IL-2 and HIV: Two Definitive Studies Published

Rajesh T. Gandhi, MD


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In This Article

Abstract and Introduction


Although interleukin-2 raises CD4-cell counts in HIV-infected patients, it does not improve clinical outcomes.


Interleukin (IL)-2, originally called T-cell growth factor, is known to increase CD4-cell counts in HIV-infected patients. What has not been certain is whether this increase improves clinical outcomes in patients receiving antiretroviral therapy (ART). Now, answers are available from two large randomized trials—one in patients with lower CD4-cell counts and the other in patients with higher counts.

In the SILCAAT study (sponsored by the manufacturer of IL-2), 1695 patients with CD4 counts of 50 to 299 cells/mm3 were randomized to receive ART either alone or with cycles of IL-2. On average, during a median follow-up of 7.6 years, the CD4 count was 53 cells/mm3 higher in the IL-2 group than in the ART-alone group. However, no difference was seen in the rate of opportunistic disease or death.

In the ESPRIT study, 4111 patients with CD4 counts ≥300 cells/mm3 were randomized to receive ART with or without IL-2. Again, the CD4 count was higher in the patients who received IL-2—this time, by 159 cells/mm3 during a median follow-up of 7.0 years. Despite the substantial increase in CD4-cell counts, use of IL-2 did not reduce the rate of opportunistic disease or death. What is worse, patients who received IL-2 had a significantly higher rate of severe complications, including vascular events such as deep venous thrombosis.


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