Reduced Number of Peripheral Blood Granulocytic Progenitor Cells in Patients with Down's Syndrome

Abstract

The number of granulocytic progenitor cells (colony forming units in culture: CFUc) in the blood of patients with Down''s syndrome was reduced by 73.2% when compared to age and sex matched controls. The blood CFUc of the Down''s syndrome patients and the controls showed similar sensitivity to hydroxyurea [in vitro] suggesting that the low number of progenitor cells in Down''s syndrome was not compensated by a marked increase in their cellular proliferation. The colony size distributions were similar for the patients and the controls and repeated assays at various intervals revealed no marked fluctuation in the number of blood CFUc in either group. The significance of the reduced number of circulating CFUc in Down''s syndrome in relation to the known susceptibility of such patients to leukemia was discussed.