Ways of Expressing Results of Human Bone Marrow Progenitor Cell Culture

SUMMARY In human bone marrow culture studies the number of granulocyte progenitor cells (CFU_c) is expressed as the numbcr of colonies per 10⁵ incubated, nucleated cells. However, this provides little information on cell proliferation kinetics of granulopoiesis. The ratio of progenitors (CFU_c) to end cells (metamyelocytcs or granuloc)-tcs) is related to the effectiveness of granulopoiesis and this allows an estimate to be made of an amplification factor within the maturing and proliferating compartments. We measured an index equal to the number of CFU_c per 10⁵ nietamyelocytes incubated in both normal individuals and in patients. The index falls when a large number of granulocytes is produced by each progenitor cell. This was observed in many patients with a neutropenia. An estimation of the total number of mctamyelocytes is based on the ratio of the number of metamyelocytes to the number of blood granulocytes. This allows an estimate of the total number of CFU_cs, which is of clinical interest.