To investigate the contribution of genetic susceptibility to infection with human immunodeficiency virus, 50 subjects with lymphadenopathy syndrome (LAS) and 7 subjects with acquired immunodeficiency syndrome (AIDS) and Kaposi's sarcoma were typed for HLA A, B, C, and DR antigens. The frequency of B35 was significantly higher in LAS patients who progressed to AIDS than in those who did not or in healthy controls. The association between DR5 and AIDS/Kaposi's sarcoma was also confirmed in these patients.