Granulopoiesis in aged people: inverse correlation between bone marrow cellularity and myeloid progenitor cell...

Results of a study on bone marrow (BM) cytology and cellularity, BM granulocytic-macrophage colony formation (GM-CFU-C), peripheral blood (PB) colony stimulating factor (CSF) and serum lysozyme activity in 20 elderly people aged from 64 to 89 are presented. Besides slight iron deficiency anemia, no hematological abnormality was detected. No change in PB and BM differential counts was found as compared to those obtained for normal adults. The BM cellularity and colony incidence were assessed using aliquots of the same specimen. GM-CFU-C frequency ranged from 15 to 156 (average 67.5) per 2 X 10(5) BM cells seeded. The largest number of colonies was observed in hypocellular BM samples (p less than 0.002). The level of serum lysozyme activity for the entire group was significantly higher than that obtained in healthy persons up to the age of 60 (p less than 0.001). The overall results support the notion that in old age, increased proliferation of committed granulopoietic stem cells in hypoplastic areas of the BM, assure normal numbers of mature blood cells in the periphery.