Intravenous gamma globulin in the treatment of chronic idiopathic thrombocytopenic purpura in adults.

Eight adult patients with chronic idiopathic thrombocytopenic purpura have been treated with an intravenous gamma globulin preparation. All patients received at least one "induction" course of intravenous gamma globulin for five consecutive days at a dose of 400 mg/kg per day. There were a total of 12 induction treatments. In five instances, patients also received single "maintenance" infusions of intravenous gamma globulin at the same dose. The mean peak increment in platelet count (X 10(3)/microliters) after induction was 87.3 +/- 42.37; after maintenance therapy it was 62.2 +/- 12.99. In only one instance was the platelet count increment less than 50 X 10(3)/microliters. In 13 of 17 intravenous gamma globulin treatments (both induction and maintenance), the platelet count returned to baseline or near-baseline levels within one to two weeks. In four instances, more prolonged remissions were observed. Measurements of platelet-associated IgG demonstrated the following: when platelet-associated IgG was greater than 100 ng/10(6) platelets, platelet-associated IgG usually decreased markedly after intravenous gamma globulin therapy. When platelet-associated IgG was less than 20 ng/10(6) platelets, platelet-associated IgG usually increased with therapy. There was no correlation between starting platelet-associated IgG levels or changes in platelet-associated IgG levels with therapy and the increment in the patient's platelet count.