Efficacy, safety, and dose response of intravenous anti-D immune globulin (WinRho SDF) for the treatment of idiopathic thrombocytopenic purpura in children.

We analyzed data from 20 children treated for acute or chronic idiopathic (immune) thrombocytopenic purpura (ITP) at a single institution to determine the relationship between dose of intravenous anti-D immune globulin (WinRho SDF; Nabi, Boca Raton, FL), increase in platelet count, and decrease in hemoglobin in the therapy of ITP. Higher doses of anti-D were clearly associated with a greater therapeutic response in the platelet count, with no increase in hemolysis for both acute and chronic ITP. A significant correlation was found between dose and peak increase in platelet count measured in the 14 days following administration. This effect was present for both acute ITP (17 infusions, P = .0001) and chronic ITP (30 infusions, P = .038). Although hemolysis was seen in nearly all infusions, with a median hemoglobin fall of 1.9 g/dL (range, 0 to 4.2), the decrease in hemoglobin was greater than 2.5 for only three infusions, and the largest fall in hemoglobin (4.2) was in a child with an underlying hemolytic anemia. Furthermore, for both acute and chronic ITP there was no relationship between the decrease in hemoglobin and the dose given (P = .22), nor between the increase in platelet count and fall in hemoglobin (P = .27). This analysis supports the use of higher doses of anti-D for the treatment of ITP, and demonstrates the need for a trial of high-dose anti-D (>100 microg/kg) in acute and chronic ITP.