Donor-origin cell engraftment after intraosseous or intravenous bone marrow transplantation in a rat model

We compared the effects of intraosseous BMT with those of standard i.v. BMT on the efficacy on donor-cell engraftment into the BM and lymphoid organs across an MHC barrier in rats. Twenty-four intraosseous and 24 i.v. BMTs were performed from 48 ACI (RT1(a)) donors to 48 Lewis (RT1(1)) recipients. Each transplant group received either intraosseous or i.v. BMT. Groups I and II served as controls without immunosuppression (n=16); groups III and IV received cyclosporine monotherapy (n=16); and V and VI received alpha beta-TCR monoclonal antibody and cyclosporine A (alpha beta-TCR/CsA) for 7 days (n=16). In each group, four rats received 35 x 106 transplanted bone marrow cells (BMCs) and four received 70 x 106 cells. All animals survived without GVHD. Mean (+/- s.d.) donor-cell engraftment into BM of recipients after intraosseous BMT was 7.9% (+/- 1.3%) in recipients receiving alpha beta-TCR-CsA and 70 x 10(6) BMCs, and 4.2% (+/- 1.4%) in recipients after i.v. transplantation. The seeding efficacy of donor cells into lymphoid tissue was greater after intraosseous BMT and alpha beta-TCR-CsA than after standard i.v. transplantation. In our model, intraosseous BMT facilitated donor-cell engraftment under short-term immunodepletive alpha beta-TCR/CsA protocol, which resulted in a temporary state of immune unresponsiveness.