Background: Serological methods are unreliable for accurate determination of blood group antigens in multi-transfused thalassemia patients. The MNS blood group system has five high-frequency antigens. Many studies demonstrated that some antibodies including anti-S, anti-s, and anti-U may cause acute and delayed transfusion reactions and hemolytic disease of the fetus and newborn. This study aimed to determine the genotype of the MNS blood group in thalassemia patients with alloantibodies by molecular methods.
Material and methods: In this study, 104 blood samples from thalassemia patients were collected. The blood group phenotype for M, N, S and s antigens was determined by the tube hemagglutination method. MNS blood group genotyping was performed using PCR-SSP and DNA Sequencing methods.
Results: All patients were genotyped with a total of 6 pairs of primers. Discrepancies between genotype and phenotype were observed in 22 patients with S/s alleles and 2 patients with M/N alleles, however, there was full accordance between the results of SSP-PCR and DNA sequencing. The frequency of MNS blood group alleles was determined as follows: 25 % MNSs, 23 % MNss, 21 % MMSs, 9% MMSS, 9% MMss, 8% NNss, 2%MNSS, and NNSS, NNSs, MM genotypes at 1% each.
Conclusion: In conclusion, molecular genotyping is more reliable than serological methods in multiple transfusion patients and can lead to a more compatible blood unit for transfusion in these patients.
Keywords: Alloimmunization; Genotype; MNS blood group; Thalassemia.
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