Abstract
Background - The s antigen expression is mainly determined by a single nucleotide polymorphism at c.143C (p.Thr48) on the exon 4 of GYPB gene. Several mutations on the GYPB gene have been reported to cause aberrant s antigen expression. GP.Mur has an extra 31-amino acid insertion encoded by the active compound GYP(B-A) exon 3, which closely locates at the upstream of p.Thr48. It has been reported to cause altered s antigen expression.
Materials and methods - Serologic testing and flow cytometry analysis were performed to detect s antigen expression on RBCs of GP(B-A-B) hybrid glycophorins, including GP.Mur, GP.Bun and GP.HF. Several mutant plasmids based on the different sites between GYPB and GYP(B-A-B) alleles were constructed and transfected into HEK293T cells for in vitro expression, to reveal the key amino acids for the aberrant s antigen expression.
Results - Serologic testing and flow cytometry assay showed the RBCs of GP.Mur homozygotes reacted positively with IgG anti-s (P3YAN3) but negatively with IgM anti-s (P3BER). Flow cytometry analysis also revealed half level of s antigen expressed on the RBCs of GP.Mur, GP.Bun and GP.HF heterozygotes with ss genotype compared to S-s+ controls when detected by IgM anti-s (P3BER). Furthermore, in vitro expression study showed that p.Asn45 is critical for the epitope expression of s antigen detected by IgM anti-s (P3BER).
Discussion - The results demonstrated partial s antigen expression on GP(B-A-B) RBCs. In addition to p.Thr48, p.Asn45 is also important for the epitope expression of s antigen detected by IgM anti-s (P3BER). To avoid false negative serologic typing, it is recommended to use several different clones of monoclonal anti-s for the correct s typing, especially in the regions with high frequency distribution of GP(B-A-B) hybrid glycophorins.
References
Downloads
pdf
Authors
Ling Wei
Institute of Blood Transfusion and Hematology, Guangzhou Blood Center, Guangzhou Medical University, Guangzhou, China; The Key Medical Laboratory of Guangzhou, Guangzhou, China
Siying Zhu
Department of Whole Blood Processing, Guangzhou Blood Center, Guangzhou, China
Jizhi Wen Institute of Blood Transfusion and Hematology, Guangzhou Blood Center, Guangzhou Medical University, Guangzhou, China; The Key Medical Laboratory of Guangzhou, Guangzhou, China
Zhijian Liao Institute of Blood Transfusion and Hematology, Guangzhou Blood Center, Guangzhou Medical University, Guangzhou, China; The Key Medical Laboratory of Guangzhou, Guangzhou, China
Shuangshuang Jia Institute of Blood Transfusion and Hematology, Guangzhou Blood Center, Guangzhou Medical University, Guangzhou, China; The Key Medical Laboratory of Guangzhou, Guangzhou, China
Yanli Ji
Institute of Blood Transfusion and Hematology, Guangzhou Blood Center, Guangzhou Medical University, Guangzhou, China; The Key Medical Laboratory of Guangzhou, Guangzhou, China
- Abstract viewed - 853 times
- pdf downloaded - 0 times