Booster irradiation to the spleen following total body irradiation. A new immunosuppressive approach for allogeneic bone marrow transplantation.

摘要: Graft rejection presents a major obstacle for transplantation of T cell-depleted bone marrow in HLA-mismatched patients. In primate model, after conditioning exactly as leukemia patients, it was shown that over 99% the residual host clonable cells are concentrated spleen on day 5 completion cytoreduction. We have now corroborated these findings mouse model. After 9-Gy total body irradiation (TBI), number Thy-1.2+ reaches peak between days 3 and 4 TBI. The cell population is composed both L3T4 (helper) Lyt-2 (suppressor) cells, former being subpopulation. Specific booster to (5 Gy twice) 2 TBI greatly enhances production donor-type chimera allogeneic marrow. Similar enhancement can be achieved by splenectomy or but not if performed 1 before TBI, strengthening hypothesis that, lethal mice, remaining migrate from periphery spleen. These results suggest delayed may beneficial an additional immunosuppressive agent order reduce incidence allograft rejection.