Immune restoration in patients with HIV infection: HAART and beyond.

Since the introduction of highly active antiretroviral therapy (HAART), there has been a dramatic decrease in HIV-related morbidity and mortality. Suppressing HIV replication by HAART can result in a restoration of the CD4+ T-cell count and, consequently, a diminished risk of opportunistic infections. However, the degree of immune restoration that can be achieved with HAART varies from patient to patient. It is often incomplete and can be poorest in those patients who, because of their very low CD4+ counts, need it the most. Additional approaches are needed to increase immune restoration still further. Structured treatment interruptions, therapeutic immunization, and recombinant interleukin-2 are three such options that are currently being investigated.

Randomized, open-label study of the impact of two doses of subcutaneous recombinant interleukin-2 on viral burden in patients with HIV-1 infection and CD4+ cell counts of > or = 300/mm3: CPCRA 059.

The effect of intermittent courses of recombinant interleukin-2 (rIL-2) on HIV-1 load in patients receiving combination antiretroviral therapy remains uncertain. CPCRA 059 was an open-label, randomized, multicenter trial in which 511 patients with HIV-1 infection and CD4+ cell counts of > or = 300/mm3 who were receiving antiretroviral therapy were assigned to receive no rIL-2 (255 patients [controls]) or subcutaneous rIL-2 in dosages of 4.5 MIU (130) or 7.5 MIU (126) twice daily for 5-day courses every 8 weeks to maintain CD4+ cell counts that were twice the baseline value or > or = 1,000/mm3. The primary objective of this study was to compare the effects of the two doses of rIL-2 and no rIL-2 on viral load and CD4+ cell counts over 12 months. There was no difference in the following viral load measurements between the rIL-2 treatment groups and the control treatment group: percentage of patients with viral loads of <50 copies/mL at 12 months (p =.55), time to viral load of > or = 50 copies/mL for patients who had baseline viral loads of <50 copies/mL (p =.35), and change in viral load from baseline for patients who had viral loads of > or = 50 copies/mL at baseline (p =.63). At each follow-up visit, the change in CD4+ cell count from baseline was significantly greater in the rIL-2 treatment groups than in the control treatment group, with a mean difference of 251/mm3 at month 12 (95% confidence interval, 207-295; p <.0001). No unanticipated adverse experiences were seen in this trial, to our knowledge the largest randomized evaluation of rIL-2 treatment conducted to date.