THE IMMUNOPATHOLOGY OF HIV-INFECTION

Fourteen years into the global epidemic of the acquired immunodeficien cy syndrome, the exact mechanisms by which the human immunodeficiency virus (HIV) causes the destruction of the immune system remain unresol ved. Infection with HIV is characterized by both continual virus repli cation and a vigorous immune response. The length of time from initial infection to the almost inevitable loss of CD4 positive T helper lymp hocytes averages 10 years, indicating the dramatic and prolonged inter play of the virus and the host immune response. In this article we dis cuss many of the leading hypotheses for both direct and indirect mecha nisms that have been proposed to explain the loss of CD4 cells. Curren t evidence suggests strongly that direct infection of CD4 cells is ade quate to explain their loss, but that cofactors and indirect mechanism s may contribute to the overall process. This leads to the conclusion that the immunopathology of HIV infection can be most effectively coun tered by using antiretroviral chemotherapy.