After a screening period lasting not more than four weeks, patients will be randomized into one of two cross-over groups. Patients randomized to Group 1 will receive their first IGIV-C, 10% dose at a rate of 0.08 mL/kg/min and their second infusion at a rate of 0.14 mL/kg/min, whereas patients randomized to Group 2 will receive IGIV-C, 10% at a rate of 0.14 mL/kg/min on the first infusion day and then 0.08 mL/kg/min on the second infusion day. All patients just prior to each IGIV-C, 10% infusion will receive the same volume of 5% dextrose as calculated for their IGIV-C, 10% infusion and given at a target rate according to the schema below.