Sbds RNAi inhibits secondary transplant engraftment. Bone marrow was harvested from primary transplant recipients 6 months after transplantation (n = 3), pooled, and transplanted into secondary recipients. The percentage of YFP⁺ leukocytes in the (A) blood (n = 8) and (B) bone marrow (n = 2-3) was measured at 6 weeks. Data are presented as the ratio of the percentage of YFP⁺ cells in the peripheral blood (A) or bone marrow (B) of the recipient to the percentage of YFP⁺ cells in the bone marrow of the donor (average ± SEM). **P ≤ .01.