Study on the antigens and antibodies of Mur and Mia blood groups in southern China.

BACKGROUND: The frequency of Mur and Mia blood group antigens in Asian population is much higher than that in Caucasian population. However, due to the scarcity and high price of commercial detection reagents, there are few studies on antigen and antibody detection and comparative analysis in large samples. OBJECTIVE: To study the occurrence frequency, antigen correlation and antibody properties of Mur and Mia antigens and their corresponding antibodies in southern China. METHODS: Mur and Mia antigens and antibodies in local blood donors and patients were detected by routine serological microplate method. Statistical methods were used to calculate the incidence of two antigens and antibodies and analyze their correlation. RESULTS: Among blood donors, the positive rates of Mur and Mia antigens were 6.4 % and 6.5 % respectively, with no significant difference (P > 0.05). In this region, the incidence of anti-"Mur" and anti-"Mia" was 0.65 % and 0.45 % respectively. But significant difference existed between blood donors and patients (P < 0.05). Among the anti-"Mur" and anti-"Mia" positive patients, most of the antibodies were IgM or IgM + IgG mixed type and had saline activity. CONCLUSION: Mur and Mia antigens and their corresponding antibodies have a high frequency in the population of southern China. In the routine clinical detection of irregular antibodies, Mur or Mia positive (GP.Mur) should be added to screen erythrocytes. Moreover, given the high correlation between Mur and Mia antigens expression on red blood cells, using monoclonal antibodies against Mia could predict the presence of Mur antigen.

Molecular genetic analysis of Mia -positive hybrid glycophorins revealed two novel alleles of GP.Vw and multiple variant transcripts of GYPB existing in both the homozygous GP.Mur and wild-type GPB individuals.

BACKGROUND: The hybrid glycophorins of MNS blood group system express a series of low incidence antigens including Mia , which are commonly found in Southeast Asian populations. In this study, the molecular basis of Mia -positive hybrid glycophorins was firstly clarified in the Chinese Southern Han population. RNA transcripts of GYPB gene in the homozygous GP.Mur individuals were also analyzed. STUDY DESIGN AND METHODS: DNAs were extracted from the whole blood samples of 111 Mia -positive donors. Then, high-resolution melting (HRM) analysis for GYP(B-A-B) was used to analyze the genotypes. Sequencing of GYPB pseudoexon 3 was conducted in the samples with variant melting curves. TA-cloning and subsequent sequencing of GYPA exons 2-4 were performed in the Mia -positive samples with normal GYPB/GYPB genotype by HRM. The transcript analysis of GYPB was conducted in homozygous GP.Mur and wild-type glycophorin B (GPB) individuals using RNA extracted from the cultured erythroblast. RESULTS: The heterozygous GYP*Mur/GYPB (n = 101), homozygous GYP*Mur/GYP*Mur (n = 7) including one novel GYP*Mur allele with an extra GYPA/GYPE specific nucleotide substitution (c.229+110A>T), heterozygous GYP*Bun/GYPB (n = 1) and GYP*Vw/GYPA (n = 2) with two novel GYP*Vw alleles were identified. RNA transcript analysis revealed multiple transcripts of GYPB existing in both homozygous GP.Mur and normal GPB individuals. CONCLUSION: The results showed the genetic diversity of hybrid glycophorins in the Chinese population. Besides, the successful analysis of GYPB transcripts indicates that the cultured erythroblast is a good source for RNA transcript analysis for the protein only expressed on the red blood cells.