Morphologic alterations in canine marrow of long-term survivors after 1200 R whole-body x-irradiation and autologous blood leukocyte engraftment.

The marrow matrix of total-body x-irradiated dogs (1200 R midline dose) was able to support effective hemopoiesis for several hundred days if the animals were transfused with their own mononuclear leukocytes collected from the blood prior to irradiation and preserved at ultralow temperatures. However, a lesion developed in the marrow, consisting of a fibrosis originating in conjunction with or from the endosteum. The fibrotic tissue substantially reduced the available marrow space in dogs with advanced lesions. The number of autologous, cryopreserved mononuclear leukocytes transfused ranged from 0.32 X 10(9) to 1.63 X 10(9)/kg body weight. The observation period extended to a maximum of 898 days after irradiation.