Evolution of technology for molecular genotyping in blood group systems

The molecular basis of the blood group antigens was identified first in the 1980s and 1990s. Since then the importance of molecular biology in transfusion medicine has been described extensively by several investigators. Molecular genotyping of blood group antigens is one of the important aspects and is successfully making its way into transfusion medicine. Low-, medium- and high-throughput techniques have been developed for this purpose. Depending on the requirement of the centre like screening for high- or low-prevalence antigens where antisera are not available, correct typing of multiple transfused patients, screening for antigen-negative donor units to reduce the rate of alloimmunization, etc. a suitable technique can be selected. The present review discusses the evolution of different techniques to detect molecular genotypes of blood group systems and how these approaches can be used in transfusion medicine where haemagglutination is of limited value. Currently, this technology is being used in only a few blood banks in India. Hence, there is a need for understanding this technology with all its variations.

Minor red blood cell antigen phenotyping of athletes sampled in international competitions

Blood transfusion is performed by cheating athletes to rapidly increase oxygen delivery to exercise muscles and enhance their performance. This method is banned by the World Anti-doping Agency (WADA). Heterologous or allogenic blood transfusion happens when blood from a different person is transfused. The method used to detect this type of doping is based on flow cytometry, by identifying variations in blood group minor antigens present on the red blood cells' surface. Transfusion practices have regained interest since the introduction of human recombinant erythropoietin detection method. It has been reported that the number of occurrences of two athletes sharing an identical phenotype in the same sport was five times higher than the theoretical populational probability. The present work describes the prevalence of 10 erythrocytes surface antigens in a population of 261 athletes from all five continents. The matching phenotype per sport is also described.

HLA and red blood cell antigen genotyping in SARS-CoV-2 convalescent plasma donors

Aim: More data is required regarding the association between HLA allele and red blood cell (RBC) antigen expression in regard to SARS-CoV-2 infection and COVID-19 susceptibility. Methods: ABO, RhD, 37 other RBC antigens and HLA-A, B, C, DRB1, DQB1 and DPB1 were determined using high throughput platforms in 90 Caucasian convalescent plasma donors. Results: The AB group was significantly increased (1.5×, p = 0.018) and some HLA alleles were found to be significantly overrepresented (HLA-B*44:02, C*05:01, DPB1*04:01, DRB1*04:01 and DRB1*07:01) or underrepresented (A*01:01, B51:01 and DPB1*04:02) in convalescent individuals compared with the local bone marrow registry population. Conclusion: Our study of infection-susceptible but non-hospitalized Caucasian COVID-19 patients contributes to the global understanding of host genetic factors associated with SARS-CoV-2 infection and severity.

Major and minor subgroup profile of blood in patients receiving multiple transfusions and donors

OBJECTIVE

It was aimed to profile the blood subgroups of our region and to reveal the prevalence of auto/alloimmune sensitization in patients who had to undergo multiple erythrocyte transfusions and to establish the sensitization profile by screening major and minor subgroups.

MATERIALS AND METHODS

In this study, the distribution of ABO and Rh system major subgroups was studied in 100 donor blood. As the patient group, 50 patients who received three or more red blood cell transfusions were included. In addition to this group, Kell, Lewis, Duffy blood group systems were studied.

RESULTS

According to the ABO system, 35% of the donors were in O, 33% in A, 17% in AB, and 15% in B. According to the Rh system, 75% is Dvi positive. Rh system is 99% e positive and 33% E positive in major subgroups and Kell1 positivity is 8%. In the patient group, 22% D(-) was determined compared to Rh blood group. Among the major subgroups of Rh, C was 68%, E was 14%, c was 76%, and e positivity was found to be 100%. The Kell1 negativity rate is 96%. The highest negativity was found in 86% Lea antigen in Lewis system, in 36% S antigen in MNS system, 34% Fyb antigen in Duffy system, and 24% Jka antigen in Kidd system. When inappropriate blood is given for any antigen, a double population is formed. The double negativities we detected in our study occurred as follows according to blood group systems: E 18%, C 12%, c 8%, Cw 2%, Kell 1 2%, M 8%, N 4%, S 18%, s 6%, Fya 8%, Jka 6%, Jkb 22%. Indirect Agglutination Test (IAT) was negative in all patients.

CONCLUSION

IAT negativity in all patient groups suggests that we do not develop alloimmunization, but the high rates of double population suggest a high risk of alloimmunization.

Application of blood group genotyping in complex cases of immunohematology

BACKGROUND

Red blood cell (RBC) group systems are depicted by antigens on the surface of RBCs, which when transfused to a recipient that lacks them, can result in alloimmunization. Thus, transfusion of matched RBC components to the recipient is recommended, especially for the more immunogenic blood group antigens, such as Rh (E, e, C, and c), Kell, Kidd, Duffy, and MNS.

AIMS

The aim of this study was to perform the blood group genotyping from blood samples of 12 polytransfused patients whose phenotyping was inconclusive or incomplete.

METHODS

The amplicons were amplified by polymerase chain reaction-sequence-specific primers for the following alleles: RHCE (RHCE * C, RHCE * c, RHCE * E, and RHCE * e), KEL (KEL * 01 and KEL * 02), FY (FY * 01 and FY * 02), and KID (JK * 01 and JK * 02), in addition to the GATA1-mutated gene (FY * 02N.01).

RESULTS

Discrepancies were found in the Rh (E) and Kidd systems, in addition to cases of Fyb antigen silencing attributed to the GATA mutation, which was present in all individuals with Fy (a-b-) phenotype. The technique also solved the inconclusive phenotyping caused by mixed-field agglutination.

CONCLUSION

The results show the contribution of blood group genotyping in complex immunohematology cases, optimizing the delivery of RBC components suitable for transfusion safety, and expanding the number of compatible donors for patients with the Fy (a-b) phenotype related to the FY (02N.01) allele.

Determination of the Rh/Kell phenotypes in donor as well as patients might be significant to provide phenotype-matched blood to cancer patients: A retrospective analysis from a tertiary care oncology center in North India

BACKGROUND

Multiple reports are available from different parts of the globe indicating the incidences of alloimmunization and blood transfusion-related reactions, which emphasizes the need for phenotyping and providing antigen-matched safe blood.

AIMS AND OBJECTIVES

This study aims to determine the frequency of Rh and Kell antigens and phenotype for both donors and patients to propose the importance of providing Rh Kell phenotype cross-matched packed red blood cell (RBC) units to minimize the alloimmunization and transfusion reactions.

MATERIALS AND METHODS

Ten thousand blood donors and four thousand patients were investigated between October 2017 and July 2019. Each donor unit was tested for blood grouping, antibody screening, and Rh Kell antigen Phenotyping, and the blood unit was issued after the patient's blood grouping, antibody screening by 3 cell panels, and Rh Kell antigen phenotyping followed by cross-matching with an Rh Kell-matched phenotype RBC unit.

RESULTS

Nine thousand four hundred and fifty-two donors were D positive (94.5%) while 548 tested D negative (5.5%). Overall Rh and K antigens frequencies in donors were: "e" (98%) >"D" (94.5%) >"C" (86.6%) > "c" (57.5%) >"E" (18.8%) >K (0.98%). Among patients, 3762 tested D positive (94.05%), and 238 tested D negative (5.95%). Overall Rh and K antigens frequencies in patients were: "e" (98.5%) >"D" (94.05%) >"C" (90.2%) >"c" (51%) >"E" (18.2%) >K (1.8%).

CONCLUSION

Our study has given us more clarity on the prevalence of major Rh and K antigens in our donor as well as patient populations, highlighting the similarities as well as differences. This variance holds a great significance, since such donor units when transfused into patients may lead to alloimmunization and adverse transfusion reactions. Hence, the determination of Rh and Kell phenotypes and providing phenotype-matched blood will help prevent such events.

Procuring rare (しい)* Japanese red blood cell units for a bleeding patient with anti-K11 requiring a life-saving procedure

Alloimmunization to K11 is an extremely rare event. However, given the potential clinical significance of K11 alloantibodies, allocating antigen-negative red blood cell (RBC) units is a clinical necessity. In brief, we report a 39-year-old woman with multiple comorbidities including a right lower-extremity, below-the-knee amputation, who developed aggressive osteomyelitis associated with continuous bloody oozing, leading to anemia. To address these issues, the patient required extremity amputation. Surgery required addressing the concomitant critical anemia (hemoglobin <5 g/dL). However, with anti-K11 (in addition to anti-Jk^a) identified, no compatible units were immediately on hand and transfusing crossmatch-incompatible, antigen-positive units was deemed too high a risk. After a national search by the American Rare Donor Program (ARDP) was unsuccessful, the ARDP identified 2 irradiated, group O, K₀ (Kell_null), Jk(a-) RBC units in Japan that were predicted to be crossmatch-compatible with the patient's plasma. The units were successfully procured and infused, without evidence of adverse reactions, and the patient was able to safely undergo amputation to save her life. This case report reviews the complexities of anti-K11 detection and confirmation, as well as the processes by which K11- RBC units may be procured, which could help others in the global transfusion community should they be faced with similar challenging cases.