Adult onset cyclic hematopoiesis in a patient with myelodysplastic syndrome.

A 75-year-old woman presenting with myelodysplastic syndrome showed cyclic oscillations in her white blood cell and platelet counts. Each cycle lasted for 5 to 6 months, with 4 cycles occurring over the course of a 2-year period. During successive cycles, the white blood cell count fluctuated from 10.1 to 2.6; 13.8 to 1.8; 11.0 to 1.6, and 8.6 to 1.3 x 10(9)/L. The platelet count fluctuated from 242 to 38, 199 to 11, 110 to 5, and 75 to 3 x 10(9)/L. The patient underwent red blood cell transfusions because of red blood cell aplasia; the frequency of the transfusions and the erythropoietin concentration in serum were inversely correlated. The number of circulating granulocyte-macrophage colony-forming units and CD34-positive cells in peripheral blood oscillated in phase with the white blood cell and platelet counts. These patterns suggested a periodic influx of progenitor cells from hematopoietic stem cells. The ratio of neutrophils to mononuclear cells remained essentially constant throughout the clinical course. Lymphocyte subset assessments using monoclonal antibodies showed an inverse CD4/CD8 ratio (less than 1) and extreme B cell lymphopenia throughout the fourth cycle. The percentage of CD3-positive cells oscillated inversely, suggesting that the cyclic cytopenia had an immune mechanism involving T lymphocytes.