Brief Note: Marrow Repopulating Ability of Peripheral Blood Cells Compared to Thoracic Duct Cells

Ten dogs were exposed to 1200 r. of whole body irradiation at a dose rate of 9.2 r./min. Five of these dogs were then given infusions of 21 to 74 x 10⁹ autologous peripheral blood cells which had been previously stored at -80 C. 4.0 to 19.4 x 10⁹ of these cells were lymphocytes, 0.4 to 4.9 x 10⁹ were monocytes and 16.4 to 50.3 x 10⁹ were granulocytes. All five dogs showed clinical or histologic evidence of bone marrow repopulation. The remaining 5 dogs were given 7 to 22 x 10⁹ autologous thoracic duct lymphocytes. In none of these dogs was marrow repopulation observed.

It was concluded that hemopoietic stem cells are not present in the thoracic duct lymph of the dog in any appreciable number.