Frequency of Red Cell Alloimmunization and Autoimmunization in Thalassemia Patients: A Report from Eastern India

Current challenges of blood transfusions in patients with thalassemia in India and future perspectives

The introduction of regular red blood cell transfusions transformed thalassemia major from a fatal childhood disease into a chronic disorder. Thalassemia is highly prevalent in South Asia, including the Indian subcontinent, and blood transfusion remains the cornerstone of management for these patients. But safe blood transfusions still remain a major problem in India. Difficulties in maintaining adequate blood inventory, a lack of a national blood act, and fragmented blood transfusion services are some of the major contributing factors for the delay in blood supply. In most of the blood centers, alloantibody detection facilities and extended red cell antigen typing are unavailable. Awareness is the key to reducing alloimmunization, which limits the effectiveness of transfusions and the potential availability of blood. Patients with thalassemia are also at high risk of transfusion-transmitted infections unless appropriate blood screening is in place. Hence, many patients remain under-transfused, resulting in decreased health and quality-of-life outcomes. Facilities such as leucoreduction and immunohematological monitoring following a blood transfusion are often lacking in India, especially at the sub-district level. Continuous efforts to raise community awareness, regular training of health-care workers, and proper utilization of available resources are essential to ensuring safe blood transfusions for patients with thalassemia. Access to the new treatments at an affordable cost may reduce the blood transfusion burden for thalassemia patients in India.

Challenging the dogma: Red blood cell-directed autoimmunity as risk factor for red blood cell alloimmunisation after blood transfusion

Red blood cell autoimmunity and alloimmunity are potentially linked. Quantification of this association can tailor extensively matched red blood cell transfusions in patients with autoimmunity. Using an incident new-user cohort comprising 47 285 previously non-transfused, non-alloimmunised patients, we compared transfusion-induced red blood cell alloimmunisation incidences in direct antiglobulin test (DAT)-positive and control patients. Additionally, we performed case-control analyses to handle potential confounding by clinical immunomodulators. Among (IgG and/or C3d) DAT-positive patients (N = 380), cumulative red blood cell alloimmunisation incidences after 10 units transfused reached 4.5% (95% confidence interval [CI] 2.5-8.2) versus 4.2% (CI 3.9-4.5, p = 0.88) in controls. In case-control analyses, alloimmunisation relative risks among DAT-positive patients increased to 1.7 (CI 1.1-2.8). Additional adjustments for pre-DAT transfusion exposure or the extent of Rh/K mismatching did not impact results. In conclusion, while patients with DAT positivity show an intrinsically increased alloimmune red blood cell response, their absolute risk is comparable to control patients due to counteracting co-existing immunosuppressive conditions. Consequently, isolated DAT positivity in patients lacking overt haemolysis or complicated alloantibody testing does not seem to warrant extended matching strategies.

Red cell alloimmunization and associated risk factors in multiply transfused thalassemia patients: A prospective cohort study conducted at a tertiary care center in Northern India

BACKGROUND

One of the complications of chronic transfusions in thalassemia is the development of red cell alloimmunization.

AIMS

The aim of the study was to determine the frequency, specificity of red cell alloantibodies, and factors influencing alloimmunization in multiply transfused thalassemia patients.

MATERIALS AND METHODS

The study was carried out prospectively on beta-thalassemia patients over 10 months. Plasma samples were used for antibody screening and identification using the column agglutination technique. Patients' clinical, laboratory, and transfusion details were obtained from hospital information system and patient files.

STATISTICAL ANALYSIS

Continuous variables were reported as median and quartile, whereas categorical variables were provided as numbers and proportions. P < 0.05 was considered statistically significant.

RESULTS

Out of 255 patients, 17 (6.6%) patients developed alloantibodies. Alloimmunized patients had significantly higher median ages at their first transfusions (1 year vs. 0.5 years; P = 0.042) than nonalloimmunized patients. Alloimmunized patients had significantly higher conjugated bilirubin (P = 0.016) and serum ferritin (P = 0.007). The majority of alloantibodies had specificity toward K antigen, followed by E, C, D, JKa, and JKb antigens. Alloimmunized patients received more units per year than nonalloimmunized patients (median, 30 vs. 24 units; P < 0.001). The average transfusion interval time between two successive transfusions showed a significant difference (P < 0.001).

CONCLUSIONS

The prevalence of alloimmunization in thalassemia patients in North India is relatively low. Since most of the alloantibodies belong to Rh and Kell blood group system, extended phenotype-matched blood for Rh and Kell will be helpful in further preventing or decreasing the development of alloantibodies in multiply transfused thalassemia patients.

Role of Hemin in the Immune Response of T Follicular Helper Lymphocytes Expressing T-Cell Immunoreceptor with Immunoglobulin and Immunoreceptor Tyrosine-Based Inhibitory Domains, Programmed Cell Death-1, and Interleukin-21 in Allo-Auto Positive and Negative Thalassemia

Introduction

Repeated transfusions in thalassemia patients can cause several complications, including alloimmunization and autoimmunization.

Purpose

This study compares the immune response of T follicular helper (Tfh) lymphocytes expressing T-cell immunoreceptor with immunoglobulin and immunoreceptor tyrosine-based inhibitory domains (TIGIT), programmed cell death-1 (PD-1), and interleukin-21 (IL-21) between patients with allo-auto positive and negative thalassemia before and after hemin administration.

Materials and Methods

This study used a quasi-experimental pre- and post-test design and was performed between April and November 2021 at the Dr. Soetomo General Academic Hospital in Surabaya, Indonesia. It enrolled 29 patients with allo-auto positive thalassemia and 28 with allo-auto negative, and 9 mL of whole blood (WB) was drawn from each patient. Hemin solution (20 µM) was added to 5 mL of WB, incubated for two hours, processed into peripheral blood mononuclear cells (PBMCs) in RPMI media, and cultured with 5% CO₂ for three days. The 4 mL WB sample was also processed into PBMCs. PBMC cells cultured and without cultured were examined by flow cytometry using a BD FACSCalibur after surface and intracellular staining. Differences in Tfh cells expressing TIGIT, PD-1, and IL-21 between thalassemia groups before and after hemin administration were compared using independent t-tests or Mann-Whitney U-tests (p < 0.05).

Results

Tfh cell expression did not differ between groups before hemin administration and increased after hemin administration. The increase in Tfh cell expression was higher in the allo-auto positive group. TIGIT and PD-1 expression in Tfh cells did not differ between groups, but TIGIT decreased after hemin administration in contrast to PD-1 result. IL-21 expression in Tfh cells did not differ between groups and did not change after hemin administration.

Conclusion

Hemin affected the expression of Tfh cells in both group thalassemia, but there was no difference of Tfh cell expression between the groups.

Frequency of Kell and Rh alloantibodies in Iranian Thalassemia Patients in Khorasan Razavi Province, Iran

Background: Thalassemia is an inherited disease with anemia and hemolysis. Blood transfusion is a routine treatment for thalassemia patients; alloimmunization is one of the complications of blood transfusion, which is very serious for these patients, especially girls and young women. Materials and Methods: In this cross-sectional study, 446 thalassemia patients were examined. Demographic information of patients was extracted and recorded. The phenotype of ABO, Rh, and Kell antigens (tube method) with antisera from IMMUNDIANOSTICA Company (Germany) and the frequency of alloantibodies were determined. Results: 55.8% of the studied individuals were male, and 44.2% were female. Mean age of the studied patients was 19.94±10.63. The alloantibodies were detected in 7.5% of cell-pack receivers. The most prevalent phenotype of the ABO system was the O blood group (37.4%), and the most abundant antigen of the Rh group was 'e', which was found in 99.8% of the studied population. The most common alloantibody detected was Anti K (38.2%); concerning kell phenotype, (K_k+) and (K+k+) were found in 99.3% and 0.7% of patients, respectively. The frequency of Anti-D, Anti-C, Anti-c, and Anti-E was 23.5%, 14.7%, 2.9%, and 14.7%, respectively. Conclusion: According to the results of this paper, finding the compatible packed cells in terms of Kell and Rh systems antigens in addition to the ABO blood group is recommended to decrease the rate of alloantibodies in thalassemia patients.

Red Blood Cell Alloimmunization in Pediatric group with Beta Thalassemia: A Five-Year Experience

Beta-thalassemia is one of the most frequently occurring hematological disorders in [Removed for blinded peer-review]. Regular blood transfusion is required in almost all cases for management. However, this is associated with significant major complications like red blood cell (RBC) alloimmunization. This retrospective cross-sectional is conducted to evaluate the RBC alloimmunization frequency in children with beta-thalassemia aged between 6 months and 16 years in [Removed for blinded peer-review]. Antibody screening was performed using the Dia clon3 cell antigen panel. If the screening came back positive, a detailed panel was created for the identification of specific antibody. In our sample, the frequency of RBC alloimmunization was found in 22 (26.19%) patients. Of these 22 patients, the Rhesus system was found in most patients 17 (77.3%), followed by Kell 5 (22.7%). RBC alloimmunization was significantly associated with a family history of a blood disorder and splenectomy.

Red blood cell alloimmunization among recipients of blood transfusion in India: A systematic review and meta-analysis

BACKGROUND AND OBJECTIVES

There is a varied prevalence of red cell alloimmunization being reported from different parts of India. This study aimed to estimate the overall prevalence of alloimmunization in India by performing a systematic review of the literature and to establish the most suitable antigen-matching strategy to reduce the red blood cell (RBC) alloimmunization rate among transfusion recipients.

MATERIALS AND METHODS

A systematic search of all the original articles published in English on RBC alloimmunization among transfusion recipients from India in MEDLINE, SCOPUS, CINAHL and Google Scholar bibliographic databases was conducted. After screening the articles as per inclusion/exclusion criteria, data extraction was done independently by two sets of investigators. Meta-analysis was performed by the binary random-effects model using the restricted maximum likelihood method.

RESULTS

A total of 44 studies on RBC alloimmunization, with a cumulative sample size of 309,986 patients, were grouped into hospital-based and multiply-transfused patients, which yielded a prevalence of 0.5 (95% confidence interval; 0.3-0.8) and 4.8 (95% confidence interval; 3.9-5.7) per 100 patients, respectively. As many as 1992 alloantibodies were identified among the 1846 alloimmunized patients. The most common antibody identified was anti-E (127; 31.99%), followed by anti-c (75; 18.89%) in multiply-transfused patients.

CONCLUSION

The rate of alloimmunization was 0.5 per 100 patients tested for antibodies and 4.8 per 100 patients receiving transfusion. Considering E- and c-antigen-matched red cells along with ABO and RhD matching may significantly reduce the overall occurrence of alloimmunization among Indian population who are transfusion-dependent.

Post-Hematopoietic Stem Cell Transplantation Immune-Mediated Anemia: A Literature Review and Novel Therapeutics

Anemia after allogeneic hematopoietic stem cell transplantation (HSCT) can be immune or non–immune mediated. Auto- or alloimmunity resulting from blood group incompatibility remains an important cause in post-HSCT immune-mediated anemia. ABO incompatibility is commonly encountered in HSCT and may lead to serious clinical complications, including acute hemolysis, pure red cell aplasia, and passenger lymphocyte syndrome. It remains controversial whether ABO incompatibility may affect HSCT outcomes, such as relapse, nonrelapse mortality, graft-versus-host disease, and survival. Non-ABO incompatibility is less frequently encountered but can have similar complications to ABO incompatibility, causing adverse clinical outcomes. It is crucial to identify the driving etiology of post-HSCT anemia in order to prevent and treat this condition. This requires a comprehensive understanding of the mechanism of anemia in blood group–incompatible HSCT and the temporal association between HSCT and anemia. In this review, we summarize the literature on post-HSCT immune-mediated anemia with a focus on ABO and non-ABO blood group incompatibility, describe the underlying mechanism of anemia, and outline preventive and treatment approaches.

Red Blood Cell Alloimmunization Rates and Related Factors of Patients with Thalassemia in Shiraz, Iran

OBJECTIVE

The development of antibodies against red blood cell (RBC) antigens is one of the most significant adverse effects of chronic blood transfusions. This study aimed to estimate the frequency and causes of RBC immunization in patients with major thalassemia.

METHODS

The findings could help determine the limitation of current practices and help future developments in the selection of suitable blood units for the transfusion support of patients with thalassemia.

RESULTS

The alloimmunization rate was detected in 52 of 650 patients with major thalassemia (8%). The most frequent antibodies were against K (50%), D (26%), and E (15.4%). Sex, age, and splenectomy did not have any impact on the immunization rate. Immunization was lower in patients who had received only leuko-reduced blood units.

CONCLUSION

It is recommended that antibody screening before the first transfusion and extended RBC matching particularly for the most frequent antigens (ABO/Rh/Kell) should be performed for patients with thalassemia.

Autoimmune Hemolytic Anemia as a Complication of Congenital Anemias. A Case Series and Review of the Literature

Congenital anemias may be complicated by immune-mediated hemolytic crisis. Alloantibodies are usually seen in chronically transfused patients, and autoantibodies have also been described, although they are rarely associated with overt autoimmune hemolytic anemia (AIHA), a serious and potentially life-threatening complication. Given the lack of data on the AIHA diagnosis and management in congenital anemias, we retrospectively evaluated all clinically relevant AIHA cases occurring at a referral center for AIHA, hemoglobinopathies, and chronic hemolytic anemias, focusing on clinical management and outcome. In our cohort, AIHA had a prevalence of 1% (14/1410 patients). The majority were warm AIHA. Possible triggers were recent transfusion, infection, pregnancy, and surgery. All the patients received steroid therapy as the first line, and about 25% required further treatment, including rituximab, azathioprine, intravenous immunoglobulins, and cyclophosphamide. Transfusion support was required in 57% of the patients with non-transfusion-dependent anemia, and recombinant human erythropoietin was safely administered in one third of the patients. AIHA in congenital anemias may be challenging both from a diagnostic and a therapeutic point of view. A proper evaluation of hemolytic markers, bone marrow compensation, and assessment of the direct antiglobulin test is mandatory.

Distribution of antenatal alloimmunization in the southern districts of West Bengal and its significant associated factor

OBJECTIVES:

Detection of maternal irregular antibodies against red blood cell antigen is vital in the management of hemolytic disease of fetus and newborn. There are no uniform guidelines related to antenatal antibody screening and identification in the developing Country like India. This study was aimed to identify such alloimmunization and its associations.

MATERIALS AND METHODS:

This prospective study was conducted on antenatal mothers at a tertiary care center. The mothers having a history of anti-D administration, blood transfusion, and autoimmune disorders were excluded from the study. Initial indirect antiglobulin test (IAT) was performed in all blood samples by conventional tube technique (CTT) to identify alloimmunization. IAT-positive samples were screened for irregular antibody by column agglutination technology (CAT). Antibody screen-positive samples were further analyzed in 11-cell panel by CAT. Antibody strength was measured by serial double dilution by CTT. The source of isoimmunization was identified by extended Rh phenotype of women, husband, and newborn.

RESULTS:

A total of 12 (2.3%) women out of 530 were positive for IAT and antibody screen. Antibody could be identified in 11 women, of which anti-D (5) was the most common, followed by anti-C + anti-D (4), anti-C + anti-E (1), and anti-C (1). All four cases of anti-D + anti-C were distinguished from anti-G by differential adsorption and elution. There was a significant association with alloimmunization versus increased gravid status, antepartum hemorrhage, and past history of newborns with neonatal jaundice.

CONCLUSION:

All pregnant women with history of antepartum haemorrhage, newborn with neonatal jundice should be screened for alloantibody for early detection and better management of HDFN.

Red blood cell exchange in sickle cell disease patient with multiple alloantibodies

There are several reports in medical literature about Red Cell Exchange (RCE) being routinely performed pre-operatively in sickle cell disease patients to provide immediate decrease in HbS concentration and prevent post-operative complications. We would like to present one such case of SCD who also had multiple allo-antibodies and had to undergo hemi-arthroplasty for avascular necrosis of head femur. Grouping and antibody screening was performed using column agglutination technique. 3-cell and 11- cell panel were used for antibody screening and identification, respectively. Automated RBC exchange was performed on apheresis machine Com. Tec using the standard PL1 kit (Fresenius Kabi, Germany). Multiple (anti-c, E) allo-antibodies were identified and successful pre-operative RCE was done with corresponding antigen-negative AHG compatible RBC units. Single RCE procedure reduced HbS concentration from 65% to 25%. The patient underwent uneventful hemi-arthroplasty and was discharged on post-operative day-7. Patient is on regular follow-up and continues to do well two months after the day of surgery. This is possibly the first case report from India, which illustrates successful automated RCE in a SCD patient with alloimmunization.

Analysis of red cell alloimmunization in multi transfused patients at a Tertiary care teaching hospital

Background:

Red blood cell (RBC) alloimmunization is an immune response against foreign RBC antigens; this generally occurs after sensitization due to multiple blood transfusions and pregnancies. Antibody detection plays a critical role in transfusion medicine as it can detect irregular or unexpected antibodies. This study was done to know the frequency and specificity of unexpected red cell antibodies in the multitransfused patients.

Materials and Methods:

This prospective study was done in the Department of Immuno-Haematology and Blood Transfusion. Antibody screening of 100 multitransfused patients with initial negative antibody screen was carried out prior to compatibility testing and followed for a period of 12 months for each transfusion. Depending on the results, patients were given corresponding antigen-negative blood units.

Results:

In this study, the rate of alloimmunization was 7%. Total number of samples that were positive for irregular alloantibodies were 4 of 54 cases of thalassemia, that is, 7.4%, whereas 3 of 40, that is, 7.5%, cases of solid malignancies developed alloantibodies. None of the patients of chronic kidney disease formed any alloantibody. Anti-K antibody was the most frequent antibody detected in 3 of 7, that is, 42.8% patients. Anti-E was the second most frequent antibody observed in 2 of 7, that is, 28.57%. However, anti-c and anti-M were detected in one each of 7, that is, in 14.28% each.

Conclusion:

It is concluded here that red cell alloimmunization should not be overlooked in multitransfused patients. To avoid the effects of alloimmunization, routine RBC antibody screening at set time intervals after transfusion should be performed.

Comparative study of alloimmunization against red cell antigens in sickle cell disease & thalassaemia major patients on regular red cell transfusion

Background & objectives:

Sickle cell disease (SCD) patients require red cell transfusion during different clinical complications of the disease. Such patients are at a high risk for developing alloantibody against red cell antigens. From India, there are limited data available on alloantibody formation in multiply transfused SCD patients. The present study was thus undertaken to fill up this lacunae by looking at the development of red cell alloantibodies in SCD and β-thalassaemia patients on regular transfusion.

Methods:

All sickle cell disease patients undergoing red cell transfusion between 2008 and 2016, were included. During this period, a large number of β-thalassaemia major patients also underwent regular red cell transfusion. These thalassaemia patients were also included to compare the tendency of antibody formation between SCD and β-thalassaemia major patients. All patients before regular transfusion were regularly assessed for the development of red cell antibody. Red cell antigen, antibody screen crossmatch and antibody identification were done using the standard technique.

Results:

A total of 138 patients with SCD aged between 4 and 53 yr (mean 17.6 yr) consisting of 83 males and 55 females (male:female, 1.5:1) along with 333 transfusion-dependent β-thalassaemia patients were studied. Over the last eight years, 15 patients with SCD and four patients with thalassaemia developed alloantibody (P<0.001). Antibody specificity of their alloantibodies was against Rhc, RhE, Kell, Fy^a and Fy^b only. Sickle cell disease patients with and without alloantibody required on the average 11.8 and 8.6 units of red cell concentrate, respectively (P<0.05).

Interpretation & conclusions:

About 11 per cent of the transfused sickle cells patients developed alloantibodies. The antibody specificity was restricted to Rh, Kell and Duffy blood group systems. Extended antigen matching involving Rh, Kell and Duffy antigens may prevent alloantibody in such patients.

Molecular genotyping of clinically important blood group antigens in patients with thalassaemia

Background & objectives:

In multitransfused thalassaemic patients, haemagglutination fails to phenotype the patient's blood group antigens due to the presence of donor-derived erythrocytes. DNA-based methods can overcome the limitations of haemagglutination and can be used to determine the correct antigen profile of these patients. This will facilitate the procurement of antigen-matched blood for transfusion to multitransfused patients. Thus, the aim of this study was to compare the serological phenotyping of common and clinically important antigens of Rh, Duffy, Kell, Kidd and MNS blood group systems with molecular genotyping amongst multitransfused thalassaemic patients.

Methods:

Blood samples from 200 patients with thalassaemia and 100 ‘O’ group regular blood donors were tested using standard serological techniques and polymerase chain reaction-based methods for common antigens/alleles (C, c, D, E, e, Fy^a, Fy^b, Jk^a, Jk^b, K, k, M, N, S, s).

Results:

Genotyping and phenotyping results were discordant in 77 per cent of thalassaemic patients for five pairs of antithetical antigens of Rh, Duffy, Kell and Kidd blood group systems. In the MNS blood group system, 59.1 per cent of patients showed discrepancy. The rate of alloimmunization among thalassaemics was 7.5 per cent.

Interpretation & conclusions:

Molecular genotyping enabled the determination of the actual antigen profile in multitransfused thalassaemia patients. This would help reduce the problem of alloimmunization in such patients and would also aid in the better management of transfusion therapy.

Red blood cell alloimmunizations in beta-thalassemia patients in Casablanca/Morocco: Prevalence and risk factors

Red blood cell alloimmunization is one of the major challenges to regular transfusions in β-thalassemic patients. In Morocco, rare studies have focused on this hemoglobinopathy.

OBJECTIVE

We aimed to study the prevalence and risk factors of red cell alloimmunization in β-thalassemic patients.

PATIENTS AND METHODS

Retrospective study during 9 years (2009-2018) was conducted on 160 β-thalassemic patients transfused regularly in pediatric department of children's hospital in Casablanca, Morocco. The main clinical, demographic and transfusional characteristics of alloimmunized and non-alloimmunized patients were compared. Red blood cells units transfused were leukodeplated and phenotypically matched for RH-KELL systems and for other systems after immunization. Screening and antibody identification were performed by gel-filtration method on BIO-RAD caseds using 3 and 11 red blood cells panels. To detect autoantibodies, autocontrol and direct antiglobulin tests were carried out using polyspecific coombs (IgG/C3d) gel cards.

RESULTS

The prevalence of alloimmunizations was 8.75% during the study period. Seventeen alloantibodies identified were directed mainly against antigens of KELL and RH systems: KEL 1 (35.29%), RH 3 (23.52%), RH1 (11.76%), Kpa (11.76%), RH2 (5.88%). Red blood cells autoantibodies had been detected in 6 of 14 (42.85%) of alloimmunized patients versus 12 of 146 (11.76%) of non-alloimmunized patients (P<0.01). Presence of autoantibodies, transfusional interval<3weeks and gender were associated with high rate of red cells alloimmunization.

CONCLUSION

This study proves the data of literature. The presence of red cell autoantibodies appears to be a major risk factors for alloimmunization in thalassemic children, and could advocate specific transfusion guidelines.

Red blood cell alloimmunisation in transfusion-dependent thalassaemia: a systematic review

BACKGROUND

Chronic red blood cell transfusion is the first-line treatment for severe forms of thalassaemia. This therapy is, however, hampered by a number of adverse effects, including red blood cell alloimmunisation. The aim of this systematic review was to collect the current literature data on erythrocyte alloimmunisation.

MATERIALS AND METHODS

We performed a systematic search of the literature which identified 41 cohort studies involving 9,256 patients.

RESULTS

The prevalence of erythrocyte alloimmunisation was 11.4% (95% CI: 9.3-13.9%) with a higher rate of alloimmunisation against antigens of the Rh (52.4%) and Kell (25.6%) systems. Overall, alloantibodies against antigens belonging to the Rh and Kell systems accounted for 78% of the cases. A higher prevalence of red blood cell alloimmunisation was found in patients with thalassaemia intermedia compared to that among patients with thalassaemia major (15.5 vs 12.8%).

DISCUSSION

Matching transfusion-dependent thalassaemia patients and red blood cell units for Rh and Kell antigens should be able to reduce the risk of red blood cell alloimmunisation by about 80%.

Regional gender differences in an autosomal disease result in corresponding diversity differences

Regional gender differences in autosomal chromosome disorders have been observed repeatedly. However, the corresponding diversity changes remain unconfirmed. By analyzing previously published thalassemia data from the Dai people in Dehong and Xishuangbanna (two regions in Yunnan Province, China), we found that several sequence types, including HBA CNV and HBB mutations, significantly depend on gender in Xishuangbanna but not in Dehong. With the supportive evidence from previous researches, we accept that some certain mutations depend on gender regionally. This association seems peculiar. It is among one common people on a small geographical scale, while other recorded thalassemia gender difference varies by ethnics and continent.

Red Blood Cell Alloimmunization in Multitransfused Pediatric Population in a Tertiary Care Hospital

OBJECTIVES

To estimate the prevalence and specificity pattern of red blood cell (RBC) alloimmunization among pediatric multitransfused patients, and to identify the factors associated with alloimmunization.

METHODS

This was a descriptive cross-sectional study conducted among mutitransfused pediatric patients over a period of two years. The relevant clinical details of patients were collected, and RBC antibody screening was done. Samples with positive antibody screen were subjected to antibody identification. Patient factors were analysed to find any significant relation to the development of RBC alloimmunization.

RESULTS

Alloantibodies were obtained in 4 (6.35%) of the total 63 patients, and autoantibody in 1 (1.59%). The specificities of alloantibodies identified were all against Rh antigens-one each of anti E, anti c, anti Cw and anti D + anti C. A significant association was seen between development of alloimmunization and first transfusion at more than 2 y of age.

CONCLUSIONS

RBC alloimmunization against Rhesus (Rh) antigens is a significant problem for multitransfused children in our population. Extended RBC phenotyping at least for antigens of the Rh system and provision of antigen matched RBCs may be an option for such children, where ongoing transfusion requirement is anticipated.

ABO, Rhesus, and Kell Antigens, Alleles, and Haplotypes in West Bengal, India

Background

Few studies have documented the blood group antigens in the population of eastern India. Frequencies of some common alleles and haplotypes were unknown. We describe phenotype, allele, and haplotype frequencies in the state of West Bengal, India.

Methods

We tested 1,528 blood donors at the Medical College Hospital, Kolkata. The common antigens of the ABO, Rhesus, and Kell blood group systems were determined by standard serologic methods in tubes. Allele and haplotype frequencies were calculated with an iterative method that yielded maximum-likelihood estimates under the assumption of a Hardy-Weinberg equilibrium.

Results

The prevalence of ABO antigens were B (34%), O (32%), A (25%), and AB (9%) with ABO allele frequencies for O = 0.567, A = 0.189, and B = 0.244. The D antigen (RH1) was observed in 96.6% of the blood donors with RH haplotype frequencies, such as for CDe = 0.688809, cde = 0.16983 and CdE = 0.000654. The K antigen (K1) was observed in 12 donors (0.79%) with KEL allele frequencies for K = 0.004 and k = 0.996. Conclusions: For the Bengali population living in the south of West Bengal, we established the frequencies of the major clinically relevant antigens in the ABO, Rhesus, and Kell blood group systems and derived estimates for the underlying ABO and KEL alleles and RH haplotypes. Such blood donor screening will improve the availability of compatible red cell units for transfusion. Our approach using widely available routine methods can readily be applied in other regions, where the sufficient supply of blood typed for the Rh and K antigens is lacking.

An approach to incompatible cross-matched red cells: Our experience in a major regional blood transfusion center at Kolkata, Eastern India

INTRODUCTION

With the increased utilization of immunohematology (IH) analyzers in the transfusion medicine, type, and screen policy is the method of choice. Still, the importance of routine crossmatching could not be overruled. Here, we tried to understand the clinical conditions and safety of red cell transfusion and their outcomes.

MATERIALS AND METHODS

This prospective study was conducted by IH laboratory, Medical College Kolkata, Blood Bank from October 1, 2015 to March 31, 2016. A set of 3cc ethylenediaminetetraacetic acid and clotted blood samples of the patients were received according to sample acceptance criteria. Blood grouping by conventional tube technique followed by crossmatching was performed by column agglutination technology (CAT) in polyspecific (IgG + C3d) gel media. Any positive result was rechecked in duplicate with additional two group-specific donor units. The persistent incompatibility was further evaluated using direct anti-human globulin test, auto control, antibody screening, and antibody identification by CAT.

RESULTS

On the evaluation of 14,387 sets of patients' sample, only 100 were found to be incompatible (0.69%). Incompatibility rate is higher in females (59%). Eighty-five of these patients were repeatedly transfused. Only 38% of incompatible crossmatch were positive on indirect anti-human globulin test/antibody screening. Antibody could be identified in 16 of them. Seventeen of 100 incompatible samples (17%) presented with panagglutination, were managed with Rh, Kell phenotype/best-matched red cell units. In these 16 patients, 23 alloantibodies were identified; allo anti-E was the most common.

CONCLUSION

This study showed antibody against the Rh system as the most common cause of incompatibility.

Thalassemia Major: Transplantation or Transfusion and Chelation

Thalassemia is the most common monogenic hematologic disease that affects millions in the world and kills thousands of patients every year. Without transfusion or transplantation, patients with thalassemia major are expected to die within months of diagnosis. However, long-term transfusion and chelation therapy is highly challenging for many developing countries where the disease is prevalent, representing a major and unsustainable health burden. Stem cell transplantation is the only cure for thalassemia. It has witnessed major developments that have made it less toxic, more successful, and feasible for a larger number of patients with diverse comorbidities and from a wider range of donors. Advances in human leukocyte antigen typing have greatly refined alternate donor selection with results of matched unrelated donors similar to matched sibling donors. Novel strategies such as haploidentical and cord blood transplantation have increased the possibility of patients with no healthy donor to get a better opportunity to survive and avoid chronic transfusion complications. Cost-effectively, transplantation should be considered the primary treatment of choice in the presence of a suitable related or unrelated donor and at centers with a satisfactory experience in the field of transplantation and particularly, in managing those with thalassemia. Despite some complications such as graft-versus-host disease and late conditioning effects, the overall improvement in the quality of life of thalassemia is difficult to deny. Unfortunately, the number of transplants for thalassemia represents only a minority of all transplants conducted globally and the essential requirement for transplants for thalassemia in limited-resources countries should mandate the transplant societies, including Worldwide Network for Blood and Marrow Transplantation, to collaborate to help initiate and support specialized transfusion and transplant programs for managing thalassemia.