ITPの血小板動態に対するVincristineの影響

抄録

Vincristine therapy was performed for 10 patients with ITP and a thrombocytopenic patient with SLE. Two excellent, six good and three poor responses to vincristine were observed. No serious side effects were encountered. In order to investigate the mechanism of elevation of platelet count, platelet kinetic studies were performed before and after vincristine administration; four well responded patients were studied. Prolongation of platelet half-disappearance time and decreased platelet turnover rate were obtained in all of four patients after the administration. While immature megakaryocytes were predominant before vincristine therapy on bone marrow examination, mature platelet producing megakaryocytes were abundant after the treatment.
These findings suggest that vincristine suppresses the destruction of platelets. It induces the elevation of platelet count, which may result in the decreased production of platelet through a regulatory feedback mechanism.