Allogeneic Marrow Engraftment by Cross Circulation in Lethally Irradiated Dogs

Dogs given 1200 r of total body irradiation were cross-circulated with dogs having normal marrow function. Irradiated controls died in from 4 to 11 days with marrow aplasia. Dogs cross-circulated daily for 6 to 9 days showed histologic evidence of bone marrow repopulation after 1 week. Male dogs cross-circulated with female partners showed typical female drumsticks on mature granulocytes after repopulation had occurred. Cytogenetic studies of an irradiated male dog cross-circulated with a female partner showed all mitotable cells from the bone marrow and peripheral blood to be of female donor type. Allogeneic bone marrow engraftment was associated with an early and severe secondary syndrome which resulted in the death of the animals in the second week. When methotrexate was given, survival was increased to 3 weeks.

It was concluded that (1) cross circulation provided leukocytes and platelets adequate for support during the period of radiation-induced marrow aplasia, (2) allogeneic marrow engraftment was produced consistently by cells transferred in the peripheral blood of the normal cross circulation partner, (3) the grafts were associated with an early and severe form of secondary disease, and (4) methotrexate given during the early period of engraftment reduced the severity of the secondary disease.