| Objectives: Blood group serology and molecular biology tests were conducted on ABO antigenweakened specimens to explore the correlation between FUT1,GTA/GTB gene mutations and ABO subtypes and para-bombay blood types.In vitro expression studies of B3 subtype patients with ABO gene mutation B313(c.646T>A)were conducted to elucidate part of the mechanism of ABO antigen reduction caused by mutations.It can help us to accurately identify ABO blood types at the molecular biological level,supplement the insufficient serological test results,and provide necessary and powerful guarantee for the safe and effective transfusion of blood products,the safety of organ transplantation and the prevention and treatment of fetal/neonatal immunological hemolysis.Methods: ABO blood group screening was conducted by routine ABO blood group detection method.ABH antigen detection,red blood cell absorption and release experiment and saliva blood group material detection confirmed that ABO blood group antigen was weakened.GTA/GTB and FUT1 gene sequence analysis were further performed.By comparing the expression of B antigen on the surface of patients’ red blood cells and wild-type control cells,the expression of B antigen on the surface of B3 c DNA-transfected He La cells and wild-type control cells,the overall activity of GTB,and the expression level of GTB protein,the in vitro expression of B3 subtype patients with ABO gene mutation B313(c.646 t >A)was studied.Results: We found 55 ABO antigen-weakened specimens in 84,750 blood type specimens,and a total of 39 ABO subtypes were detected,including 12 ABO subtype alleles,which were Ael107,Ax02,Ael02,Ax03,A204,A220,B313,B302,Bw36,Bw19,Bw37 and cis-AB02.Sixteen para-bombay blood types were detected,including 3 FUT1 alleles,h1,h2 and h3,respectively.In our study,the detection rate of ABO subtypes was 0.036%,of which "el" and "x" were the most common subtypes in subtypes A,"3" and "m" in subtypes B,and 0.013% in para-bombay blood groups,mainly homozygotes of h1,h2 and h3.In our study,we found that4 individuals who were considered the weakening of ABO antigen caused by disease,their ABO blood group antigens were reexpressed with the progress of treatment and remission of the disease.In our study,we found that no gene mutation was detected in 3 patients with allogenic ABO blood group incompatibility with hematopoietic stem cell transplantation.Their genotyping has been converted to donor blood type,and the blood group serological test results were still recipient blood type.The expression of B3 subtype carrying B313(c.646 T > A)mutation was studied in vitro.The results of flow cytometry indicated that the expression of the B-antigen was significantly lower than that of the wild-type control cells,and the expression of the surface B antigen of the He La cell transfected with the B3 c DNA and the overall activity of the GTB were significantly lower than that of the wild-type control cells.The expression of GTB protein in the transfected cells was detected by western blotting,and the GTB p.F216 I mutant in the He La cell was consistent with the wild-type molecular weight,and the expression level was comparable.Conclusion:(1)Blood group genotyping plays an indispensable role in the correct identification of blood group and the correct information of clinical blood use.The dynamic monitoring of ABO blood group antigen may play an auxiliary role in the early diagnosis,treatment and prognosis of some malignant hematological diseases and solid tumors.(2)The mechanism of B3 subtypes caused by ABO gene mutation B313(c.646 T > A)is not by reducing the number of GTB,but by changing the catalytic activity of glycosyltransferase in GTB,thus affecting the number of B antigens on cells. |
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