How an ABO-incompatible graft may contribute to its survival by phenotype-specific glycosylation of the host. A hypothesis.

In contrast to non-nucleated ABO(H)-incompatible red cells, which when transfused to an HLA-compatible 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 selective disappearance of preexisting donor-specific HLA-antibodies after a HLA-incompatible liver transplantation without any rejection episodes, has been reported by Bastiani (2006), and according to Taner et al. (2014), such decrease of donor-specific HLA-antibodies is not uncommon after liver transplantation. While this phenomenon represents a metabolic achievement of the graft in overcoming one of the mechanism of rejection, respective observations on anti-A/B-isoagglutinins are missing, because they are always removed before transplantation. 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 ABO(H)-incompatible, metabolically active tissue may use its phenotype-specific enzymatic equipment to contribute to a compatible environment by consistent glycosylation of complementary sites of the plasma proteins and the differentiating B-cell surfaces of a HLA-compatible recipient.

与输注至人类白细胞抗原(HLA)相容的O(H)血型受者后数分钟内即遭破坏的无核ABO(H)血型不相合红细胞(ABO(H)-incompatible red cells)不同，此类超急性体液排斥反应在有核且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 1991; Della-Guardia et al. 2008）。此外，Bastiani（2006）曾报道1例HLA不相合肝移植术后未发生任何排斥反应，但预先存在的供者特异性HLA抗体(Donor-specific HLA-antibodies)选择性消失的病例；而Taner等（2014）指出，肝移植术后供者特异性HLA抗体水平下降并非罕见现象。尽管这一现象体现了移植物在克服某一排斥反应机制方面的代谢优势，但针对抗A/B同种凝集素(anti-A/B-isoagglutinins)的相关观察仍存在缺失——这是因为此类抗体通常会在移植前被清除。目前已明确，组织移植物始终保留其固有的表型特异性代谢特性；进一步拓展"糖苷排除(glycosidic exclusion)"这一概念，移植后的ABO(H)血型不相合、代谢活跃的组织可借助其表型特异性酶系统，通过持续对HLA相容受者的血浆蛋白互补位点及分化中的B细胞表面进行糖基化修饰，从而构建相容的微环境。