Intravenous immunoglobulin therapy for idiopathic thrombocytopenic purpura and other immune-related disorders: review and update of our experiences.

Idiopathic thrombocytopenic purpura (ITP) is a disorder characterized by a destructive thrombocytopenia. Since the demonstration of a humoral antiplatelet factor which causes a transient ITP when given to healthy volunteers, ITP has been thought of as an autoimmune disease. The target antigen seems to be heterogeneous; it is either a primary platelet membrane autoantigen or a secondary autoantigen absorbed on the platelet. The former was recently confirmed by the observation that serum and platelet eluates of patients with ITP bind to normal platelets, but not to Glanzmann's thrombasthenic platelets which are deficient in glycoproteins IIb and IIIa. The heterogeneity of ITP is also reflected in the difference in response to immunoglobulin prepared for intravenous administration (IVIG) treatment. In our multicenter studies for severe ITP (less than 30 X 10(9)/liter platelet count) in children, we observed the existence of at least two subgroups of ITP, namely rapid responders (greater than or equal to 30 X 10(9)/liter platelet at 72 hours after the start of IVIG) and slow responders (less than 30 X 10(9)/liter platelet counts at 72 hours). Rapid responders mostly showed a permanent increase of their platelet counts while slow responders often had a transient platelet increase. Slow responding children were therefore comparable with adults with ITP. Because the adult type of ITP occurs often in young women, fetal risk must frequently be addressed. The situation of neonatal ITP reflects both the antigenic and therapeutic heterogeneity of ITP. The severity of the disease probably depends on the character of the antigen and its related autoantibody.(ABSTRACT TRUNCATED AT 250 WORDS)