The characteristics of ABO antibodies in group O Thai blood donors

Irregular red blood cell antibodies, abnormal hemoglobin and dangerous universal blood donor insights from a public blood center in a Brazilian metropolitan area

BACKGROUND

Immunohematology tests are crucial in transfusion safety. This study aimed to assess irregular red blood cell (RBC) antibodies, abnormal hemoglobin and dangerous universal blood donors at a public blood center in a Brazilian metropolitan area.

METHODS

A cross-sectional study included all consecutive blood donors from January 2018 to December 2021 at the Brasília Blood Center Foundation, Federal District (FD), Brazil.

RESULTS

Among 205,965 blood donations, irregular RBC antibodies were found in 743 (0.4 %). Abnormal hemoglobin was observed in 5396 (2.6 %): 3959 (1.9 %) with Hb AS, 1344 (0.7 %) with Hb AC, and 93 (< 0,1 %) with other hemoglobin variants. Of O group donors, 12.5 % (9646) had hemolysins: 12.5 % (2410) both anti-A and anti-B, 8.7 % (9646) only anti-A, and 1.6 % (1763) only anti-B hemolysins. Female sex (p < 0.001) and increasing age (p < 0.001) were associated with irregular RBC antibodies. O and/or Rh(D)-positive blood groups had a lower prevalence of irregular RBC antibodies compared to other ABO and/or Rh(D)-negative groups. Age (p < 0.001) and female sex (p < 0.001) were associated with anti-A/anti-B hemolysins, while FD residency was associated with reduced incidence (p < 0.001).

CONCLUSION

Anti-A/anti-B hemolysins in O group donors, abnormal hemoglobin and irregular RBC antibodies pose risks to transfusion practice and should not be overlooked. Advancing age, female sex, ABO blood group other than O, or Rh(D)- negative are independently associated with the presence of irregular RBC antibodies. Dangerous universal blood donors were associated with advanced age, female gender, Rh(D)-positive blood type, and individuals residing in a Brazilian state other than where the blood center was located.

Anti-A and anti-B titers in A, B and O whole blood donors: Beyond "dangerous O"

BACKGROUND AND OBJECTIVES

Hemolytic transfusion reactions (HTRs) pose significant risks in transfused patients, with anti-A and anti-B antibodies in donor plasma being potential contributing factors. Despite advancements in component preparation, HTRs remain a concern, particularly with apheresis-derived platelets. This study aimed to determine the prevalence of high anti-A and anti-B titers among A, B, and O blood group donors and to explore factors associated with high titers.

MATERIALS AND METHODS

A cross-sectional observational study was conducted over 18 months, enrolling 978 participants from a tertiary care teaching hospital in Western India. Anti-A and anti-B titers were determined using the Conventional Tube Technique (CTT). Statistical analysis assessed correlations between high titers and demographic factors.

RESULTS

The majority of participants were young males (98.8%). Prevalence of high titers for IgM anti-A was 12.2% and IgG anti-A was 2.5%. For anti-B, IgM titers were 2.3% and IgG titers were 0.2%. The prevalence of dangerous O was found to be 14.1%, while 3.52% and 10.5% of A and B blood group donors were found to have high titers, respectively. Factors associated with high titers included female gender, vegetarian diet, age <30 years, and O blood group.

CONCLUSION

The study sheds additional light and provides supplementary information regarding the prevalence and correlation of high anti-A and anti-B titers among O, A and B blood donors. Understanding these factors is crucial for optimizing transfusion safety protocols, including selective screening of platelet units and tailored transfusion strategies based on donor characteristics.

Characteristics of ABO Antibodies in Group O Malaysian Blood Donors

Background

Haemolytic transfusion reactions (HTRs) due to anti-A and anti-B antibodies in Group O blood products are rare but potentially fatal. This study aimed to identify the prevalence of high ABO antibody titre and the immunoglobulin (Ig) classes (IgM only or with IgG) and the prevalence of haemolysin antibodies in Group O blood donors.

Methods

Plasma from Group O blood donors was tested by using antibody titration at room temperature. Titres ≥ 64 were considered high. The plasma was treated with 0.01 M dithiothreitol (DTT) to determine the presence of IgG antibodies and titre. IgG titres ≥ 64 were considered high. Tests for haemolysis were conducted by mixing the plasma with 3% fresh A1 and B cell suspensions and incubating at 37 °C. The haemolysis was observed macroscopically.

Results

Of 311 donors, 238 (76.5%) showed high anti-A and/or anti-B antibody titres. The highest antibody titre obtained was 256. Female and younger donors (< 40 years old) had higher anti-A and anti-B titres. The anti-B titre showed an association with gender (P < 0.001), and was high in female donors (77.8%). Males aged over 50 years old were found to have low mean titre antibodies. Most donors had both IgM and IgG ABO antibodies. The prevalence of haemolysins in our population was 3.5%.

Conclusion

Most of our O blood donors had a high ABO antibody titre but a low prevalence of haemolysins. Males aged over 50 years old are the best O donors for preventing HTRs, particularly when mismatch transfusion is required. We recommend a transfusion unit screen for ABO antibody titre in younger female donors (< 40 years old), to prevent the transfusion of high titre O blood products into non-O recipients.

Lower Levels of ABO Anti-A and Anti-B of IgM, IgG and IgA Isotypes in the Serum but Not the Saliva of COVID-19 Convalescents

Individuals with ABO type O, naturally possessing anti-A and anti-B antibodies in their serum, are underrepresented among patients infected with SARS-CoV-2 compared with healthy controls. The ABO antibodies might play a role in the viral transmission. Therefore, we aimed to quantify anti-A/anti-B, including their subclasses IgM, IgG and IgA, in the serum and saliva of Caucasians (n = 187) after mild COVID-19 to compare them with individuals who had never been infected with SARS-CoV-2. Two samples were collected within two months after the diagnosis (median days: 44) and two months later. ABO antibodies were determined by flow cytometry. Additionally, total IgA in saliva and antibodies specific to SARS-CoV-2 were tested by ELISA. COVID-19 convalescents had significantly lower levels of anti-A/anti-B IgM, IgG and IgA in their serum than control subjects (p < 0.001). Interestingly, no significant differences were observed in saliva. ABO antibody levels remained stable over the period considered. No relation of ABO to the level of SARS-CoV-2-specific antibodies was observed. Total IgA was lower in convalescents than in controls (p = 0.038). Whereas ABO antibodies in the saliva may not contribute to the pathogenesis of COVID-19, individual pre-existing high serum concentrations of anti-A/anti-B may have a protective effect against SARS-CoV-2 infection.

Prevalence of alpha and beta haemolysin among blood group O donors in Bamenda, Cameroon

Background

The occurrence of high titres of alpha (anti-A) and beta (anti-B) haemolysin immunoglobulin G antibodies in blood causes haemolysis during blood transfusion from a group O donor, commonly and inappropriately known as the 'universal blood donor', to a group A, B or AB recipient. Surprisingly, haemolysin testing is not routinely done during blood transfusion services in Bamenda, Cameroon.

Objective

This study aimed to determine the prevalence of haemolysin among blood group 'O' donors at the Regional Hospital Bamenda Blood Bank, Bamenda, Cameroon.

Methods

This was a cross-sectional descriptive study carried out between June and September 2020 at the Regional Hospital Bamenda Blood Bank, Bamenda, Cameroon. Blood group O donors who were free from transfusion-transmissible infections were selected systematically and serially and their serum tested for the presence of haemolysin. Haemolysin titres were determined, and titres ≥ 8 were considered significant. The associations between haemolysin prevalence and age group, gender and Rhesus D blood group were determined using the chi-square test.

Results

The prevalence of haemolysin among the 480 study participants was 52.1% and significant haemolysin titres were detected in 18.5%. There was no association between haemolysin and gender, age group or the Rhesus D blood group.

Conclusion

The prevalence of significant titres of haemolysin among participants in this study was high. There is the need to test for haemolysin in blood group O donors to prevent the potential risk to blood group A, B, and AB recipients and to provide safer blood for transfusion.

High titers of anti-A1 and anti-B antibodies among Peruvian group O platelet donors

Critical antibody titers have been described as factors associated with hemolysis in ABO plasma-incompatible platelet (PLT) transfusions. This study was carried out to describe the frequency of high-titers anti-A and antiB IgM and IgG antibodies in group O apheresis platelet donors, and to explore differences according to the donor characteristics. A cross-sectional study was carried out at the Blood Bank of a National Hospital in Peru from January to March 2019. IgM and IgG antibodies against A1 and B antigens were quantified in 339 platelet donors using the direct hemagglutination technique and the solid-phase adherence technique, respectively. For analysis purposes, two cut-off points; ≥128 and ≥64, were used to define a critical titer for IgM due to a lack of consensus. An IgG titer of ≥256 was also defined as critical. Of the donors, 22.1 % had critical IgM titers when the cut-off point was defined as ≥128. However, when the IgM cut-off was ≥64, the frequency of platelet donors with critical titers increased to 54.0 %. The frequency of donors with critical IgG titers was 23.5 %. Higher IgG titers were associated with female donors while higher IgM titers were negative associated with age. One in two or three platelet donors, depending on the cutoff point used to define a critical IgM titer, had at least one critical titer of anti-A or anti-B antibodies. Early identification of platelet donors with critical antibody titers could prevent passive transfusion of ABO antibodies to non-isogroup recipients.

Comparison of ABO antibody titration, IgG subclasses and qualitative haemolysin test to reduce the risk of passive haemolysis associated with platelet transfusion

BACKGROUND

One of the strategies used to reduce the risk of haemolysis due to ABO-minor incompatible platelet transfusions is to perform a screening test to identify group O donors with high titres of anti-A and anti-B. However, critical immunoglobulin M/ immunoglobulin G (IgM/IgG) titres remain unclear.

OBJECTIVE

This study aimed to determine IgM titres of anti-A and anti-B in individual donor serum vs platelet products plasma and identify a possible association between IgM/IgG titres, haemolysin test and IgG subclasses in Brazilian blood donors from group O.

METHODS

IgM anti-A and Anti-B titration tests were performed on single-donor serum and platelet product plasma by gel agglutination (GA) at room temperature. For IgG anti-A and anti-B titration, serum was first treated with 0.01 M dithiothreitol (DTT), and the test was performed by GA with incubation at 37°C. Dilution of 1:64 as the cut-off was considered for both IgM/IgG. The qualitative haemolysin test was performed in tube, adding AB fresh serum, with incubation at 37°C. IgG subclasses were determined by GA using specific monoclonal antibodies.

RESULTS

An association between anti-A and anti-B IgM titres and haemolysin were demonstrated (P < .001). IgM titres in plasma samples from platelet components correlated to those in single-serum samples. IgG1/IgG3 subclasses were associated with total haemolysis and titres above 64, whereas IgG2/IgG4 subclasses were associated with the absence of haemolysis and titres below 64 (P < .001).

CONCLUSION

Our data suggest that a value of 64 as a critical titre can be used as a screening test of anti-A and anti-B IgM to prevent transfusion reactions. This can be a safe and cost-effective approach for managing ABO-incompatible platelet transfusions.

Immunoglobulin M anti-A and anti-B titers in South Texas group O D+ male donors

BACKGROUND

The success of whole blood (WB) in damage control resuscitation on the battlefield has generated interest in its use for civilian trauma. Blood centers must maintain a committed donor pool with low isoagglutinin titers to provide this product. Information regarding isoagglutinin titers in different donor populations will help with targeted recruitment of these donors.

STUDY DESIGN AND METHODS

Sequential O D+ male donors with a history of two or more donations at a fixed site were tested for immunoglobulin (Ig)M anti-A and anti-B using a single titer cutoff of 256. Donors testing negative at this cutoff were considered "low titer" while positive donors were considered "high titer." Age and self-identified race/ethnicity were retrospectively obtained from the blood establishment computer system. Fisher's exact analysis was used for statistical analysis with a p value of less than 0.05 considered significant.

RESULTS

Of 3274 donors, 426 tested as high titer, while 2848 tested as low titer. The data show an association of donor age and prevalence of high titers with older age groups showing a lower prevalence of high titers. In addition, different races/ethnicities have different prevalences of high titers with the Caucasian/white group showing a lower prevalence of high-titer donors versus the Hispanic and undeclared race groups.

CONCLUSION

The prevalence of high-titer IgM anti-A or -B donors varies by age group and race/ethnicity in our data set. This information will provide information on what donor groups to target for collection of low-titer O WB.

Whole blood transfusion closest to the point-of-injury during French remote military operations

To improve the survival of combat casualties, interest in the earliest resort to whole blood (WB) transfusion on the battlefield has been emphasized. Providing volume, coagulation factors, plasma, and oxygenation capacity, WB appears actually as an ideal product severe trauma management. Whole blood can be collected in advance and stored for subsequent use, or can be drawn directly on the battlefield, once a soldier is wounded, from an uninjured companion and immediately transfused.Such concepts require a great control of risks at each step, especially regarding ABO mismatches, and transfusion-transmitted diseases. We present here the "warm and fresh" WB field transfusion program implemented among the French armed forces. We focus on the followed strategies to make it applicable on the battlefield, even during special operations and remote settings, and safe for recipients as well as for donors.

Evaluation of Magnetized-Erythrocyte Group Antigens to Detect ABO Antibodies

Screening for IgM titers of anti-A and anti-B is recommended when providing ABO incompatible platelet transfusion. The life-time of reagent cells depends upon the preservative diluents. We aimed to evaluate the IgM titers of anti-A and anti-B testing with magnetized-erythrocyte group antigens (MEGA) and fresh RBCs and study the relationship of ABO antibody titers between both techniques. Altogether, 100 serum samples from group O donors at the National Blood Centre, Thai Red Cross Society, Bangkok, Thailand were included. EDTA blood from three different A and B blood group individuals was prepared as fresh reagent RBCs and MEGA. Each serum sample was tested simultaneously for IgM anti-A and anti-B titers using fresh RBCs and MEGA by standard tube technique. Antibody titers were compared between both techniques. Test for reproducibility and stability of MEGA were performed. The IgM anti-A and anti-B titers using fresh RBCs yielded higher agglutination scores than MEGA (P < 0.001). However, a good correlation was obtained in the agglutination titers (anti-A, r = 0.838 and anti-B, r = 0.877). The mean and standard deviation of anti-A and anti-B titers using MEGA from five sera in triplicate showed no significant difference (P > 0.05). Moreover, the titer test results using MEGA after dilution remained stable up to 8 h. The MEGA can be used as a replacement for fresh RBCs to perform ABO serum grouping. It is simple to use, avoids centrifugation and provides good results in terms of stability and reproducibility.

Dangerous universal donors: the reality of the Hemocentro in Belo Horizonte, Minas Gerais

BACKGROUND

The term dangerous universal blood donor refers to potential agglutination of the erythrocytes of non-O recipients due to plasma of an O blood group donor, which contains high titers of anti-A and/or anti-B hemagglutinins. Thus, prior titration of anti-A and anti-B hemagglutinins is recommended to prevent transfusion reactions.

OBJECTIVE

The aim of this study was to estimate the frequency of dangerous universal donors in the blood bank of Belo Horizonte (Fundação Central de Imuno-Hematologia - Fundação Hemominas - Minas Gerais) by determining the titers of anti-A and anti-B hemagglutinins in O blood group donors.

METHOD

A total of 400 O blood group donors were randomly selected, from March 2014 to January 2015. The titers of anti-A and anti-B hemagglutinins (IgM and IgG classes) were obtained using the tube titration technique. Dangerous donors were those whose titers of anti-A or anti-B IgM were ≥128 and/or the titers of anti-A or anti-B IgG were ≥256. Donors were characterized according to gender, age and ethnicity. The hemagglutinins were characterized by specificity (anti-A and anti-B) and antibody class (IgG and IgM).

RESULTS

Almost one-third (30.5%) of the O blood group donors were universal dangerous. The frequency among women was higher than that of men (p-value=0.019; odds ratio: 1.66; 95% confidence interval: 1.08-2.56) and among young donors (18-29 years old) it was higher than for donors between 49 and 59 years old (p-value=0.015; odds ratio: 3.05; 95% confidence interval: 1.22-7.69). There was no significant association between dangerous universal donors and ethnicity, agglutinin specificity or antibody class.

CONCLUSION

Especially platelet concentrates obtained by apheresis (that contain a substantial volume of plasma), coming from dangerous universal donors should be transfused in isogroup recipients whenever possible in order to prevent the occurrence of transfusion reactions.

Prophylactic strategies for acute hemolysis secondary to plasma-incompatible platelet transfusions: correlation between qualitative hemolysin test and isohemagglutinin titration

OBJECTIVE

Brazilian legislation has recently suggested the use of the qualitative hemolysin test instead of isohemagglutinin titers as prophylaxis for acute hemolysis related to plasma-incompatible platelet transfusions. The efficacy of this test in preventing hemolytic reactions has never been evaluated while isohemagglutinin titers have been extensively studied. The main objective of this study was to evaluate the correlation between the results of these two tests. The impact of each type of prophylaxis on the platelet inventory management and the ability of the qualitative hemolysin test to prevent red cell sensitization after the transfusion of incompatible units were also studied.

METHODS

A total of 246 donor blood samples were evaluated using both isohemagglutinin titers and the qualitative hemolysin test, and the results were statistically compared. Subsequently, 600 platelet units were tested using the hemolysin assay and the percentage of units unsuitable for transfusion was compared to historical data using isohemagglutinin titers (cut-off: 100). Moreover, ten patients who received units with minor ABO incompatibilities that were negative for hemolysis according to the qualitative hemolysin test were evaluated regarding the development of hemolysis and red cell sensitization (anti-A or anti-B).

RESULTS

Isohemagglutinin titration and the results of qualitative hemolysin test did not correlate. The routine implementation of the qualitative hemolysin test significantly increased the percentage of platelet units found unsuitable for transfusions (15-65%; p-value <0.001). Furthermore the qualitative hemolysin test did not prevent red blood cell sensitization in a small exploratory analysis.

CONCLUSION

Qualitative hemolysin test results do not correlate to those of isohemagglutinin titers and its implementation as the prophylaxis of choice for hemolysis associated with plasma-incompatible platelet transfusions lacks clinical support of safety and significantly affects platelet inventory management.