Lymphocyte subset changes in persons infected with human immunodeficiency virus.

The severe complications of the acquired immunodeficiency syndrome represent the final phase of a prolonged course of immune system destruction during the infection by human immunodeficiency virus (HIV). Many of these complications can be predicted by measuring the depletion of CD4 positive lymphocytes. The CD4 positive lymphocyte counts are now widely accepted as a surrogate marker to assess the stage of disease and to determine immune response in major clinical trials. Other lymphocyte subsets are candidate surrogate markers for antiretroviral therapy. Our laboratory has utilized flow cytometry to perform lymphocyte subset testing, including CD4, CD8, CD4/CD8 ratio, and others for more than three years on persons with suspected immune deficiency. Results from our laboratory are presented to illustrate the use of these procedures in an urban, predominantly inner city population. The role of flow cytometry in monitoring patients with HIV infection is discussed.