Differential prevalence of pathobionts and host gene polymorphisms in chronic inflammatory intestinal diseases: Crohn's disease and intestinal tuberculosis

Abstract

Background and objectives Crohn's disease (CD) and Intestinal tuberculosis (ITB) are chronic inflammatory ulcero-constrictive intestinal diseases with similar phenotype. Although both are disease models of chronic inflammation and their clinical presentations, imaging, histological and endoscopic findings are very similar, yet their etiologies are diverse. Hence, we aimed to look at differences in the prevalence of pathobionts like adherent-invasive Escherichia coli (AIEC), Listeria monocytogenes, Campylobacter jejuni and Yersinia enterocolitica in CD and ITB as well as their associations with host-associated genetic polymorphisms in genes majorly involved in pathways of microbial handling and immune responses. Methods The study cohort included 142 subjects (69 patients with CD, 32 with ITB and 41 controls). RT- PCR amplification was used to detect the presence of AIEC, L. monocytogenes, C. jejuni, and Y. enterocolitica DNA in colonic mucosal biopsies. Additionally, we tested three SNPs in IRGM (rs13361189, rs10065172, and rs4958847), one SNP in ATG16L1 (rs2241880) and one SNP in TNFRSF1A (rs4149570) by real-time PCR with SYBR green from peripheral blood samples in this cohort. Results In patients with CD, AIEC was most frequently present (16/ 69, 23.19%) followed by L. monocytogenes (14/69, 20.29%), C. jejuni (9/69, 13.04%), and Y. enterocolitica (7/69, 10.14%). Among them, L. monocytogenes and Y. enterocolitica were significantly associated with CD (p = 0.02). In addition, we identified all the three SNPs in IRGM (rs13361189, rs10065172, and rs4958847), one SNP in ATG16L1 (rs2241880) and TNFRSF1A (rs4149570) with a significant difference in frequency in patients with CD compared with ITB and controls (p<0.05). Conclusion Higher prevalence of host gene polymorphisms, as well as the presence of pathobionts, was seen in the colonic mucosa of patients with CD as compared to ITB, although both are disease models of chronic inflammation.