HUMAN-SERUM MEGAKARYOCYTE COLONY-STIMULATING ACTIVITY INCREASES IN RESPONSE TO INTENSIVE CYTO-TOXIC CHEMOTHERAPY

  • 1 January 1984
    • journal article
    • research article
    • Vol. 12  (8) , 624-628
Abstract
Sera from patient with aplastic anemia and amegakaryocytic thrombocytopenia contain an activity that stimulates megakaryocyte colony formation in vitro. This megakaryocyte colony-stimulating activity (Meg-CSA) was assayed insera of 4 patients receiving intensive antileukemic chemotherapy to determine whether the appearance of Meg-CSA is a physiologic response to the suppression of megakaryocytopoiesis. Three of the 4 patients were receiving consolidation or late intensification therapy for acute myeloblastic leukemia (AML) in remission. The 4th was receiving induction therapy for de novo AML. During all or part of 4 chemotherapeutic cycles, serial Meg-CSA levels were assessed and correlated with the corresponding peripheral platelet counts. All courses of cytotoxic chemotherapy resulted in increases in serum Meg-CSA comparable to activity levels present in sera from patients with aplastic anemia. Two of the 3 patients studied during the early postchemotherapy interval manifested initial serum Meg-CSA elevations 7 days before their thrombocytopenic nadirs when platelet counts were still between 100,000/mm3 and 140,000/mm3. Bone marrow recovery from chemotherapy was characterized by a decrease in serum Meg-CSA to pretherapy levels that occurred concurrently with the rise in platelet count to normal. These observations support the hypothesis that Meg-CSA is a physiologic humoral regulator of megakaryocytopoiesis elaborated in response to the depletion of either bone marrow megakaryocytes or megakaryocyte progenitor cells.