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 treatment 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 including a protease inhibitor. Unstimulated and pokeweed mitogen (PWM)‐, interleukin (IL)‐2‐ and phytohaemagglutinin (PHA)‐stimulated lymphocyte proliferative responses increased during follow‐up reaching average levels from 1.3‐fold (PHA) to 3.7‐fold (PWM) above baseline values. The total CD4+ lymphocyte 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‐encoding recombinant Vaccinia virus was increased after 3–6 months, whereas the specific HIV‐directed CTL activity and the concentration and lytic activity of natural killer (NK) cells were unchanged during follow‐up. These results demonstrate that the initiation of a treatment including an HIV protease inhibitor is followed by an increase in lymphocyte proliferation and lymphocyte‐mediated cytotoxicity. However, unchanged levels of specific HIV CTL and NK cell activity warn us that not all measures of immune function may respond simultaneously to anti‐retroviral treatment.