Neutrophil kinetics in man

Abstract

A method is described for the measuring of neutrophil cellularity in normal human bone marrow, in which the neutrophil erythroid ratio was determined from marrow sections and marrow normoblasts were estimated by the erythron iron turnover. Neutrophil maturational categories, defined by morphologic criteria, were supported by autoradiographs of marrow flashed labeled with 3H thymidine. Correction for multiple counting error was empirically derived by counting serial sections through cells of each maturational category. The normal neutrophil erythroid ratio in 13 normal human subjects was 1.5±0.07. The mean number of normoblasts in the same subjects was estimated to be 5.07±0.84 x 109 cells/kg. Total marrow neutrophils (x 109 cells/kg) were 7.70±1.20, the postmitotic pool (metamyelocytes, bands, and segmented forms) was 5.59± 0.90 and the mitotic pool (promyelocytes + myelocytes) was 2.11±0.36. Marrow neutrophil ('total') production has been determined from the number of neutrophils comprising the postmitotic marrow pool divided by their transit time. Transit time was derived from the appearance in circulating neutrophils of injected 3H thymidine. The postmitotic pool comprised 5.59±0.90 x 109 neutrophils/kg, and the transit time was 6.60±0.03 days. From these data marrow neutrophil production was calculated to be 0.85 x 109cells/kg per day. Effective production, measured as the turnover of circulating neutrophils labeled with 3H thymidine, was 0.87±0.13 x 109 cells/kg per day. This value correlated well with the calculation of marrow neutrophil production. A larger turnover of 1.62±0.46 x 109 cells/kg per day was obtained when diisopropylfluorophosphate 32P was used to label circulating neutrophils. Studies using isologous cells doubly labeled with 3H thymidine and diisopropylfluorophosphate 32P demonstrated a lower recovery and shorter t 1/2 of the 32P label.