上海地区人群红细胞A2亚型血清学与分子生物学研究

Serological characteristic and molecular basis of A2 subgroup in Shanghai population

目的研究献血员和患者红细胞A2亚型血型血清学和分子生物学异同点。方法应用抗-A1试剂对A和AB型样本进行筛选，应用PCR-直接碱基序列分析基因分型技术技术对ABO基因第1～7外显子及第6内含子区域进行测序，参照红细胞血型抗原基因突变数据库（Blood Group Antigen Gene Mutation Database，BGMUT）确定血型基因型。结果7111份样本中75例为血型血清学A2亚型，而分子生物学亦为A2亚型仅为28例，其中以A205／B101（12例）最多。非A2亚型者以A102／B101（25例）最多。总人群、献血员组和患者组在血型血清学水平A2B亚型发生率显著高于A2亚型发生率，分别相互比较差异有统计学意义（x2=64．613，33．137，34．963，P〈0．01）；总人群和献血员组在分子生物学水平A2B亚型发生率也显著高于A2亚型，分别相互比较差异有统计学意义（x2=17．678，14．157，P〈0．01），而在患者组则差异无统计学意义（连续校正x2=2．351，P=0．125）。结论上海地区人群A2亚型血清学与分子生物学结果一致率较低应引起重视。另外，A102／B101基因型是血型血清学判为A2亚型但分子生物学确认为非A2亚型的最多的基因型，其机制有待于进一步研究。

Objective To investigate the similarity and difference in blood group serology and molecular biology of A2 and A2B phenotypes between healthy blood donors and patients. Methods The A and AB phenotypes were screened with anti-A1. Exons 1 to 7 and intron 6 of the ABO gene were analyzed with polymerase chain reaction-sequence-based typing （PCR-SBT） method. The blood type was determined by referring to the Blood Group Antigen Gene Mutation Database （BGMUT）. Results Among 7111 tested individuals, 75 were assigned as A2 or A2B phenotypes. However, only 28 individuals still belonged to the A2-related allele group based on genetic analysis. Among these, A205/B101 was the most common genotype. Among those non-A2-related alleles, A102/B101 was the most common genotype. Based on serologic testing, there was an imbalance between the A2 and A2B subgroups. In both donor group and patient group, the proportion of A2B was significantly higher than that of the A2. There were statistical differences between different groups （72 =64. 613, 33. 137, 34. 963, P〈0. 01）. At the gene level, the imbalance still existed in both the overall population and the donor group, though there was a statistical difference between the two （x2 = 17. 678, 14. 157, P〈0. 01）. The same imbalance did not exist in the patient group （with continuous correction, X2 =2. 351, P=0. 125）. Conclusion The concordance rate for blood type determined by serology and genetic analysis has been low and deserves attention. For A2 and A2B phenotypes by serological screening, A102/B101 was the most common gene among non-A2-related alleles. Further study is needed to clarify this phenomenon.