Hemolytic Transfusion Reactions Research Articles

Screening and Identification of Erythrocyte Antibodies: A Narrative Literature Review

Red blood cell (RBC) alloimmunization, the development of antibodies against foreign red blood cell antigens, is a critical concern in transfusion medicine. Alloantibodies can lead to adverse transfusion reactions, including hemolytic disease of the fetus and newborn (HDFN) and delayed hemolytic transfusion reactions (DHTR). This comprehensive literature review explores the intricacies of RBC alloimmunization, focusing on the screening and identification of erythrocyte antibodies. We delve into the prevalence and clinical significance of various alloantibodies, the underlying immunological mechanisms, and the evolution of laboratory techniques for their detection. Additionally, we discuss the challenges and future directions in managing alloimmunization, emphasizing the importance of personalized medicine and innovative approaches to ensure safe and effective blood transfusions.

Alloimmunization and autoimmunization among multitransfused thalassemia and sickle cell disease patients

Blood transfusion is the mainstay for management of hemoglobinopathies, including thalassemia and sickle cell disease (SCD). Apart from other transfusion related adverse effects, immunization is a significant complication, particularly in multitransfused recipients. Alloimmunization rates vary widely, both in thalassemia and SCD patients. Alloimmunization complicates the management in form of hemolytic transfusion reactions, difficulty in finding compatible units, delays in transfusion and increasing costs. Exact pathogenesis and prevention modality have not been elucidated. Apart from antigenic differences, immunomodulatory effects and inflammation also play a role in pathogenesis. Ethnic heterogeneity between donors and recipients predisposes to higher alloimmunization.Transfusion management of hemoglobinopathies across the globe is fragmented, with different levels of care. Guidelines propose red cell antigen profiling, transfusion of leucoreduced red cells, preferably matched for Rh and Kell antigens, over and above ABO-D matching. For alloimmunized patients, corresponding antibody negative red cells need to be transfused. However, patients from different backgrounds are variably transfused with whole blood/red cells, which may or may not be leukoreduced. Prophylactic antigen matching reduces the risk of alloimmunization, however, has limitations. RH variants may not be picked up by phenotyping alone. Moreover, the approach of prophylactic antigen matching is expensive, labour intensive, time consuming and may cause delays in transfusions. There is limited, low quality evidence on best practices for transfusion management of SCD and thalassemia. The review analyses the magnitude of problem, factors contributing and modalities for prevention and management of immunization.

Genetic profile of RHCE, Kell, Duffy, Kidd, Diego and MNS hybrid glycophorins blood groups in ethnic northeastern Thais: Alleles, genotypes and risk of alloimmunisation.

Antibodies against blood group antigens play a key role in the pathophysiology of haemolytic transfusion reactions (HTRs) and haemolytic disease of the fetus and newborn (HDFN). This study aimed to determine the frequencies of alleles, genotypes, and risk of alloimmunisation of clinically significant blood group systems in ethnic northeastern Thais. In total, 345 unrelated, healthy, ethnic northeastern Thais were tested using the in-house PCR-sequence specific primers (PCR-SSP) method for simultaneously genotyping of RHCE, Kell, Duffy, Kidd, Diego and MNS glycophorin hybrids and results confirmed by Sanger sequencing. In this cohort, the alleles RHCE*C (81.0%) and RHCE*e (84.8%) were more prevalent than RHCE*c (19.0%) and RHCE*E (15.2%). The most common predicted haplotype combinations of the RHCE alleles were C+c-E-e+(R1R1) (59.4%) followed by the C+c+E+e+ (R1R2) (20.6%) and C+c+E-e+ (R1r) (11.3%). The KEL*01 allele was not found in this study. The frequencies of FY*01 and FY*02 were 88.3% and 11.7%, respectively. The genotype FY*02/02 was found in four samples (1.2%). The frequencies of JK*01 and JK*02 were 52.5% and 47.5%, respectively. Homozygous JK*02/02 was found in 81 samples (23.5%). The frequencies of DI*01 and DI*02 were 0.6% and 99.4%, respectively. In total, 64 samples (18.6%) were found to carry the MNS glycophorin hybrids. Our results indicated a possible high risk of c, E, Fyb, Jka, Jkb and Mia alloimmunisation in these populations. Moreover, methods established for genotyping clinically significant blood groups in this study can now be utilised in routine clinical application.

Distribution of ABO, Rh, and MNS blood groups from students in Walailak University, Thailand: A descriptive cross-sectional study

BackgroundThe presence or absence of blood group antigens can lead to alloimmunization, causing hemolytic transfusion reactions and hemolytic disease of the fetus and newborn. The distribution of these antigens varies among different ethnic populations, making it essential to study their prevalence in specific regions. ObjectivesThis study aimed to investigate ABO, Rh, and MNS blood group antigens, phenotypes, and allele frequencies among university students in Southern Thailand. Materials and methodsBlood samples were collected and typed for blood group antigens using serological tests. Antigen, phenotype, and allele frequencies were calculated based on the observed phenotypes. ResultsThe most common ABO blood group was O (37.29%), followed by B (35.98%), A (19.47%), and AB (7.26%). Allele frequencies for ABO system were found to be 0.6107 for ABO*O, 0.2453 for ABO*B, and 0.1427 for ABO*A. Rh blood group distribution revealed a high prevalence of the D antigen (99.01%), followed by e (96.37%), C (95.05%), c (39.27%), and E (29.37%). The allele frequencies for D and d were 0.9005 and 0.0995, respectively. The MNS system showed M and N antigen frequencies of 85.81% and 67.66%, respectively. The most common phenotype was M+N+ (53.47%), followed by M+N− (32.34%) and M−N+ (14.19%). Mia antigen was present in 10.56% of our population. ConclusionsThis study provides an understanding of blood group distribution and gene frequency in our young population, which is crucial for blood management in community transfusion. Additionally, this knowledge holds significant value for population genetics studies.

Erythrocyte Alloimmunization and Autoimmunization in the Pediatric Population: A Multicenter, Cross-Sectional Study in Central China

Background: Erythrocyte alloantibodies and autoantibodies complicate transfusion. However, the prevalence of erythrocyte alloimmunization and autoimmunization has not been estimated in the Chinese pediatric population. Therefore, we investigated the prevalence of erythrocyte alloimmunization and autoimmunization in the Chinese pediatric population with the aim of developing a reasonable transfusion management policy in children from China. Methods: This study included 30,603 pediatric inpatients who were admitted to three tertiary hospitals in central China from May 2020 to October 2022. Antibody screening was carried out with a three-cell panel by column agglutination technology, and samples with positive screening were analyzed for antibody specificity with a 16-cell identification panel. Clinical details of the patients were collected to identify associations with antibody formation. Results: The alloimmunization rate was 0.55% (169/30,603), and the autoimmunization rate was 0.14% (43/30,603). Alloantibodies comprised 80.09% of the antibodies. The most frequent alloantibodies were anti-M (58.77%), anti-E (9.48%), and anti-P1 (4.27%). Autoantibodies comprised 19.91% of antibodies. Age (p = 0.000), sex (p = 0.016), geographical area (p = 0.000), ABO blood group (p = 0.008), and diagnosis (p = 0.000) were independent risk factors for antibody formation. The risk of antibody formation at the ages of 0–28 days and 1–3 months was zero (odds ratio = 0.000). The antibody distribution was significantly different by age (p = 0.000) and diagnosis (p = 0.000). Conclusion: Repeat pre-transfusion testing for infants less than 4 months of age can be omitted for no risk of antibody formation. MNS system antibodies, especially anti-M, are prominent in younger children, and this decreases with age. Provision of extended phenotype-matched transfusion for Rh system antigens, especially antigen E, is necessary in children to control erythrocyte alloimmunization. The presence of antibodies with high evanescence rates in the pediatric population suggests the pressing need for nationwide shared transfusion records to avoid hemolytic transfusion reactions in children.

Comparison of the solid-phase red cell adherence assay and tube method for detection and identification of red blood cell antibodies.

Identifying antibodies to red blood cell antigens is one of transfusion medicine's critical responsibilities. The International Society of Blood Transfusion recognizes 354 red blood cell antigens. Accurate identification of clinically significant alloantibodies is imperative for preventing hemolytic transfusion reactions and hemolytic disease of the fetus and newborn. We compared the performance of the tube (polyethylene glycol-indirect antiglobulin test [PEG-IAT]) and solid-phase red cell adherence assay techniques. We performed a retrospective study on all antibody screens performed between 2007 and 2021 at Stanford Transfusion Services. Initially, 631,535 antibody screens were performed using a solid-phase technique. Subsequent antibody identifications were performed using a combination of tube testing and solid-phase techniques. Antibody screening resulted in 28,316 (4.5%) positive samples. Antibody identification performed on both platforms identified 50 discordant samples. The anti-E antibody had the lowest sensitivity (98.99%) in the automated solid-phase technique, while anti-Jkb had the lowest sensitivity (98.78%) with the PEG-IAT method. To our knowledge, this is the first robust, 15-year study comparing methodologic sensitivity to detect clinically significant alloantibodies. The incidence of discordant results between PEG-IAT and the solid-phase technique was low. Among discordant samples, anti-Jka was commonly detected using the solid-phase method but not with the PEG-IAT. In contrast, anti-E was commonly detected by PEG-IAT but not by the solid-phase method.

Integrated analyses reveal unexpected complex inversion and recombination in RH genes

AbstractPhenotype D-- is associated with severe hemolytic transfusion reactions and hemolytic disease of the fetus and newborn. It is typically caused by defective RHCE genes. In this study, we identified a D-- phenotype proband and verified Rh phenotypes of other 6 family members. However, inconsistent results between the phenotypic analysis and Sanger sequencing revealed intact RHCE exons with no mutations in the D-- proband, but the protein was not expressed. Subsequent whole-genome sequencing by Oxford Nanopore Technologies of the proband revealed an inversion with ambiguous breakpoints in intron 2 and intron 7 and copy number variation loss in the RHCE gene region. Given that the RHCE gene is highly homologous to the RHD gene, we conducted a comprehensive analysis using Pacific Biosciences long-read target sequencing, Bionano optical genome mapping, and targeted next-generation sequencing. Our findings revealed that the proband had 2 novel recombinant RHCE haplotypes, RHCE∗Ce(1-2)-D(3-10) and RHCE∗Ce(1-2)-D(3-10)-Ce(10-8)-Ce(3-10), with clear-cut breakpoints identified. Furthermore, the RH haplotypes of the family members were identified and verified. In summary, we made, to our knowledge, a novel discovery of hereditary large inversion and recombination events occurring between the RHD and RHCE genes, leading to a lack of RhCE expression. This highlights the advantages of using integrated genetic analyses and also provides new insights into RH genotyping.

Prevention of potential delayed hemolytic transfusion reaction in two sickle cell patients using intravenous immunoglobulins and steroids before and after red blood cell exchange with antigen positive units and review literature

Emergent Red Blood Cell (RBC) exchange is indicated in sickle cell disease (SCD) patients with severe acute chest syndrome. However, fully matched RBC units may not be available for patients with multiple RBC antibodies. Intravenous immunoglobulin (IVIG) and steroids were reported for preventing potential delayed hemolytic transfusion reaction (HTR) in simple transfusion of antigen-positive RBCs. We investigated the efficacy and safety of IVIG and steroids in two SCD patients presented with acute chest syndrome receiving RBC exchange with multiple incompatible units. The first patient had multiple historical alloantibodies, including anti-Jsb, although none of them were reactive. IVIG (1 g/kg) was given before and after RBC exchange with methylprednisolone (500 mg IV) one hour before exchange. Her sickle hemoglobin (HbS) was reduced from 89.4% to 17.4% after the exchange with five Jsb-positive units. The patient improved clinically without acute or delayed hemolysis. The second patient had reactive anti-Jsb on two different admissions 18 months apart. Only one of the sixteen units used in the exchanges was Jsb negative. He received the same IVIG regimen during both admissions but 100 mg IV hydrocortisone instead of methylprednisolone. His HbS was reduced from 63.4% to 22.4% after the first exchange. Significant clinical improvements were achieved after both exchanges. No delayed HTR was observed. Our experience of these two patients suggested that IVIG and steroids may be used in preventing potential delayed HTR in some SCD patients with rare antibodies receiving large amounts of antigen-positive RBC products.

The Trajectory of Haptoglobin in Haemolysis, Inflammation and Transfusion Reaction

Introduction: Haptoglobin is an acute-phase α2-glycoprotein produced in the liver with the major biological function of binding free haemoglobin with very high affinity to prevent the loss of iron following hemolysis. Haptoglobin has an anti-inflammatory property and is raised during inflammation whereas, low level is associated with haemolysis. Transfusion is linked with haemolysis thereby increasing the level of free haemoglobin due to anti-haptoglobin and storage effect. Studies have revealed interplay of haptoglobin in haemolysis, inflammation and transfusion reaction although, the underlying mechanism is not well understood. Besides, its utilization as a diagnostic biomarker and therapeutic advantage have not been well explored hence, this study. Method: In this review 20 primary studies from various electronic databases such as Google scholar, Semantic scholar and PubMed were obtained on the basis that they were focused on haptoglobin, haptoglobin in haemolysis, inflammation and transfusion. This was made possible by the use of Boolean function. Results: Haptoglobin, is measured in blood due to its complex formation with hemoglobin, forming a protective non-covalent complex with CD63 as receptor. The finding from this review shows that, haptoglobin plays a crucial role in scavenging surplus hemoglobin, iron and heme in haemolysis with antioxidant function and immunomodulatory effect in transfusion reactions. The concept of the trajectory of haptoglobin explored the multi-dimensional course of this acute phase scavenger protein in the course of clinical conditions of haemolysis, inflammation and transfusion reaction. The review confirmed specific roles of haptoglobin such as physiologic-antioxidant, prognostic, diagnostic biomarker, immunologic and therapeutic. Additionally, an inverse relationship exists between haptoglobin and haemolysis as well as transfusion reaction consequent to hypohaptogloinaemia whereas, direct relationship exists with inflammation resulting to hyperhaptoglobinaemia observed in those clinical conditions respectively. Haptoglobin synthesis is elevated by the liver in response to inflammation, countering oxidative damage and inflammation by neutralizing free hemoglobin. When there is an immunological mismatch, haemolytic transfusion reactions can occur and transfusion of prolonged stored blood potentiate same effect. Conclusion: The role of haptoglobin cannot be overemphasized. Based on the widespread roles and clinical relevance of haptoglobin, it is vital that haptoglobin be utilized

Utility of hemoglobin electrophoresis to distinguish between severe delayed hemolytic transfusion reaction versus hyperhemolysis syndrome

Delayed hemolytic transfusion reaction (DHTR) and hyperhemolysis syndrome (HHS) are both complications of red blood cell transfusions in patients with sickle cell disease.Clinically, both present with hemolysis and can be difficult to differentiate. Hemoglobin electrophoresis may aid in the diagnosis. Herein we describe a case in which a patient with hemoglobin SC disease presented with features of severe hemolysis several days after initiation of red blood cell exchange. Increase in reticulocyte count and complete absence of hemoglobin A on electrophoresis during this event supported the diagnosis of severe DHTR, indicating a rapid and selective destruction of the transfused red blood cells. Ability to interpret the hemoglobin electrophoresis can help clinicians distinguish between these two severe transfusion complications in patients living with sickle cell disease. It is important to identify the presence or absence of concomitant HHS, as patients with HHS tend to have a worse prognosis and there is a higher rate of recurrence of HHS with subsequent transfusions. Accurate diagnosis can lead to prompt management and decrease morbidity and mortality.

An oral carbon monoxide–releasing molecule protects against acute hyperhemolysis in sickle cell disease

AbstractAcute hyperhemolysis is a severe life-threatening complication in patients with sickle cell disease (SCD) that may occur during delayed hemolytic transfusion reaction (DHTR), or vaso-occlusive crises associated with multiorgan failure. Here, we developed in vitro and in vivo animal models to mimic endothelial damage during the early phase of hyperhemolysis in SCD. We then used the carbon monoxide (CO)–releasing molecule CORM-401 and examined its effects against endothelial activation, damage, and inflammation inflicted by hemolysates containing red blood cell membrane–derived particles. The in vitro results revealed that CORM-401: (1) prevented the upregulation of relevant proinflammatory and proadhesion markers controlled by the NF-κB enhancer of activated B cells, and (2) abolished the expression of the nuclear factor erythroid-2-related factor 2 (Nrf2) that regulates the inducible antioxidant cell machinery. We also show in SCD mice that CORM-401 protects against hemolysate-induced acute damage of target organs such as the lung, liver, and kidney through modulation of NF-κB proinflammatory and Nrf2 antioxidant pathways. Our data demonstrate the efficacy of CORM-401 as a novel therapeutic agent to counteract hemolysate-induced organ damage during hyperhemolysis in SCD. This approach might be considered as possible preventive treatment in high-risk situations such as patients with SCD with history of DHTR.

A Case Report of Hyperhemolytic Syndrome in Sickle Cell Disease, with a Special Focus on Avoiding the Use of Transfusions

A Case Report of Hyperhemolytic Syndrome in Sickle Cell Disease, with a Special Focus on Avoiding the Use of Transfusions

Study of the antigenic characteristics of red blood cells units and their sickle cell disease recipients and the G6PD activity of transfused red blood cells units

IntroductionLa transfusion occupe une place centrale au cours de la drépanocytose. La compatibilité des groupes sanguins des concentrés de globules rouges (CGR) avec ceux du patient est essentielle pour prévenir l'allo-immunisation. La concordance des CGR de donneurs d’origine africaine est la meilleure avec les patients drépanocytaires. Cependant, ces CGR peuvent présenter des caractéristiques altérant leur conservation et leur qualité, tel le déficit en glucose-6-phosphate déshydrogénase (G6PD). L'objectif est d'analyser les protocoles transfusionnels, les taux d'immunisation et les situations d’incompatibilité phénotypique au cours de la drépanocytose et d'évaluer la fréquence du déficit en G6PD dans les CGR de donneurs d'ancestralité africaine. MéthodeDes échantillons de CGR transfusés à des patients drépanocytaires ont été analysés. Les données transfusionnelles ont été collectées à partir des bases institutionnelles. L'activité de la G6PD a été mesurée dans un segment de CGR. RésultatsUn total de 98 échantillons de CGR transfusés à 37 patients au cours de 41 épisodes transfusionnels a été analysé. Parmi les patients, 35,1% (n=13) n’étaient pas alloimmunisés, 10,8% (n=4) avaient des anticorps contre Fya/Fyb, Jka/Jkb, M/N, S/s ; 21,6% (n=8) contre les antigènes RH/K. Dans tous les cas, le protocole transfusionnel était conforme aux recommandations. Un déficit en G6PD a été retrouvé pour 9 CGR, provenant tous de donneurs d’ancestralité afro-antillaise. ConclusionLes protocoles transfusionnels sont respectés et diminuent les réactions immunitaires. Les CGR de donneurs d'origine africaine, avec la meilleure phénocompatibilité, présentent un taux élevé de déficit en G6PD. La question de l’impact de ce déficit, quant à leur conservation et leur rendement transfusionnel doit se poser.

Discrepancy in ABO Blood Grouping: A Report of B Subgroup with Cold Alloantibody

The ABO antigens are the most important in both blood transfusion and transplantation as their antibody can cause severe haemolytic transfusion reaction when ABO-incompatible transfusion occurs. It has been claimed that variants of the ABO blood group are very rare, including B subgroups. We reported a young healthy female with B subgroup and underlying cold-reacting alloantibody causing challenges in determining of her ABO blood group. Initial ABO blood grouping was misinterpreted as group O. Presence of alloantibody in her plasma was suspected after revealing positive antibody screening. Repeated blood grouping at 37oC revealed a discrepancy of the forward and reverse grouping, which suggested B subgroup. Cross-matching showed difficulties in finding compatible blood with both group O and B cells due to the presence of clinically significant cold alloantibody. Determining of correct ABO blood group is mandatory in transfusion practices as haemolytic transfusion reaction can be prevented.

A case report on incidentally detected A2B blood group

The two primary subgroup of AB is A1B and A2B. A2B is extremely rare. The differentiation between A1B and A2B is based on the reactivity of A1 cells with anti- A1 lectin. Subgroups can result from inheritance of rare alleles at ABO locus and can cause discrepancy but rarely cause haemolytic transfusion reaction. Most of the subgroups are found incidentally during a pre transfusion testing or pregnancy follow up. Here we report an incidental case of A2B in a 28-year female. The case report highlights the need to be aware of such uncommon and rare blood groups. It also emphasizes on the need to do both forward and reverse grouping routinely.

Evaluating the TaqMan Jra-Genotyping Method for Rapidly Predicting the Presence of Anti-Jra Antibodies.

The Jra antigen is a high-prevalence red blood cell (RBC) antigen. Reports on cases of fatal hemolytic disease of the fetus and newborn and acute hemolytic transfusion reactions suggest that antibodies against Jra (anti-Jra) have potential clinical significance. Identifying anti-Jra is challenging owing to a lack of commercially available antisera. We developed an alternative approach to rapidly predict the presence of anti-Jra using the TaqMan single-nucleotide polymorphism (SNP)-genotyping method. Residual peripheral blood samples from 10 patients suspected of having the anti-Jra were collected. Two samples with confirmed Jr(a-) RBCs and anti-Jra were used to validate the TaqMan genotyping assay by comparing the genotyping results with direct sequencing. The accuracy of the assay in predicting the presence of anti-Jra was verified through crossmatching with in-house Jr(a-) O+ RBCs. The TaqMan-genotyping method was validated with two Jr(a-) RBC- and anti-Jra-confirmed samples that showed concordant Jra genotyping and direct sequencing results. Jra genotyping for the remaining samples and crossmatching the serum samples with inhouse Jr(a-) O+ RBCs showed consistent results. We validated a rapid, simple, accurate, and cost-effective method for predicting the presence of anti-Jra using a TaqMan-based SNP-genotyping assay. Implementing this method in routine practice in clinical laboratories will assist in solving difficult problems regarding alloantibodies to high-prevalence RBC antigens and ultimately aid in providing safe and timely transfusions and proper patient care.

Haemolytic transfusion reactions caused by non-ABO red cell antibodies reported to the Norwegian Haemovigilance System 2004-2020.

The aim of this study was to analyse the reports received in the Norwegian Haemovigilance System from 2004 to 2020 on acute and delayed haemolytic transfusion reactions caused by non-ABO red cell antibodies. Antibody specificity, clinical symptoms and outcomes were included when available. After transfusion of 3.7 million red cell concentrates, reports on 78 cases of haemolytic transfusion reactions caused by non-ABO red cell antibodies were received, corresponding to an incidence of 1 in 47,000 transfused red cell concentrates. There were 30 acute and 48 delayed haemolytic transfusion reactions. A total of 113 red cell antibodies were found: 82 alloantibodies, 6 autoantibodies and 25 cases where the antibody specificity could not be determined. Two fatalities occurred: one caused by anti-Wra and one caused by an unidentified red cell antibody. The most frequently reported antibody specificities were those in the Rh and Kidd blood group systems, representing 24% and 14%, respectively, of all the antibodies identified. In six cases, errors occurred, leading to the issuing of blood units without the required phenotype match. Despite the possible underreporting, the low number of serious haemolytic transfusion reactions reflects an adequate pre-transfusion practice by the Norwegian blood banks.

Characterization of Novel RHD Allele Variants and Their Implications for Routine Blood Group Diagnostics.

The Rh system, including the highly immunogenic D antigen, is one of the clinically most important blood group systems in transfusion medicine. Numerous alleles of the RHD gene are associated with variant RhD phenotypes. In case of Rh incompatibility, some of them can induce hemolytic transfusion reactions and hemolytic disease of the fetus and newborn. Thus, accurate blood group diagnostics are critical for safe transfusion therapy. We characterized phenotypes of four individuals revealing weakened D expression during routine pre-transfusion testing. Standard gel card matrix techniques with monoclonal and polyclonal anti-D antibodies were used for serological typing, complemented using D epitope and antigen density analysis. Genotyping employing PCR with sequence-specific primers, genomic and allele-specific Sanger sequencing and in silico protein analysis were performed. Four novel RHD alleles associated with weak D or partial D phenotypes were identified. One of the mutations is predicted to disrupt the terminal stop codon and result in an elongated translation of the mutant D protein that phenotypically exhibits a loss of D epitopes. Furthermore, a hybrid gene formed with the homologue RHCE gene is described. The presented data enhances the understanding of the Rh system and may contribute to continued advances in blood group diagnostics.

Phenotyping of Rh and Kell blood group antigen in thalassemia and its impact on alloimmunization in a tertiary care hospital

Objectives: Alloimmunization to red cell antigens is a dreaded complication in multitransfused patients, leading to difficulty in obtaining compatible red blood cell units and development of delayed hemolytic transfusion reactions. The objective of this study was to assess the impact of partial matched phenotype blood (for RhD, C, c, E, e, and Kell antigens) on alloimmunization in thalassemics versus non-phenotype matched blood (ABO & RhD). Materials and Methods: This cross-sectional study was conducted over a period of two years where 250 patients with thalassemias were enrolled. They were divided into two groups, patients in Group I (n = 180) who received partial matched phenotype blood since initiation of transfusion therapy and those in Group II (n = 70) subjects who received usual matched blood. Statistical analysis: All statistical calculations were done using statistical package for the social sciences (SPSS) 21 version. Data were described in terms of range, median (interquartile range [IQR]), frequencies, etc. Results: The median (IQR) age of the study population was 12 (7–18) years (range 6 months–36 years). The most common Rh antibodies were anti-D (2.85%), anti-E (2.85%), anti-C (1.42%), and anti-c (1.42%), and Kell antibodies were (7.1%). It was seen that chances of developing autoantibodies (37% vs. 5%), alloantibodies 11 (15.7% vs. 0%), and transfusion reactions 25 (35.7% vs. 3.3%) were more in Group II subjects as compared to Group I. A significant difference was seen with febrile non-hemolytic transfusion reactions in between two groups 0.001 (95% confidence interval 2.98–65.73). Conclusions: Patients with thalassemia should be typed for RhD (C, c, E, and e) and Kell antigen before initiation of transfusion, which will help in reducing the rate of alloimmunization, autoimmunization, and frequency of transfusion and will improve the overall survival rate in thalassemia.

Comparative analysis of alloimmunization in healthy voluntary blood donors versus general patients: A 6-year experience from regional transfusion center in Northwestern part of India

Abstract BACKGROUND: Alloimmunization is a significant complication of blood transfusion and can lead to hemolytic transfusion reactions. The prevalence of alloimmunization in healthy voluntary blood donors and patients in the northwestern part of India is not well documented. AIM AND OBJECTIVE: This study aims to investigate the prevalence, specificity, and clinical significance of antibodies in blood donors and general patients in a regional transfusion centre in the North Western part of India. MATERIAL AND METHODS: This study aimed to investigate the prevalence of alloimmunization in voluntary blood donors and patients over a six-year period in a regional transfusion center. A total of 145,299 donor samples and 58,009 patient samples were screened for unexpected antibodies using standard techniques. RESULTS: Of the 145,299 donor samples screened, only 16 (0.011%) were positive for unexpected antibodies, with anti-M being the most common (62.5%). In contrast, among the 58,009 patients screened, 275 (0.47%) were found to be positive for alloantibodies, with blood group B showing the highest prevalence. The most common alloantibodies found in patients were anti-D, anti-E, anti-c, and anti-K in the Rh and Kell blood group systems. CONCLUSION: The incidence of alloimmunization in voluntary blood donors is low and comparable to other regions, which can be attributed to strict donor selection criteria and pre-donation screening practices. However, the incidence of alloimmunization in patients is higher, highlighting the need for routine screening for unexpected antibodies in patients to prevent hemolytic transfusion reactions. Further studies are needed to explore the underlying factors contributing to the higher incidence of alloimmunization in patients.