The study of variant s antigen expression revealing a novel c.160C>T (p.Arg54Cys) variant on GYPB*s allele associated with partial s phenotype.

BACKGROUND: Little s antigen is mainly defined by a single nucleotide polymorphism at c.143C (p.Thr48) on the GYPB gene. Several variants on GYPB can alter the expression of s antigen. The aim of this study was to investigate the molecular basis of variant s antigen expression in the Chinese population. STUDY DESIGN AND METHODS: A total of 4983 whole blood samples were collected to screen the individuals with discrepant s typing results using two different monoclonal anti-s. Then, the sequence of GYPB exon 4 was analyzed by Sanger sequencing. Flow cytometry analysis was performed to quantify s antigen expression on red blood cells (RBCs). In vitro expression study was performed to verify the effect of the GYPB variants identified on the expression of s antigen. RESULTS: Four donors were identified to have discrepant s typing results. Sanger sequencing showed that three donors carried the c.173C > G variant (p.Pro58Arg) specific for sD antigen, the other one carried a novel GYPB (c.160C > T, p.Arg54Cys) variant. Flow cytometry identified a partial and weak expression of s antigen on the RBCs of the four donors. Furthermore, in vitro expression study confirmed the effect of the two variants on the s antigen expression. CONCLUSION: The results demonstrated that in addition to p.Thr48, the two extra amino acids p.Arg54 and p.Pro58 are also important for full expression of s antigen. Since the individuals with partial s antigen are at risk for the development of alloanti-s, it is important to select at least two different monoclonal anti-s for correct s typing.

Genetic profile of RHCE, Kell, Duffy, Kidd, Diego and MNS hybrid glycophorins blood groups in ethnic northeastern Thais: Alleles, genotypes and risk of alloimmunisation.

BACKGROUND: Antibodies against blood group antigens play a key role in the pathophysiology of haemolytic transfusion reactions (HTRs) and haemolytic disease of the fetus and newborn (HDFN). This study aimed to determine the frequencies of alleles, genotypes, and risk of alloimmunisation of clinically significant blood group systems in ethnic northeastern Thais. METHODS: In total, 345 unrelated, healthy, ethnic northeastern Thais were tested using the in-house PCR-sequence specific primers (PCR-SSP) method for simultaneously genotyping of RHCE, Kell, Duffy, Kidd, Diego and MNS glycophorin hybrids and results confirmed by Sanger sequencing. RESULTS: In this cohort, the alleles RHCE*C (81.0%) and RHCE*e (84.8%) were more prevalent than RHCE*c (19.0%) and RHCE*E (15.2%). The most common predicted haplotype combinations of the RHCE alleles were C+c-E-e+(R1R1) (59.4%) followed by the C+c+E+e+ (R1R2) (20.6%) and C+c+E-e+ (R1r) (11.3%). The KEL*01 allele was not found in this study. The frequencies of FY*01 and FY*02 were 88.3% and 11.7%, respectively. The genotype FY*02/02 was found in four samples (1.2%). The frequencies of JK*01 and JK*02 were 52.5% and 47.5%, respectively. Homozygous JK*02/02 was found in 81 samples (23.5%). The frequencies of DI*01 and DI*02 were 0.6% and 99.4%, respectively. In total, 64 samples (18.6%) were found to carry the MNS glycophorin hybrids. CONCLUSIONS: Our results indicated a possible high risk of c, E, Fyb, Jka, Jkb and Mia alloimmunisation in these populations. Moreover, methods established for genotyping clinically significant blood groups in this study can now be utilised in routine clinical application.

Hipertensión arterial y marcadores de grupo sanguíneo: asociación con el polimorfismo MN / Hypertension and blood group markers: association with MN polymophins

El objetivo de este trabajo fue analizar la relación entre presión arterial y marcadores genéticos eritrocitarios MN. La expresión de los antígenos M y N, se investigó por el Test de hemaglutinación en tubo, en una muestra de 164 individuos clasificados según presión arterial (normales e hipertensos) y fenotipo MN. De los 53 pacientes hipertensos, los porcentajes de cada fenotipo fueron: MN 56,6 por ciento,MM 34,0 por ciento, NN 9,4 por ciento mientras que entre los 111 individuos normotensos, la distribución resultó: MN 70,3 por ciento, MM 18,9 por ciento y NN 10,8 por ciento. De los resultados obtenidos en este trabajo, por la Prueba x², se concluye que sólo existe asociación entre el fenotipo MM y la hipertensión arterial. Diferencias en el patrón de agregación, debido a diferencias estructurales de los distintos grupos sanguíneos, podrían generar susceptibilidad a cambios en la viscosidad sanguínea, afectando el proceso de perfusión. El estudio de marcadores eritrocitarios, que pueden ser determinados por metodologías accesibles, podrían aportar datos de interés para la investigación de factores de riesgo en el desarrollo de la hipertensión arterial