Platelet count >= 100,000/ul Platelet count > 75,000/uL Platelet count >= 100,000/uL Platelet count >= 100,000/uL Platelet count >= 100,000/uL (transfusion independent) Platelet count >= 75,000/uL (transfusion independent) CD4 count >= 50 cells/ul Platelet count >= 100,000/uL; Note: no transfusions are permitted 7 days prior to laboratory studies to determine eligibility Platelet count >= 100,000/uL, obtained within 4 weeks prior to randomization Platelet count >= 100,000/uL Platelets >= 75,000 cells /uL (unsupported, defined as no platelet transfusion within 7 days) INCLUSION CRITERIA FOR STRATUM C: Platelets >= 75,000 cells/uL (unsupported, defined as no platelet transfusion within 7 days) Platelet count >= 50,000/uL Absolute CD4 count > 200 cells/uL Platelet count >= 75,000/uL CD4+ T-cell count >= 100 cells/uL Platelet count >= 100,000/uL (transfusion independent)