Microbiome variation in ASCA-positive and ASCA-negative patients with Crohn's disease

Abstract

Background and Aim: Inflammatory bowel diseases (IBDs) are chronic relapsing conditions affecting the gut. There is a lack of literature around the clinical significance of anti-Saccharomyces cerevisiae antibody (ASCA) and the correlation of ASCA to gut microbiome in pediatric IBD. This study aimed to determine the correlation of ASCA to clinical features of pediatric CD patients and also the microbiome differences between ASCA-positive and ASCA-negative CD patients. Methods: ASCA analyses were performed on all patients with suspected IBD from 2003 to 2013. Microbiome analyses were performed on a subset of these patients from whom gut biopsies were available from the time of diagnosis. These results were correlated to disease location, age of onset, and severity based on the Paris modification of Montreal classification for pediatric IBD. Statistical analysis for microbiome variation was performed via PERMANOVA using the ADONIS function from the R package vegan. Results: Microbiome analyses revealed significant differences in the gut microbiome of ASCA-positive and ASCA-negative patients. ASCApositive patients were observed to have multiple oligotype species (OTPs), identified as Bacteroides fragilis, Escherichia coli, Fecalibacterium prausnitzii, Fusobacterium mortiferum, Hemophilus parainfluenzae, Prevotella copri, and Suturrella wadsworthensis, in more than 1% concentration. ASCA-negative patients had multiple but different OTPs, identified as all of the above besides a number of completely different OTPs, which were either absent or present in extremely low abundance in ASCApositive patients. Conclusion: Significant microbiome variation was observed between ASCA-positive and ASCA-negative patients. Variation in microbiome could be responsible for the variable positive rate of ASCA in CD patients.L6180063842017-08-31 <br />