ARCHITECTURE AND DYNAMICS OF NORMAL AND ABNORMAL HEMATOPOIESIS

David Dingli, Department of Internal Medicine, Division of Hematology, Mayo Clinic, Rochester, Minnesota

Blood cells undergo continuous cell turnover and are replaced by the physiological process known as hematopoiesis. At the root of hematopoiesis lie the hematopoietic stem cells (HSC). The number of active HSC is small (~400 cells in humans) and the cells replicate slowly ~1/year. However, the daily bone marrow output in a healthy individual is of the order of cells. We have developed a hierarchical compartmental model of hematopoiesis based on the principle of stationary cell flow conservation that links the active HSC pool with the circulating blood. We will present patient based data in combination with this model to explore the dynamics of chronic myeloid leukemia. Subsequently, we will focus on paroxysmal nocturnal hemoglobinuria, an acquired HSC disorder that may lead to marrow failure.