Stimulation of myelopoiesis in chronic lymphocytic leukemia and in other lymphoproliferative disorders by recombinant human granulocyte‐macrophage colony‐stimulating factor

Abstract

In an attempt to stimulate granulopoiesis, we administered recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSF) to 11 patients with lymphoproliferative disorders. Ten patients had neutropenia, six of whom had severe neutropenia (less than 500 neutrophils), including two with agranulocytosis. GM-CSF (60-250 micrograms/m2/day) was administered by continuous intravenous infusion daily for 14 days at 2-week intervals. Significant increases in white blood cell counts (1.3-to 11.7-fold) and neutrophils (1.7- to more than 29-fold) were seen in 10 of 11 patients, including one patient with agranulocytosis. Eosinophils (3.9- to greater than 65-fold) and monocytes (1.3- to 5-fold) increased as well. In contrast, no significant increases were seen in total lymphocytes or in different phenotypic subsets of lymphocytes during treatment. The overall proportion of myeloid and lymphoid elements in bone marrow remained stable. These results indicate that GM-CSF is effective in stimulating myelopoiesis in neutropenic states associated with lymphoproliferative disorders. Further studies will be necessary to determine whether the correction of neutropenia ultimately translates into clinical benefit.