心脏移植后骨髓腔内供者骨髓移植诱导供者特异性免疫低反应性再探讨

An improved strategy of intra-bone marrow-bone marrow transplantation in tolerance induction in clinical heart transplantation trials

目的再次探讨骨髓腔内供者骨髓移植诱导心脏移植后供者特异性免疫耐受的可行性。方法2011年10月至2012年12月间，对3例心脏移植受者进行分期骨髓腔内供者骨髓移植。采用改良灌流法采集骨髓细胞，以增加骨髓细胞采集数目。应用抗胸腺球蛋白、氟达拉滨及巴利昔单抗进行预处理，以降低预处理不良反应。结果应用改进灌流法采集的单核细胞数目由1．2×10^7／k增加至5．8X10^7／艇（P〈O．01）；CD34’细胞数目由2．38×10^7／k增加至6．7×10^7／kg（P〈0．01）。骨髓移植后随访3个月，3例均无巨细胞病毒和真菌感染，未发生移植物抗宿主病等并发症。心内膜活检证实无排斥反应发生。体外混合淋巴细胞反应提示受者淋巴细胞对供者脾细胞呈免疫低反应性，而对无关第三者抗原仍维持良好的免疫活性。结论改进的心脏移植后骨髓腔内供者骨髓移植诱导方案可降低骨髓移植后早期感染发生，提高了治疗的安全性，但仍可成功诱导供者特异性免疫低反应性。

Objective From our previous findings in the first clinical trial undergoing heart transplantation and subsequent intra-bone marrow-bone marrow transplantation （IBM-BMT）, we investigate an improved strategy of bone marrow transplantation （BMT） concerning safety besides efficacy for donor-specific tolerance induction after heart transplantation. Method The first clinical trial underwent heart transplantation and subsequent IBM-BMT in August 2010, and consecutive 3 trials were performed using improved BMT regimens from October 2011 to December 2012. This improved BMT regimens consist of modified perfusion method （PM） to improve the efficiency of havesting bone marrow cells （BMCs） and non-radiation precondition of BMT to reduce the toxicity to the host. Result In harvesting of BMCs, modified PM showed higher efficiency in number of monocytes （5.8 10^7/kg vs. 1.2x 10^7/kg, P〈0. 01） and CD34＋ cells （6. 7x 10^5/kg vs. 2. 38x 10^5/ kg, P〈0. 01） as compared with the previous method. After 3-month follow up, neither was infection of cytomegalovirus or fungus nor graft versus host disease in the group treated with improved BMT regimens. Moreover, no rejection （Class 0） was confirmed by endomyocardial biopsy either. Mixed lymphocyte reactions revealed donor-specific hyporesponsiveness while immunocompetence was well preserved to third-party antigens. Conclusion These findings indicate that the improved BMT strategy of modified PM ＋ non-radiation preconditioning regimens ＋ two-stage IBM-BMT is a safer method for inducing donor-specific tolerance without incidence of early-stage infection in clinical heart transplantation trials than the previous regimens.