Delayed Mortality in Sublethally Irradiated Mice Treated With Allogeneic Lymphoid and Myeloid Cells

Summary

RF mice were irradiated with a high sublethal dose (530 rads) of X rays and treated with C57BL spleen cells, bone marrow, or both. Administration of spleen cells produced high mortality attributable to an acute graft-vcrsus-host reaction and myeloid tissue depletion. Administration of bone marrow cells produced transient chimerism and, occasionally, midlethal dose effect. Treatment with mixed cell inocula containing 5–10 × 10⁶ spleen cells and 30–40 × 10⁶ bone marrow cells resulted in development of a chronic wasting syndrome terminating in death 1–2 months after treatment. In these mice, chimerism was more frequently present than in mice receiving bone marrow only. It is concluded that allogeneic immunocompetent cells may promote the take of a simultaneously administered bone marrow graft by reinforcing irradiation damage to the recipient's hematopoietic tissue. This may result in a chronic secondary disease.