HLA B8 and granuloma formation in Crohn's disease.

In a retrospective survey, patients with Crohn's disease who were HLA B8 were found to have significantly fewer granulomas in rectal biopsies (p less than 0.002) and in resected bowel specimens (p less than 0.02) than non-HLA B8 patients. No statistically significant difference was found between HLA B12 and non-B12 patients. This in vivo evidence of differing immune response capabilities between HLA B8 and non-HLA B8 individuals is compatible with previously reported in vitro studies. Despite these differences, the clinical manifestations and disease course of the two groups of patients was similar, suggesting that neither the presence of HLA B8 nor the development of granuloma directly influence the course of Crohn's disease.