Acquired Cyclic Amegakaryocytic Thrombocytopenia Associated with an Immunoglobulin Blocking the Action of Granulocyte–Macrophage Colony-Stimulating Factor

INCREASING evidence over the past decade has indicated that certain patients with aplastic anemia and single-lineage deficiencies of hematopoietic cells have disorders of immunologic origin.^{1 2 3} Recently, a family of specific glycoproteins collectively known as colony-stimulating factors, which interact to control the differentiation of hematopoietic cells, have been identified, purified, and cloned.^{4 5 6} Granulocyte–macrophage colony-stimulating factor (GM-CSF) stimulates the development of megakaryocyte colony-forming units (CFU-MK) as well as granulocytes and macrophages. We report evidence that cyclic amegakaryocytic thrombocytopenia may be due to an antibody that selectively blocks the action of GM-CSF on megakaryocyte progenitor cells.Case ReportA 21-year-old woman first experienced . . .