High-dose intravenous gamma globulin to suppress alloimmune destruction of donor platelets.

We report the use of high-dose intravenous gamma globulin to overcome refractoriness to platelet transfusion in an alloimmunized patient with acute leukemia and thrombocytopenia. For two years the patient suffered recurrent gastrointestinal bleeding from an arteriovenous malformation and was given multiple transfusions, providing a basis for his allosensitization. Platelet counts had not increased following transfusions of random-donor or HLA-matched platelets. With intravenous gamma globulin, one hour after the transfusion of 9 to 15 units of platelets, the count increased by 30,000 to 90,000 and the half-life of transfused platelets increased to three to four hours from an estimated 0.05 hours prior to therapy. Intravenous gamma globulin arrested massive gastrointestinal bleeding and allowed the patient to undergo surgical resection of the small bowel with minimal operative blood loss.