HIV target cells: effect of their infection by HIV on the pathogenesis of AIDS.

Pathogenesis of HIV infection and expression of retroviral proteins are gradually being elucidated. Antibody to HIV is a marker of past or present viral infection. The virus can be isolated from cultured lymphocytes of seropositive but not seronegative patients. Sero-epidemiological studies show that the majority of infected patients are asymptomatic carriers without biological sign of immune depression. Some then show immune abnormalities such as a decrease of CD4 cells in the blood; some patients present with lymphadenopathies or signs of AIDS-related complexes. Frank AIDS is a late stage of the disease. Some cofactors increase the immunodeficiency and then accelerate the passage from asymptomatic carrier to persistent generalized lymphadenopathies or AIDS by spreading the virus into target cells, susceptible T4 cells, bone marrow precursors, or brain. These AIDS patients then present with opportunistic infections and/or malignancies like Kaposi's sarcoma, lymphoma, and/or brain diseases (dementia or encephalitis).