Physiology and clinical applications of platelet growth factors.

Recombinant human thrombopoietin, or pegylated recombinant human megakaryocyte growth and development factor, produces log-linear increases in megakaryocytopiesis and platelet production. Recent clinical studies investigating the efficacy, safety, and cost benefit of administering platelet growth factors indicate that appropriate dosing of pegylated recombinant human megakaryocyte growth and development factor, or recombinant human thrombopoietin, during chemotherapeutic marrow suppression produces these increases in four ways. First, these factors improve ensuant thrombocytopenia without producing platelet-dependent thrombo-occlusive complications. Second, recombinant human thrombopoietin or pegylated recombinant human megakaryocyte growth and development factor mobilize hematopoietic progenitor cells into the peripheral blood. Third, chronic dosing of HIV-infected thrombocytopenic patients with pegylated recombinant human megakaryocyte growth and development factor normalizes peripheral platelet counts without antibody formation. Fourth, the administration of pegylated recombinant human megakaryocyte growth and development factor to normal human volunteer platelet donors increases platelet yields nearly fourfold, with corresponding increases in peripheral platelet counts when transfused into thrombocytopenic recipients. The clinical application of platelet growth factors is continuing to be defined.