ABSTRACT
T cells is a hallmark of AIDS that accounts for the immunodeficiency late in the course of HIV infection, but qualitative defects in T lymphocytes can be discovered in HIV-infected persons who are asymptomatic. Infection of macrophages and monocytes is very important, and the dendritic cells in lymphoid tissues are the principal sites of HIV infection and persistence. In addition to the lymphoid system, the nervous system is the major target of HIV infection. It is widely accepted that HIV is carried to the brain by infected monocytes. The microglia in the brain are the principal cell type infected in that tissue. The natural history of HIV infection is divided in three phases that include (1) an early acute phase, (2) a middle chronic phase, and (3) a final crisis phase. Viremia, measured as HIV-1 RNA, is the best marker of HIV disease progression and it is valuable clinically in the management of HIV-infected patients. Clinically, HIV infection can range from a mild acute illness to a severe disease. The adult AIDS patient may present with fever, weight loss, diarrhea, generalized lymphadenopathy, multiple infections, neurologic disease, an in some cases secondary neoplasms. Opportunistic infections account for 80% of deaths in AIDS patients. Prominent among these is pneumonia caused by
Pneumocystis carnii
as well as other common pathogens. AIDS patients also have a high incidence of certain tumors, especially Kaposi’s sarcoma, non-Hodgkin’s lymphoma, and cervical cancer in women. No effective vaccine has yet been developed.
