To determine whether genetic factors could be involved in the pathogenesis of rheumatic heart disease, we performed HLA-A and HLA-B typing in 59 Indian patients with severe chronic rheumatic heart disease requiring cardiac surgery, and HLA-DR and HLA-DQ typing in 58 of these patients. The HLA typing was done by a standard microlymphocytotoxicity method. Patients were 12 to 59 years old (mean 32...