MHC class I antigen expression in patients with IDDM and their siblings

MHC class I antigen expression was found to be low on the lymphocytes of patients with insulin dependent diabetes mellitus (IDDM). Thus, it has been proposed that the defective expression of MHC antigens could lead to faulty immunological responses with the eventual destruction of the pancreatic beta cells. The objective in this study was to compare MHC antigen expression in IDDM patients and their presently healthy siblings. Nineteen children (mean age 10.8 +/- 3.9 years) with diabetes and their 25 siblings (mean age 10.7 +/- 4.6 years) were enrolled in the study. Peripheral blood lymphocytes isolated from venous blood samples were incubated with FITC conjugated monoclonal antibody W6/32. The amount of antibody binding by cell surface MHC class I antigens was assessed by flow cytometry. MHC class I molecule expression did not differ significantly among IDDM patients and their siblings. It was concluded that MHC class I antigen expression did not appear to be indicative of a susceptibility to develop autoimmune diabetes.