AIDS PROGRESSION

HIV infects and induces cell death in a variety of human cell lines. T-helper lymphocytes (also known as CD4 cells) are a major target of viral infection, and circulating CD4 cells become steadily depleted from peripheral blood in most untreated infected persons.
Untreated HIV infection is a chronic illness that progresses through characteristic clinical stages; AIDS is an endpoint of HIV infection, resulting from severe immunologic damage, loss of an effective immune response to specific opportunistic pathogens, and tumors. AIDS is diagnosed by the occurrence of these specific infections and cancers or by CD4 cell depletion to less than 200/mm3.