A treatment of interleukin II (IL-2) is being developed as an immune stimulant for HIV-positive individuals who have responded to medication, but have not had their immune system recover. While new antiviral drugs are effective in inhibiting HIV, they have not been shown to restore a patient's damaged immune system. IL-2 therapy will be administered to promote the return of normal helper T cells and boost the number of cytotoxic T cells which can then destroy HIV-infected cells. Pioneered by researchers at Weill Medical College of Cornell University, New York, the low-dose, nontoxic regimen is being investigated in clinical trials. IL-2 has been used as an immune stimulant for cancer patients for more than 10 years. More recently, HIV-positive individuals have been treated with high doses of IL-2, but experienced severe side effects. IL-2 could therefore only be given for a few days every 2 months. This new regimen is different because it involves the daily low-dose administration of IL-2. Since it appears to be completely nontoxic, patients can be treated without interrupting their daily lives.