Efficacy of recombinant interleukin-2 (rIL-2) in patients with advanced HIV-1 infection and blunted immune response to HAART.

Objective: The efficacy of recombinant interleukin-2 (rIL-2) was assessed in HIV-infected patients with advanced immune suppression and a discordant immune response to highly active antiretroviral therapy (HAART). The primary endpoint was median change in CD4+ T-cell counts at the end of treatment as compared to baseline. Secondary endpoints were safety and changes in the various T-cell subpopulations.

Material And Methods: In a prospective cohort study, 19 patients with HIV-RNA < 50 copies/mL and < 200 CD4+ T cells/mm3 without a significant increase in the previous 12 months were scheduled to receive 6 cycles of 4.5 x 10(6) IU subcutaneous rIL-2 daily for 5 consecutive days, every 4 weeks.

Results: Median age was 43 years, and 64% had a previous AIDS-defining event. Median nadir and baseline CD4+ cell counts were 36 and 99 cells/mm3, respectively. Three patients discontinued treatment and one experienced grade 4 side effects. CD4+ T-cell counts increased to 147 cells/mm3 (range, 24-285) at 1 month following completion of treatment (P = 0.002), and 180 cells/mm3 (range, 38-280) at 18 months (P < 0.001). This improvement was associated with a significant decrease in expression rates of the activation markers, HLA-DR and CD38.

Conclusion: Our results suggest that in patients with advanced HIV-infection showing a blunted immune response to HAART, rIL-2 might increase the pool of CD4+ T-cells by down-regulating the status of immune activation.