Multiplex-PCR technique to predict polymorphic antigens - M, N, S and s - and associations between their alleles and Mia-associated hybrid glycophorins

Serological typing of MNS polymorphic antigens - M, N, S and s - remains a fundamental technique in transfusion medicine and prenatal care, providing essential information for matching blood donors and recipients and managing haemolytic disease. Although this method is well proven and routinely used, it is not a comprehensive solution, as it has several weaknesses. Alternatively, multiplex polymerase chain reaction (PCR) is a commonly used genotyping tool due to its potency and ability to amplify several DNA targets simultaneously in a single reaction. In this work, we aimed to develop multiplex PCR and evaluate its performance for GYPA*M, GYPA*N, GYPB*S, and GYPB*s allele identification using serological and DNA sequencing methods. We also aimed to investigate the correlation between these alleles and Mia-associated hybrid glycophorins (GPs). Remarkably, multiplex PCR was well optimised, and the results aligned with serological phenotyping and DNA sequencing data with maximum accuracy and reliability; this confirmed our findings on its validity in predicting MNSs phenotypes. In addition, this work strongly demonstrates, for the first time, a moderate correlation between the GYPA*M/M and GYPB*s/s genotypes and Mia-associated hybrid GPs among Thai donors. Individuals with the GYPA*M/M and GYPB*s/s genotypes, predicted M + N - S- s + phenotypes, will thus most likely to express the Mi(a+) antigen. Nevertheless, further studies are required to validate these results and elucidate the underlying correlations.

Hemolytic disease of the fetus and newborn caused by anti-sD antibody in a GP.Mur/Mur Thai mother and review of the prevalence of sD in Thai blood donors

BACKGROUND

Low-prevalence antigen s^D (MNS23) is encoded by GYPB c.173C > G. Hemolytic disease of the fetus and newborn (HDFN) due to anti-s^D is rare. A mother delivered a newborn whose red blood cells (RBCs) were DAT-positive and was later diagnosed with HDFN. Serum from the mother was incompatible with the father's RBCs and was used to screen 184 Thai blood donors. This study aimed to investigate the cause of HDFN in a Thai family and determine the prevalence of s^D in Thai blood donors.

MATERIALS AND METHODS

Three family members and four blood donors were investigated in the study. Massively Parallel Sequencing (MPS) was used for genotyping. Standard hemagglutination techniques were used in titration studies, phenotyping, and enzyme/chemical studies. Anti-s, anti-Mi^a , anti-JENU, and anti-s^D reagents were used in serological investigations.

RESULTS

The mother was GYP*Mur/Mur. The father and the four donors were GYPB*s/s^D predicting S - s + s^D +. The baby was GYP*Mur/sD and his RBCs were Mi^a +, s + ^w with anti-s (P3BER) and JENU+^w . RBCs from two GYPB*s^D -positive blood donors reacted with anti-s^D (Dreyer). Proteolytic enzyme α-chymotrypsin-treated s^D + cells did not react with anti-s^D (Wat) produced by the GP.Mur/Mur mother but reacted with the original anti-s^D (Dreyer).

DISCUSSION

This is the first report of HDFN due to anti-s^D in the Asian population. The genotype frequency for GYPB*s^D in a selected Thai blood donor population is 2.2% (4/184). Anti-s^D should be considered in mothers with Southeast Asian or East Asian background when antibody identification is unresolved in pregnancies affected by HDFN.