Frequencies and specificities of red cell alloantibodies in the Southern Thai population

Application of a simplified PCR-SSP method to detect A4GALT*01 and A4GALT*02 typing among Thai blood donors

OBJECTIVES

An intronic A4GALT single nucleotide variant, rs5751348:G>T, P2 or A4GALT*02 allele has a lower level of the enzyme-encoding A4GALT transcripts than the P1 individuals. Here, we first develop and validate a simple inhouse PCR-SSP method to detect A4GALT*01 and A4GALT*02 alleles, and second, apply this method to compare the allele frequencies between Thai and other populations.

MATERIAL AND METHODS

The conventional test tube technique was used to detect the P1 antigen in 222 blood samples from Thai blood donors at Thammasat University Hospital. A PCR-SSP method was optimized and validated for reproducibility and specificity to identify these alleles and was subsequently tested on 1,840 DNA samples of unknown phenotypes obtained from central, northern and southern Thais. In addition, allele frequencies of central Thais were compared with those of other populations.

RESULTS

In the tested cohort (n = 222), P1 and P2 phenotypes were typed in 26.13 and 73.87% of donors, respectively. The developed PCR-SSP was successfully optimized, and the outcomes were consistent with those of serological phenotyping and DNA sequencing results, demonstrating its validity for predicting P1/P2 phenotype. For central, northern and southern Thais, the A4GALT*01 frequency was 0.1579 (430/2,724), 0.1183 (71/600), and 0.2575 (206/800), whereas the A4GALT*02 frequency was 0.8421 (2,294/2,724), 0.8817 (529/600), and 0.7425 (594/800), respectively. Their observed frequencies among central Thais significantly differed from those in other populations (p < 0.05).

CONCLUSION

Our study has successfully developed a simple, precise, and reliable method to genotype A4GALT*01 and A4GALT*02 using inhouse developed PCR-SSP for predicting P1/P2 status.

Prevalence of GP. Mur variant phenotype among Malaysian blood donors

BACKGROUND AND OBJECTIVE

A number of glycophorin variant phenotypes or hybrid glycophorin variants of the MNS blood group system bear multiple immunogenic antigens such as Mia, Mur, and MUT. In the East and Southeast Asian populations, glycoprotein (GP.) Mur is the most common glycophorin variant phenotype expressing those three immunogens. The aim of this study was to detect MNS system glycophorin variant phenotypes (GP. Mur, GP. Hop, GP. Bun, GP. HF, and GP. Hut) among Malaysian blood donors.

MATERIALS AND METHODS

In this cross-sectional study, 144 blood donors were selected under stratified random sampling. The deoxyribonucleic acid was extracted from whole blood samples, followed by a polymerase chain reaction assay. Sanger sequencing was used to identify the specific MNS variants and then validated by a serological crossmatch with known anti-Mur and anti-MUT.

RESULTS

GP. Mur was identified among Malaysian blood donors with a prevalence of 6.94%, and no other variants of the MNS system were found.

CONCLUSION

The present study substantiates that GP. Mur is the main variant of the MNS system glycophorin (B-A-B) hybrid in Malaysian blood donors. GP. Mur-negative red blood cells must therefore be considered in the current transfusion policy in order to prevent alloimmunization and immune-mediated transfusion reactions, particularly in transfusion-dependent patients.

Better resolving of anti-CD38 antibody interference with blood compatibility testing by using manual polybrene method compared with dithiothreitol-pretreatment indirect antiglobulin test

BACKGROUND

It is advised to pretreat the reagent erythrocytes with Dithiothreitol (DTT) to denature the surface CD38 to prevent anti-CD38 monoclonal antibodies (MoAb) from interfering with the blood compatibility test. Anti-CD38 has little impact on the Polybrene test, but it is still unknown how sensitive it is to detect irregular antibodies and how effective it is when compared to the standard DTT-based method.

METHODS

Twenty-one patients receiving daratumumab (N = 13) and isatuximab (N = 8) had their serum collected. Standard anti-sera (anti-c, D, E, Fy^b , Jk^a , M, Mi^a ) with serial dilution were added to patients' serum. Antibody screening tests were performed simultaneously using the manual polybrene method (MP) and DTT-pretreated, automatic indirect antiglobulin test (DTT-IAT) to compare the detection sensitivity. These two methods' operating times and costs were also analyzed.

RESULTS

Both MP and DTT-IAT can overcome the interference caused by anti-CD38 MoAb. However, MP is more sensitive in detecting anti-M and anti-Mi^a and is comparable to DTT-IAT in detecting other antibodies. In terms of cost and operating time, MP is also far superior to DTT-IAT.

CONCLUSION

MP is a cost-effective alternative to DTT-IAT in resolving anti-CD38 interference and is especially suitable for populations with a high prevalence of anti-M and anti-Mi^a . However, both methods have a well-known drawback of low detection sensitivity for anti-K, and K-units should be provided to patients to prevent hemolytic transfusion reactions.

Red Blood Cell Alloimmunization and Its Associated Factors among Chronic Liver Disease Patients in a Teaching Hospital in Northeastern Malaysia

Red blood cell (RBC) alloimmunization is an important complication of blood transfusion. Variations in the frequency of alloimmunization have been noted among different patient populations. We aimed to determine the prevalence of RBC alloimmunization and associated factors among chronic liver disease (CLD) patients in our center. This is a case-control study involving 441 patients with CLD who were being treated at Hospital Universiti Sains Malaysia and subjected to pre-transfusion testing from April 2012 until April 2022. Clinical and laboratory data were retrieved and statistically analyzed. A total of 441 CLD patients were included in our study, with the majority being elderly, with the mean age of patients 57.9 (SD ± 12.1) years old, male (65.1%) and Malays (92.1%). The most common causes of CLD in our center are viral hepatitis (62.1%) and metabolic liver disease (25.4%). Twenty-four patients were reported to have RBC alloimmunization, resulting in an overall prevalence of 5.4%. Higher rates of alloimmunization were seen in females (7.1%) and patients with autoimmune hepatitis (11.1%). Most patients developed a single alloantibody (83.3%). The most common alloantibody identified belonged to the Rh blood group, anti-E (35.7%) and anti-c (14.3%), followed by the MNS blood group, anti-Mia (17.9%). There was no significant factor association of RBC alloimmunization among CLD patients identified. Our center has a low prevalence of RBC alloimmunization among CLD patients. However, the majority of them developed clinically significant RBC alloantibodies, mostly from the Rh blood group. Therefore, phenotype matching for Rh blood groups should be provided for CLD patients requiring blood transfusions in our center to prevent RBC alloimmunization.

Genotyping Approach to Predict Coa and Cob Antigens in Thai Blood Donor Populations

Purpose

Co^a and Co^b antigens of the Colton (CO) blood group system are implicated in acute and delayed hemolytic transfusion reactions (HTRs). Owing to the inadequate supply of specific antiserum, data on CO phenotypes remain limited. This study aimed to develop genotyping methods to predict Co^a and Co^b antigens and to estimate transfusion-induced alloimmunization risks in three Thai blood donor populations.

Materials and Methods

The study included 2451 blood samples from unrelated healthy Thai blood donors obtained from central, northern, and southern Thailand. DNA sequencing was used to determine the CO*A and CO*B alleles. In-house PCR with sequence-specific primers (PCR-SSP) and high-resolution melting curve (HRM) assays were performed and genotyping results were compared using DNA sequencing. CO*A and CO*B allele frequencies among Thais were determined using PCR-SSP and their frequencies were compared with other populations. The risks of Co^a and Co^b transfusion-induced alloimmunization among Thai donor populations were calculated.

Results

The validated genotyping results by PCR-SSP and HRM assays agreed with DNA sequencing. The CO*A/CO*A was the most common (100.0, 100.0, and 99.3%), followed by CO*A/CO*B (0.0, 0.0, and 0.7%) among central, northern and southern Thais. Homozygous CO*B/CO*B was not found. The CO*A and CO*B allele frequencies among central Thais significantly differed compared among southern Thais (p < 0.01) but not among northern Thais. Those allele frequencies among Thais were similar to those of Taiwanese, Chinese and Malay-Malaysian populations but not to South Asian, Southeast Asian, Korean, Japanese, Filipino, French Basque, and Maltese populations (p < 0.01). A higher risk of anti-Co^b production rather than anti-Co^a production was particularly noted in the southern Thai population.

Conclusion

This study constitutes the first to determine CO*A and CO*B genotypes using PCR-SSP and HRM assays among Thais and this finding would be beneficial in predicting alloimmunization risk and providing safe transfusions among Thais.

Adding further evidence for clinically significant anti-Leb antibody in a voluntary blood donor

Herein, we report a case of naturally occurring anti-Le^b alloantibody identified in the plasma of a first time voluntary blood donor. The immunohematology workup was done on the pilot sample tubes collected during blood donation by the conventional tube technique and using ID-Micro Column System Glass Beads card (anti-IgG, C₃d; Ortho-Clinical Diagnostics, Raritan, New Jersey, USA). Blood group of the donor was confirmed to be B RhD positive, and the alloantibody in his plasma was identified as anti-Le^b, having clinically significant characteristics. Since in this particular case, anti-Le^b was IgM and IgG in nature, it was clinically significant and can lead to hemolytic transfusion reaction, especially if such fresh frozen plasma unit is transfused to Le^b negative patients.

Prevalence of red blood cell antibodies in whole blood donors: A single-centre experience in north India

Background & objectives

Blood transfusion therapy involves multiple steps to ensure selection of safe blood component for transfusion. This includes testing for infectious markers, full ABO compatibility, free from any clinically significant red cell antibodies and acceptable donor's red cell survival rates without destruction of recipient's red cells. The red cell antibodies present in healthy blood donors can cause severe haemolytic transfusion reaction, especially in massive blood transfusion recipients and paediatric patients. Hence, screening of red cell antibodies in donor blood is important to provide compatible blood products and to avoid haemolytic transfusion reactions in susceptible patient population. This study was planned to assess prevalence, aetiology and type of unexpected red cell antibodies in a large number of whole blood donor population in north India.

Methods

This three-year prospective observational study included blood donor samples for antibody screening from January 2015 to December 2017. A total of 166,803 healthy blood donors including 156,128 (93.6%) males and 10,675 (6.4%) females were screened.

Results

The prevalence of red cell antibodies was 0.17 per cent in our donor population. Of the total 286 donors with red cell antibodies, 248 (86.7%) had alloantibodies, 30 (10.5%) had autoantibodies and eight donors (2.8%) showed positive antibody screening with inconclusive results.

Interpretation & conclusions

Alloimmunization to red cell antigens is a challenging task for current transfusion practices. The antibody screening in blood donors may improve the quality and safety of blood transfusion in the recipients. It also reduces the risk of complications from incompatible blood transfusions.

Prevalence of Red Blood Cell Alloimmunization among Transfused Chronic Kidney Disease Patients in Hospital Universiti Sains Malaysia

Objectives

Red blood cell (RBC) immunization is a common complication in blood transfusion recipients. Patients with chronic kidney disease (CKD) eventually develop anemia, which is multifactorial, and requires regular blood transfusions, which exposes patients to the development of RBC antibodies. We sought to determine the prevalence and specificity patterns of RBC immunization and its risk factors among transfused CKD patients.

Methods

We conducted a cross-sectional study over one year from January to December 2018 in the Transfusion Medicine Unit, Hospital Universiti Sains Malaysia. A total of 249 samples were recruited from CKD patients who received a blood transfusion (at least one-pint), which only match for ABO and Rh(D) antigen. The serum was screened for the presence of the RBC antibody using the gel agglutination technique (Diamed gel cards). Samples with positive antibody screening were subjected to antibody identification.

Results

Of the 249 transfused CKD patients, 31 (12.4%) developed RBC immunization. Thirty (12%) were alloimmunized, and one (0.4%) was autoimmunized. Anti-Mia was the most common antibody (n = 14, 46.7%) among alloantibodies, followed by anti-E (n = 7, 23.3%). There was a significant association between pregnancy history with the development of antibodies whereas, no significant association was found between sociodemographic background, stage of CKD, hemodialysis status, underlying medical illness, and number of packed cell transfusions with the development of RBC antibodies.

Conclusions

One-eighth of our patient cohort had RBC alloimmunization, and the risk was increased in patients with a history of pregnancy. We propose Rhesus RBC phenotyping and to supply blood match Rhesus antigen in CKD patients, especially patients of reproductive age.

Silent red blood cell autoantibodies: Are they naturally occurring or an effect of tolerance loss for a subsequent autoimmune process?

Unexpected anti-red blood cell (RBC) alloantibodies are routinely investigated in immunohematology and blood banking since their existence in pregnant women may induce haemolytic disease of the foetus and newborn, and their presence in donors may induce haemolytic transfusion reactions or hyperacute rejection in solid organ transplantation. Unexpected anti-RBC alloantibodies may target antigens of the most blood types excluding the expected antibodies targeting the ABO antigens. Their incidence in humans was originally linked to alloimmunization events such as blood transfusions, transplants, or pregnancies. But later, many findings revealed their existence in pathogenic processes such as malignancies, infections, and autoimmune diseases; and usually (but not always) associated to autoimmune haemolytic anaemia (AIHA). Nevertheless, unexpected anti-RBC autoantibodies are also occasionally found in healthy individuals in the absence of AIHA and with no history of alloimmunization or the associated pathologic processes. Hence, they are generally known as non-clinically significant, are excluded for typification and called "silent red blood cell autoantibodies (SRBCAA)". This review highlights evidence related to genetic predisposition, molecular mimicry, immune dysregulation, and immune tolerance loss surrounding the existence of anti-RBC antibodies, describing the presence of SRBCAA as possible early witnesses of the development of autoimmune diseases.

Red blood cell alloimmunization in multi-transfused patients with chronic kidney disease in Port Harcourt, South-South Nigeria

BACKGROUND

Serological safety is an integral part of overall safety for blood banks.

OBJECTIVES

The aim of the study was to determine the prevalence and specificities of red blood cell alloimmunization in multi-transfused patients with chronic kidney disease (CKD).

METHODS

A cross-sectional case-control study carried out at the University of Port Harcourt Teaching Hospital in which 186 patients with CKD were enrolled consecutively, 124 had received multiple transfusions (more than one unit of blood in one month, or at least 10 units within 3 months), while 62 had never been transfused. Antibody screen test was performed by the gel agglutination technique. RBC antibody identification was performed on the sera of those that tested positive to antibody screening test.

RESULTS

Out of the 124 multi-transfused patients (total of 789 transfusions), 4 (3.2%) were alloimmunised. The alloimmunised patients received a higher mean number of 17.5 ± 12 blood units, compared to 6 ± 6 units by the non-alloimmunised multi-transfused patient (p= <0.001). Six clinically significant alloantibodies were identified with all of the alloimmunised patients forming more than one antibody. Anti-E was detected in all alloimmunised patients.

CONCLUSION

The prevalence of RBC alloimmunisation in multi-transfused CKD patients was 3.2% with anti-E being the most frequently identified antibody.

DI*A and DI*B Allele Frequencies Among Southern Thai Blood Donors

Diego (DI) blood group genotyping is clinically important in Asian populations. Data of Diego blood type among southern Thais is still unknown. This study aimed to report DI*A and DI*B allele frequencies in southern Thai blood donors and to estimate potential risk of Di^a incompatibility and alloimmunization in Thai populations. DNA samples obtained from 427 southern Thai blood donors were genotyped for DI*A and DI*B alleles by polymerase chain reaction with sequence-specific primer. DI*A and DI*B allele frequencies among southern Thais were 0.0047 and 0.9953. Their frequencies were similar to those among American Native, Italian, Filipino, Alaska Native/Aleut and Hawaiian/Pacific Islander populations; while, the frequencies significantly differed from central and northern Thai, Southeast Asian, Brazilian, Southern Brazilian, Brazilian Japanese descendants, Japanese, Han Chinese, Chinese, and Korean populations (P < 0.05). The Di^a incompatibility among southern Thais (0.93%) was lower than among central Thais (3.49%), corresponding to a significantly lower probability of Di^a alloimmunization (P < 0.05). This is the first report of DI*A and DI*B allele frequencies among southern Thais, which is beneficial for not only creating information for estimating risk of alloimmunization, but also providing antigen-negative red cell donors to prevent both alloimmunization and adverse transfusion reactions.

Erythrocyte Alloimmunization and Autoimmunization among Blood Donors and Recipients visiting a Tertiary Care Hospital

INTRODUCTION

The ultimate aim of pretransfusion testing is the acceptable survival of donor red cells in recipient's body and antibody detection plays a critical role in achieving the same. The cornerstone of antibody detection method is detecting an unexpected antibody as against the expected antibodies of ABO blood group system. Autoantibodies can also interfere with the detection of clinically significant alloantibodies.

AIM

To study the frequency of alloantibodies and autoantibodies in the healthy blood donors and patient population visiting our hospital.

MATERIALS AND METHODS

The Column Agglutination Technology (CAT) was used for ABO RhD blood grouping, Direct Antiglobulin Test (DAT), Autocontrol (AC), Indirect Antiglobulin Test (IAT) and red cell antibody screening and the unexpected reactions in any of these tests were recorded for further evaluation. Ethylene Diamine Tetra Acetic Acid (EDTA) blood samples were used for all these tests for both blood donors and admitted patients. The CAT was exercised for the blood grouping (using ABD-Reverse Diluent cassettes) and antibody screening (using 0.8% Surgiscreen, Ortho Clinical Diagnostics Limited, USA and Low Ionic Strength Saline Ortho BLISS with AHG cassettes) on the automated immunohaematology platform ORTHO AutoVue^® Innova system (Ortho Clinical Diagnostics Limited, USA).

RESULTS

Among all blood donors (n=6350), seven (0.11%) donors had showed unexpected reaction. Of these, four had positive antibody screen (three having naturally occuring antibodies 2=anti-M, 1=anti-Le^a and 1=inconclusive) and the other three had positive DAT. Of all the patient samples (n=6136) screened for irregular red cell antibodies, four (0.06%) patients were found to have unexpected reaction revealing one (0.02%) with anti-M antibody and the other three (0.05%) had autoantibodies in their serum.

CONCLUSION

The combined prevalence for both blood donor and recipient population (n=12,486) was found to be 0.11% at our center. The alloimmunisation among patient population was found to be lower than many other studies worldwide as our hospital does not cater to multitransfused or transfusion dependant patients with haematological disorders and majorly elective surgery patients with no history of previous blood transfusions visit our hospital.

Prevalence of irregular red blood cell antibodies among healthy blood donors in Delhi population

OBJECTIVES

To evaluate the prevalence of the anti-red blood cell antibodies among healthy blood donors.

MATERIAL AND METHODS

Antibody screening of all voluntary blood donor serum was performed as routine immunohematological procedure. Positive sera were further investigated to identify the specificity of irregular erythrocyte antibody by commercially available red cell panel (ID-Dia Panel, Diamed-ID Microtyping System).

RESULT

A total of 47,450 donors were screened for the presence of irregular erythrocyte antibodies. A total of forty-six donors showed presence of alloantibodies in their serum (46/47,450%, 0.09%), yielding a prevalence of 0.09%. Most frequent alloantibodies identified were of MNS blood group system. The results showed statistically a higher prevalence of RBC alloantibodies in females than in males.

CONCLUSION

Screening for presence of alloantibodies in donor blood is important to provide compatible blood products and to avoid transfusion reactions.