The colony forming cell in the myeloproliferative disorders and aplastic anaemia.

Bone marrow colony forming cell (CFC) concentration and the proportion of CFC in DNA synthesis were studied in myeloproliferative disorders and aplastic anaemia. Growth patterns of bone marrow cells in agar cultures were able to supplement traditional morphological and clinical criteria in the diagnosis of these haematological conditions. Bone marrow CFC concentration tended to be increased in chronic myeloid leukaemia (CML) and polycythaemia vera (PV), but decreased in myelofibrosis, erythroleukaemia, paroxysmal nocturnal haemoglobinuria (PNH) and the aplastic phase of aplastic anaemia. The proportion of CFC in DNA synthesis was decreased in CML, myelofibrosis and aplastic anaemia, but increased in blastic transformation, PV, PNH and during regeneration from aplastic anaemia. The proportion of CFC in DNA synthesis in bone marrow from patients with CML in blastic transformation was directly related to the percentage of myeloblasts in the bone marrow. CFC kinetics in blastic transformation have been demonstrated to be different from those in acute leukaemia.