The radial expansion of the Diego blood group system polymorphisms in Asia: mark of co-migration with the Mongol conquests

Comparison of the Detection Rate and Specificity of Irregular Red Blood Cell Antibodies Between First-Time Pregnant Women and Women With a History of Multiple Pregnancies Among 18,010 Chinese Women

Background: There is insufficient evidence to assess the risk of the production of clinically important alloimmune irregular red blood cell (RBC) antibodies in first-time pregnant women. Methods: Using the microcolumn gel antiglobulin method, 18,010 Chinese women with a history of pregnancy and pregnant women were screened for irregular RBC antibodies, and for those with positive test results, antibody specificity was determined. The detection rate and specificity of irregular RBC antibodies in women with a history of multiple pregnancies (two or more) and first-time pregnant women were determined. Results: In addition to 25 patients who passively acquired anti-D antibodies via an intravenous anti-D immunoglobulin injection, irregular RBC antibodies were detected in 121 (0.67%) of the 18,010 women. Irregular RBC antibodies were detected in 93 (0.71%) of the 13,027 women with a history of multiple pregnancies, and antibody specificity was distributed mainly in the Rh, MNSs, Lewis, and Kidd blood group systems; irregular RBC antibodies were detected in 28 (0.56%) of the 4983 first-time pregnant women, and the antibody specificity was distributed mainly in the MNSs, Rh, and Lewis blood group systems. The difference in the percentage of patients with irregular RBC antibodies between the two groups was insignificant (χ 2 = 1.248, P > 0.05). Of the 121 women with irregular RBC antibodies, nine had anti-Mur antibodies, and one had anti-Dia antibodies; these antibodies are clinically important but easily missed because the antigenic profile of the reagent RBCs that are commonly used in antibody screens does not include the antigens that are recognized by these antibodies. Conclusion: Irregular RBC antibody detection is clinically important for both pregnant women with a history of multiple pregnancies and first-time pregnant women. Mur and Dia should be included in the antigenic profile of reagent RBCs that are used for performing antibody screens in the Chinese population.

A case of naturally occurring anti-Dia antibody in a young man

The Diego (Di) blood group system comprises 22 antigens located on the band 3 protein, most of which are low-prevalence antigens. The majority of antibodies to Diego system antigens were of clinically insignificant; however anti-Dia, -Dib, -Wra, -ELO and-DISK may cause hemolytic disease of the fetus and newborn (HDFN) and transfusion reaction. We reported a case of naturally occurring of anti-Dia in a young man who presented to our hospital for wound debridement of fingers injury. His serological results were suggestive of anti-Dia antibody, and his molecular blood group showed he has Di (a-b+) antigen. Anti-Dia may be clinically significant. It can cause mild-to-severe HDFN, but there are only infrequent reports of it being clearly implicated in a hemolytic transfusion reaction. We suggest the need for reagent red blood cell panels to include Dia antigen-positive cells in antibody identification tests for our populations.

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

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/Di^b and W^ra/W^rb, 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.

Identification of a novel DI*02(2558T) allele associated with weakened expression of DI2 antigen

BACKGROUND

The distribution of DI1/DI2 antigens of the Diego blood group system is polymorphic in Mongoloid populations and the corresponding alloantibodies are clinically significant. Here a novel DI variant was found by donor screening, and the effect of the novel and previously reported mutations on expression of DI1/DI2 antigens and Band 3 protein was explored.

STUDY DESIGN AND METHODS

DNA samples of 1150 Chinese donors were collected. DI*01/DI*02 genotyping was determined by Sanger sequencing. For the carrier of novel allele, the expression of Band 3 and DI1/DI2 antigens on red blood cells (RBCs) was detected by Western blot and flow cytometry, respectively. in vitro expression studies were conducted by transfecting the mutant (including the novel and three reported DI*02(2534T), DI*02(2358_2359insCAC), and DI*02(2572T) alleles) or wild-type DI*02 constructs into HEK 293T cells, the expression of Band 3 and DI1/DI2 antigens was analyzed.

RESULTS

A novel heterozygous mutation (c.2558C>T, p.Thr853Met), which is located near the DI1/DI2 polymorphism site (c.2561T>C), was identified in a donor with DI:-1,2 phenotype. Reduced expression of DI2 antigen was observed on the RBCs, while weakened expression of Band 3 and absence of DI2 antigen were detected in cells transfected with the mutant DI*02(2558T) construct. In addition, absent or decreased expression of Band 3 and DI2 antigen was also detected in cells transfected with three reported mutant constructs.

CONCLUSION

The novel DI*02(2558T) allele and three previously described DI mutations can affect the expression of Band 3 protein and/or DI2 antigen and/or interfere with DI*01/DI*02 genotyping result.