HEMATOPOIETIC PROGENITOR CELLS ARE REDUCED IN APLASTIC-ANEMIA

We investigated the frequencies of early populations of progenitors in aplastic anaemia (AA) bone marrow, from patients with a range of disease severity, compared with normal. Double-colour immunofluorescent staining for CD34 and CD33 was carried out on bone marrow mononuclear cells (BMMC) and analysed using fluorescence activated cell sorting (FACS). AA CD34(+) cells were reduced by 68% compared to normal. In addition, AA CD33(+) cells and the three progenitor subsets (CD34(+)/CD33(-), CD34(+)/CD33(+) and CD34(-)/CD33(+)) were reduced by 44-80%. Our data lend further suppor for an early stem cell deficiency in AA.