Immunological changes in human immunodeficiency virus (HIV)-infected individuals during HIV-specific protease inhibitor treatment

The present study examines the influence of effective anti-retroviral treat ment on immune function, evaluated by a broad array of immunological tests. We followed 12 individuals infected with human immunodeficiency virus (HIV ) for 6 months after initiation of combination anti-retroviral treatment in cluding a protease inhibitor. Unstimulated and pokeweed mitogen (PWM)-, int erleukin (IL)-2- and phytohaemagglutinin (PHA)-stimulated lymphocyte prolif erative responses increased during follow-up reaching average levels from 1 .3-fold (PHA) to 3.7-fold (PWM) above baseline values. The total CD4(+) lym phocyte count increased mainly due to increases in numbers of CD4(+)CD28(+) and CD4(+)CD45RO(+) cells, whereas increases in numbers of CD4(+) CD45RA() cells contributed little to the increase in CD4(+) cell count. The total cytotoxic T-cell (CTL) killing of autologous B cells infected with HIV-enco ding recombinant Vaccinia virus was increased after 3-6 months, whereas the specific HIV-directed CTL activity and the concentration and lytic activit y of natural killer (NK) cells were unchanged during follow-up. These resul ts demonstrate that the initiation of a treatment including an HIV protease inhibitor is followed by an increase in lymphocyte proliferation and lymph ocyte-mediated cytotoxicity. However, unchanged levels of specific HIV CTL and NK cell activity warn us that not all measures of immune function may r espond simultaneously to antiretroviral treatment.