Effectiveness of Interleukin-2 (IL-2) Plus Anti-HIV Therapy in HIV-Positive Patients

At the time of initial HIV infection, CD4 cells are susceptible to infection, and the virus infects many T cells during the first 4 to 6 weeks. Many of these infected cells subsequently maintain the virus in a latent state. Immune reconstitution with daily low-dose IL-2 therapy is intended to correct or improve the deficiency in CD4 cells, while maintaining a high frequency of CD8+ HIV-specific CTL and increasing natural killer (NK) cells. After a year of HAART plus IL-2, it may be possible to discontinue HAART while maintaining IL-2 stimulatory therapy, and the immune reactivity repaired and stimulated by IL-2 should be able to contain the virus and maintain latency.

Patients are randomized to add IL-2 to their current HAART regimen or simply to remain on their current HAART regimen. IL-2 therapy is initiated at Month 3 of HAART. IL-2 is injected subcutaneously daily for 9 months, in addition to HAART. After completion of this 1-year treatment period, patients are evaluated for discontinuation of HAART. Patients with a viral load below 50 copies/ml throughout HAART plus IL-2, a CD4 count of at least 500 cells/mm3, and no onset of opportunistic infections may have HAART discontinued and IL-2 continued as monotherapy for an additional 6 months. After completing 6 months of IL-2 monotherapy, eligible patients may have IL-2 therapy discontinued.