Common functional alterations identified in blood transcriptome of autoimmune cholestatic liver and inflammatory bowel diseases.

Primary biliary cholangitis (PBC), primary sclerosing cholangitis (PSC), and inflammatory bowel diseases (IBDs), including Crohn's disease (CD) and ulcerative colitis (UC), are heterogeneous chronic autoimmune diseases that may share underlying pathogenic mechanisms. Herein, we compared simultaneously analyzed blood transcriptomes from patients with PBC, PSC, and IBD. Microarray-based measurements were conducted using RNA isolated from whole blood samples from 90, 45, 95 and 93 patients with PBC, PSC, CD, and UC, respectively, and 47 healthy controls. Expression levels of selected transcripts were analyzed by quantitative reverse-transcribed PCR using an independent cohort of 292, 71 and 727 patients with PBC, PSC, and IBD, respectively. Of 4026, 2650 and 4967 probe sets differentially expressed (adjusted p-value < 0.05) in samples from patients with PBC, PSC, and IBD, respectively, compared with healthy controls, 1946 were common to all three comparisons. Functional analyses indicated that most terms enriched for genes differentially expressed in PBC, PSC, and IBD patients compared with healthy controls were related to mitochondrial function, the vesicle endomembrane system, and GTPase-mediated processes. This study indicates that microarray-based profiling of blood gene expression supports research into the molecular mechanisms underlying disease, rather than being useful for selection of diagnostic biomarkers for use in clinical practice.

Redefining the Practical Utility of Blood Transcriptome Biomarkers in Inflammatory Bowel Diseases.

BACKGROUND AND AIMS: The study investigates the practical utility of whole-blood gene expression profiling to diagnose inflammatory bowel diseases [IBDs]. METHODS: The discovery cohorts included 102 and 51 paediatric IBD patients and controls, and 95 and 46 adult IBD patients and controls, respectively. The replication cohorts included 447 and 76 paediatric IBD patients and controls, and 271 and 108 adult IBD patients and controls, respectively. In the discovery phase, RNA samples extracted from whole peripheral blood were analysed using RNA-Seq, and the predictive values of selected biomarkers were validated using quantitative polymerase chain reaction [qPCR]. RESULTS: In all, 15 differentially expressed transcripts [adjusted p ≤0.05] were selected from the discovery sequencing datasets. The receiver operating characteristic curves and area under the curve [ROC-AUC] in replication analyses showed high discriminative power [AUC range, 0.91-0.98] for 11 mRNAs in paediatric patients with active IBD. By contrast, the AUC-ROC values ranged from 0.63 to 0.75 in comparison among inactive paediatric IBDs and active/inactive adult IBDs, indicating a lack of discriminative power. The best multi-mRNA diagnostic classifier showed moderate discriminative power [AUC = 0.81] for paediatric inactive IBD, but was not able to discriminate active or inactive adult IBD patients from controls. The AUC-ROC values did not confirm an ability of the mRNAs abundances to discriminate between active ulcerative colitis and active Crohn's disease in paediatric or adult populations. CONCLUSIONS: This study identifies and validates blood transcriptional biomarkers that could be used in clinical settings as diagnostic predictors of IBD clinical activity in paediatric, but not adult, IBD patients.

Genetic architecture differences between pediatric and adult-onset inflammatory bowel diseases in the Polish population.

Most inflammatory bowel diseases (IBDs) are classic complex disorders represented by common alleles. Here we aimed to define the genetic architecture of pediatric and adult-onset IBDs for the Polish population. A total of 1495 patients were recruited, including 761 patients with Crohn's disease (CD; 424 pediatric), 734 patients with ulcerative colitis (UC; 390 pediatric), and 934 healthy controls. Allelotyping employed a pooled-DNA genome-wide association study (GWAS) and was validated by individual genotyping. Whole exome sequencing (WES) was performed on 44 IBD patients diagnosed before 6 years of age, 45 patients diagnosed after 40 years of age, and 18 healthy controls. Altogether, out of 88 selected SNPs, 31 SNPs were replicated for association with IBD. A novel BRD2 (rs1049526) association reached significance of P = 5.2 × 10-11 and odds ratio (OR) = 2.43. Twenty SNPs were shared between pediatric and adult patients; 1 and 7 were unique to adult-onset and pediatric-onset IBD, respectively. WES identified numerous rare and potentially deleterious variants in IBD-associated or innate immunity-associated genes. Deleterious alleles in both groups were over-represented among rare variants in affected children. Our GWAS revealed differences in the polygenic architecture of pediatric- and adult-onset IBD. A significant accumulation of rare and deleterious variants in affected children suggests a contribution by yet unexplained genetic components.

Monotherapy with infliximab versus combination therapy in the maintenance of clinical remission in children with moderate to severe Crohn disease.

OBJECTIVES: The aim of the present study was to compare the efficacy and safety of 2 protocols of maintenance therapy with infliximab (IFX) and an immunomodulatory agent in pediatric patients with Crohn disease (CD): withdrawal of immunomodulators versus continuation of immunosuppressants. METHODS: The present multicenter randomized open-label trial included 99 patients with CD (ages 14.5 ±â€Š2.6 years) who were administered IFX (5 mg/kg body weight) along with an immunomodulatory agent (azathioprine 1.5-3 mg/kg body weight per day, methotrexate 10-25 mg/week). After 10 weeks of the induction therapy, 84 responders were centrally randomized into 1 of the following groups: group I (n = 45) in which IFX and an immunomodulatory agent were continued up to week 54 and group II (n = 39) in which the immunomodulatory agent was discontinued after 26 weeks. RESULTS: The induction therapy was reflected by a significant decrease in Pediatric Crohn's Disease Activity Index (PCDAI) and Simplified Endoscopic Activity Score for Crohn's Disease (SES-CD) values. After the maintenance phase, the analyzed groups did not differ significantly in terms of the clinical response loss rates and final PCDAI and SES-CD scores. Furthermore, no significant intragroup differences were documented between mean PCDAI scores determined at the end of induction and maintenance phases. Intensification/modification of the treatment was required in 13 of 45 (29%) and 11 of 39 (28%) patients of groups I and II, respectively. A total of 9 serious adverse events were documented; none of the patients died during the trial. CONCLUSIONS: Twenty-six weeks likely represent the safe duration of combined IFX/immunomodulatory therapy in our sample of pediatric patients with CD.