Effects of prednisone and splenectomy in patients with idiopathic thrombocytopenic purpura: only splenectomy induces a complete remission

Idiopathic thrombocytopenic purpura (ITP) is a heterogeneous disease, whereby it is unclear if and in which way prednisone and splenectomy affect the platelet kinetics leading to a complete remission. To determine the effects of prednisone and splenectomy on the mean platelet life (MPL) and platelet production, platelet kinetic studies with Indium-111 tropolonate-labeled autologous platelets were performed in patients with ITP (n=41). In 17 patients platelet kinetic studies were performed before and during prednisone treatment, and in 24 patients before and after splenectomy. MPL increased after prednisone therapy only in patients (n=13) with a full recovery (FR, platelets >150x10(9)/l) and partial recovery (PR, 50x10(9)/l <platelets <150x10(9)/l) from 2.1+/-1.5 days to 4.9+/-1.3 days in FR patients (p=0.03) and from 1.1+/-0.8 days to 2.4+/-1.1 days in PR patients, which is significantly shorter than in normal controls (9.2+/-1.2, p<0.0001). The platelet production demonstrated an impressive increase (threefold) during prednisone treatment in all responding and nonresponding patients. These results suggest that the clinical response to prednisone is more related to the effect on MPL than on platelet production. In contrast, the group of splenectomized patients showed that a full recovery of platelet count was associated with near normalization of the MPL (2.4+/-1.6 days vs 8+/-1.4 days) and platelet production (119+/-60 vs 162+/-35x10(9)/day). These results demonstrate that prednisone as well as splenectomy increase MPL and production in patients with ITP. However, only after splenectomy is a complete remission obtained, defined as a normal platelet count, mean platelet life, and platelet production.