anti-B Antibodies Research Articles

ABO blood group and COVID-19: a review on behalf of the ISBT COVID-19 Working Group.

Growing evidence suggests that ABO blood group may play a role in the immunopathogenesis of SARS‐CoV‐2 infection, with group O individuals less likely to test positive and group A conferring a higher susceptibility to infection and propensity to severe disease. The level of evidence supporting an association between ABO type and SARS‐CoV‐2/COVID‐19 ranges from small observational studies, to genome‐wide‐association‐analyses and country‐level meta‐regression analyses. ABO blood group antigens are oligosaccharides expressed on red cells and other tissues (notably endothelium). There are several hypotheses to explain the differences in SARS‐CoV‐2 infection by ABO type. For example, anti‐A and/or anti‐B antibodies (e.g. present in group O individuals) could bind to corresponding antigens on the viral envelope and contribute to viral neutralization, thereby preventing target cell infection. The SARS‐CoV‐2 virus and SARS‐CoV spike (S) proteins may be bound by anti‐A isoagglutinins (e.g. present in group O and group B individuals), which may block interactions between virus and angiotensin‐converting‐enzyme‐2‐receptor, thereby preventing entry into lung epithelial cells. ABO type‐associated variations in angiotensin‐converting enzyme‐1 activity and levels of von Willebrand factor (VWF) and factor VIII could also influence adverse outcomes, notably in group A individuals who express high VWF levels. In conclusion, group O may be associated with a lower risk of SARS‐CoV‐2 infection and group A may be associated with a higher risk of SARS‐CoV‐2 infection along with severe disease. However, prospective and mechanistic studies are needed to verify several of the proposed associations. Based on the strength of available studies, there are insufficient data for guiding policy in this regard.

Association of the ABO blood group with SARS-CoV-2 infection in a community with low infection rate.

Background and objectivesReports on the association of the ABO phenotypes with infection by the SARS‐CoV‐2 virus have mostly come from countries with high infection rates. This study examined the possible association between SARS‐CoV‐2 infection and the ABO phenotype in Black Africa.Materials and methodsThis report is from a single centre where both asymptomatic and symptomatic patients were quarantined. At the time of this report, Oyo State, Nigeria had carried out 15 733 tests of which 3119 were positive for the virus with 1952 recoveries and 37 deaths. The ABO distribution of patients was compared with that of a blood donor population.ResultsOf the 302 participants, 297 (98%) had their blood group determined, asymptomatic and symptomatic individuals were 123 (40·7%) and 179 (59·3%) respectively. Blood group O was significantly less represented among the patients (P < 0·01) while blood groups B and AB were significantly more represented (P < 0·01, P = 0·03 respectively). Patients with anti‐B (groups A and O) were significantly less represented than those without anti‐B (B and/or AB): B and AB (P < 0·001), B (P = 0·002), AB (P = 0·01). There was no difference in the blood group distribution of symptomatic and asymptomatic patients (χ2 (3, N = 302) = 2·29; P = 0·51), but symptomatic patients with anti‐A (groups B and O) were more represented than asymptomatic patients with anti‐A (χ2 4·89; P = 0·03).ConclusionThe higher prevalence of blood group O and more potent beta haemolysins (anti‐B antibodies) are likely reasons for the lower infectivity by the SARS‐CoV‐2 virus and severity of COVID‐19 disease in the community.

ABO Blood Types and COVID-19: Spurious, Anecdotal, or Truly Important Relationships? A Reasoned Review of Available Data.

Since the emergence of COVID-19, many publications have reported associations with ABO blood types. Despite between-study discrepancies, an overall consensus has emerged whereby blood group O appears associated with a lower risk of COVID-19, while non-O blood types appear detrimental. Two major hypotheses may explain these findings: First, natural anti-A and anti-B antibodies could be partially protective against SARS-CoV-2 virions carrying blood group antigens originating from non-O individuals. Second, O individuals are less prone to thrombosis and vascular dysfunction than non-O individuals and therefore could be at a lesser risk in case of severe lung dysfunction. Here, we review the literature on the topic in light of these hypotheses. We find that between-study variation may be explained by differences in study settings and that both mechanisms are likely at play. Moreover, as frequencies of ABO phenotypes are highly variable between populations or geographical areas, the ABO coefficient of variation, rather than the frequency of each individual phenotype is expected to determine impact of the ABO system on virus transmission. Accordingly, the ABO coefficient of variation correlates with COVID-19 prevalence. Overall, despite modest apparent risk differences between ABO subtypes, the ABO blood group system might play a major role in the COVID-19 pandemic when considered at the population level.

Prevalence of ABO blood group phenotypes and antibody titers of the blood donor population in and around Puducherry

Background: For any blood transfusion services, knowing the prevalence and distribution of blood groups in their corresponding geographical area is essential. Hence, this study was done to know the prevalence and distribution of the ABO blood group and the antibody titer levels of blood donors at a premier tertiary care center in Southern India. Methodology: This was a cross-sectional study conducted over 22 months from September 2015 to June 2017 in the Department of Transfusion Medicine, JIPMER, Puducherry, among blood donors in a single tertiary care teaching hospital blood center. The ABO blood group and Rhesus factors (Rh) were determined by the antigen-antibody agglutination test by the test tube method. Titration of anti-A and anti-B antibodies was also done for selected “O” group donors by the doubling dilution technique in the tube method. Results: It was found that the most common blood group in our blood donor population was the “O” blood group with 11,904 (38.43%) followed by “B” 10,643 (34.37%), “A” 6,201 (20.02%), and “AB” 2,219 (7.17%). We had 4 Bombay blood group donors during the study period (0.01%). A titer of 1:32 was the most frequently encountered for IgM anti-A and anti-B antibodies; in Group “O” donors and IgG antibodies, it was 1:8. Conclusion: The prevalence of ABO in and around Puducherry is comparable to those published from other regions in Southern India, with the “O” group being the most common. The distribution of antibody titers for anti-A and anti-B is similar to other studies in India.

Immunity to glycan α-Gal and possibilities for the control of COVID-19.

This initiative is based on research that has been funded by the Consejeria de Educacion, Cultura y Deportes, JCCM, Spain, project ´ CCM17-PIC-036 (SBPLY/17/180501/000185)

Covid-19 and blood groups: ABO antibody levels may also matter

BackgroundSusceptibility to Covid-19 has been found to be associated with the ABO blood group, with O type individuals being at a lower risk. However, the underlying mechanism has not been elucidated. Here, we aimed to test the hypothesis that Covid-19 patients might have lower levels of ABO antibodies than non-infected individuals as they could offer some degree of protection. MethodsAfter showing that the viral spike protein harbors the ABO glycan epitopes when produced by cells expressing the relevant glycosyltransferases, like upper respiratory tract epithelial cells, we enrolled 290 patients with Covid-19 and 276 asymptomatic controls to compare their levels of natural ABO blood group antibodies. ResultsWe found significantly lower IgM anti-A + anti-B agglutination scores in blood group O patients (76.93 vs 88.29, P-value = 0.034) and lower levels of anti-B (24.93 vs 30.40, P-value = 0.028) and anti-A antibodies (28.56 vs 36.50, P-value = 0.048) in blood group A and blood group B patients, respectively, compared to controls. ConclusionIn this study, we showed that ABO antibody levels are significantly lower in Covid-19 patients compared to controls. These findings could indicate that patients with low levels of ABO antibodies are at higher risk of being infected.

Blood group systems

Blood group systems

Donation testing and transfusion transmissible infections

Donation testing and transfusion transmissible infections

ABO/Rh Blood Group and COVID-19 Infection Severity

Introduction:Early epidemiological studies of U.S. patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have suggested a possible association between ABO/Rh blood group phenotype and both susceptibility and severity of COVID-19 infection. Given the remarkable heterogeneity of the host inflammatory response in this viral syndrome and the widespread expression of ABO/Rh antigens on vascular and alveolar endothelial cells, it is biologically plausible that certain blood group phenotypes, with their unique repertoire of anti-A and/or anti-B antibodies, may differentially augment the host-pathogen response. We conducted a retrospective review of patients hospitalized for COVID-19 within our regional healthcare network in San Diego County to identify an association between ABO/Rh blood group type and the severity of infection.Methods:All patients hospitalized at one of five Scripps Health hospitals in San Diego County from March 1, 2020 to July 30, 2020 with a PCR confirmed diagnosis of COVID-19 and blood type on record were included in the initial analysis (n = 316). Demographic, laboratory and clinical data were extracted from the electronic medical record and included age, ethnicity, BMI, sex, medications, co-morbidities and admission white blood cell and lymphocyte count, hemoglobin, platelets, ESR, CRP and D-dimer. Outcomes of interest included length of hospitalization, intensive care unit (ICU) admission, mechanical ventilation need, and mortality. Significant associations between each parameter of interest and blood group type were determined using either linear or logistic regression analysis. To address potential confounding variables, an adjusted multivariate model accounting for potential significant (p< 0.1) predictors of each outcome on univariate analysis, in addition to blood type groups, was conducted to further refine any associations. The study was approved by the Scripps Health Institutional Review Board.Results:316 patients met inclusion criteria for analysis. Hospitalized COVID patients were predominantly male, obese (BMI 30.6) and were an average age of 63 years. Almost 70% of patients hospitalized were Hispanic. 57.0% of patients were blood type O, 30.4% were type A, 3.8% were type B and 8.9% were type AB. 7% were Rh negative. Median length of hospital stay was 16.5±14.7 days, 59% were admitted to the ICU, 37% were intubated, and 27% died. Further relevant laboratory values on admission, co-morbidities, and medications administered during hospitalization are summarized in Table 1. Blood type, with or without adjusting for other clinical variables, was not predictive of length of hospital stay, ICU admission, or intubation during the hospitalization. Type B blood alone was associated with decreased odds of death (OR: 0.27, 95% CI: 0.06-0.85, p<0.05), though this effect was not seen after adjusting for significant confounding variables (OR: 0.39, 95% CI: 0.08-1.43, p>0.18).Conclusion:In this large, multi-hospital, retrospective analysis of patients hospitalized for COVID-19 in San Diego County, there was a low relative percentage of Rh negative blood type and type B blood compared to historical population averages. Blood type was not determined to be independently associated with hospital length of stay, mechanical ventilation, ICU admission or death. ABO/Rh blood typing appears to have a limited prognostic role in COVID-19 severity of hospitalized patients, though further analysis of the protective effects of type B and/or Rh negative blood type may be warranted in a larger sample.DisclosuresNo relevant conflicts of interest to declare.

Advancement in Cancer Immunotherapy in Veterinary Medicine: A Review

Cancer is one of the leading cause of death in human beings throughout the world. Attempts to treat cancer are made but not effectively. Surgical removal, use of radiation therapy, chemotherapy and combination of these therapies have been tried to cure cancer but every therapy had its own side effects. Due to potential side effects, these therapies failed to develop as the permanent cure for cancer. Stem cell transplantation has also been attempted as an alternative but the recovery rate was very low. The most recent therapy, nowadays, to treat cancer is immunotherapy in which utilises the immunity of the patient to get modulated in such a way that cancerous cells get killed. So this review enlightens the eminent immunotherapies used for veterinary patients. T cell checkpoint inhibitors, engineered T cells, cancer vaccines, and anti-B and anti-T cell antibodies are amongst the important immunotherapies used in human as well as veterinary patient. Inhibition of T cell checkpoint molecules, such as PD-1 and CTLA-4, using monoclonal antibodies are the most advanced techniques developed in humans. These significant immunotherapies have achieved notable success against some of the advanced tumors in humans, including melanoma, renal cell carcinoma and non small cell lung cancer. However, a recent clinical trial with a caninized monoclonal antibody against canine PD-L1 showed response in canine melanoma.

Clinical Cases of Bacterial and Fungal Sensitization in Patients with Coxarthrosis and Gonarthrosis depending on Blood Group Differences

Aim: To analyze bacterial and fungal sensitization in persons that have ability to absorb anti-A and anti-B antibodies incompatible with blood group type. Material and methods: 8 people had A blood group, 2 persons had B blood group, 22 persons showed O blood group type. 9 patients with O blood group and 2 patients with B blood group absorbed anti-A antibody. 2 patients with O blood group and 5 patients with A blood group absorbed anti-B antibody. 7 persons with 0 blood group without absorbing activity of anti-A, 4 persons with O blood group and 3 persons with A blood group without anti-B absorbing activity served as control groups. Leukocyte migration inhibition reaction was performed to estimate bacterial and fungal sensitization. Results: Persons with anti-A absorbing ability were characterized by increased antibodies, sensitization to Penicillium, Candida Albicans, Pseudomonas aeruginosa, E. Coli and Clebsiella pneumoniae, increased CIC as compared to those without anti-A absorbing ability. Patients with anti-B absorbing ability showed decreased spontaneous leukocyte migration inhibitory factor production, sensitization to Streptococcus pneumoniae and Staphylococcus aureus by cell type, sensitization to Candida Lusitaniae by humoral type. Persons with anti-A absorbing ability as compared to the persons with anti-B absorbing ability showed sensitization to Penicillium, Candida Albicans, while the persons with anti-B sensitization revealed sensitization to Streptococcus pyogenes. During incubation of erythrocytes with the heated polyclonal anti-A (and anti-B) and complement at room temperature the erythrocytes of the persons with corresponding anti-A (anti-B) absorbance were increased in size and agglutinated by sides. Conclusion: Anti-A and anti-B absorbing activity of erythrocytes is associated with different fungal and bacterial sensitization.

Novel approach to protein-protein interaction assessment

Past decades, the study of proteins and small molecules interaction has been at least lagging behind the study of other types of interactions such as protein-protein, protein-DNA and protein-RNA. The aim of this study is to evaluate the effect of low-molecular biologically active compounds, lactate and pyruvate, on protein-protein interactions and to provide quantitative assessment. Using AB0 blood groups system model and labeled monoclonal anti-A and anti-B antibodies we studied the effect of natural metabolites lactate and pyruvate on antigen-antibody interaction. Erythrocytes of A(II) and B(III) blood groups were incubated with lactate and pyruvate before the agglutination reaction. Then the agglutination reaction was performed. Visualization of agglutination complexes was carried out by means of confocal laser scanning microscopy with further processing of noise pixels. A series of in vitro experiments with further visualization and mathematical processing showed the co-directed but more pronounced effect of lactate on the antigen-antibody reaction as compared to pyruvate. In case of influence on antigen A the aggregation process intensification was noted, while this process was inhibited in case of influence on antigen B. The obtained results demonstrate possibility of using small molecules, in particular lactate and pyruvate, as molecular probes and prospects of erythrocytes with antigenic determinants of AB0 system expressed on their membranes for studying protein-protein interactions due to visualization clarity and possibility of quantitative assessment of this process. It is proved that lactate and pyruvate can act as regulators of protein-protein interactions on the example of antigen-antibody reaction.

Cross-linked chitosan biofunctionalized paper-based microfluidic device towards long term stabilization of blood typing antibodies

Long term stability of antibodies at room temperature is a major challenge in the commercialization of point-of-care devices for diagnostics. Since chitosan has been proven to be an excellent biofunctionalization material, the effects of four different biofunctionalization processes were studied to improve the room temperature stability of antibodies immobilized on chitosan modified paper-based microfluidic devices using blood typing antibodies as candidates. The devices used in this work have a flower-shaped design with 4 test zones at each corner. In three zones Anti-A, Anti-B, and Anti-D (Anti-Rh) antibodies are immobilized and the fouth zone represents the control (no antibodies) after biofunctionalization. The biofunctionalization of the paper devices was done with chitosan and chitosan cross-linked with sodium triphosphate pentabasic, glutaraldehyde, and sodium hydroxide. These devices were used for blood typing assays using real blood samples. A similar assay was also performed on unmodified (non-biofunctionalized) paper devices for comparison. Chitosan based biofunctionalized paper-devices showed better stability, up to 100 days as compared to 14 days on unmodified paper, at room temperature. Such biofunctionalized paper-based devices will be suitable for on-field and remote testing without any technical expertise and requirement for the cold chain.

Immunohistochemical identification of T and B lymphocytes in formalin-fixed paraffin-embedded chicken tissues using commercial antibodies

Immunohistochemical method to detect avian lymphocytes is an efficient and reliable tool for accurate diagnosis, and immunological analysis of avian diseases. However, there are scarce studies reporting immunohistochemistry (IHC) using commercially available antibodies against lymphocytes in formalin-fixed paraffin-embedded (FFPE) chicken tissues. In the present study, we established an immunohistochemical method to identify chicken T and B lymphocytes in FFPE chicken tissues using commercial antibodies against chicken or human antigens. For this IHC method, the five tested anti-T lymphocyte antibodies reacted with chicken T lymphocytes on the FFPE sections. Further, 10 commercial anti-B lymphocyte antibodies were tested; of these, three successfully detected chicken B lymphocytes for IHC. In particular, anti-human CD3 (clone F7.2.38) antibody was most suitable for the detection of chicken T lymphocytes, whereas anti-chicken B cell activating factor receptor (BAFF-R) antibody (clone 2C4) was most suitable for the detection of chicken B lymphocytes under our IHC staining conditions. These two antibodies reacted with numerous lymphocytes of all representative lymphoid tissues without problematic background staining and nonspecific reactions. Our results indicate that T and B lymphocytes in FFPE chicken tissues can be immunohistochemically detected using commercial antibodies.

ABO-Incompatible Kidney Transplantation After Bone Marrow Transplantation: A Case Report

Many studies have been made on ABO-compatible kidney transplants following hematopoietic stem cell transplantation. However, there have been few reports on ABO-incompatible kidney transplantation following hematopoietic stem cell transplantation (HSCT). We report on the case of a successful ABO-incompatible kidney transplantation with high titers after bone marrow transplantation experienced no infectious episodes. The patient was a 38-year-old man with end-stage kidney disease resulting from interstitial nephritis induced by drug toxicity or graft-vs-host disease (GVHD). He had received allogeneic bone marrow transplantation from a human leukocyte antigen-identical unrelated donor to treat chronic myelogenous leukemia. The patient with high anti-B antibody titers (IgM 1:1024 IgG 1:256) received a desensitization protocol consisting of 2 doses of rituximab and 5 courses of plasmapheresis. The patient had prolonged depletion of circulating B cells 2 years after the transplant and was infected with cytomegalovirus viremia, pneumocystis jiroveci pneumonia, and adenovirus urinary tract infection at 2, 3, and 17 months post-transplant, respectively. Currently, at 6 years after his transplant, the patient has had no rejection and is in good clinical condition with only mild renal insufficiency. Our results suggest that ABO-incompatible kidney transplantation may be an effective renal replacement therapy for patients with end-stage kidney disease after HSCT, but desensitization in combination with immunosuppressants could lead to a state of over-immunosuppression, causing various infections.

IMMUNE ANTIBODIES IN MOKSHA AND ERZYA ETHNIC GROUPS OF THE REPUBLIC OF MORDOVIA

ABO system's immune antibodies are common, but not as persistent as natural anti-A and anti-B antibodies. They are the result of hyper immunization of an iso- or heteroimmune nature and belong to the IgG class. The study of serum for the presence of immune antibodies of the ABO, Rh system is necessary for the diagnosis of hemolytic disease cases of newborns with ABO, Rh-conflict pregnancy. Clinically significant immune antibodies of erythrocyte systems capable to cause in vivo destruction of red blood cells are of great importance in transfusiology and immunohematology. The most common cause of their occurrence is alloimmunization with red blood cell antigens during childbirth. The aim of this study was to determine the characteristics of the immune anti-erythrocyte antibodies in residents of the Republic of Mordovia belonging to the ethnic groups of Moksha and Erzya. Methods. The cross-sectional study involved 294 people from the Moksha and 387 people and Erzya ethnic groups, randomly selected in 7 districts of the Republic of Mordovia. Detection of IgG anti-A, anti-B ABO systems was performed by inactivation of disulfide bonds in IgM molecules using a 5 % unitiol solution and then by direct agglutination method at indoor temperature with standard red blood cells of group O(I), A(II), and B(III). The study of incomplete anti-erythrocyte antibodies of other systems was performed by indirect Coombs' test using gel technology. Results. The study of immune antibodies of the ABO system revealed from 10.61 to 16.00 % of anti-A antibodies and from 2.27 to 6.38 % of anti-B antibodies in both men and women Moksha and Erzya. We studied immune anti-erythrocyte antibodies: anti-D 0.34 % in Moksha and anti-D 0.26% and anti-Kell 0.26 % antibodies in Erzya. The scale of immunogenicity of red blood cell antigens in the studied groups: A&gt;, B&gt;, D&gt; and K&gt;. The alloimmunization index of transfusion-hazardous antigens was calculated as 0.34 for Moksha and 0.52 for Erzya. Conclusions. Physiologically, the immune system in Moksha and Erzya actively reacts with antibody's production and it is sensitive to immunization by the group of antigens.

Prolonged Anhepatic Phase after Liver Transplantation Failure Followed by ABO Incompatible Liver Transplantation: A Case Report and Review of the Literature

Objective: To describe the experience with a multimodal therapeutic approach in a patient who developed toxic liver syndrome and fulminant hepatic failure following orthotopic liver transplantation (OLT) as a result of occlusion of the portal vein. Setting: Department of Intensive Care. Patient: A patient with liver cirrhosis secondary to autoimmune hepatitis and primary biliary cirrhosis who underwent orthotopic liver transplantation (OLT). Interventions: Transplant hepatectomy, plasmapheresis and retransplantation. Case Report: A 39-year-old man underwent an elective OLT. A routine postoperative doppler ultrasound examination a few hours after surgery revealed portal vein thrombosis. Attempts at recanalization failed, and the patient developed acute fulminant liver failure, which remained resistant to supportive therapy. A transplant hepatectomy was performed 9 hours later and plasmapheresis started. Following a 10-hour anhepatic period, the patient received a second liver, from an ABO-incompatible donor. The patient underwent column plasmapheresis and subsequent splenectomy to remove anti-B antibody to preserve the incompatible transplanted liver from immunogenic complications. The patient spent a total of 21 days in the Intensive Care Unit (ICU) before being discharged to a step-down ward. Conclusion: Our experience suggests that multimodal therapy, including transplant hepatectomy, plasmapheresis and retransplantation of an even non-ABO compatible liver may result in the successful outcome in patients with acute fulminant liver failure complicating OLT.

A Clinical Case of Weak A Antigen on the Erythrocytes in a Person with Coexistent Anti-A Antibodies.

This study investigated a person with an AB0 discrepancy. Her blood group initially typed at the birth as AB Rh+ (positive); however, it was B Rh+ (positive) or Rh- (negative) when she was in her teens. At room temperature, her erythrocytes were agglutinated by anti-B, and the agglutination was significantly weaker at 37 &amp;ordm;C. As a result, her erythrocytes did not absorb anti-B but anti-A. Furthermore, her erythrocytes were agglutinated by anti-A at 37 &amp;ordm;C with signs of hemolysis in the presence of complement. The unwashed erythrocytes were also agglutinated in an antiglobulin test by polyclonal anti-A at 37 &amp;ordm;C and by heated polyclonal anti-A and anti-A MAB 2-8 at room temperature. Moreover, her serum agglutinated A erythrocytes at room temperature with less activity at 37 &amp;ordm;C; however, it agglutinated B erythrocytes at 37 &amp;ordm;C. The ability of the erythrocytes of this person to absorb anti-A came along with the agglutination of her erythrocytes at 37 &amp;ordm;C by polyclonal serum and decreased activity of the serum to agglutinate A erythrocytes at 37 &amp;ordm;C, compared to room temperature. The absence of anti-B absorbance by the person&amp;rsquo;s erythrocytes was accompanied by the presence of anti-B in the serum, which was active at 37 &amp;ordm;C. The incubation of the person&amp;rsquo;s serum with 0 erythrocytes induced the ability of erythrocytes to absorb anti-A and to be hemolyzed by anti-A in the presence of complement in accordance with the person&amp;rsquo;s characteristics of erythrocytes. The reaction of absorption and agglutination at room temperature and 37 &amp;ordm;C by heated serum with the use of complement may help to reveal both weak A and B antigens and anti-A and anti-B antibodies while AB0 blood typing.

Rare Incidental Detection Of Bombay Blood Group In A Patient Of Marfans Syndrome With Subsequent Clustering And Unusual Inheritance Pattern In Four Individuals Of Same Family In South West Region Of Punjab

The Bombay Blood Group (Oh) is characterized by absence of normal ABH antigens and presence of corresponding antibodies in serum. This blood group is suspected when a sample doesn’t show any reaction to anti-A and anti-B antibodies just like a normal O group would do but shows agglutination in reverse grouping or during antibody screening. Present case report highlights a case of 25 year old female who was incidentally detected having Bombay blood group and on further evaluation, one sibling and two first degree cousins were also detected having Bombay blood group. Such a clustering of Bombay blood group cases in a single-family is very rare and has never been reported in Punjab as per literature.

Prevalence of high titered anti-A and anti-B antibodies among O blood group individuals and their associated factors

Background and Objectives: Severe hemolytic transfusion reactions due to minor incompatibility are usually associated with the so-called “High titred” antibodies in the plasma of donors especially the O group as it is generally regarded as universal donors. Critical titers of 1:64 or higher was considered high titered antibodies for IgM anti-A and anti-B. Critical titers of 1:256 or higher was considered high titered antibodies for IgG anti-A and anti-B. The objective of this study was to see the prevalence of such high titered antibodies among our donor population and to observe for an association if any with the age, gender, and diet type and probiotic intake of the donors. Methodology: This was a cross-sectional analytical study conducted over 20 months from September 2015 to May 2017. About 560 donors were chosen randomly after screening and counseling and titration of anti-A and anti-B antibodies was done by the double dilution tube agglutination technique. The information on age, gender, diet type, and probiotic intake was gathered from the donor history questionnaire and an association between the factors described and the distribution of critical titers of anti-A and anti-B was elicited. Results: In the present study, the prevalence of high titer anti-A and anti-B IgM antibodies was 36% and 32%, respectively. The prevalence of high titer anti-A and anti-B IgG antibodies was 9.6% and 5.5%, respectively. The median IgM antibody titers reduced with the increasing age of the donors starting 18 years. There was a statistically significant association between a vegetarian diet and high titers. Conclusion: There are a considerable proportion of O group donors with high titers of antibodies and hence a routine pretransfusion screening for such antibodies can prevent the development of hemolytic reactions by segregating units into “high titer” and “low titer” antibodies and issuing only low titer products for out of group transfusions.