P287 Serologic responses to microorganisms in IBD patients - a prospective longitudinal study
I. Goren1, L. Yahav2, H. Tulchinsky3, I. Dotan*1
1Sackler Faculty of Medicine, Tel Aviv Israel, IBD Center, Department of Gastroenterology and Liver Diseases, Tel Aviv Sourasky Medical Center , Tel Aviv, Israel, 2Tel Aviv Medical center, IBD Center, Department of Gastroenterology and Liver Diseases, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel, 3Sackler Faculty of Medicine, Tel Aviv Israel, Department of Surgery, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel
Inflammatory bowel diseases (IBD), specifically Crohn's disease (CD) are characterized by loss of tolerance towards intestinal microorganisms that may be reflected by serologic responses such as the anti-glycan antibodies. Patients with ulcerative colitis (UC) undergoing large bowel resection and ileal pouch anal anastomosis (pouch surgery), tend to develop small intestinal inflammation resembling CD. We hypothesized that pouch and CD patients have serologic similarities, and aimed to evaluate their serologic responses over time compared to unoperated UC.
IBD patients were prospectively recruited. Disease phenotype was determined clinically. Sera were tested for anti-glycan antibodies (anti-Saccharomyces cerevisiae, anti-laminaribioside, anti-chitobioside, and anti-mannobioside carbohydrate antibodies, ASCA, ALCA, ACCA, and AMCA, respectively) were assessed by ELISA.
A total of 232 IBD patients (112 CD, 39 UC, 81 pouch) were included. Mean age 38.1, 38.5 and 44.7 years, males 54.5%, 51.3% and 59.3%, Ashkenazi origin 29.5%, 25.6% and 39.5%, smoking 22.3%, 38.5% and 30.9%, disease duration at sampling 10.85, 8.95, 23.2 years for CD, UC and pouch patients respectively (duration for pouch was calculated from UC diagnosis).The mean visit number was 3.5, 4.2 and 2.4 over a period of 262.8, 335.4 and 505.4 days for CD, UC and pouch , respectively (p<0.0001 for both). Serum samples (2-14)were obtained during short, intermediate and long (1-3, 3-12, more than 12 months, respectively)follow-up periods. The prevalence of any positive serology upon recruitment was 67.9% ,30.8% and 45.7%, (p<0.0001) whereas ASCA positivity was 45.5%, 7.7% and 8.6% (p<0.0001) for CD, UC and pouch patients respectively. No significant short-term serologic changes were observed in any phenotype. However, a steady increase in AMCA mean titers was observed in CD and UC (36.2 IU, p=0.0001 and 37.4 IU, p=0.002, respectively). ALCA titer was modestly increased in the pouch group (mean change 8.4 IU, p=0.028). The rate of disease complications was comparable between short vs. long term follow-up groups. While ASCA positivity in CD was associated with surgical interventions, no associations between disease complications or phenotype and serology in UC and pouch patients were found. Male gender was an independent risk for having at least one positive antibody across the entire cohort with an OR of 5 (CI 1.3-19.2, p=0.02).
Serologic responses in IBD over time are generally stable, but AMCA tends to increase. Serologic stability after disease diagnosis may suggest that the causative processes are ongoing and that the major serologic changes occur before diagnosis or at its early stages.