Studies on the property and transplantation of haemopoietic stem cells from peripheral blood.

Comparative studies of the properties of murine haemopoietic stem cells from different sources revealed that the peripheral haemopoietic stem cell is relatively weaker than the haemopoietic stem cell from bone marrow in promoting the recovery of hemopoiesis in the irradiated animals. This is due to the heterogenity of stem cell population in which some aged cellsubpopulations are co-existing. The modified potential in proliferation and differentiation of haemopoietic stem cells in the peripheral blood seems to be irreversible under normal physiological conditions. In a preliminary experiment, the use of an anti-thymocyte immunoglobulin to eliminate immunocompetent cells proved effective in reducing the severity and incidence of secondary diseases and in increasing the number of survivors of lethally irradiated semi-isologous mice after transplantation of parental peripheral mononuclear cells.