The acute retroviral syndrome presents very much like infectious mononucleosis, and is often prolonged for more than two weeks. Diagnosis of acute retroviral syndrome requires HIV antibody and HIV-RNA (viral load) testing. Acute retroviral syndrome diagnosis is important, because if patients are treated with HAART therapy early they may have a better outcome and increased control of HIV viral replication. After the acute retroviral syndrome, the disease reaches a "set point," which is the viral load (HIV-RNA) level that corresponds, in the absence of HAART, to the battle between the virulence of the disease and the host's ability to contain HIV replication. In the absence of therapy the viral load increases, leading to the more rapid progression of CD4 cell decline and the development of symptomatic disease or AIDS.
In the latent phase, patients may proceed for a number of years completely asymptomatically. Later, as the virus continues to replicate and CD4 cells are lost over time, patients develop symptomatic disease that may include fever, weight loss, night sweats, lymphadenopathy or an AIDS-related opportunistic infection. AIDS is defined as the presence of an AIDS-related opportunistic infection or a CD4 count of less than 200 per ml. As the CD4 count drops below 200, the patient experiences an increased risk of opportunistic infections due to:
Prophylaxis based on the patient's CD4 count is effective in preventing many of these opportunistic infections, and treatment with HAART and for the specific AIDS-related opportunistic infection is recommended.