11 patients with chronic neutropenia were evaluated. In 6 patients low numbers of CFU-DG were observed. Only 3 of these patients also had low CFU-C numbers, suggesting that these two precursors are not identical. Bone marrow samples from 2 patients were restudied a year later. The number of CFU-DG remained low while CFU-C numbers increased to control range in 1 patient. Studies for serum inhibitors were negative. No cytogenetic abnormalities were observed.This study suggests that abnormalities at different levels in the haemopoietic precursor cell hierarchy can be detected either simultaneously or independently in patients with chronic neutropenia.
CLINICAL BEARING The concentration of haemopoietic precursor cells has been assessed in a number of myeloprollferatlve disorders by culturing cells in vitro.In chronic neutropenia, normal, increased, and decreased numbers of CFU-C, which are assayed in agar In vitro, have been observed. In this study, by utilizing an in vivo diffusion chamber culture technique, we demonstrated that in some patlents, granulocytlc precursor cells (CFU-DG), which are more prlmltlve than CFU-C, may be decreased. These studies suggest that in chronic neutropenia the proliferative capabilities of haemopoietic precursors at several levels of differentiation, may be defective.