Objective

Mycobacterium avium subspecies paratuberculosis (MAP) and specially its cell wall deficient form has been suspected to play a role in the pathogenesis of Crohn disease (CD). There are very few studies of Mexican patients with CD and none of them investigated the possible link between MAP and CD.

Methods

Solitary or multiple specimens from 14 patients with CD (10 with granulomas and 13 without granulomas); 15 paratuberculosis (8 Ziehl Neelsen (ZN) positive and 4 ZN negative) as well as 1 intestinal tuberculosis were analyzed by in situ hybridization (ISH) based on the avidin biotin-labeled MAP IS900 fragment. Samples were counterstained with light green.

Results

8/10 (80%) samples and all patients with granulomatous CD showed positive signals in macrophages, epitheliod cells and giant cells. All positive signals were observed within granulomas. 4/13 (30.76%) and 4 patients with nongranulomatous disease were MAP positive, the signal appears in few macrophages cytoplasm. In paratuberculosis samples, 8/8 (100%) ZN positive were also positive for ISH as well as 4/4 (100%) without acid fast rods detectable by ZN. Tuberculosis patient were MAP negative as expected.

Conclusion

These initial results are consistent with the exhibition of the Mexican population to MAP. The demonstration of MAP DNA from CD tissues supports and confirms previous reports of its association with the granulomatous type of the disease