Immunopathogenesis of human immunodeficiency virus infection

The acquired immunodeficiency syndrome (AIDS) is associated with a broad spectrum of opportunistic infections and neoplasias that differ from those occurring in the general population by their high aggressiveness, unusual location, early tendency to generalization, frequent relapse, and short survival. The severe complications of AIDS, however, represent only the last phase in a prolonged course of progressive dysfunction and destruction of the immune system set in motion by the infection with the human immunodeficiency virus (HIV). While substantial progress was achieved in the ultrastructural identification and biochemical characterization of HIV, its mode of action in the causation of AIDS is not yet fully understood. This article explores the main processes involved in the HIV infection and in its role in the origin of AIDS. It describes the phases of HIV infection, investigates the effects of HIV on the various components of the immune system, and analyzes the pathogenesis of the HIV-induced lymphadenopathies and encephalopathy, as well as the causes and mechanisms of AIDS-associated opportunistic infections and opportunistic neoplasias. The total failure of immune surveillance against a host of infectious and oncogenic agents, unprecedented in human pathology, is thus traced to the initial event of specific HIV infection of the CD4 T-lymphocytes.