Heterogeneity of HPLC profiles of human class II MHC-bound peptides isolated from intestine with inflammatory bowel disease.

Studies of the T-cell-receptor repertoire and oligoclonal expansion of lamina propria T cells in patients with Crohn's disease suggest restricted antigen processing in this disease. We examined HPLC elution profiles of HLA-DR-bound peptides isolated from human intestine. Surgical samples of colon and ileum were obtained from patients with ulcerative colitis, patients with Crohn's disease, and normal colon from patients undergoing colon carcinoma treatment as controls. Specimens were homogenized and HLA-DR molecules were isolated using anti-HLA-DR antibody-coupled immunoaffinity chromatography. HLA-DR-bound peptides were dissociated from the HLA-DR groove by acid treatment, isolated, and analyzed by reversed-phase HPLC. HPLC elution profiles of HLA-DR-bound peptides were similar in patients with ulcerative colitis and controls. Large peaks were found in patients with Crohn's disease, but the retention times of these peaks differed among individuals. Elution profiles of HLA-DR bound peptides suggest that specific antigen presentation might occur in patients with Crohn's disease, although the specific antigens appear to differ between patients.