Immune function and phenotype before and after highly active antiretroviral therapy

Immune functions represented by equal CD4 counts before and after highly ac tive antiretroviral therapy (i.e., pre- and post-HAART) in the same HIV-inf ected patients, were examined. Twelve HIV-infected patients were included. Patients had equal CD4 counts pre- and post-HAART and were studied on avera ge 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 CD28 (p < .01). Proliferation increased (p < .10) in lymphocyte cell cultures stimul ated with pokeweed mitogens or Candida, and was correlated to expression of CD28 on T cells (p <.02). The proportion of CD3(-)CD16(-)CD56(+) natural k iller (NK) cells increased (p < .05) and CD3(-)CD16(+)D56(-) NK cells decli ned (p < .01). Production of interferon-gamma increased (p < .10). The numb er of naive and memory T cells, the non-major histocompatibility complex (n on-MHC)-restricted and HIV-specific MHC-restricted cytotoxicity and the pro duction of macrophage inflammatory protein-lp were unchanged. The finding o f increased expression of CD28, correlating to increased proliferation capa city, and diminished expression of CD38 on T cells, indicates that followin g long-term HAART, repopulation occurs with less activated cells with incre ased proliferative capacity. This finding may be of clinical importance in considering risk and vulnerability for progression of opportunistic infecti ons post-HAART.