Interleukin-2 (IL-2) increases the number of CD4 cells in HIV-1 infected patients under highly active antiretroviral therapy (HAART) with a CD4 cell count over 200/mm3, but its activity in patients without antiretroviral therapy is unknown. This study will test the efficacy and safety of IL-2 in naïve patients with a CD4 count between 300 and 500/m3.