Physiological and therapeutic glycosidic adaptation between graft and host in ABO(H)-incompatible transplantation, a hypothesis.

onIn contrast to non-nucleated ABO(H)-incompatible red cells, which when transfused to a blood group O(H) recipient undergo destruction within minutes, such hyperacute, humoral rejection occurs relatively rare in transplantations of highly nucleated, metabolically active solid organs, and it is extremely rare in liver transplantations (Adams 1991; Della-Guardia et al. 2008). Moreover, a case of transient, selective disappearance of preexisting donor-specific HLA-antibodies after an incompatible liver transplantation, without any rejection episodes, has been reported by Bastiani (2006), and according to Taner et al. (2014), such transient decrease of donor-specific HLA-antibodies is not uncommon after liver transplantation. In addition, a transient exponential fall in both anti-A/B reactive IgM and IgG titers were also observed after ABO(H) incompatible bone marrow transplantation (Rowley et al. 2000; Lee et al. 2003). These phenomena most likely represent a metabolic achievement of the graft in overcoming the rejection. It appears to be established that tissue transplants always maintain their original, phenotype-specific metabolic properties, and expanding the concept of “glycosidic exclusion”,”, a transplanted A/B metabolically active, solid tissue may use its phenotype-specific enzymatic equipment to contribute to a compatible environment by consistent glycosylation of the non-completed, free H-receptor sites of the plasma proteins and the differentiating B-cell surfaces of an O(H) recipient.

与无核ABO(H)不相容红细胞不同——这类红细胞输注给O(H)血型受者后会在数分钟内发生破坏——这种超急性体液排斥反应在高有核、代谢活跃的实体器官移植中相对少见，在肝移植中则极为罕见（Adams等，1991；Della-Guardia等，2008）。此外，Bastiani（2006）曾报道1例不相容肝移植术后，预先存在的供者特异性HLA抗体（HLA-antibody）出现一过性选择性消失，且未发生任何排斥反应；据Taner等（2014）报道，肝移植术后供者特异性HLA抗体出现一过性降低并非少见情况。另外，ABO(H)不相容骨髓移植术后，也观察到抗A/B反应性免疫球蛋白M（IgM）与免疫球蛋白G（IgG）滴度出现一过性指数下降（Rowley等，2000；Lee等，2003）。上述现象大概率代表移植物在对抗排斥反应过程中展现的代谢适应机制。目前已有共识：组织移植物始终保留其原始的表型特异性代谢特性；结合“糖苷排除（glycosidic exclusion）”这一概念，具有代谢活性的移植A/B型实体组织可借助其表型特异性酶系统，通过持续糖基化O(H)受者血浆蛋白未完成的游离H受体位点以及分化中的B细胞表面，构建出相容的体内环境。