摘要
This study looked into a family involving a rare mother-child ABO blood type inconsistency and explored its genetic and molecular basis. In the family, the mother had type AB blood and the father was blood type B and they gave birth to a baby of blood type O. Their blood types were phenotypically identified by using different techniques, including micro-column gel test, immune inhibition test, absorption and elution tests. The sequences of all 7 exons of ABO allele from the core family members were determined by using PCR and clone-based sequencing. The loci of mutated gene were compared against normal human genes. The result showed that the mother＇s erythrocytes were agglutinable with monoclonal anti-A antibody（2＋） and had agglutination reaction with anti-B antibody（4＋）. The mother＇s serum registered agglutination action with standard blood type A cells. The findings showed an ABO inconsistency. When domestic antibodies were used, the mother＇s erythrocytes yielded agglutination reaction with humanized anti-B serum（4＋） and anti-B monoclonal antibody but were non-agglutinable with humanized anti-A serum and anti-A monoclonal antibody. Upon absorption and elution, the titer of anit-A antibody was 128 both before and after the absorption test, with no significant difference found between pre- and post-absorption values. Our results confirmed that the mother＇s allelic gene was type B and contained type A. The father＇s blood type was type B, and son＇s blood type was type O. Clone-based sequencing revealed that the mother carried a heterozygous gene of B101.01（nt A640→G）/O01, which contained an M214→V mutation that could express a weak expression of antigen A, resulting in blood type AB. However, their son did not have the M214→V mutation, which yielded a false ABO-inconsistency between him and his mother. We were led to conclude that type B gene with a M214→V mutation can encode both antigen B and weak antigen B that can lead to false ABO-inconsistencies.
This study looked into a family involving a rare mother-child ABO blood type inconsistency and explored its genetic and molecular basis. In the family, the mother had type AB blood and the father was blood type B and they gave birth to a baby of blood type O. Their blood types were phenotypically identified by using different techniques, including micro-column gel test, immune inhibition test, absorption and elution tests. The sequences of all 7 exons of ABO allele from the core family members were determined by using PCR and clone-based sequencing. The loci of mutated gene were compared against normal human genes. The result showed that the mother＇s erythrocytes were agglutinable with monoclonal anti-A antibody（2＋） and had agglutination reaction with anti-B antibody（4＋）. The mother＇s serum registered agglutination action with standard blood type A cells. The findings showed an ABO inconsistency. When domestic antibodies were used, the mother＇s erythrocytes yielded agglutination reaction with humanized anti-B serum（4＋） and anti-B monoclonal antibody but were non-agglutinable with humanized anti-A serum and anti-A monoclonal antibody. Upon absorption and elution, the titer of anit-A antibody was 128 both before and after the absorption test, with no significant difference found between pre- and post-absorption values. Our results confirmed that the mother＇s allelic gene was type B and contained type A. The father＇s blood type was type B, and son＇s blood type was type O. Clone-based sequencing revealed that the mother carried a heterozygous gene of B101.01（nt A640→G）/O01, which contained an M214→V mutation that could express a weak expression of antigen A, resulting in blood type AB. However, their son did not have the M214→V mutation, which yielded a false ABO-inconsistency between him and his mother. We were led to conclude that type B gene with a M214→V mutation can encode both antigen B and weak antigen B that can lead to false ABO-inconsistencies.
