Peripheral blood granulocyte, lymphocyte, and platelet counts in dogs treated with ²¹¹At–anti-CD45 mAb-conditioned nonmyeloablative DLA identical bone marrow transplantation. Eight dogs received 155 to 625 μCi/kg ²¹¹At-labeled anti-CD45 mAb on day −3 followed by marrow grafts from a DLA- identical donor on day 0. The total anti-CD45 mAb dose was 0.5 mg/kg, whereof 10% was administered as unlabeled mAb 1 hour before the radioimmunoconjugate. Posttransplant immunosuppression consisted of cyclosporine 15 mg/kg twice daily from day −1 to day 35 and mycophenolate mofetil 10 mg/kg twice daily from day 0 to day 27. The solid and dashed curves represent median values from historical controls conditioned with 200 cGy (n = 5)³¹  or ²¹³Bi-anti-CD45 (n = 11)^10,11  before receiving bone marrow from DLA-identical donors, respectively.