Numbers and functions of transplantable primitive immunohematopoietic stem cells. Effects of age.

摘要: This report introduces a new method in immunology, use of the binomial formula with covariance to estimate numbers and proliferative patterns most primitive lymphoid precursors. We studied stem cells (PSC) from which circulating lymphocytes erythrocytes were descended during 300 400 days recipients genetically distinguishable marrow mixtures competitive repopulation. Equivalent PSC concentrations (Eq. Conc. or Conc.) estimated, notion common PSCs contributing equally myeloid compartments. Similar estimation was done for (and erythrocytes) drawn at successive sampling times about 100 apart descended. The percentages lymphocyte erythrocyte types, P1 Pe, measured each recipient closely correlated, especially after 6 months later. Close correlations also found sampled one hundred day intervals, first. Apparently few their direct descendents produced blood E, this production continued many months. Concentrations these (Equivalent concentrations) per 10(5) young donors. is much lower than previous estimates, probably because our methods focus only on interesting precursors, those two-fold higher old donors; correspondingly Pe values, but declined time. There small increases time values To explain temporal trends, we suggest that excess precursors less are present marrow, contribution differentiated cell population gradually declines. Possibly such as well true PSC, proliferate donors compensate deficiencies develop age.