Presenting Author:

Madeline Bertha, M.D.

Principal Investigator:

Subra Kugathasan, M.D.

Department:

Pediatrics

Keywords:

Inflammatory bowel disease, Crohn's disease, serology, African Americans

Location:

Ryan Family Atrium, Robert H. Lurie Medical Research Center

C87 - Clinical

IBD Serology and Disease Outcome in African-Americans with Crohn’s Disease

Background: Recent studies have identified the role of serological markers in characterizing disease phenotype, location, complications and severity among Northern Europeans (NE) with Crohn’s Disease (CD). However, very little is known about the role of serology in CD among African Americans (AA). The primary aim of this study is to evaluate common IBD antimicrobial serologic antibodies in AA with CD to determine their association with disease phenotype, location and severity, while controlling for genetic ancestry. Methods: AAs with CD were enrolled as participants through multi-center collaborative efforts. Serological levels of IgA ASCA, IgG ASCA, anti-OmpC, anti-CBir, and ANCA were measured using enzyme linked immunosorbent assays. Genotyping was performed using Illumina immunochip technology and admixture rate was calculated for each subject. Multiple imputation by chained equations was performed to account for data missing at random. Logistic regression was used to calculate adjusted odds ratios (OR) for associations between serological markers and complicated disease, ileal disease, and disease requiring surgery. Results: 358 patients were included in the analysis. The majority of our patients had inflammatory, non-complicated disease (58.4%), perianal disease (55.7%), and documented colonic inflammation (86.8%). On multivariable analysis, both IgG ASCA and OmpC were associated with complicated disease (OR: 2.67, CI:1.67-4.28; OR: 2.23, CI: 1.41-3.53) and disease requiring surgery (OR: 2.51, CI: 1.49-4.22; OR: 3.57, CI: 2.12-6.00). NE admixture to African genome did not have any associations or interactions in relation to clinical outcome. Conclusions: The diagnostic value of serological antibodies appears comparable in AA and NE with CD with respect to IgG ASCA and anti-OmpC suggesting that perhaps these similarities are more of a function of likenesses among the intestinal microbiome than differences in genetic make-up, further emphasizing the role of the environment in the etiopathogenesis of IBD. IBD serological studies from NE populations can be applied to AA populations.