Crohn's disease associated with diffuse lymphoid hyperplasia of the large intestine: a possible role of the lymph follicle in HLA-DR antigen expression on epithelium.

A 14-year-old girl diagnosed as Crohn's disease had lymphoid hyperplasia throughout the large bowel. Biopsy specimens from the lymphoid hyperplasia demonstrated non-caseous granulomas within the lymph follicles. An immuno-histochemical study of biopsy specimens showed that HLA-DR antigens were expressed on epithelium close to the lymph follicle, which was observed in all specimens containing the lymph follicle. This case provides evidence for the importance of the lymph follicle in the etiopathogenesis of Crohn's disease by demonstration of non-caseous granulomas within the lymph follicle and expression of HLA-DR antigens on epithelium close to the lymph follicle.