Samuelsson Bo E, Magnusson Stefan, Rydberg Lennart, Scherstén Tore, Breimer Michael E
Department of Clinical Chemistry and Transfusion Medicine, Sahlgrenska University Hospital, Goteborg, Sweden.
Xenotransplantation. 2006 Mar;13(2):160-5. doi: 10.1111/j.1399-3089.2006.00287.x.
Biochemical studies of organ blood group antigen expression show a mixed pattern originating from both the organ tissue and remaining blood cells trapped in the organ despite in vitro perfusion of the vascular tree. The blood group A glycolipid expression was studied in a unique case in which a human liver had been in situ perfused by recipient blood.
A blood group O recipient was re-transplanted with an ABO incompatible A1Le (a - b +) liver. Because of discrepancy in size, liver segments II and III were removed 2 h after re-vascularization. Thereafter, the removed A1 liver segment was physiologically in situ perfused with O blood, eliminating a major part of the donor blood cells/plasma.
Total neutral glycolipids were isolated from the liver tissue and separated by high-performance liquid chromatography. Purified glycolipid fractions were stained with anti-A monoclonal antibodies (mAbs) and structurally characterized by mass spectrometry and proton nuclear magnetic resonance (NMR) spectroscopy.
Two blood group A reactive glycolipid compounds were isolated. One component had a thin-layer chromatography (TLC) mobility as a six-sugar glycolipid and reacted with mAbs specific for A type 1 mono-fucosyl structures. The second glycolipid fraction migrated as seven-sugar components and reacted with mAbs specific for type 1 difucosyl (ALeb) as well as Leb determinants. Mass spectrometry of the six-sugar component showed a structure similar to a blood group A hexaglycosylceramide with one fucose. Mass spectrometry and proton NMR spectroscopy of the seven-sugar fraction revealed a mixture of blood group Leb hexa- and ALeb hepta-glycosylceramides, respectively. All fractions were non-reactive with antibodies specific for A antigens based on types 3 and 4 core chain structures. In addition, TLC immunostaining of glycolipids isolated from blood group A livers, harvested for organ transplantation but discarded for various reasons, revealed trace amounts of several A glycolipids with a complex pattern.
The in situ perfused liver tissue contains blood group A glycolipids based exclusively on type 1 core chains. The secretor gene (Se) codes for a fucosyltransferase acting on all core chain precursors while the H-gene fucosyltransferase only utilizes the type 2 chain precursor. Whether this explains that only A type 1 chain compounds were found has to be established.
器官血型抗原表达的生化研究表明，尽管对血管树进行了体外灌注，但器官组织中血型抗原的表达模式是混合的，既源于器官组织，也源于滞留在器官中的残留血细胞。在一个独特的案例中，研究了血型A糖脂的表达情况，该案例中人类肝脏接受了受者血液的原位灌注。
一名O血型受者接受了ABO血型不相容的A1Le(a - b +)肝脏再次移植。由于大小差异，在重新血管化2小时后切除了肝段II和III。此后，将切除的A1肝段用O型血进行生理原位灌注，去除了大部分供体血细胞/血浆。
从肝组织中分离出总中性糖脂，并通过高效液相色谱法进行分离。纯化的糖脂馏分用抗A单克隆抗体（mAb）染色，并通过质谱和质子核磁共振（NMR）光谱进行结构表征。
分离出两种与血型A反应的糖脂化合物。一种成分在薄层色谱（TLC）中的迁移率与六糖糖脂相同，并与针对A1型单岩藻糖基结构的mAb反应。第二种糖脂馏分以七糖成分迁移，并与针对1型二岩藻糖基（ALeb）以及Leb决定簇的mAb反应。六糖成分的质谱显示其结构类似于带有一个岩藻糖的血型A六糖神经酰胺。七糖馏分的质谱和质子NMR光谱分别显示为血型Leb六糖神经酰胺和ALeb七糖神经酰胺的混合物。所有馏分与基于3型和4型核心链结构的A抗原特异性抗体均无反应。此外，对因各种原因被废弃但用于器官移植而采集的A型肝脏中分离出的糖脂进行TLC免疫染色，发现了几种具有复杂模式的微量A型糖脂。
原位灌注的肝组织中仅含有基于1型核心链的血型A糖脂。分泌基因（Se）编码一种作用于所有核心链前体的岩藻糖基转移酶，而H基因岩藻糖基转移酶仅利用2型链前体。这是否解释了仅发现A型1链化合物还有待确定。
