Mycobacterium avium subspecies paratuberculosis in children with early-onset Crohn's disease

Abstract

Background: Mycobacterium avium subspecies paratuberculosis (MAP) is the most enduring infectious candidate that may be associated with inflammatory bowel disease (IBD). It is possible that the inconsistencies in the prevalence studies of MAP in adults reflect clinical differences in adult patients studied, including duration of disease and treatment regimens, and also in lack of specificity of some of the assays used. The aim was to determine the presence of MAP in children with symptoms of Crohn's disease (CD) and ulcerative colitis (UC), using gut biopsy tissue and peripheral blood mononuclear cells (PBMC) collected at initial endoscopic examination prior to clinical treatment.

Methods: Mucosal biopsies and/or PBMC specimens were collected from a total of 142 children, comprising 62 with CD, 26 with UC, and 54 with non-IBD. MAP-specific IS900 polymerase chain reaction (PCR) analysis was performed on all biopsies and PBMC specimens. Conventional MAP culture technique was performed on a subset of 10 CD, 2 UC, and 4 non-IBD patients to isolate MAP.

Results: MAP was identified by IS900 PCR significantly more often in mucosal biopsies from CD 39% (22/56) than from non-IBD 15% (6/39) patients (P < 0.05), and in PBMC from CD 16% (8/50) than from non-IBD 0% (0/31) patients (P < 0.05). Viable MAP were cultured from mucosal biopsies from 4/10 CD, 0/2 UC, and 0/4 non-IBD patients, but were not cultured from PBMC specimens.

Conclusions: This unique study on the occurrence of MAP in gut tissue and blood from pediatric IBD patients suggests the possible involvement of MAP in the early stages of development of CD in children.