This study evaluated the efficacy of donor recipient chimeric cell (DRCC) therapy created by fusion of donor and recipient derived bone marrow cells (BMC) in chimerism and tolerance induction in a rat vascularized composite allograft (VCA) model. Twenty-four VCA (groin flaps) from MHC-mismatched ACI (RT1^a) donors were transplanted to Lewis (RT1^l) recipients. Rats were randomly divided into (n = 6/group): Group 1—untreated controls, Groups 2—7-day immunosuppression controls, Group 3—DRCC, and Group 4—DRCC with 7-day anti-αβTCR monoclonal antibody and cyclosporine A protocol. DRCC created by polyethylene glycol-mediated fusion of ACI and Lewis BMC were cultured and transplanted (2–4 × 10⁶) to VCA recipients via intraosseous delivery route. Flow cytometry assessed peripheral blood chimerism while fluorescent microscopy and PCR tested the presence of DRCC in the recipient’s blood, bone marrow (BM), and lymphoid organs at the study endpoint (VCA rejection). No complications were observed after DRCC intraosseous delivery. Group 4 presented the longest average VCA survival (79.3 ± 30.9 days) followed by Group 2 (53.3 ± 13.6 days), Group 3 (18 ± 7.5 days), and Group 1 (8.5 ± 1 days). The highest chimerism level was detected in Group 4 (57.9 ± 6.2%) at day 7 post-transplant. The chimerism declined at day 21 post-transplant and remained at 10% level during the entire follow-up period. Single dose of DRCC therapy induced long-term multilineage chimerism and extended VCA survival. DRCC introduces a novel concept of customized donor-recipient cell-based therapy supporting solid organ and VCA transplants.

本研究在大鼠血管化复合同种异体移植物 (VCA) 模型中评估了通过融合供体和受体来源的骨髓细胞 (BMC) 在嵌合和耐受诱导中产生的供体受体嵌合细胞 (DRCC) 疗法的功效。来自 MHC 不匹配的 ACI (RT1 ^a ) 供体的 24 个 VCA (腹股沟皮瓣) 被移植到 Lewis (RT1 ^l ) 受体。将大鼠随机分为（n  = 6/组）：第 1 组—未治疗的对照组、第 2 组—7 天免疫抑制对照组、第 3 组—DRCC 和第 4 组—DRCC，使用 7 天抗 αβTCR 单克隆抗体和环孢素 A协议。由聚乙二醇介导的 ACI 和 Lewis BMC 融合产生的 DRCC 被培养和移植（2-4 × 10 ⁶) 通过骨内递送途径发给 VCA 接受者。流式细胞术评估外周血嵌合，而荧光显微镜和 PCR 在研究终点（VCA 排斥）测试受体血液、骨髓 (BM) 和淋巴器官中 DRCC 的存在。DRCC 骨内分娩后未观察到并发症。第 4 组的 VCA 平均存活时间最长（79.3 ± 30.9 天），其次是第 2 组（53.3 ± 13.6 天）、第 3 组（18 ± 7.5 天）和第 1 组（8.5 ± 1 天）。在移植后第 7 天，在第 4 组 (57.9 ± 6.2%) 中检测到最高嵌合水平。嵌合体在移植后第 21 天下降，并在整个随访期间保持在 10% 的水平。单剂量的 DRCC 治疗可诱导长期多谱系嵌合体并延长 VCA 生存期。