Further investigation on the Rh blood group system for the expression of the RH gene and the epitopes of the Rh antigens

完全测定了含有人类基因RH30的同源基因Rhced的小鼠基因组序列，并与相应的人类基因组区域进行了比较。两个基因Smp1和AK003528(与FLJ10747同源)，侧翼Rhced。在测序的小鼠区域中，既没有发现与人类(恒河猴盒子)RHD基因两侧的特征核苷酸元件同源的序列，也没有发现额外的Rh基因。这一结果表明，小鼠的该染色体区域包含5个基因(FLJ10474-RHCE-SMP1-NPD014-P29)，它们与相应的人类区域具有同线同源性，这表明RHD基因和恒河猴盒子是后来插入的。跨膜区的G212C(新的弱D型)、V270G(弱D型1)和G358A(2型)突变对抗D单抗识别的D表位有明显影响。这一结果提供了直接证据，表明这些突变可以解释弱D表型。发现一种新的部分D表型，命名为DT1。DT1表型影响第四外环内的D多肽，形成新的RHD-CE(完整外显子5)-D杂交基因。值得注意的是，由外显子5编码的P226来源于DT1多肽中RhCE的E。利用多种重组Rh抗原或表达带3蛋白的KU812细胞构建了检测自身免疫性溶血性贫血自身抗原的筛选体系。20例AIHA患者中15例自身抗原为Rh相关抗原，7例为带3蛋白。

The mouse genomic sequence of the region containing the gene Rhced, the orthologue to the human gene RH30, was entirely determined and compared with the corresponding human genomic region. Two genes Smpl and AK003528 (an orthologue of FLJ10747), flank Rhced. Neither sequences homologous to the characteristic nucleotide elements flanking the RHD gene in human (rhesus boxes) nor an additional Rh gene were found within the mouse region sequenced. This result demonstrate that this chromosomal region of the mouse comprises five genes (FLJ10474-RHCE-SMP1-NPD014-P29) that exhibit syntenic homology with the corresponding human region, which suggests that the RHD gene and rhesus boxes were inserted later.The molecular characterization of weak D and partial D phenotypes was performed. The mutations - G212C (new weak D type), V270G (weak D type 1), and G358A (type 2) - in transmembranous regions had obvious effects on the D epitopes recognized by monoclonal anti-D antibodies. This result provide direct evidence that these mutations can account for weak D phenotypes. A novel partial D phenotype, termed DT1 was found. The DT1 phenotype affected the D polypeptide within the fourth external loop, resulting in a new RHD-CE (entire exon 5)-D hybrid gene. It is worth noting that P226, encoded by exon 5, is derived from E of RhCE in the DT1 polypeptide.The screening system for detecting the autoantigens in autoimmune hemolytic anemia (AIHA) was constructed by using several recombinant Rh antigens or band 3 protein-expressing KU812 cells. The autoantigens in twenty patients with AIHA were Rh-related ones in 15 cases and band 3 protein in 7 cases.