Frequency of the DI*A, DI*B and Band 3 Memphis polymorphism among distinct groups in Brazil

ABSTRACT Introduction: The Band 3 is a red blood cell protein that carries the Dia and Dib antigens from the Diego blood system. The SLC4A1 gene encodes Band 3; Band 3 Memphis is a polymorphism of normal Band 3 and has two variants, but only the variant II carries the Dia antigen. Objectives: Describe the frequencies of the DI*A and DI*B alleles and the Band 3 Memphis among blood donors, sickle cell disease (SCD) patients and Amazonian Indians. Methods: A total of 427 blood samples were collected and separated into three groups: 206 unrelated blood donors, 90 patients with SCD and 131 Amazonian Indians. We performed DI*A/B, normal Band 3 and Band 3 Memphis genotyping, using the Polymerase Chain Reaction Restriction Fragment Length Polymorphism (PCR-RFLP). Results: The frequency of the DI*A/DI*A genotype was 0.5% in blood donors and it was not found in other groups. The frequency of the DI*A/DI*B was higher in Amazonian Indians (33.6%) and the frequency of the DI*B/DI*B was highest in blood donors (92.2%). All 105 individuals tested were positive for the presence of normal Band 3 and of these individuals, only 5/105 (4.8%) presented the Band 3 Memphis mutation. Conclusion: We observed a higher frequency of the DI*B allele in blood donors and a low frequency of the DI*A/DI*A genotype in all groups studied. The Band 3 Memphis was found in a higher frequency in the blood donor group. Our findings highlight the importance of analyzing different population groups to gain a better understanding of the genetic association of blood group antigens.

Frequency of antigen Dia on the blood donor population of the Hemocenter coordinator of the Hemopa Foundation

ABSTRACT Introduction: Erythrocyte phenotyping is a very important test in the adoption of prophylactic measures to reduce transfusion reactions/alloimmunizations in polytransfused patients. The blood group Diego, in its current, form has 22 antigens, of which 4 are immunogenic, being Dia/Dib and Wra/Wrb, while the others are less expressive. The antigen Dia is of low incidence among whites and blacks, however, it is common in the South American indigenous and Asian Mongolian populations. It is also considered a system of clinical importance for its immunogenicity. Method: The present study aimed to carry out a retrospective and descriptive survey of the frequency of the Dia antigen in the blood donor population at the HEMOPA Foundation Coordinating Blood Center from 12/2018 to 1/2000. The data obtained were from the HEMOPA Foundation SBS Progress and SBS WEB Systems databases. Results: During this period, 941,744 blood bags were collected and, of these, 930 bags were phenotyped for the Dia antigen, of which 842 were negative and 88 (9.7%) positive. The research showed that, among the positive donors for the antigen Dia, 88.6% were brown, 3.4%, black and 8%, white. In the statistical analysis, the frequency observed was higher in browns. Conclusion: In the present investigation, we concluded that our region has a relatively higher frequency of the Dia antigen, when compared to the rest of Brazil, and it occurs more often in browns.