Stratification of risk of progression to colectomy in ulcerative colitis via measured and predicted gene expression.

An important goal of clinical genomics is to be able to estimate the risk of adverse disease outcomes. Between 5% and 10% of individuals with ulcerative colitis (UC) require colectomy within 5 years of diagnosis, but polygenic risk scores (PRSs) utilizing findings from genome-wide association studies (GWASs) are unable to provide meaningful prediction of this adverse status. By contrast, in Crohn disease, gene expression profiling of GWAS-significant genes does provide some stratification of risk of progression to complicated disease in the form of a transcriptional risk score (TRS). Here, we demonstrate that a measured TRS based on bulk rectal gene expression in the PROTECT inception cohort study has a positive predictive value approaching 50% for colectomy. Single-cell profiling demonstrates that the genes are active in multiple diverse cell types from both the epithelial and immune compartments. Expression quantitative trait locus (QTL) analysis identifies genes with differential effects at baseline and week 52 follow-up, but for the most part, differential expression associated with colectomy risk is independent of local genetic regulation. Nevertheless, a predicted polygenic transcriptional risk score (PPTRS) derived by summation of transcriptome-wide association study (TWAS) effects identifies UC-affected individuals at 5-fold elevated risk of colectomy with data from the UK Biobank population cohort studies, independently replicated in an NIDDK-IBDGC dataset. Prediction of gene expression from relatively small transcriptome datasets can thus be used in conjunction with TWASs for stratification of risk of disease complications.

Progression of Pediatric Crohn's Disease Is Associated With Anti-Tumor Necrosis Factor Timing and Body Mass Index Z-Score Normalization.

BACKGROUND & AIMS: The evolution of complicated pediatric Crohn's disease (CD) in the era of anti-tumor necrosis factor (aTNF) therapy continues to be described. Because CD progresses from inflammatory to stricturing (B2) and penetrating (B3) disease behaviors in a subset of patients, we aimed to understand the risk of developing complicated disease behavior or undergoing surgery in relation to aTNF timing and body mass index z-score (BMIz) normalization. METHODS: Multicenter, 5-year longitudinal data from 1075 newly diagnosed CD patients were analyzed. Descriptive statistics, univariate and stepwise multivariate Cox proportional hazard regression (CPHR), and log-rank analyses were performed for risk of surgery and complicated disease behaviors. Differential gene expression from ileal bulk RNA sequencing was correlated with outcomes. RESULTS: Stricturing complications had the largest increase: from 2.98% to 10.60% over 5 years. Multivariate CPHR showed aTNF exposure within 3 months from diagnosis (hazard ratio [HR], 0.33; 95% CI, 0.15-0.71) and baseline L2 disease (HR, 0.29; 95% CI, 0.09-0.92) to be associated with reduced B1 to B2 progression. For children with a low BMIz at diagnosis (n = 294), multivariate CPHR showed BMIz normalization within 6 months of diagnosis (HR, 0.47; 95% CI, 0.26-0.85) and 5-aminosalicyclic acid exposure (HR, 0.32; 95% CI, 0.13-0.81) were associated with a decreased risk for surgery while B2 (HR, 4.20; 95% CI, 1.66-10.65) and B2+B3 (HR, 8.24; 95% CI, 1.08-62.83) at diagnosis increased surgery risk. Patients without BMIz normalization were enriched for genes in cytokine production and inflammation. CONCLUSIONS: aTNF exposure up to 3 months from diagnosis may reduce B2 progression. In addition, lack of BMIz normalization within 6 months of diagnosis is associated with increased surgery risk and a proinflammatory transcriptomic profile.

Early Change in Fecal Calprotectin Predicts One-Year Outcome in Children Newly Diagnosed With Ulcerative Colitis.

INTRODUCTION: While fecal calprotectin (FC) is used to assess disease activity in ulcerative colitis (UC) there are little data concerning the role of serial FC levels at diagnosis in predicting clinical course. We sought to determine whether FC at diagnosis or early change following therapy predicts clinical outcomes in pediatric UC.Methods: Children with newly diagnosed UC were treated with standardized regimens of mesalamine or corticosteroids (CS). CS tapering and escalation to additional therapy or colectomy were by protocol. Patients with baseline or week 4 or week 12 FC levels were included in the analysis. Our primary outcome was CS-free remission on mesalamine at week 52. We compared the prognostic value of a baseline FC as well as a change in FC by week 4 or week 12 in predicting clinical outcomes. RESULTS: The study included 352 children (113 initial mesalamine, 239 initial CS, mean age 12.6 years) with UC. At Week 52, 135 (38.3%), 84 (23.8%), and 19 (5.4%) children achieved CS-free remission, needed anti-tumor necrosis factor therapy or had colectomy respectively. Baseline FC was not associated with CS-free remission at week 52. However, both week 4 (odds ratio [OR] 0.95, 95% confidence interval [CI] 0.901.00) and week 12 FC levels (OR 0.91, 95% CI 0.87-0.96) were associated with outcomes, with the latter having a stronger association with CS-free remission. Patients with a >75% decrease by 12 weeks, had a 3-fold increased likelihood of CS-free remission at 1 year. DISCUSSION: Longitudinal changes in FC may predict 1 year outcomes better than values at diagnosis in children with a new diagnosis of UC.

P072 Non-invasive Vagal Nerve Stimulation to Treat Crohn Disease and Ulcerative Colitis in Children and Young Adults: A Proof-of-Concept Clinical Trial.

BACKGROUND: Current inflammatory bowel disease (IBD) therapies are limited by incomplete efficacy, loss of response, side effects and high costs. Vagal nerve stimulation (VNS) is an investigational Bioelectronic Medicine therapy targeting the nervous system to treat IBD through an 'inflammatory reflex' that reduces systemic inflammation. Data in humans with IBD are promising but limited to two small studies using a cervically implanted VNS device in adults with Crohn disease (CD); no data exist to date using a non-invasive VNS modality in IBD. This study aimed to evaluate the efficacy and safety of transcutaneous auricular VNS (ta-VNS) in children and young adults with CD or ulcerative colitis (UC). METHODS: IBD patients 10-21 years of age with mild/moderate CD or UC who did not achieve remission with conventional therapy, and a fecal calprotectin (FC) >200 ug/g within 4 weeks of study entry were enrolled. Subjects were randomized to receive either ta-VNS using a transcutaneous electrical nerve stimulator unit targeting the cymba conchae of the external left ear, or sham stimulation of the posterior lower leg, for 5 minutes once daily for a 2-week duration followed by a switch to the alternative stimulation for an additional 2 weeks. At week 4, all subjects were assigned to receive active ta-VNS for 5 minutes twice daily until week 16 so that all received 14 weeks of active ta-VNS by the end of the study. Primary study endpoint was defined as ∆FC ≥50% reduction from baseline to week 16. Secondary endpoints included improvement in weighted Pediatric Crohn Disease Activity Index (wPCDAI) or Pediatric Ulcerative Colitis Activity Index (PUCAI). RESULTS: Twenty-two subjects were enrolled (12 UC, 10 CD; median age 14.4 years [range 10-21] 54.5% male). Median baseline FC was 587 (range 18 - 3828, SD 1074). 5 subjects (4 UC, 1 CD) had FC levels 12.5 at baseline, 3 (50%) achieved clinical remission (wPCDAI ≤ 10) at week 16. In the full UC cohort (n = 12), baseline PUCAI ranged from 0-45. In the 6 with PUCAI > 10 at baseline, 2 (33%) achieved clinical remission at week 16. There were no safety concerns. CONCLUSION: Non-invasive ta-VNS reduced FC levels and improved symptoms in a pediatric cohort with mild/moderate IBD. Further research is needed to identify optimal electrical dose and settings to achieve peak anti-inflammatory effect and to identify the mechanistic principles for this therapy.

Clinical and biological predictors of response to standardised paediatric colitis therapy (PROTECT): a multicentre inception cohort study.

BACKGROUND: Lack of evidence-based outcomes data leads to uncertainty in developing treatment regimens in children who are newly diagnosed with ulcerative colitis. We hypothesised that pretreatment clinical, transcriptomic, and microbial factors predict disease course. METHODS: In this inception cohort study, we recruited paediatric patients aged 4-17 years with newly diagnosed ulcerative colitis from 29 centres in the USA and Canada. Patients initially received standardised mesalazine or corticosteroids, with pre-established criteria for escalation to immunomodulators (ie, thiopurines) or anti-tumor necrosis factor-α (TNFα) therapy. We used RNA sequencing to define rectal gene expression before treatment, and 16S sequencing to characterise rectal and faecal microbiota. The primary outcome was week 52 corticosteroid-free remission with no therapy beyond mesalazine. We assessed factors associated with the primary outcome using logistic regression models of the per-protocol population. This study is registered with ClinicalTrials.gov, number NCT01536535. FINDINGS: Between July 10, 2012, and April 21, 2015, of 467 patients recruited, 428 started medical therapy, of whom 400 (93%) were evaluable at 52 weeks and 386 (90%) completed the study period with no protocol violations. 150 (38%) of 400 participants achieved week 52 corticosteroid-free remission, of whom 147 (98%) were taking mesalazine and three (2%) were taking no medication. 74 (19%) of 400 were escalated to immunomodulators alone, 123 (31%) anti-TNFα therapy, and 25 (6%) colectomy. Low baseline clinical severity, high baseline haemoglobin, and week 4 clinical remission were associated with achieving week 52 corticosteroid-free remission (n=386, logistic model area under the curve [AUC] 0·70, 95% CI 0·65-0·75; specificity 77%, 95% CI 71-82). Baseline severity and remission by week 4 were validated in an independent cohort of 274 paediatric patients with newly diagnosed ulcerative colitis. After adjusting for clinical predictors, an antimicrobial peptide gene signature (odds ratio [OR] 0·57, 95% CI 0·39-0·81; p=0·002) and abundance of Ruminococcaceae (OR 1·43, 1·02-2·00; p=0·04), and Sutterella (OR 0·81, 0·65-1·00; p=0·05) were independently associated with week 52 corticosteroid-free remission. INTERPRETATION: Our findings support the utility of initial clinical activity and treatment response by 4 weeks to predict week 52 corticosteroid-free remission with mesalazine alone in children who are newly diagnosed with ulcerative colitis. The development of personalised clinical and biological signatures holds the promise of informing ulcerative colitis therapeutic decisions. FUNDING: US National Institutes of Health.

Blood-Derived DNA Methylation Signatures of Crohn's Disease and Severity of Intestinal Inflammation.

BACKGROUND & AIMS: Crohn's disease is a relapsing and remitting inflammatory disorder with a variable clinical course. Although most patients present with an inflammatory phenotype (B1), approximately 20% of patients rapidly progress to complicated disease, which includes stricturing (B2), within 5 years. We analyzed DNA methylation patterns in blood samples of pediatric patients with Crohn's disease at diagnosis and later time points to identify changes that associate with and might contribute to disease development and progression. METHODS: We obtained blood samples from 164 pediatric patients (1-17 years old) with Crohn's disease (B1 or B2) who participated in a North American study and were followed for 5 years. Participants without intestinal inflammation or symptoms served as controls (n = 74). DNA methylation patterns were analyzed in samples collected at time of diagnosis and 1-3 years later at approximately 850,000 sites. We used genetic association and the concept of Mendelian randomization to identify changes in DNA methylation patterns that might contribute to the development of or result from Crohn's disease. RESULTS: We identified 1189 5'-cytosine-phosphate-guanosine-3' (CpG) sites that were differentially methylated between patients with Crohn's disease (at diagnosis) and controls. Methylation changes at these sites correlated with plasma levels of C-reactive protein. A comparison of methylation profiles of DNA collected at diagnosis of Crohn's disease vs during the follow-up period showed that, during treatment, alterations identified in methylation profiles at the time of diagnosis of Crohn's disease more closely resembled patterns observed in controls, irrespective of disease progression to B2. We identified methylation changes at 3 CpG sites that might contribute to the development of Crohn's disease. Most CpG methylation changes associated with Crohn's disease disappeared with treatment of inflammation and might be a result of Crohn's disease. CONCLUSIONS: Methylation patterns observed in blood samples from patients with Crohn's disease accompany acute inflammation; with treatment, these change to resemble methylation patterns observed in patients without intestinal inflammation. These findings indicate that Crohn's disease-associated patterns of DNA methylation observed in blood samples are a result of the inflammatory features of the disease and are less likely to contribute to disease development or progression.

Analysis of Using the Total White Blood Cell Count to Define Severe New-onset Ulcerative Colitis in Children.

OBJECTIVES: The aim of this study was to assess common laboratory tests in identifying severe ulcerative colitis in children at diagnosis. METHODS: A cohort of 427 children 4 to 17 years of age newly diagnosed with ulcerative colitis (UC) was prospectively enrolled. Boosted classification trees were used to characterize predictive ability of disease attributes based on clinical disease severity using Pediatric Ulcerative Colitis Activity Index (PUCAI), severe (65+) versus not severe (<65) and total Mayo score, severe (10-12) versus not severe (<10); mucosal disease by Mayo endoscopic subscore, severe (3) versus not severe (<3); and extensive disease versus not extensive (left-sided and proctosigmoiditis). RESULTS: Mean age was 12.7 years; 49.6% (n = 212) were girls, and 83% (n = 351) were Caucasian. Severe total Mayo score was present in 28% (n = 120), mean PUCAI score was 49.8 ±â€Š20.1, and 33% (n = 142) had severe mucosal disease with extensive involvement in 82% (n = 353). Classification and regression trees identified white blood cell count, erythrocyte sedimentation rate, and platelet count (PLT) as the set of 3 best blood laboratory tests to predict disease extent and severity. For mucosal severity, albumin (Alb) replaced PLT. Classification models for PUCAI and total Mayo provided sensitivity of at least 0.65 using standard clinical cut-points with misclassification rates of approximately 30%. CONCLUSIONS: A combination of the white blood cell count, erythrocyte sedimentation rate, and either PLT or albumin is the best predictive subset of standard laboratory tests to identify severe from nonsevere clinical or mucosal disease at diagnosis in relation to objective clinical scores.

Association Between Plasma Level of Collagen Type III Alpha 1 Chain and Development of Strictures in Pediatric Patients With Crohn's Disease.

BACKGROUND & AIMS: There are few serum biomarkers to identify patients with Crohn's disease (CD) who are at risk for stricture development. The extracellular matrix components, collagen type III alpha 1 chain (COL3A1) and cartilage oligomeric matrix protein (COMP), could contribute to intestinal fibrosis. We investigated whether children with inflammatory CD (B1) who later develop strictures (B2) have increased plasma levels of COL3A1 or COMP at diagnosis, compared with children who remain B1. We compared results with previously studied biomarkers, including autoantibodies against colony-stimulating factor 2 (CSF2). METHODS: We selected 161 subjects (mean age, 12.2 y; 62% male) from the Risk Stratification and Identification of Immunogenic and Microbial Markers of Rapid Disease Progression in Children with Crohn's cohort, completed at 28 sites in the United States and Canada from 2008 through 2012. The children underwent colonoscopy and upper endoscopy at diagnosis and were followed up every 6 months for 36 months; plasma samples were collected at baseline. Based on CD phenotype, children were separated to group 1 (B1 phenotype at diagnosis and follow-up evaluation), group 2 (B2 phenotype at diagnosis), or group 3 (B1 phenotype at diagnosis who developed strictures during follow-up evaluation). Plasma samples were collected from patients and 40 children without inflammatory bowel disease (controls) at baseline and analyzed by enzyme-linked immunosorbent assay to measure COL3A1 and COMP. These results were compared with those from a previous biomarker study. The Kruskal-Wallis test and the pairwise Dunn test with Bonferroni correction were used to compare differences among groups. RESULTS: The median baseline concentration of COL3A1 was significantly higher in plasma from group 3 vs group 1 (P < .01) and controls (P = .01). Median baseline plasma concentrations of COMP did not differ significantly among groups. A model comprising baseline concentrations of COL3A1 and anti-CSF2 identified patients with B2 vs B1 CD with an area under the curve of 0.80 (95% CI, 0.71-0.89); the combined concentration identified patients with strictures with a sensitivity value of 0.70 (95% CI, 0.55-0.83) and a specificity value of 0.83 (95% CI, 0.67-0.93). CONCLUSIONS: We found median plasma concentrations of COL3A1, measured by enzyme-linked immunosorbent assay at diagnosis, to be significantly higher in patients with CD who later developed strictures than in patients without strictures. The combination of concentrations of COL3A1 and anti-CSF2 might be used to identify pediatric patients at CD diagnosis who are at risk for future strictures. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT00790543.

Should We Assess Vitamin D Status in Pediatric Patients With Celiac Disease?

OBJECTIVES: Screening for vitamin D status in celiac disease (CD) has been recommended but the literature provides varying support. We sought to assess the vitamin D status in newly diagnosed children with CD and in a non-CD control population and relate them to vitamin D intake. METHODS: In a cross-sectional study, serum 25-hydroxyvitamin D (25-OHD) levels were drawn in children with newly diagnosed CD and compared with pediatric outpatients with functional abdominal complaints. Anthropometric data as well as vitamin D intake based on milk and multivitamin ingestion were collected. RESULTS: Thirty-eight newly diagnosed CD patients (10.4 ±â€Š3.0 years old; 50% girls) and 82 controls (11.2 ±â€Š4.2 years old; 58.5% girls) were studied. Both groups were similar except for average daily D intake and BMI. There was no statistical difference in mean 25-OHD levels between CD (26.4 ±â€Š8.0 ng/mL) and controls (23.5 ±â€Š8.2 ng/mL) [P ≤ 0.07]. Both groups had high percentages of suboptimal D status (65.8% CD and 79.3% controls). 25-OHD levels significantly correlated with age (r = -0.262; P < 0.0038) and estimated vitamin D intake (r = 0.361; P < 0.0001). CONCLUSIONS: No significant difference in 25-OHD levels was noted between newly diagnosed CD and controls, but inadequate 25-OHD levels were common in both. 25-OHD levels were highly associated with vitamin D intake demonstrating similar vitamin D absorption between patients and controls. As CD is associated with bone disease and D status is frequently low, efforts at optimizing D, such as screening levels at diagnosis need to be conducted.

Prediction of complicated disease course for children newly diagnosed with Crohn's disease: a multicentre inception cohort study.

BACKGROUND: Stricturing and penetrating complications account for substantial morbidity and health-care costs in paediatric and adult onset Crohn's disease. Validated models to predict risk for complications are not available, and the effect of treatment on risk is unknown. METHODS: We did a prospective inception cohort study of paediatric patients with newly diagnosed Crohn's disease at 28 sites in the USA and Canada. Genotypes, antimicrobial serologies, ileal gene expression, and ileal, rectal, and faecal microbiota were assessed. A competing-risk model for disease complications was derived and validated in independent groups. Propensity-score matching tested the effect of anti-tumour necrosis factor α (TNFα) therapy exposure within 90 days of diagnosis on complication risk. FINDINGS: Between Nov 1, 2008, and June 30, 2012, we enrolled 913 patients, 78 (9%) of whom experienced Crohn's disease complications. The validated competing-risk model included age, race, disease location, and antimicrobial serologies and provided a sensitivity of 66% (95% CI 51-82) and specificity of 63% (55-71), with a negative predictive value of 95% (94-97). Patients who received early anti-TNFα therapy were less likely to have penetrating complications (hazard ratio [HR] 0·30, 95% CI 0·10-0·89; p=0·0296) but not stricturing complication (1·13, 0·51-2·51; 0·76) than were those who did not receive early anti-TNFα therapy. Ruminococcus was implicated in stricturing complications and Veillonella in penetrating complications. Ileal genes controlling extracellular matrix production were upregulated at diagnosis, and this gene signature was associated with stricturing in the risk model (HR 1·70, 95% CI 1·12-2·57; p=0·0120). When this gene signature was included, the model's specificity improved to 71%. INTERPRETATION: Our findings support the usefulness of risk stratification of paediatric patients with Crohn's disease at diagnosis, and selection of anti-TNFα therapy. FUNDING: Crohn's and Colitis Foundation of America, Cincinnati Children's Hospital Research Foundation Digestive Health Center.

Infliximab Is Not Associated With Increased Risk of Malignancy or Hemophagocytic Lymphohistiocytosis in Pediatric Patients With Inflammatory Bowel Disease.

BACKGROUND AND AIMS: Immunosuppressive therapy for inflammatory bowel disease (IBD) in pediatric patients is thought to increase the risk of malignancy and lymphoproliferative disorders, including hemophagocytic lymphohistiocytosis (HLH). We compared unadjusted incidence rates of malignancy and HLH in pediatric patients with IBD exposed to infliximab (IFX) with patients not exposed to biologics and calculated standardized incidence ratios (SIRs). METHODS: We collected and analyzed data from 5766 participants in a prospective study of long-term outcomes of pediatric patients with IBD (NCT00606346), from May 31, 2007 through June 30, 2016. Patients were 17 years old or younger and had Crohn's disease, ulcerative colitis, or IBD-unclassified with 24,543.0 patient-years of follow-up. We estimated incidence rates for malignancy and HLH as events/1000 patient-years of follow-up. We calculated age-, sex-, and race-adjusted SIRs, with 95% confidence intervals (CIs), using the Surveillance, Epidemiology, and End Results Program (SEER) database. RESULTS: Thirteen of the 15 patients who developed a malignancy and all 5 of the patients who developed HLH had been exposed to thiopurines; 10 patients with malignancy had also been exposed to a biologic agent. Unadjusted incidence rates showed no increased risk of malignancy (0.46/1000 patient-years) or HLH (0.0/1000 patient-years) in patients exposed to IFX as the only biologic vs those unexposed to biologics (malignancy: 1.12/1000 patient-years; HLH: 0.56/1000 patient-years). SIRs did not demonstrate an increased risk of malignancy among patients exposed to IFX (SIR, 1.69; 95% CI, 0.46-4.32) vs patients not exposed to a biologic agent (SIR, 2.17; 95% CI, 0.59-5.56), even when patients were stratified by thiopurine exposure. CONCLUSIONS: In determination of age-, sex-, and race-adjusted SIRs using data from a large clinical study and the SEER database, we found that IFX exposure did not associate with increased risk of malignancy or HLH in pediatric patients with IBD. Thiopurine exposure is an important precedent event for the development of malignancy or HLH in pediatric patients with IBD.

Biologics Delay Progression of Crohn's Disease, but Not Early Surgery, in Children.

BACKGROUND & AIMS: Up to 30% of patients with Crohn's disease (CD) require surgery within the first 5 years from diagnosis. We investigated the recent risk of bowel surgery in an inception cohort of pediatric patients with CD and whether early use of biologics (tumor necrosis factor antagonists) alters later disease course. METHODS: We collected data from the Pediatric Inflammatory Bowel Disease Collaborative Research Group registry on 1442 children (age, ≤16 y) diagnosed with CD from January 2002 through December 2014. Data were collected at diagnosis, 30 days following diagnosis, and then quarterly and during hospitalizations for up to 12 years. Our primary aim was to determine the 10-year risk for surgery in children with CD. Our secondary aim was to determine whether early use of biologics (<3 mo of diagnosis) affected risk of disease progression. RESULTS: The 10-year risk of first bowel surgery was 26%. The 5-year risk of bowel surgery did not change from 2002 through 2014, and remained between 13% and 14%. Most surgeries occurred within 3 years from diagnosis. The only predictor of surgery was disease behavior at diagnosis. CD with inflammatory behavior had the lowest risk of surgery compared to stricturing disease, penetrating disease, or both. We associated slowing of disease progression to stricturing or penetrating disease (but not surgery) with early use of biologics, but this effect only became evident after 5 years of disease. Our results indicate that biologics slow disease progression over time (hazard ratio, 0.85; 95% CI, 0.76-0.95). CONCLUSIONS: In an analysis of data from a registry of pediatric patients with CD, we found that among those with significant and progressing disease at or shortly after presentation, early surgery is difficult to prevent, even with early use of biologics. Early use of biologics (<3 mo of diagnosis) can delay later disease progression to stricturing and/or penetrating disease, but this affect could become evident only years after initial management decisions are made.

Mucosal Expression of Type 2 and Type 17 Immune Response Genes Distinguishes Ulcerative Colitis From Colon-Only Crohn's Disease in Treatment-Naive Pediatric Patients.

BACKGROUND & AIMS: There is controversy regarding the role of the type 2 immune response in the pathogenesis of ulcerative colitis (UC)-few data are available from treatment-naive patients. We investigated whether genes associated with a type 2 immune response in the intestinal mucosa are up-regulated in treatment-naive pediatric patients with UC compared with patients with Crohn's disease (CD)-associated colitis or without inflammatory bowel disease (IBD), and whether expression levels are associated with clinical outcomes. METHODS: We used a real-time reverse-transcription quantitative polymerase chain reaction array to analyze messenger RNA (mRNA) expression patterns in rectal mucosal samples from 138 treatment-naive pediatric patients with IBD and macroscopic rectal disease, as well as those from 49 children without IBD (controls), enrolled in a multicenter prospective observational study from 2008 to 2012. Results were validated in real-time reverse-transcription quantitative polymerase chain reaction analyses of rectal RNA from an independent cohort of 34 pediatric patients with IBD and macroscopic rectal disease and 17 controls from Cincinnati Children's Hospital Medical Center. RESULTS: We measured significant increases in mRNAs associated with a type 2 immune response (interleukin [IL]5 gene, IL13, and IL13RA2) and a type 17 immune response (IL17A and IL23) in mucosal samples from patients with UC compared with patients with colon-only CD. In a regression model, increased expression of IL5 and IL17A mRNAs distinguished patients with UC from patients with colon-only CD (P = .001; area under the receiver operating characteristic curve, 0.72). We identified a gene expression pattern in rectal tissues of patients with UC, characterized by detection of IL13 mRNA, that predicted clinical response to therapy after 6 months (odds ratio [OR], 6.469; 95% confidence interval [CI], 1.553-26.94), clinical response after 12 months (OR, 6.125; 95% CI, 1.330-28.22), and remission after 12 months (OR, 5.333; 95% CI, 1.132-25.12). CONCLUSIONS: In an analysis of rectal tissues from treatment-naive pediatric patients with IBD, we observed activation of a type 2 immune response during the early course of UC. We were able to distinguish patients with UC from those with colon-only CD based on increased mucosal expression of genes that mediate type 2 and type 17 immune responses. Increased expression at diagnosis of genes that mediate a type 2 immune response is associated with response to therapy and remission in pediatric patients with UC.

The Effect of Early-Life Environmental Exposures on Disease Phenotype and Clinical Course of Crohn's Disease in Children.

OBJECTIVES: Environmental factors play an important role in the pathogenesis of Crohn's Disease (CD). In particular, by virtue of the instability of the microbiome and development of immunologic tolerance, early life factors may exert the strongest influence on disease risk and phenotype. METHODS: We used data from 1119 CD subjects recruited from RISK inception cohort to examine the impact of early life environment on disease progression. Our primary exposures of interest were breastfeeding in infancy and exposure to maternal, active, or passive smoke. Our primary outcomes were development of complicated (stricturing or penetrating) disease, and need for CD-related hospitalization, and surgery. Multivariable logistic regression models were used to define independent associations, adjusting for relevant covariates. RESULTS: Our study cohort included 1119 patients with CD among whom 15% had stricturing (B2) or penetrating disease (B3) by 3 years. 331 patients (35%) and 95 patients (10.6%) required CD-related hospitalizations and surgery respectively. 74.5% were breastfed in infancy and 31% were exposed to smoking among whom 7% were exposed to maternal smoke. On multivariable analysis, a history of breastfeeding was inversely associated with complicated (B2/B3 disease) 0.65, CI 95% 0.44-96; P = 0.03) in pediatric CD. Maternal smoking during pregnancy was associated with increased risk of hospitalization during the 3-year follow-up period (OR 1.75, CI 95% 1.05-2.89; P = 0.03). CONCLUSIONS: Early life environmental factors influence the eventual phenotypes and disease course in CD.

Concomitant Use of Immunomodulators Affects the Durability of Infliximab Therapy in Children With Crohn's Disease.

BACKGROUND & AIMS: It is important to determine the effects of immunomodulators on the ability of children to remain on infliximab therapy for Crohn's disease (durability of therapy), given the potential benefits and risks of concomitant therapy-especially with thiopurines in male patients. We investigated how immunomodulatory treatment affects the durability of infliximab therapy. METHODS: We collected data from the Pediatric Inflammatory Bowel Disease Collaborative Research Group Registry, from January 2002 through August 2014, on 502 children with Crohn's disease who participated in a prospective multicenter study. Data were collected from patients who received at least a 3-dose induction regimen of infliximab, and their concomitant use of immunomodulators: no thiopurine or methotrexate treatment, treatment for 6 months or less during infliximab therapy, or treatment for more than 6 months during infliximab therapy. RESULTS: The probabilities (± standard error) that children remained on infliximab therapy for 1 year, 3 years, and 5 years after the treatment began were 0.84 ± 0.02, 0.69 ± 0.03, and 0.60 ± 0.03, respectively. Age, sex, and disease extent or location did not affect the durability of infliximab therapy. Greater length of concomitant use of immunomodulators was associated with increased time of infliximab therapy. The probability that patients with more than 6 months of immunomodulator use remained on infliximab therapy for 5 years was 0.70 ± 0.04, compared with 0.48 ± 0.08 for patients who did not receive immunomodulators and 0.55 ± 0.06 for patients who received immunomodulators for 6 months or less (P < .001). In boys who received immunomodulators for 6 months or more after starting infliximab, the overall durability of infliximab therapy was greater among patients receiving methotrexate than thiopurine (P < .01); the probabilities that they remained on infliximab therapy for 5 years were 0.97 ± 0.03 vs 0.58 ± 0.08, respectively. CONCLUSIONS: In children with Crohn's disease, concomitant treatment with an immunomodulator for more than 6 months after starting infliximab therapy increases the chances that patients will remain on infliximab. In boys, methotrexate appears to increase the durability of infliximab therapy compared with thiopurine.

Increased effectiveness of early therapy with anti-tumor necrosis factor-α vs an immunomodulator in children with Crohn's disease.

BACKGROUND & AIMS: Standard therapy for children newly diagnosed with Crohn's disease (CD) includes early administration of immunomodulators after initial treatment with corticosteroids. We compared the effectiveness of early (≤3 mo after diagnosis) treatment with an anti-tumor necrosis factor (TNF)α with that of an immunomodulator in attaining clinical remission and facilitating growth of pediatric patients. METHODS: We analyzed data from the RISK study, an observational research program that enrolled patients younger than age 17 diagnosed with inflammatory (nonpenetrating, nonstricturing) CD from 2008 through 2012 at 28 pediatric gastroenterology centers in North America. Patients were managed by physician dictate. From 552 children (median age, 11.8 y; 61% male; 63% with pediatric CD activity index scores >30; and median C-reactive protein level 5.6-fold the upper limit of normal), we used propensity score methodology to identify 68 triads of patients matched for baseline characteristics who were treated with early anti-TNFα therapy, early immunomodulator, or no early immunotherapy. We evaluated relationships among therapies, corticosteroid and surgery-free remission (pediatric CD activity index scores, ≤10), and growth at 1 year for 204 children. Treatment after 3 months was a covariate. RESULTS: Early treatment with anti-TNFα was superior to early treatment with an immunomodulator (85.3% vs 60.3% in remission; relative risk, 1.41; 95% confidence interval [CI], 1.14-1.75; P = .0017), whereas early immunomodulator therapy was no different than no early immunotherapy (60.3% vs 54.4% in remission; relative risk, 1.11; 95% CI, 0.83-1.48; P = .49) in achieving remission at 1 year. Accounting for therapy after 3 months, early treatment with anti-TNFα remained superior to early treatment with an immunomodulator (relative risk, 1.51; 95% CI, 1.20-1.89; P = .0004), whereas early immunomodulator therapy was no different than no early immunotherapy (relative risk, 1.00; 95% CI, 0.75-1.34; P = .99). The mean height z-score increased compared with baseline only in the early anti-TNFα group. CONCLUSIONS: In children newly diagnosed with comparably severe CD, early monotherapy with anti-TNFα produced better overall clinical and growth outcomes at 1 year than early monotherapy with an immunomodulator. Further data will be required to best identify children most likely to benefit from early treatment with anti-TNFα therapy.

Clinical Presentation and Five-Year Therapeutic Management of Very Early-Onset Inflammatory Bowel Disease in a Large North American Cohort.

OBJECTIVE: To evaluate the presentation, therapeutic management, and long-term outcome of children with very early-onset (VEO) (≤ 5 years of age) inflammatory bowel disease (IBD). STUDY DESIGN: Data were obtained from an inception cohort of 1928 children with IBD enrolled in a prospective observational registry at multiple centers in North America. RESULTS: One hundred twelve children were ≤ 5 years of age with no child enrolled at <1 year of age. Of those, 42.9% had Crohn's disease (CD), 46.4% ulcerative colitis (UC), and 10.7% had IBD-unclassified. Among the children with CD, children 1-5 years of age had more isolated colonic disease (39.6%) compared with 6- to 10-year-olds (25.3%, P = .04), and 11- to 16-year-olds (22.3%, P < .01). The change from a presenting colon-only phenotype to ileocolonic began at 6-10 years. Children 1-5 years of age with CD had milder disease activity (45.8%) at diagnosis compared with the oldest group (28%, P = .01). Five years postdiagnosis, there was no difference in disease activity among the 3 groups. However, compared with the oldest group, a greater proportion of 1- to 5-year-olds with CD were receiving corticosteroids (P < .01) and methotrexate (P < .01), and a greater proportion of 1- to 5-year-olds with UC were receiving mesalamine (P < .0001) and thiopurine immunomodulators (P < .0002). CONCLUSIONS: Children with VEO-CD are more likely to have mild disease at diagnosis and present with a colonic phenotype with change to an ileocolonic phenotype noted at 6-10 years of age. Five years after diagnosis, children with VEO-CD and VEO-UC are more likely to have been administered corticosteroids and immunomodulators despite similar disease activity in all age groups. This may suggest development of a more aggressive disease phenotype over time.

Can we change the natural history of Crohn's disease with early immunomodulation?

In both children and adults, the natural history of Crohn's disease (CD) is characterized by relapsing and remitting bouts of intestinal inflammation, often associated with a progressive shift from inflammatory to complicated stricturing or penetrating disease behavior. The past 2 decades have seen a dramatic shift in therapeutic approach with the increasingly common use of early thiopurine immunomodulation. These maintenance medications were initially introduced primarily as corticosteroid-sparing agents capable of minimizing recurrent flares of inflammatory disease and have proven to be quite efficacious. Increasing evidence suggests, however, that thiopurines may only delay rather than prevent the development of complicated disease behavior. Data from both adult and pediatric CD populations from around the world are reviewed in terms of the effect of early immunomodulation on progression to complicated disease behavior, need for surgery, and prevention of recurrent disease after resection. The effect of thiopurines on the growth of children is also reviewed.

Liver enzyme elevations within 3 months of diagnosis of inflammatory bowel disease and likelihood of liver disease.

BACKGROUND: Inflammatory bowel disease-associated liver diseases (IBD-LDs) include autoimmune hepatitis (AIH), primary sclerosing cholangitis (PSC), and an overlap syndrome. Prospective unbiased multicenter data regarding the frequency of IBD-LD in patients with pediatric inflammatory bowel disease (IBD) are lacking. We examined early alanine aminotransferase (ALT) and γ-glutamyl transpeptidase (GGT) elevations in children diagnosed as having IBD and assessed the likelihood of IBD-LD. METHODS: Data collected from the prospective observational Pediatric Inflammatory Bowel Disease Collaborative Research Group Registry enrolling children of age <16 years within 30 days of diagnosis. AIH, PSC, and overlap syndrome were diagnosed using local institutional criteria. RESULTS: A total of 1569 subjects had liver enzymes available. Of the total, 757 had both ALT and GGT, 800 had ALT only (no GGT), and 12 had GGT only (no ALT). Overall, 29 of 1569 patients (1.8%) had IBD-LD. IBD-LD was diagnosed in 1 of 661 (0.15%) of patients with both ALT and GGT ≤ 50 IU/L compared with 21 of 42 (50%) of patients with both ALT and GGT > 50 (odds ratio 660, P < 0.0001). Of the 29 patients with IBD-LD, 21 had PSC, 2 had AIH, and 6 had overlap syndrome. IBD-LD was more common in patients with ulcerative colitis and IBD-unclassified (indeterminate colitis) than in those with Crohn disease (4% vs 0.8%, respectively, P < 0.001). CONCLUSIONS: Elevation of both ALT and GGT within 90 days after the diagnosis of IBD is associated with a markedly increased likelihood of IBD-LD. Both ALT and GGT levels should be measured in all of the pediatric patients newly diagnosed as having IBD.