Leukapheresis - In this procedure, whole blood is collected through a needle placed in an arm vein. The blood circulates through a cell separator machine where the white cells are removed and collected. The rest of the blood is returned to the body, either through the same needle used to draw the blood or through a second needle placed in the other arm. The collected white cells are used for special studies of the level and function of T cells before and after drug treatment. Patients with CD4 counts > 500 cells/microliter and < 300 cells/microliter will undergo leukapheresis up to four times - at study entry and about 2, 6 and 12 months after starting antiretroviral therapy. Patients with CD4 counts between 300 and 500 cells/microliter will have this procedure either at study entry and 6 and 12 weeks after initiation therapy, or on the same schedule as the other patients.