Use of intravenous gamma globulin for the treatment of autoimmune neutropenia of childhood and autoimmune hemolytic anemia.

Intravenous gamma globulin (IVIG) was used to treat autoimmune neutropenia of childhood and autoimmune hemolytic anemia, two autoimmune disorders not previously treated with this modality. Six children younger than two years of age, who presented with severe infections and persistent absolute neutrophil counts (300/mm3), were treated with 1 g of gamma globulin per kilo body weight until counts reached more than 1,000/mm3. The average response occurred with a dose of 3.0 g/kg within five to seven days and lasted an average of 14 days before counts decreased to baseline levels. Four patients with autoimmune hemolytic anemia were also treated with IVIG, 1 g/kg for five to seven days (average dose of 5 g/kg), for severe Coombs'-positive hemolytic anemia. Response of the hemolytic anemia to IVIG was excellent in one patient and good in two patients. No response occurred in the fourth patient. Response was slower in these patients than in patients treated for immune thrombocytopenic purpura (ITP). The average total amount of gamma globulin required for a response is markedly different: 1 g/kg for ITP, 3.0 g/kg for autoimmune neutropenia, and 5 g/kg for hemolytic anemia. Possible mechanisms of action include blockade of reticuloendothelial system Fc receptors, suppression of autoantibody production, and/or interference in the binding of autoantibodies to target cells.