Reticulated platelet monitoring after autologous peripheral haematopoietic progenitor cell transplantation.

Reticulated platelets are the youngest marker of megakaryopoiesis. We monitored 13 haematological patients undergoing autologous peripheral haematopoietic progenitor cell transplantation. We used a flow cytometric method based on thiazole orange platelet staining. Patients showed a fall in reticulated platelet percentage at a mean of 5 days before a nadir of the platelet count. In all cases, platelet recovery is preceded by a rise of reticulated platelets; in 10 cases patients received platelet prophylactic transfusions after RP rise. The rise in reticulated platelets is an early sign of engraftment and may represent an easy parameter for transfusion management of transplanted patients.