Immune Function and Phenotype Before and After Highly Active Antiretroviral Therapy

Abstract

Summary: Immune functions represented by equal CD4 counts before and after highly active antiretroviral therapy (i.e., pre- and post-HAART) in the same HIV-infected patients, were examined. Twelve HIV-infected patients were included. Patients had equal CD4 counts pre- and post-HAART and were studied on average 30 months pre-HAART and 17 months post-HAART. Post-HAART, CD8⁺ T cells expressed greater amounts of CD28 (p < .02), smaller amounts of CD38 (p < .02), and a reduced proportion of CD4⁺CD28⁺ T cells expressed CD38⁺ (p < .01). Proliferation increased (p < .10) in lymphocyte cell cultures stimulated with pokeweed mitogens or Candida, and was correlated to expression of CD28 on T cells (p < .02). The proportion of CD3^-CD16^-CD56⁺ natural killer (NK) cells increased (p < .05) and CD3^-CD16⁺CD56^- NK cells declined (p < .01). Production of interferon-γ increased (p < .10). The number of naive and memory T cells, the non-major histocompatibility complex (non-MHC)-restricted and HIV-specific MHC-restricted cytotoxicity and the production of macrophage inflammatory protein-1β were unchanged. The finding of increased expression of CD28, correlating to increased proliferation capacity, and diminished expression of CD38 on T cells, indicates that following long-term HAART, repopulation occurs with less activated cells with increased proliferative capacity. This finding may be of clinical importance in considering risk and vulnerability for progression of opportunistic infections post-HAART.