Granulopoiesis : studies of bone marrow culture in chronic granulocytopenia and comparison with granulocyte kinetics.

Granulopoiesis was studied in 20 cases of chronic granulocytopenia (adults and children; acquired and congenital). Bone marrow colony growth in methylcellulose culture was compared with the turnover-rate of blood granulocytes labelled with 51Cr and with the bone marrow granulocyte labelling index (L.I.) after "in vitro" flash labelling with 3H-thymidine (3H-TDR). There was a positive correlation between colony forming cells (C.F.C.) content and turnover rate and between C.F.C. content and bone marrow cellularity but there was no statistically valid correlation between C.F.C. content and labelling index. In patients with acquired granulocytopenia the colony counts were increased in cases with autoimmune destruction of neutrophils and in one patient during granulocytic regeneration. The C.F.C. numbers were low in cases with neutropenia associated with granulocyte hypoplasia but the prognosis was better in those cases with the highest colony count. On the other hand, colony counts were variable and had no prognostic value in cases of neutropenia secondary to a bone marrow abnormality in maturation or mutiplication, either acquired or congenital, as revealed by turnover studies and autoradiographic data.