Opportunistic infections in the acquired immune deficiency syndrome.

The acquired immune deficiency syndrome (AIDS) results in a T lymphocyte deficiency and, consequently, a susceptibility to opportunistic infections with organisms that previously were better known as causes of disease in patients with Hodgkin's disease or recipients of immunosuppressive therapy. Pneumocystis carinii, Candida albicans, and cytomegalovirus (CMV) are among the most frequently observed pathogens in AIDS patients, followed by atypical mycobacteria, Toxoplasma gondii, Mycobacterium tuberculosis, Salmonella sp, and herpes simplex virus. Cryptosporidia sp, rarely encountered in iatrogenically immunosuppressed patients, have also emerged as important pathogens in the setting of AIDS. Although some opportunistic infections in AIDS patients can be effectively treated, others are only temporarily suppressed or do not respond to the drugs currently available. The severity of the underlying immune deficit remains the most important prognostic factor, and opportunistic infection remains the cause of death in most AIDS patients.