Effects of subcutaneous interleukin-2 therapy on phenotype and function ofperipheral blood mononuclear cells in human immunodeficiency virus infected patients

In the context of clinical therapy with recombinant human interleukin-2 (IL -2), we monitored immunological alteration in 10 human immunodeficiency vir us type-1 (HIV-1)-infected individuals, on stable antiretroviral therapy, w ho had a CD4(+) cell count between 200 and 500 cells/mm(3). Subcutaneous IL -2 was prescribed thrice weekly (at a dose of 3 x 10(6) IU) for 24 weeks an d the patients were followed-up for 32 weeks. IL-2 treatment induced an inc rease in the CD4(+) percentage (P < 0.001) and CD4(+) cell count (P < 0.009 ). Furthermore, natural killer (NK) cell activity was increased (P < 0.001) at week 8 of treatment, whereas lymphokine-activated killer (LAK) cell act ivity showed a transient, nonsignificant increase at week 8 and was reduced (P < 0.001) at 32 weeks. However, the cytotoxic T-lymphocyte (CTL) activit y decreased against HIV antigens, and the proliferative response to Candida , IL-2 and phytohaemagglutinin (PHA) declined during the first 8 weeks (P < 0.05) and returned to baseline levels after 32 weeks. The HIV RNA level di d not change during IL-2 therapy; however, after 8 weeks of follow-up a sig nificant increase (P < 0.001) in viral load was observed. In conclusion, co ntinuous IL-2 treatment to HIV-infected individuals enhanced the CD4 count, but the in vitro lymphocyte function was impaired and an increase in viral replication occurred after treatment.