INTERIM EVALUATION OF 2 COOPERATIVE STUDIES ASSESSING THE EFFECTS OF INTRAVENOUS IMMUNOGLOBULIN (IV IGG) ON CHILDHOOD IDIOPATHIC THROMBOCYTOPENIC PURPURA (ITP) .1. RANDOMIZED STUDY COMPARING IV IGG WITH ORAL CORTICOSTEROIDS IN PREVIOUSLY UNTREATED ACUTE ITP .2. PROSPECTIVE-STUDY OF IV IGG IN ACUTE AND CHRONIC ITP UNRESPONSIVE TO PREVIOUS TREATMENTDY