The bone marrow colony forming cell in megaloblastic anaemia and iron deficiency anaemia

Bone marrow samples from patients with megaloblastosis and iron deficiency have been assayed for their content of in vitro colony forming cells (CFC), and compared with a group of normal patients. The concentration of these cells was found to be significantly increased in the megaloblastic group, while their content in the iron deficient patients was slightly higher than the controls. An in vitro thymidine suicide procedures was utilised to assay the proportion of CFC in the S phase of the cycle. This was found to be increased in the megaloblastic group and only slightly increased in the iron deficient group. The findings in megaloblastosis seem to be consistent with the concept of impaired DNA synthesis. As the CFC monitors an early granulocytic progenitor these data suggest some impairment in DNA synthesis or an abnormal increase in amplification in this myeloid stem cell compartment. Such alterations in granulopoietic proliferation may contribute to the ineffective granulopoiesis of megaloblastosis and accordingly may be an important factor in the development of neutropenia sometimes associated with this condition. The slightly increased CFC concentration and altered cell cycle status found in iron deficiency suggest that iron is not a major requirement for granulopoiesis.