Serum megakaryocytopoietic activity after allogeneic bone marrow transplantation (BMT).

Platelet recovery after allogeneic bone marrow transplantation for treatment of different haematologic disorders was monitored by ability of sera from BMT recipients to support the clonal growth of normal megakaryocyte progenitors. The resultant megakaryocyte colonies were expressed as a Serum Factor Index-Megakaryocyte (SFI-Mk). In two patients with whole and in one with partial haematological reconstitution SFI-Mk was normal, and in others SFI-Mk value was increased. Our results indicate that sera from BMT recipients contain megakaryocytopoietic activity which inversely correlate with recovery of megakarycytic lineage following bone marrow transplantation.