Circulating Human Immunodeficiency Virus (HIV) p24 Antigen-Positive Lymphocytes: A Flow Cytometric Measure of HIV Infection

Abstract

Asymptomatic individuals seropositive for human immunodeficiency virus (HIV) progress in a heterogeneous fashion toward AIDS. To facilitate monitoring of disease progression and response to therapy, a rapid, new flow cytometric assay (FCA) lymphocyte p24-FCA, has_ been devised to quantify peripheral blood lymphocytes expressing cell-associated HIV-l p24 antigen. Results from 55 asymptomatic, HIV-1-seropositive, serum p~4 antigen-negative individuals ranged from undetectable (n = 24); 4.2% for untreated patients with AIDS (n = 16); and 0.3% for AIDS patients receiving zidovudine (n = 11). Lymphocyte p24-FCA values were inversel)Helated to the number of days to positive viral cultures and to levels of CD4+ lymphocytes. The ratio of p24⁺ lymphocytes to CD4⁺ lymphocytes may reflect the fraction of infected CD4⁺ lymphocytes. Lymphocyte p24-FCA determination may provide a method for monitoring response to antiretroviral therapy regardless of serum p24 antigen status.