Use of virologic markers in clinical practice.

A number of virologic and immunologic markers, including serum human immunodeficiency virus (HIV)-1 p24 antigen levels, quantitative HIV-1 microculture of plasma or peripheral blood mononuclear cells, and CD4 cell counts, have been used over the past decade to monitor progression of HIV infection. Although these markers are useful, they have not provided a reliable means of assessing prognosis at all stages of the disease or response to antiretroviral treatment. New molecular techniques are now available that measure viral load in HIV-infected patients by detecting and quantifying virion-associated RNA circulating in plasma. These plasma HIV-1 RNA levels appear to correlate with the clinical disease stage and reflect the response to antiretroviral treatment. Because recent studies have demonstrated that baseline plasma HIV-1 RNA levels and changes in these levels are predictive of clinical outcome, it is strongly recommended that these markers be measured routinely and used as a guide in the management of all patients with HIV disease.