Morphologic and quantitative changes in blood and marrow cells following growth factor therapy

Sequential blood and bone marrow specimens from 53 patients receiving recombinant granulocyte (G-CSF) or granulocyte macrophage colony stimulating growth factor (GM-CSF) for neutropenia were evaluated. The blood findings were marked by a neutrophilia with a prominent left shift, increased azurophilic granulation, Dohle bodies, and an elevated leukocyte alkaline phosphatase; circulating myeloblasts were observed but did not exceed 2% of the leukocytes. Nuclear segmentation abnormalities consisting of hyposegmentation, hypersegmentation, and ring nuclei were noted but were not a prominent finding. A leukoerythroblastosis was present in 54% of patients. No consistent effect on cell lines other than neutrophils was found. A monocytosis was present in 12 patients, a transient lymphocytosis in 2 and an eosinophilia in 1. No effect was evident on basophils. The morphologic changes in the neutrophils in the bone marrow specimens were most pronounced in the early period of growth factor therapy with a relative neutrophil hyperplasia with a marked increase in promyelocytes and myelocytes. With increasing duration of therapy, the myeloid to erythroid ratio normalized and the percentage of promyelocytes decreased while myelocytes and band neutrophils increased. Thirteen patients had no response to growth factor. The nonresponding patients were clinically diverse; all bone marrow biopsy specimens in this group were virtually acellular. No differences were noted between G-CSF and GM-CSF.