Immune Globulin Intravenous (Human), 10% Caprylate/Chromatography Purified (IGIV-C) at a dose of 1.0 g/kg will be given on 2 occasions as a single daily infusion for platelet counts < 30,000 microliters (uL) or if clinically indicated, at maximum intervals of six weeks. Eligible patients will be randomized into one of two cross-over groups. Patients randomized to Group 1 will receive their first IGIV-C infusion at a rate of 0.08 mL/kg/min and their second infusion at a rate of 0.14 mL/kg/min. Conversely patients randomized to Group 2 will receive their first IGIV-C infusion at a rate of 0.14 mL/kg/min and their second infusion at a rate of 0.08 mL/kg/min according to the following schema: