Effect of intermittent interleukin-2 therapy on CD4+ T-cell counts following antiretroviral cessation in patients with HIV.

Background: Interleukin (IL)-2 therapy impacts T-cell homeostasis. Whether IL-2 expanded CD4(+) T cells may persist following viral rebound has not been fully investigated. Methods: Patients with CD4(+) T cells 500/mu l or more and HIV RNA less than 50 copies/ml were randomized to continue antiretroviral therapy (ART) either alone (n = 67) or combined with three IL-2 cycles (n = 81; 6 million units) twice daily for 5 days at weeks 0, 8, and 16 before stopping ART (week 24). Patients were followed up to 168 weeks. Results: At week 24, median CD4(+) T-cell counts were 1198 and 703 cells/mu l in the IL-2 and control groups, respectively (P<0.001). At week 72, 27% (IL-2 group) and 45% (control group; P = 0.03) of patients were in failure (defined as no interruption of ART at week 24, CD4 drop below 350 cells/ml or ART resumption). After week 24, a biphasic decline (before and after week 32) of CD4 was noted =106 and =7 cells/mu l per month in controls and = 234 and =17 in IL-2 group (all P < 0.0001). At week 96, IL-2-expanded CD4(+)CD25(+) T cells remained higher than in the control group (26 vs. 16%, P = 0.006). Conclusion: In IL-2-treated patients, CD4(+)CD25(+) T cells persisting despite viral replication allow a longer period of ART interruption. (C) 2012 Wolters Kluwer Health vertical bar Lippincott Williams & Wilkins