HLA antigens are risk factors for development of AIDS.

HLA-A, -B, -C, -DR, and -DQ antigens were determined by serology and in cases of severe lymphopenia by RFLP-DNA typing in 51 Caucasians with a diagnosis of AIDS (32 with opportunistic infections and 19 with secondary cancers). In addition, 86 HIV-1 seropositive and 39 HIV-1 seronegative drug abusers and 148 healthy controls were also studied. No significant differences in HLA antigen frequencies were found in comparison of HIV-1 seropositive and HIV-1 seronegative drug abusers with controls, suggesting that HLA polymorphism does not represent a genetic risk for infection with HIV-1. In contrast, a significant increased frequency of B35 (p less than 0.01) and CW4 (p less than 0.01) was observed in both groups of AIDS patients as compared to controls. Moreover, DR2 was increased in frequency in patients with opportunistic infections (p less than 0.01) and DR3 was completely absent in patients with secondary cancers (p less than 0.05). In the latter group, the DR5 frequency was increased, although nonsignificantly. These findings provide strong evidence for the existence of HLA-linked factors of susceptibility and host resistance to AIDS.