Background:  In HIV-1-infected patients interleukin (IL) -2 has been associated with analytical benefit with significant increase in CD4 cell counts. However, this increase has not yet been linked to a clinical benefit. We reviewed long-term clinical evolution of patients with immunological discordance after HAART treated with IL-2. 

Methods:  All patients with an immunological discordance response to HAART (CD4 <250 cells/μL and viral load <50 copies/mL) who received IL-2 in our institution between January 2000 and January 2007 were included in the study. In patients with CD4 baseline >100 cells/μL response to IL-2 was defined as an increase of 50% above those of the baseline, and in patients who started IL-2 below 100 cells/μL response was defined as an increase of 50 absolute cells. End-points were death for any cause or AIDS-defining event. Survival analysis was performed with Cox´s model.

Results:  We included 63 patients:  baseline median age was 41.5 years, 86% were men, median time on ART before IL-2 was 43 months (IQR 22 to 96), nadir CD4 were 40 cells/μL (IQR 15 to 84), and CD4 at starting IL-2 was 165 (IQR 108 to 165). After IL-2 treatment 39 patients were considered as responders. CD4 cell counts were higher in R (330, IQR 248-442) than in non responders (194, IQR140 to 272) at the end of IL-2 therapy; as well as at the end of the follow-up 314 (IQR 202 to 340) vs 176 (IQR 144 to 263) (p <0.05). Median follow-up was shorter for nonresponders (7 vs 27 months, p <0.05); 13 patients developed an AIDS-defining event or died during the follow-up, being higher in the group of nonresponders than in responders (9 vs 4, p <0.05). In Kaplan-Meier survival analysis, we assessed a statistically significant higher AIDS-defining event or death for any cause in nonresponders group vs responders group (log rank = 0.001). In a multivariate Cox´s model no response to IL-2 was significantly associated with increase of death for any cause or AIDS-defining events (hazard ratio, 5.5; 95%CI 1.71 to 18.18).

Conclusions:  In patients with CD4 <250 cells/μL and an immunological discordant response to HAART, response to treatment with IL-2 is associated with a clinical benefit. IL-2 should be offered to all patients with an immunological discordant response to HAART and a CD4 cell counts <250 cells/μL.