Combination of intra-bone marrow-bone marrow transplantation and subcutaneous donor splenocyte injection diminishes risk of graft-versus-host disease and enhances survival rate.

The combination of allogeneic bone marrow transplantation (allo-BMT) and donor lymphocyte infusion (DLI) is a useful method for establishing donor chimerism and preventing a relapse of leukemia/lymphoma. However, there is a risk of inducing uncontrollable fatal graft-versus-host disease (GVHD). In fact, allo-BMT plus intravenous (IV)-DLI using donor splenocytes induces fatal GVHD in recipient mice. In this study, we examined the effects of the combination of intra-bone marrow (IBM)-BMT and the subcutaneous injection of donor splenocytes (SC-DLI) on the allo-BMT system. Recipient BALB/c mice were conditioned by sublethal irradiation (5 Gy), followed by IBM-BMT plus IV-DLI or SC-DLI in C57BL/6 mice. The IV-DLI group showed better engraftment of donor hemopoietic cells than the control group (without DLI) but showed fatal GVHD. The SC-DLI group, however, showed good reconstitution and mild GVHD. These results suggest that the combination of SC-DLI and IBM-BMT promotes the reconstitution of hemopoiesis and helps reduce the risk of GVHD.