Proliferation characteristics of lymphoid cells of human bone marrow in health and in chronic renal failure

The lymphocyte production pathway in bone marrow: possible significance of the size spectrum of lymphocytes and their precursors

It is now generally accepted that transitional ('lymphoid') cells are the precursors of small lymphocytes. Such cells have a heterogeneous size spectrum and show high proliferative capacity. To facilitate the study of the kinetics of lymphocyte production, a detailed investigation of cell sizes of the transitional cell-lymphocyte compartment was carried out using a Coulter counter modified to permit a very rapid and accurate examination of cells in suspension. Enriched populations of 'lymphoid' cells, obtained after 10 d rebound from hypoxia at half an atmosphere, were enriched further by bovine albumin and Ficoll gradients to give density fractions containing two types of cells. Differential counts of stained smears of these fractions enabled a comparison to be made between the size distribution and the specific cell types. Four distinct cell types were characterized in terms of volume and density: small and intermediate-sized lymphocytes (volume 53-59 fl, albumin fractions 19-23%), small transitional cells (154-160 fl, 21-23%), medium transitional cells (206-218 fl, 17-19%) and large transitional cells (350-400 fl, 21-27%). These findings are consistent with the view that there are at least three mitoses in the course of the lymphocyte production pathway in the bone marrow.

Proliferation characteristics of erythroblasts in chronic renal failure

Proliferation of bone marrow erythroblasts in patients with chronic renal disease was studied by combined application of cytophotometric measurement of the DNA content and 3H-TdR labeling in vitro. A striking decrease of 3H-TdR labeling was found in most of the cases. The proportion of diploid (G0 + G1) as well as of tetraploid unlabeled cells (G2) was increased. The data suggest a disturbed induction of DNA synthesis of resting cells as well as an arrest of cells in G2 being responsable for ineffective cell production in this disease.