biomarkers of disease severity, and anthropometrics with sociodemographic factors in a pediatric IBD cohort. Pediatric IBD patients (n = 114) and their parents/caregivers were enrolled from the Children's of Alabama Pediatric IBD Clinic in Birmingham, Alabama. Primary analyses examined associations of child race and ethnicity, parental income, parental education, single-parent household status, insurance type, and distance to a tertiary pediatric gastroenterology referral center with diagnosis age. Secondary analyses examined differences in biomarker levels, height, and body mass index at the time of diagnosis. Racial and ethnic minority children were diagnosed at an older age compared to Non-Hispanic White children (14.4 ± 0.40 vs. 11.7 ± 0.38 years; p < 0.001), and this trend was robust to adjustment with other sociodemographic variables. Parental attainment of a college education attenuated the link between minority race and ethnicity and the likelihood of older age at diagnosis, while other sociodemographic variables had no moderating effect. Racial and ethnic minority children were 5.7 times more likely to have clinically elevated erythrocyte sedimentation rate at diagnosis compared to Non-Hispanic White children (p = .024). These results suggest that child race and ethnicity may exert a primary effect on the age at diagnosis with pediatric-onset IBD. This study highlights the need for further research on racial and ethnic disparities to promote health equity in pediatric-onset IBD.

Racial and ethnic differences in age at diagnosis are independent of socioeconomic factors in a pediatric inflammatory bowel disease cohort

Up to 25% of inflammatory bowel disease (IBD) patients are diagnosed before the age of 18 years, and the incidence and prevalence of pediatric-onset IBD are increasing worldwide. Pediatric IBD is aggressive and delayed diagnosis is associated with stunted growth, delayed puberty, and an increased risk of complications. Historically, IBD has been viewed as a disease that predominantly affects non-Hispanic Whites. However, the incidence of IBD among racial and ethnic minorities is increasing. These demographic changes have sparked a growing awareness of disparities in the diagnosis and management of IBD, yet few studies have examined racial and ethnic differences in pediatric IBD. We enrolled a diverse cohort of 114 pediatric IBD patients (age 11–18, 71% non-Hispanic White, 19% Black, 2% Hispanic, 7% multiracial or other racial/ethnic minorities) from Children’s of Alabama in Birmingham, AL USA. The goal of this retrospective study was to investigate potential racial and ethnic differences in age and IBD biomarkers at the time of pediatric IBD diagnosis. Healthcare records were obtained within the first 30 days of diagnosis for erythrocyte sedimentation rate (ESR), C-reactive protein, albumin, hematocrit, and hemoglobin. Participants self-reported race/ethnicity and parents self-reported income and education. Multivariate models were used to examine the association of biomarker values and age at the time of diagnosis with race/ethnicity, sex, IBD disease type, parental income, and parental education. Racial/ethnic minority children (including Black, Hispanic, Asian, and multi-racial) had a greater mean age at diagnosis (11.7 ± 0.4 vs. 14.4 ± 0.4 years) compared to non-Hispanic White children, and this association was robust when adjusting for covariates ( β=1.51, p&lt;0.001). Moreover, racial/ethnic minority children were more likely to be diagnosed at &gt;12 y of age compared to non-Hispanic White children (OR=13.3, 95% CI=1.9–57.0, p=0.003). Having a college-educated parent reduced the likelihood of being diagnosed at &gt;12 y of age for racial and ethnic minority children (OR=0.1, 95% CI=0.03–2.7, p=0.049), while parental income had no mediating effect. In addition, racial/ethnic minority children were more likely to have elevated ESR at the time of their diagnosis compared to non-Hispanic White children (OR=5.76, 95% CI=1.19–55.95, p=0.024), though this association was not robust to covariate adjustment. In conclusion, minority race/ethnicity was linked to older age at diagnosis, and this association was independent of socioeconomic factors. However, parental attainment of a college education may attenuate the effect of minority race/ethnicity on age at diagnosis. This study highlights the critical need for more research examining how race/ethnicity intersect with other social determinants of health, including parental education and health literacy, to impact disparities in the diagnosis, management, and morbidity of pediatric IBD. This work was supported by a Crohn's and Colitis Foundation Translational Research Initiatives (Environmental Triggers) Award. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Identification of FCN1 as a novel macrophage infiltration-associated biomarker for diagnosis of pediatric inflammatory bowel diseases

BackgroundThe incidence of pediatric inflammatory bowel disease (PIBD) has been steadily increasing globally. Delayed diagnosis of PIBD increases the risk of complications and contributes to growth retardation. To improve long-term outcomes, there is a pressing need to identify novel markers for early diagnosis of PIBD.MethodsThe candidate biomarkers for PIBD were identified from the GSE117993 dataset by two machine learning algorithms, namely LASSO and mSVM-RFE, and externally validated in the GSE126124 dataset and our PIBD cohort. The role of ficolin-1 (FCN1) in PIBD and its association with macrophage infiltration was investigated using the CIBERSORT method and enrichment analysis of the single-cell dataset GSE121380, and further validated using immunoblotting, qRT-PCR, and immunostaining in colon biopsies from PIBD patients, a juvenile murine DSS-induced colitis model, and THP-1-derived macrophages.ResultsFCN1 showed great diagnostic performance for PIBD in an independent clinical cohort with the AUC of 0.986. FCN1 expression was upregulated in both colorectal biopsies and blood samples from PIBD patients. Functionally, FCN1 was associated with immune-related processes in the colonic mucosa of PIBD patients, and correlated with increased proinflammatory M1 macrophage infiltration. Furthermore, single-cell transcriptome analysis and immunostaining revealed that FCN1 was almost exclusively expressed in macrophages infiltrating the colonic mucosa of PIBD patients, and these FCN1+ macrophages were related to hyper-inflammation. Notably, proinflammatory M1 macrophages derived from THP-1 expressed high levels of FCN1 and IL-1β, and FCN1 overexpression in THP-1-derived macrophages strongly promoted LPS-induced activation of the proinflammatory cytokine IL-1β via the NLRP3-caspase-1 axis.ConclusionsFCN1 is a novel and promising diagnostic biomarker for PIBD. FCN1+ macrophages enriched in the colonic mucosa of PIBD exhibit proinflammatory phenotypes, and FCN1 promotes IL-1β maturation in macrophages via the NLRP3-caspase-1 axis.

Association between HLA DNA Variants and Long-Term Response to Anti-TNF Drugs in a Spanish Pediatric Inflammatory Bowel Disease Cohort.

The genetic polymorphisms rs2395185 and rs2097432 in HLA genes have been associated with the response to anti-TNF treatment in inflammatory bowel disease (IBD). The aim was to analyze the association between these variants and the long-term response to anti-TNF drugs in pediatric IBD. We performed an observational, multicenter, ambispective study in which we selected 340 IBD patients under 18 years of age diagnosed with IBD and treated with anti-TNF drugs from a network of Spanish hospitals. Genotypes and failure of anti-TNF drugs were analyzed using Kaplan-Meier curves and Cox logistic regression. The homozygous G allele of rs2395185 and the C allele of rs2097432 were associated with impaired long-term response to anti-TNF drugs in children with IBD after 3 and 9 years of follow-up. Being a carrier of both polymorphisms increased the risk of anti-TNF failure. The SNP rs2395185 but not rs2097432 was associated with response to infliximab in adults with CD treated with infliximab but not in children after 3 or 9 years of follow-up. Conclusions: SNPs rs2395185 and rs2097432 were associated with a long-term response to anti-TNFs in IBD in Spanish children. Differences between adults and children were observed in patients diagnosed with CD and treated with infliximab.

Resistin, Elastase, and Lactoferrin as Potential Plasma Biomarkers of Pediatric Inflammatory Bowel Disease Based on Comprehensive Proteomic Screens

Inflammatory bowel disease (IBD) is an immune-mediated chronic inflammation of the intestine, which can present in the form of ulcerative colitis (UC) or as Crohn’s disease (CD). Biomarkers are needed for reliable diagnosis and disease monitoring in IBD, especially in pediatric patients. Plasma samples from a pediatric IBD cohort were interrogated using an aptamer-based screen of 1322 proteins. The elevated biomarkers identified using the aptamer screen were further validated by ELISA using an independent cohort of 76 pediatric plasma samples, drawn from 30 CD, 30 UC, and 16 healthy controls. Of the 1322 proteins screened in plasma from IBD patients, 129 proteins were significantly elevated when compared with healthy controls. Of these 15 proteins had a fold change greater than 2 and 28 proteins had a fold change >1.5. Neutrophil and extracellular vesicle signatures were detected among the elevated plasma biomarkers. When seven of these proteins were validated by ELISA, resistin was the only protein that was significantly higher in both UC and CD (p < 0.01), with receiver operating characteristic area under the curve value of 0.82 and 0.77, respectively, and the only protein that exhibited high sensitivity and specificity for both CD and UC. The next most discriminatory plasma proteins were elastase and lactoferrin, particularly for UC, with receiver operating characteristic area under the curve values of 0.74 and 0.69, respectively. We have identified circulating resistin, elastase, and lactoferrin as potential plasma biomarkers of IBD in pediatric patients using two independent diagnostic platforms and two independent patient cohorts.

A45 INFLIXIMAB IN COMBINATION WITH AN IMMUNOMODULATOR IS ASSOCIATED WITH AN ATTENUATED ANTIBODY RESPONSE TO BNT162B2 SARS-COV-2 VACCINE IN PEDIATRIC INFLAMMATORY BOWEL DISEASE PATIENTS

BackgroundAdult data have shown that Infliximab (IFX) impairs the antibody response to a single dose of the mRNA-BNT162b2 SARS-CoV-2 vaccine in patients with inflammatory bowel disease (IBD). The true impact of IFX on SARS-CoV-2 vaccine efficacy in pediatric IBD (PIBD) patients is unknown.AimsTo evaluate the humoral immune response to the BNT162b2 SARS-CoV-2 in PIBD patients treated with anti-tumor necrosis factor (TNF) therapy.MethodsPIBD patients treated with anti-TNF therapy either alone or in combination with an immunomodulator, who received at least one dose of the BNT162b2 SARS-CoV-2 vaccine, were prospectively enrolled from 1st June 2021 at BC Children’s Hospital. Serum antibody levels for [spike (S) protein and receptor-binding domain (RBD)] were determined at baseline and 28 days after their first and second vaccine doses. Antibody responses were assessed using multiplex serology IgG assay against four SARS-CoV-2 antigens: S-protein, RBD, N-terminal domain (NTD) and N-protein using the SARS-CoV-2 Panel 2 (Meso Scale Diagnostics).ResultsForty-two PIBD patients received a single dose of BNT162b2 (median age 14.5yrs (IQR 14–16); 43% female; 79% crohn’s disease, 21%, ulcerative colitis). Of those on IFX monotherapy (43%), both S-protein and RBD antibody concentrations 28 days post BNT162b2 were comparable to healthy adult controls (n=20, median age: 36yrs (IQR 29–40); 65% female) who had received one dose of BNT162b2 (p = 0.07) [Figure 1]. In PIBD patients on IFX in combination with either azathioprine or methotrexate (57%) both S-protein and RBD antibody concentrations were significantly lower than controls after 1 dose of BNT162b2 (p = 0.0003) [Figure 1].In the PIBD cohort (n=27) who received 2 doses of BNT162b2 vaccine (median age 14yrs (IQR 14–16);41% female;63% crohn’s disease, 37% ulcerative colitis; median interval between doses 56 days (IQR 22–105)), there was no difference in antibody response after 2 doses compared to healthy adult controls (n=14, median age: 44 years (IQR 36–51); 29% female) whether they were on IFX monotherapy (41%) or in combination with an immunomodulator (59%) [Figure 1].ConclusionsWe provide evidence of an attenuated antibody response in PIBD patients on IFX in combination with an immunomodulator after a single dose of BNT162b2. However, our data show a robust antibody response in PIBD patients, despite their infliximab treatment, after two doses of BNT162b2 vaccine. Our results are consistent with adult IBD data and highlight the importance of administering the second vaccine dose to achieve protection in this vulnerable patient population. Long-term follow-up to assess longevity of vaccine protection is warranted. Figure 1: SARS-CoV-2 IgG RBD and S-protein antibody levels [AU/ml] in PIBD patients and healthy adults before and after receiving the BNT162b2 SARS-CoV-2 vaccine. IFX monotherapy (black triangles), IFX with immunomodulator (white triangles), healthy adults (white circles) at baseline, 28 days post first vaccine dose and 3-months post first vaccine dose (two doses of BNT162b2 vaccine). Data presented as boxes (IQR) and whiskers with p valuesFunding AgenciesNone

Vedolizumab Experience in Children and Adolescents With Inflammatory Bowel Disease: A Multicenter Observational Study.

Vedolizumab is increasingly used off-label to treat children and adolescents with inflammatory bowel disease (IBD). In the absence of rigorous clinical trial experience, multicenter observational data are important to establish expectations for efficacy and safety. We examined 1-year outcomes following vedolizumab therapy in a large multicenter pediatric IBD cohort. We performed a retrospective study of 159 pediatric patients (4-17 years old) with IBD [78, Crohn disease (CD); 81, ulcerative colitis/IBD-unspecified (UC/IBD-U)] treated with vedolizumab for 1 year at 8 pediatric medical centers in the United States. Demographics, clinical outcomes, laboratory data, and vedolizumab dosing were recorded. The primary outcome was corticosteroid (CS)-free clinical remission at 1 year. Other measured outcomes were clinical remission at 12 and/or 24 weeks, laboratory outcomes at 1 year, and endoscopy/histology results at 1 year. Among the 159 patients (mean age, 14.5 ± 2.4 years; 86% anti-TNF experienced), 68/159 (43%) achieved CS-free clinical remission at 1 year (CD, 35/78, 45%; UC/IBD-U, 33/81, 40%). Vedolizumab therapy failed and was discontinued in 33/159 (21%) patients prior to 1 year (CD, 18/78, 23%; UC/IBD-U, 15/81, 19%). While week 12 clinical remission was not predictive of 1-year clinical remission in either CD or UC/IBD-U, week 24 clinical remission was predictive of 1-year clinical remission only in CD patients. No infusion reactions or serious side effects were noted. Vedolizumab was safe and effective in this pediatric population with approximately 43% achieving CS-free clinical remission at 1 year. Similar efficacy was noted in both CD and UC.

Mutation spectrum of NOD2 reveals recessive inheritance as a main driver of Early Onset Crohn\u2019s Disease

Inflammatory bowel disease (IBD), clinically defined as Crohn’s disease (CD), ulcerative colitis (UC), or IBD-unclassified, results in chronic inflammation of the gastrointestinal tract in genetically susceptible hosts. Pediatric onset IBD represents ≥ 25% of all IBD diagnoses and often presents with intestinal stricturing, perianal disease, and failed response to conventional treatments. NOD2 was the first and is the most replicated locus associated with adult IBD, to date. However, its role in pediatric onset IBD is not well understood. We performed whole-exome sequencing on a cohort of 1,183 patients with pediatric onset IBD (ages 0–18.5 years). We identified 92 probands with biallelic rare and low frequency NOD2 variants accounting for approximately 8% of our cohort, suggesting a Mendelian inheritance pattern of disease. Additionally, we investigated the contribution of recessive inheritance of NOD2 alleles in adult IBD patients from a large clinical population cohort. We found that recessive inheritance of NOD2 variants explains ~ 7% of cases in this adult IBD cohort, including ~ 10% of CD cases, confirming the observations from our pediatric IBD cohort. Exploration of EHR data showed that several of these adult IBD patients obtained their initial IBD diagnosis before 18 years of age, consistent with early onset disease. While it has been previously reported that carriers of more than one NOD2 risk alleles have increased susceptibility to Crohn’s Disease (CD), our data formally demonstrate that recessive inheritance of NOD2 alleles is a mechanistic driver of early onset IBD, specifically CD, likely due to loss of NOD2 protein function. Collectively, our findings show that recessive inheritance of rare and low frequency deleterious NOD2 variants account for 7–10% of CD cases and implicate NOD2 as a Mendelian disease gene for early onset Crohn’s Disease.

Evaluation of Nonalcoholic Fatty Liver Disease in Pediatric Patients With Inflammatory Bowel Disease.

Adult studies demonstrate the co-existence of nonalcoholic fatty liver disease (NAFLD) and inflammatory bowel disease (IBD) without traditional risk factors. Data in children with IBD are lacking. Here, we sought to establish the prevalence of NAFLD in a single-center pediatric IBD cohort, and identify potential risk factors. After institutional review board approval, we enrolled children with IBD who underwent routine abdominal magnetic resonance enterography. Proton density fat fraction (PDFF) was then estimated on magnetic resonance enterography. A total of 83 patients with IBD were identified and PDFF maps completed. Five (6%) were found to have PDFF >5%, meeting criteria for NAFLD. Compared to the patients with IBD without NAFLD, none of the evaluated risk factors including age, sex, diagnosis, time since diagnosis, medication, median alanine aminotransferase, and weight status were statistically significant. Our findings demonstrate the occult nature of NAFLD in pediatric IBD. The prevalence is not at variance with what is expected in general teenage populations.

Dual Biologic and Small Molecule Therapy for the Treatment of Refractory Pediatric Inflammatory Bowel Disease.

Nontraditional combination of existing therapies is often the only option to avoid surgery in refractory inflammatory bowel disease (IBD) patients. We aim to assess the efficacy and safety of concomitant use of 2 biologic therapies or combination of biologic and tofacitinib in a refractory pediatric IBD cohort. As part of an ongoing single-center observational cohort study of therapeutic outcomes in pediatric IBD patients (younger than 18 years), data were collected for patients receiving dual therapy. Primary outcome was 6 months of steroid-free remission. Secondary outcomes included time to steroid-free remission, change in serum biomarkers (C-reactive protein and erythrocyte sedimentation rate) and albumin between baseline and 6 months, and adverse events. Sixteen children (9 ulcerative colitis/IBD-unspecified, 7 Crohn's disease), with a disease duration of 3 (2.1-5.0) years, initiated dual therapy at an age of 15.9 (13.5-16.8) years after failing ≥2 biologic therapies. Nine (56%) were treated with vedolizumab/tofacitinib, 4 (25%) with ustekinumab/vedolizumab, and 3 (19%) with ustekinumab/tofacitinib. Twelve (75%; 7 ulcerative colitis/IBD-unspecified, 5 Crohn's disease ) achieved steroid-free remission at 6 months. Erythrocyte sedimentation rate and C-reactive protein decreased (P = 0.021 and P = 0.015, respectively) and albumin increased (P = 0.003) between baseline and 6 months. One patient on 30 mg of vedolizumab/tofacitinib and prednisone daily developed septic arthritis and a deep vein thrombosis. Our data suggest that dual therapy may be an option for patients with limited therapeutic options remaining. Safety concerns should always be at the forefront of decision-making, and larger studies are needed to help confirm the preliminary safety data observed.

Sleep Quality in Adolescents with Inflammatory Bowel Disease

Background: The incidence and prevalence of Inflammatory BowelDisease (IBD) in the U.S. is increasing. Because adequate sleep quality and duration play a role in the mental and physical wellbeingof children, this study aimed to determine the prevalence of sleep difficulties in our urban pediatric IBD cohort and evaluateassociations between sleep quality and disease severity. Methods: Patients completed the Pittsburgh Sleep Quality Index(PSQI) questionnaire during an office visit. Chart review provided demographic information, and Pediatric Crohn’s Disease ActivityIndex (PCDAI) and Pediatric Ulcerative Colitis Activity Index (PUCAI) scores were calculated from the day of the visit. Results: The prevalence of sleep problems was 33.54% (95%CI: 26.24% to 41.48%; p-value=0.02). PUCAI scores in children with sleep problems (PSQI mean 19.17 ± 20.43) were significantlyhigher than PUCAI scores in children without sleep problems. There was no association between total PSQI scores, classification of IBD,age, gender, ethnicity, steroid use, or disease duration. Conclusion: Our IBD cohort reported a 33% prevalence ofsleep disturbance symptoms. In the small group of patients withUlcerative Colitis (UC), there was a trend toward a greater degree ofsleep disturbances and a higher PUCAI score. Further investigationinto sleep disorders among children with IBD is warranted toprovide further insight into this issue. Additional evaluation of the differences between Crohn’s disease (CD) and ulcerative colitis asthey relate to sleep quality as well as studies implementing objectivesleep assessments, such as polysomnography or actigraphy, arewarranted as they may offer better understanding of the relationshipbetween pediatric IBD and sleep quality.

Immunological Profiling of Paediatric Inflammatory Bowel Disease Using Unsupervised Machine Learning.

The current classification of inflammatory bowel disease (IBD) is based on clinical phenotypes, which is blind to the molecular basis of the disease. The aim of this study was to stratify a treatment-naïve paediatric IBD cohort through specific innate immunity pathway profiling and application of unsupervised machine learning (UML). In order to test the molecular integrity of biological pathways implicated in IBD, innate immune responses were assessed at diagnosis in 22 paediatric patients and 10 age-matched controls. Peripheral blood mononuclear cells (PBMCs) were selectively stimulated for assessing the functionality of upstream activation receptors including NOD2, toll-like receptor (TLR) 1-2 and TLR4, and the downstream cytokine responses (IL-10, IL-1β, IL-6, and TNF-α) using multiplex assays. Cytokine data generated were subjected to hierarchical clustering to assess for patient stratification. Combined immune responses in patients across 12 effector responses were significantly reduced compared with controls (P = 0.003) and driven primarily by "hypofunctional" TLR responses (P values 0.045, 0.010, and 0.018 for TLR4-mediated IL-10, IL-1β, and TNF-α, respectively; 0.018 and 0.015 for TLR1-2 -mediated IL-10 and IL-1β). Hierarchical clustering generated 3 distinct clusters of patients and a fourth group of "unclustered" individuals. No relationship was observed between the observed immune clusters and the clinical disease phenotype. Although a clinically useful outcome was not observed through hierarchical clustering, our study provides a rationale for using an UML approach to stratify patients. The study also highlights the predominance of hypo-inflammatory innate immune responses as a key mechanism in the pathogenesis of IBD.

P763 Epstein–Barr virus serological status in paediatric patients with inflammatory bowel disease

Abstract Background The impact of Epstein–Barr virus (EBV) infection on the clinical outcomes of children and adolescents with inflammatory bowel disease (IBD) is not well known. The aim of the study is to evaluate the seroprevalence, seroconversion rate and complications associated with EBV infection in a cohort of paediatric IBD (PIBD) patients at a tertiary care hospital. Methods A descriptive study was performed collecting demographic, clinical and treatment data from medical records as well as EBV serological status of paediatric IBD patients from 2012 to 2018. In seronegative patients, seroconversion rate was evaluated. Complications associated with primary EBV infection were described. Since September 2016, EBV serology was included into the initial work-up for PIBD patients. For those patients who did not have EBV study at IBD onset, it was performed during follow-up. Results A total of 307 patients with PIBD were diagnosed between 2012 and 2018. EBV status was available for 131 patients (43%). Of those, 57% had Crohn’s Disease, 41% Ulcerative Colitis, and 2% IBD unclassified (66% males; median age at IBD diagnosis: 13.2 years (IQR: 0.8–17.8)). In 102 patients serological EBV status was determined at IBD onset; while in 17 patients it was performed during the follow-up. Overall, EBV seroprevalence was 67%, and no differences were observed regarding age (over or under 10 years-old). EBV seroprevalence was higher in females than in males (80% vs. 60.5%, p = 0.02). Regarding IBD treatment, 84% had received immunosuppressive treatment [thiopurines (32%), anti-TNF (9%) and combined treatment (59%)], without differences in the seroprevalence rate according to the treatment modality. Forty-three patients were seronegative, and 12 of them had a second determination during follow-up. Overall, 5 patients showed seroconversion (42%) after a mean follow-up of 24 months (IQR: 22–26). All these patients had received treatment with thiopurines: 2 patients presented symptomatic mononucleosis with neutropenia, requiring hospital admission and withdrawal of immunosuppressive treatment and 3 patients had asymptomatic primary infection. Conclusion EBV seroprevalence in our paediatric IBD cohort is similar as previously described in the literature. EBV status study in patients with IBD, especially prior to initiation of thiopurines, may be useful to plan subsequent follow-up since a non-negligible percentage of them could present with complicactions of primary EBV infection under immunosuppressive treatment.

Biochemical Markers, Genotype, and Inflammation in Pediatric Inflammatory Bowel Disease: A Danish Population-Based Study

Background: Our aim was to characterize the biochemical markers at diagnosis in patients with inflammatory bowel disease (IBD), to assess the utility of these to predict disease course and investigate if genotype influences biochemical markers of inflammation. Summary: Patients were included from a population-based pediatric IBD cohort from Eastern Denmark. Data on biochemical markers and medical as well as surgical treatment were registered at diagnosis, 30 days, 6 and 12 months after diagnosis. Fifty-two single nucleotide polymorphisms (SNPs) known to be associated with IBD were selected for genotyping based on previous genetic studies. Key messages: A total of 190 IBD patients (97 ulcerative colitis [UC], 87 Crohn’s disease [CD], and 6 IBD unclassified) were included. UC patients with extensive disease had higher C-reactive protein, erythrocyte sedimentation rate, and platelet count at diagnosis compared to UC patients with less extensive disease. No similar differences between disease extent groups were found in CD. Low albumin at diagnosis was associated with an increased risk of surgery in both UC (OR 1.35; 95% CI: 1.05–1.75) and CD patients (OR 1.23; 95% CI: 1.01–1.48) and increased use of azathioprine and anti-tumor necrosis factor alpha use in the total IBD cohort (OR 1.15; 95% CI: 1.04–1.27 and OR 1.19 [1.08–1.34]). One SNP (rs4986791 in the TLR-4 locus) and 2 SNPs (rs6785049 in the Pregnane-x-receptor gene and rs10500264 in the SLCA10 gene) were associated with a change in albumin and hemoglobin over time respectively in our IBD cohort. Our study confirms albumin to be a marker of severe disease course. Furthermore, the patient’s genotype possibly affects the inflammatory response. Future studies in larger pediatric cohorts are needed to confirm our findings.

Genetic variants and pathways implicated in a pediatric inflammatory bowel disease cohort

In the United States, approximately 5% of individuals with inflammatory bowel disease (IBD) are younger than 20 years old. Studies of pediatric cohorts can provide unique insights into genetic architecture of IBD, which includes Crohn’s disease (CD) and ulcerative colitis (UC). Large genome-wide association studies have found more than 200 IBD-associated loci but explain a minority of disease variance for CD and UC. We sought to characterize the contribution of rare variants to disease development, comparing exome sequencing of 368 pediatric IBD patients to publicly available exome sequencing (dbGaP) and aggregate frequency data (ExAC). Using dbGaP data, we performed logistic regression for common variants and optimal unified association tests (SKAT-O) for rare, likely-deleterious variants. We further compared rare variants to ExAC counts with Fisher’s exact tests. We did pathway enrichment analysis on the most significant genes from each comparison. Many variants overlapped with known IBD-associated genes (e.g. NOD2). Rare variants were enriched in CD-associated loci (p = 0.009) and showed suggestive enrichment in neutrophil function genes (p = 0.05). Pathway enrichment implicated immune-related pathways, especially cell killing and apoptosis. Variants in extracellular matrix genes also emerged as an important theme in our analysis.

New Onset Autoimmune Hepatitis during Anti-Tumor Necrosis Factor-Alpha Treatment in Children

To evaluate a large anti-tumor necrosis factor (TNF)-treated pediatric inflammatory bowel disease cohort for drug-induced liver injury (DILI) following presentation of an index case with suspected DILI with autoimmune features after infliximab exposure. To characterize the incidence, natural history, and risk factors for liver enzyme elevation with anti-TNF use. We reviewed the index case and performed a retrospective cohort study of 659 children receiving anti-TNF therapy between 2000 and 2015 at a tertiary pediatric inflammatory bowel disease center. Patients with alanine aminotransferase (ALT) ≥×2 the upper limit of normal were included. The incidence, evolution, and risk factors for liver injury were examined with univariate and multivariable proportional hazards regression. Causality was assessed using the Roussel-Uclaf Causality Assessment Method. The index case, a teenage girl with Crohn's disease, developed elevated liver enzymes and features of autoimmune hepatitis on liver biopsy 23 weeks after starting infliximab. The injury resolved entirely within 4 months of withdrawing infliximab without additional therapy. Overall, 7.7% of our cohort developed new ALT elevations while on anti-TNF. Most ALT elevations were mild and transient and attributable to alternate etiologies. No additional clear cases of autoimmune hepatitis were identified. Transient liver enzyme abnormalities are relatively common among anti-TNF-treated children. Anti-TNF-related DILI with autoimmune features is rare but must be recognized so that therapy can be stopped.

Risk Factors and Outcomes of Thalidomide-induced Peripheral Neuropathy in a Pediatric Inflammatory Bowel Disease Cohort.

Thalidomide is an effective therapy in children with inflammatory bowel disease refractory to standard treatments, but thalidomide-induced peripheral neuropathy (TiPN) limits its long-term use. We aimed to investigate the risk factors and the outcome of TiPN in children with inflammatory bowel disease. Within a retrospective multicenter cohort study, we evaluated prevalence and evolution of TiPN. Clinical data and candidate genetic profiles of patients with and without TiPN were compared with detect predisposing factors. One hundred forty-two patients were identified. TiPN was found in 72.5% of patients (38.7% clinical and instrumental alterations, 26.8% exclusive electrophysiological anomalies, and 7.0% exclusive neurological symptoms). Median TiPN-free period of treatment was 16.5 months; percentage of TiPN-free patients was 70.0% and 35.6% at 12 and 24 months of treatment, respectively. The risk of TiPN increased depending on the mean daily dose (50-99 mg/d adjusted hazard ratio 2.62; 95% confidence interval [CI], 1.31-5.21; 100-149 mg/d adjusted hazard ratio 6.16; 95% CI, 20.9-13.06; >150 mg/d adjusted hazard ratio 9.57; 95% CI, 2.6-35.2). Single nucleotide polymorphisms in ICAM1 (rs1799969) and SERPINB2 (rs6103) genes were found to be protective against TiPN (odds ratio 0.15; 95% CI, 0.03-0.82 and 0.36; 95% CI, 0.14-0.88, respectively). TiPN was the cause of drug suspension in 41.8% of patients. Clinical symptoms resolved in 89.2% of cases, whereas instrumental alteration persisted in more than half of the patients during a short follow-up. In children with inflammatory bowel disease, TiPN is common but mild and generally reversible. Cumulative dose seems to be the most relevant risk factor, whereas polymorphisms in genes involved in neuronal inflammation may be protective.

Incidence of Bowel Surgery and Associated Risk Factors in Pediatric-Onset Crohn's Disease.

Data describing the incidence and the risk factors for surgical interventions in pediatric Crohn's disease (CD) is inconsistent. Our aim was to describe the rates of intestinal surgery and to identify associated risk factors in a large cohort of children with CD. Medical charts of 482 children with CD from the Schneider Pediatric Inflammatory Bowel Disease cohort who were diagnosed between 1981 and 2013 were carefully reviewed retrospectively. Of 482 patients, 143 (29.7%) underwent intestinal surgery with a median follow-up time of 8.6 years (range, 1-30.5). Kaplan-Meier survival estimates of the cumulative probability of CD-related intestinal surgery were 14.2% at 5 years and 24.5% at 10 years from diagnosis. Of these, 14% needed more than one operation. Multivariate Cox models showed that isolated ileal disease (hazard ratio [HR] 2.39, P = 0.008), complicated behavior (penetrating or stricturing) (HR 2.44, P < 0.001) and higher severity indices, at diagnosis, including Harvey-Bradshaw (HR 1.06, P = 0.009) and short Pediatric Crohn's Disease Activity Index (HR 1.02, P = 0.001) were associated with increased risk for intestinal surgery. Age, gender, family history of CD, early introduction of immunomodulators, treatment with anti-tumor necrosis factor α, or diagnosis before the year 2000 did not affect the risk of bowel surgery. Ileal location, complicated behavior, and higher disease activity indices at diagnosis are independent risk factors for bowel surgery, whereas anti-tumor necrosis factor α treatment and diagnosis during the "biological era" are not associated with diminished long-term surgical risk.

Adherence to Infliximab Treatment in a Pediatric Inflammatory Bowel Disease Cohort.

The aims of the study were to describe infliximab adherence in a pediatric inflammatory bowel disease cohort, to identify demographic and disease factors associated with adherence, and to examine differences in acute care use among adherent and nonadherent patients. Charts of patients who received infliximab at the Children's Hospital of Wisconsin (CHW) between October 2010 and October 2012 were retrospectively reviewed. A total of 151 patients met the inclusion criteria; 91.4% of the patients were adherent. Nonadherent patients had more emergency room visits and hospitalizations than adherent patients. The study is the first to show high adherence rates to infliximab in a pediatric cohort.