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 dise ase severity, compared with normal. Double-colour immunofluorescent st aining for CD34 and CD33 was carried out on bone marrow mononuclear ce lls (BMMC) and analysed using fluorescence activated cell sorting (FAC S). AA CD34(+) cells were reduced by 68% compared to normal. In additi on, AA CD33(+) cells and the three progenitor subsets (CD34(+)/CD33(-) , CD34(+)/CD33(+) and CD34(-)/CD33(+)) were reduced by 44-80%. Our dat a lend further suppor for an early stem cell deficiency in AA.