Effects of isoprinosine treatment of HIV-positive patients on blood mononuclear cell subsets, NK- and T-cell function, tumour necrosis factor, and interleukins 1, 2, and 6.

The immunomodulatory drug isoprinosine has been found to delay the occurrence of opportunistic infections in HIV-infected individuals. To elucidate the mechanism of action, eight HIV-positive, healthy patients were treated with isoprinosine, 3 g/day for 28 days; six patients received no treatment but were examined in parallel, and two patients were withdrawn. All patients had blood collected just before the start as well as on days 14 and 28 of isoprinosine treatment. Isoprinosine significantly enhanced the lymphoproliferative response after stimulation with phytohaemagglutinin (PHA) and purified derivative of tuberculin (PPD), while isoprinosine had no effect on the following immune parameters: the expression of surface markers on blood mononuclear cells including CD2, CD3, CD4, CD8, CD14, CD19, CD20, CD25, leu-8, and HLA-DR. Furthermore isoprinosine did not influence the ability of interleukin 2 (IL-2) to stimulate the proliferation of lymphocytes or the natural killer (NK) cell activity either unstimulated or stimulated in vitro with alpha interferon (IFN-alpha), IL-2, or indomethacin. Neither did isoprinosine affect the in vitro production of (IL-1) alpha or beta, IL-2, IL-6, or tumour necrosis factor (TNF).