Platelet and immune responses to oral cyclic dexamethasone therapy in childhood chronic immune thrombocytopenic purpura.

Abstract

To examine the effectiveness of cyclic oral high-dose (HD) dexamethasone therapy in pediatric patients with chronic immune thrombocytopenic purpura (ITP), which has been reported to cause complete remission in adults with chronic ITP. Eleven children with primary chronic ITP, with a median disease duration of 28 months (range, 6 to 120 months), were treated with cycles of HD dexamethasone therapy. Excellent short-term responses (initial platelet counts < or = 50 x 10(9)/L, increasing to > 100 x 10(9)/L within 72 hours of completion of an HD dexamethasone cycle) were observed in 78% of 41 cycles. Long-term effects include one complete response (platelet count > or = 150 x 10(9)/L) and three partial responses (platelet count > or = 50 and < 150 x 10(9)/L) in 11 children followed for 6 or more months after completing cyclic HD dexamethasone therapy. Because side effects were substantial, three children did not complete their sixth treatment cycle. At day 6 of treatment, B lymphocytes were significantly increased (p = 0.005). Dexamethasone, given orally in high doses, is an effective drug in achieving short-term platelet responses, but it induced long-term remissions in fewer than half of the children with well-established chronic ITP. Its effect on B lymphocytes requires further elucidation. A prospective, controlled study will be needed to establish whether cyclic HD dexamethasone therapy can alter the natural history of children with early chronic ITP and thus avoid splenectomy.