目的:应用分子生物学方法鉴定急性白血病患者ABO血型抗原,确定患者ABO血型正反定型不符的原因。方法:选取临床正反定型不一致白血病患者,常规血清学ABO血型正反定型;直接和间接抗人球蛋白试验检测不规则抗体;吸收放散法鉴定弱血型抗原;PCR方法扩增ABO基因的7个外显子及侧翼内含子,扩增产物进行测序及序列分析。结果:患者正定型为AB亚型,反定型为AB型;直抗和间抗为阴性;吸收放散试验证明红细胞上存在弱A和B抗原;ABO基因扩增产物测序结果表明其基因型为ABO*A102/B101。结论:该白血病患者经分子生物学方法确定为正常AB型,其血型抗原减弱由白血病所致。基因分型法可以正确区分血型抗原减弱或亚型。 OBJECTIVE: To identify ABO blood group antigens in patients with acute leukemia by molecular biology method and to determine the cause of discrepancy between positive and negative ABO blood group patients. Methods: Positive and negative patients with positive and negative leukemia were enrolled, routine serological ABO positive and negative typing, direct and indirect anti-human globulin test for detection of irregular antibodies, weak antigen identification by absorption and desorption method, PCR amplification of ABO gene 7 Exons and flanking intron, amplification products were sequenced and sequence analysis. Results: The patients were positive for AB subtypes and negative for type AB. The direct and indirect antigens were negative. Absorption and dissipation test showed weak A and B antigens on erythrocytes. The sequencing results of ABO gene amplification products showed that the genotype was ABO * A102 / B101. Conclusion: The leukemia patients were identified as normal type AB by molecular biology, and their blood group antigens were attenuated by leukemia. Genotyping can correctly distinguish blood group antigens or subtypes.