MNSs Blood Group Glycophorin Variants in Taiwan: A Genotype-Serotype Correlation Study of ‘Mia’ and Sta with Report of Two New Alleles for Sta

Abstract

BackgroundGlycophorin variants of the MNSs blood group are important in Taiwan. For more than 20 years, screening for the most frequent irregular antibody, anti-‘Mia’, has been conducted by using ‘Mia’(+) RBCs, with a significant success. However, the sensitivity and the specificity of this screening strategy have never been validated, and the true incidences of different glycophorin variants in Taiwan have been in controversy. Also, the significance of another less frequent and usually separately reported variant, Sta, has never been evaluated.Methodology/Principal FindingsWe ran a population-based screening (from unselected patients in our hospital) for MNSs blood group glycophorin variants by PCR-sequencing method. GP.Mur (Mil.III) was confirmed by sequence from 57 out of 1027 samples (5.6%), and there was no other Miltenberger subtype glycophorin variant found. Glycophorin variant Sta was found from 35 out of 1027 samples (3.4%). In contrast to anti-‘Mia’, which is the most frequently identified irregular antibody in Taiwan, the prevalence of anti-Sta was only 0.13% as determined by serologic method. In addition, two new alleles for Sta were found and reported.Conclusion/SignificanceWe confirm the long-standing assumption that GP.Mur is the only prevalent Miltenberger subtype in Taiwan. The current anti-‘Mia’ screening method used in Taiwan, although neither sensitive nor specific, is still a suitable practice. Although Sta antigen has a high prevalence in Taiwan, routine screening for anti-Sta is not warranted based on current evidence.

Selection of GP. Mur antigen‐negative RBC for blood recipients with anti‐‘Mia’ records decreases transfusion reaction rates in Taiwan

“…Chen TD et al have compared the manual polybrene serological method with a PCR method for the detection of GP. Mur‐positive blood (Chen et al , ). They found that the serological test only identified 67·2% of genetically GP.…”

“…They found that the serological test only identified 67·2% of genetically GP. Mur‐positive samples (Chen et al , ). PCR methods to detect the GYP ( B‐A‐B ) gene hybrid have been developed by several groups in Taiwan (Chen et al , ; Hsu et al , ; Shih et al , ).…”

“…As the sensitivity of current testing for anti‐‘Mi a ’ using the manual polybrene method is 67%, and the reaction strength of anti‐‘Mi a ’ antibodies may decrease significantly days after the initial alloimmunisation, there is a risk for transfusion of GP. Mur‐positive RBCs to patients with weak anti‐‘Mi a ’ antibodies (Chao et al , ; Chen et al , ). Furthermore, about 40–60% of the anti‐‘Mi a ’ contains IgG form antibodies (Heathcote et al , ; Lo et al , ).…”

Red blood cell genotyping in China

“…GP.Mur was reported with a mean frequency of 7·3% among the Taiwan Chinese ethnic group and with the highest reported frequency of 88·4% in the Taiwanese indigenous ethnic groups . St a is also reported with a frequency of 1·63–5·2% (with higher frequency of 5·2% in Chinese Hakka) and GP.Hil with a frequency of 0·38% using the serological typing or the genotyping methods (such as PCR‐RFLP ). A term ‘Mia’ is used as a collective term for most of the antigens associated with the variant hybrid glycophorins, which is easily confused with the specific Mi a antigen (MNS007) recognized by ISBT .…”

“…For St a , a total of six distinct alleles ( St a type A, B, C , D , E and F ) with the different crossover sites in intron 3 have been identified to date. Thirty‐five St a positive samples (3·4%, 35/1027) identified by specific PCR in Taiwanese were analysed, in which 29 samples belong to the previous reported St a type B , 4 to be a novel St a type E and 2 to be a novel St a type F . In the mainland of China, a novel GYP.Bun allele (GenBank accession number: ) with a different recombination site in intron 3 compared with the reported GYP.Bun sequence has been identified.…”