Detection of alloimmunization to ensure safer transfusion practice

Red blood cell alloimmunization in blood transfusion-dependent β thalassemia major patients in Sana'a City-Yemen

The development of erythrocyte alloantibodies complicates transfusion therapy in β thalassemia major patients. These antibodies increase the need for blood and intensify transfusion complications. Data on erythrocyte alloimmunization is scarce in Yemeni thalassemia patients. We studied the frequency of alloimmunization in multitransfused β-thalassemia major patients and investigated risk factors that affect antibody formation. Blood samples were taken from 100 β thalassemia major patients who received multitransfused leukodepleted packed red-blood cells. Antibody screening and identification were performed by indirect antiglobulin test using the gel column technique. All patients were tested for autoantibodies using autocontrol and direct antiglobulin test. No adsorption test was done as no autoantibodies were detected in any patient. In our study of 100 β-thalassemia patients, 50 were male and 50 were female with ages ranging from 1 to 30 years. Alloantibodies were present in 6% of patients, while no autoantibodies were detected. Of the 17 alloantibodies identified, the majority were directed against Kell (41.2%) and Rh (29.4%) blood groups. Alloimmunization was significantly associated with age group and sex (p = 0.013, p = 0.030), respectively in β thalassemia major patients. The development of alloantibodies was not significantly associated with duration, total number of transfusions and splenectomy (P = 0.445, P = 0.125, P = 0.647). No autoantibodies found in patients with β thalassemia major. The study found low rates of erythrocyte alloimmunization in multitransfused β-thalassemia major patients, but significant alloantibodies were produced primarily from Kell and Rh blood groups, suggesting the need for providing phenotypically matched cells for selective antigens to improve transfusion efficiency.

Prevalence of blood group antigens among regular blood donors: A single center study from South India with a review of national literature

BACKGROUND AND OBJECTIVES

The antigen frequencies vary across different regions and ethnic groups. Hence, we aimed to study the prevalence of blood group antigens in our population and to systemize the zone-wise prevalence of the same across India.

MATERIALS AND METHODS

Regular voluntary O group blood donors were screened for 21 blood group antigens; C, c, E, e, K, k, Kpa, Kpb, Jka, Jkb, Fya, Fyb, Lea, Leb, Lua, Lub, P1, M, N, S, s, using commercially available monoclonal antisera by column agglutination technology. A literature search was performed to identify all the studies that reported blood group antigens prevalence to estimate the zone-wise prevalence of these antigens in the country.

RESULTS

A total of 521 participants of 9248 O group donors meeting all the inclusion criteria were included. Among the study group, the male-to-female ratio was 9:1 with a mean age of 32.6 years (±10.01) ranging from 18-60 years. The majority of the donors 446 (85.6%) were D positive. The most common phenotypes among Rh, Lewis, Kell, Duffy, Kidd, Lutheran and MNSs were CcDee (34.93%), Le(a-b+) (61.80%), K-k+(98.27%), Fy(a+b-) 43.19%, Jk(a+b+) 42.61%, Lu(a-b+) ( 99.61%), M+N+ (48.17%), S-s+ (45.29%) respectively. The prevalence of D and E antigens was significantly lower in the South zone compared to other zones of India.

CONCLUSION

Significant difference in the prevalence of blood group antigens is observed between the South and other zones of India. Zone-wise prevalence of blood group phenotypes is essential in the timely management of alloimmunized patients.

Major histocompatibility complex (MHC) antigens polymorphism and alloimmunization study in thalassemia patients with febrile non-hemolytic transfusion reaction (FNHTR)

OBJECTIVES

HLA alloimmunization is one of the most troublesome consequence of regular transfusion which is itself a mainstay measure to provide longevity to the thalassemia patients. Febrile non-hemolytic transfusion reaction (FNHTR) is one of the most common complication which might be related to the HLA alloimmunization. Here, we studied the HLA antigenic system and alloimmunization rate in the Iranian β-thalassemia patients who suffered from FNHTR compare to the β-thalassemia patients without FNHTR.

MATERIALS & METHODS

Total of 60 β-thalassemia patients with FNHTR (case group) and 20 β-thalassemia patients without FNHTR (control group) randomly have been selected and enrolled in the study. All were tested for HLA-A and -B loci by PCR-SSP method and also for the presence of anti-lymphocyte antibodies by LIFT method. Comparisons between two groups were performed by Pearson's χ2 test.

RESULTS

Totally, a significant predominance was noted for two HLA alleles, HLA-A*24 (P = 0.029) and B*55 (P = 0.034) which have higher prevalence in control group. Although no significant association was found between the presence of anti-leukocyte antibodies and the development of FNHTR, the HLA-A*32 (P = 0.047) allele was considered as possible genetic markers in the susceptibility to the development of anti-leukocyte antibodies.

CONCLUSION

Here some evidences about the possible role of HLA polymorphism in susceptibility to FNHTR are provided. Those results indicated that HLA-A*24 and HLA-B*55 might play protective role on inducing FNHTR in β-thalassemia patients. Further studies which investigate the allele level of HLA-I alongside with specific reactivity of HLA-I antibodies might reveal more deep data about these phenomena.

Major and minor subgroup profile of blood in patients receiving multiple transfusions and donors

OBJECTIVE

It was aimed to profile the blood subgroups of our region and to reveal the prevalence of auto/alloimmune sensitization in patients who had to undergo multiple erythrocyte transfusions and to establish the sensitization profile by screening major and minor subgroups.

MATERIALS AND METHODS

In this study, the distribution of ABO and Rh system major subgroups was studied in 100 donor blood. As the patient group, 50 patients who received three or more red blood cell transfusions were included. In addition to this group, Kell, Lewis, Duffy blood group systems were studied.

RESULTS

According to the ABO system, 35% of the donors were in O, 33% in A, 17% in AB, and 15% in B. According to the Rh system, 75% is Dvi positive. Rh system is 99% e positive and 33% E positive in major subgroups and Kell1 positivity is 8%. In the patient group, 22% D(-) was determined compared to Rh blood group. Among the major subgroups of Rh, C was 68%, E was 14%, c was 76%, and e positivity was found to be 100%. The Kell1 negativity rate is 96%. The highest negativity was found in 86% Lea antigen in Lewis system, in 36% S antigen in MNS system, 34% Fyb antigen in Duffy system, and 24% Jka antigen in Kidd system. When inappropriate blood is given for any antigen, a double population is formed. The double negativities we detected in our study occurred as follows according to blood group systems: E 18%, C 12%, c 8%, Cw 2%, Kell 1 2%, M 8%, N 4%, S 18%, s 6%, Fya 8%, Jka 6%, Jkb 22%. Indirect Agglutination Test (IAT) was negative in all patients.

CONCLUSION

IAT negativity in all patient groups suggests that we do not develop alloimmunization, but the high rates of double population suggest a high risk of alloimmunization.

Distribution and frequency of principal Rh blood group antigens (D, C, c, E, and e) and their phenotypes in the blood donors attending blood bank in a tertiary care hospital in Barpeta district of Assam

BACKGROUND

The ABO and Rhesus grouping system antigens have been found to have the highest immunogenicity and propensity to produce alloantibodies that cause most of the transfusion reactions. The Rhesus antigens that produce most of the immunogenic transfusion reactions are D, C, c, E, and e. Knowledge of the distribution of these Rh antigens in a population helps to render compatible blood in alloimmunized patients.

AIM

The aim was to study the distribution and frequency of principal Rh blood group antigens (D, C, c, E, and e) and their phenotypes in the blood donors attending blood bank in a tertiary care hospital in Barpeta district of Assam.

MATERIALS AND METHODS

The study was conducted in 315 voluntary blood donors in the blood bank of a tertiary care center. Rh-D typing was done by conventional tube method. Specific monoclonal antisera, i.e., anti-C, anti-c, anti-E, and anti-e, were used and tests were performed by conventional tube method for detection of the presence of rest of the major Rh antigens.

RESULTS

The samples were analyzed for the five major Rhesus antigens. "D" antigen was found to be the most common antigen (99.05%), followed by e (97.14%), C (92.38%), c (51.43%), and E (20.95%). In order of descending frequency, the most common phenotypes were DCCee - 45.71%, DCcee - 30.48%, DCcEe - 11.43%, DccEe - 4.76%, DCcEE - 1.90%, DCCEe - 1.90%, Dccee - 1.90%, DCCEE - 0.95%, and dccee - 0.95%.

CONCLUSION

D antigen is the most common antigen in our study population, whereas "e" antigen is the most common in most of the studies done from other parts of India. Data on frequencies of major Rh antigens in the local donor population will help in transfusing alloimmunized patients with corresponding antibody-negative blood ensuring blood safety.

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.

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.

Red blood cell alloimmunization among hospitalized patients: transfusion reactions and low alloantibody identification rate

Background

Unexpected red blood cell alloantibodies can cause hemolytic transfusion reactions. In this study, the prevalence of alloimmunization, the rate of identification of alloantibodies and the rate of blood transfusion reactions among transfused patients were identified in a clinical emergency hospital in Brazil.

Methods

Transfusions and clinical records of patients who had a positive indirect antiglobulin test between January and December 2013 were analyzed.

Results

Of 1169 patients who received blood transfusions, 28 had positive indirect antiglobulin tests, with one patient having two positive tests at different times, resulting in 29 positive tests during the period of this study. Alloantibodies were identified in 58.6% (17/29) of the cases. In 27.5% (8/29), identification was inconclusive and it was not possible to confirm alloimmunization. The rate of red blood cell alloimmunization was 1.71% (21/1169). Of 21 cases of alloimmunization, four (19%) were unidentified due to an unusual agglutination profile. All identified alloantibodies were clinically significant (10/17 anti-Rh, 5/17 anti-Kell and 2/17 anti-MNS). In two patients who had positive indirect antiglobulin tests, one had an unidentified alloantibody, and the other had an inconclusive test and developed a hemolytic transfusion reaction.

Conclusion

The prevalence of clinically important red blood cell alloantibodies and hemolytic transfusion reactions among patients with unidentified alloantibodies suggests that specific laboratory techniques should be performed to identify alloantibodies in cases of pan-reactivity or autoantibodies to improve transfusion safety.

Transfusion Medicine and Molecular Genetic Methods

Transfusion procedures are always complicated by potential genetic mismatching between donor and recipient. Compatibility is determined by several major antigens, such as the ABO and Rhesus blood groups. Matching for other blood groups (Kell, Kidd, Duffy, and MNS), human platelet antigens, and human leukocyte antigens (HLAs) also contributes toward the successful transfusion outcomes, especially in multitransfused or highly immunized patients. All these antigens of tissue identity are highly polymorphic and thus present great challenges for finding suitable donors for transfusion patients. The ABO blood group and HLA markers are also the determinants of transplant compatibility, and mismatched antigens will cause graft rejection or graft-versus-host disease. Thus, a single and comprehensive registry covering all of the significant transfusion and transplantation antigens is expected to become an important tool in providing an efficient service capable of delivering safe blood and quickly locating matching organs/stem cells. This review article is intended as an accessible guide for physicians who care for transfusion-dependent patients. In particular, it serves to introduce the new molecular screening methods together with the biology of these systems, which underlies the tests.

Acute Hemolytic Transfusion Reaction Caused by a Red Cell Antibody That Was Missed by Pretransfusion Testing Using Tube Method

Pretransfusion testing is very important to prevent transfusion of incompatible red cells, which might result in a hemolytic transfusion reaction. This includes the detection of antibodies in recipients' serum and compatibility testing between donor cells and recipient serum. The most commonly used methods include gel and tube techniques. We present a case in which an anti-E alloantibody was detected by gel method but not by tube testing. As a result, red cells that were retrospectively phenotyped as positive for E antigen were inadvertently selected and transfused after crossmatch using the same tube method. After transfusion, the patient developed signs of hemolytic transfusion reaction. This case highlights the potential risk of transfusion of incompatible red cells when alloantibody detection is solely relied on tube testing.

Red cell alloimmunization in repeatedly transfused patients

INTRODUCTION

Repeated blood transfusions can result in the production of alloantibodies against one or more red cell antigens, which complicates subsequent transfusions. Aims: The study was done to find incidence of various red cell alloantibodies; to determine the type of alloantibody; to identify the factors such as frequency of transfusion, splenectomy status, donor ethnicity and gender and their association with the development of antibody in repeatedly transfused patients.

MATERIALS AND METHODS

This study was carried out in Dept. of IHBT, Shree M. P. Shah Medical College, Jamnagar, Gujarat. Blood was taken from the patients of thalassemia major, sickle cell disease, chronic renal failure, post partum haemorrhage, aplastic anemia, Myelodysplastic syndrome with more than 10 red cell transfusions. The plasma/serum was used for antibody screening and antibody identification test. Three cell antibody screening was performed using antihuman globulin gel cards (ID-Card LISS/Coombs) and three cell panel (ID-DiaCell I, II, III-Asia). Those with positive antibody screening were analyzed further for antibody identification test using eleven cell panel (Set ID-Dia Panel).

RESULTS

Antibody screening and identification was done in 2 consecutive set of samples (n = 300) which showed, nine (9) patients (3%) were alloimmunized. All repeatedly transfused patients had developed alloantibody before the starting of study period, no patient developed new alloantibody during study period.

CONCLUSIONS

Alloantibodies should be identified in repeatedly transfused patients and should be given corresponding antigen negative blood unit which will minimize the antibody mediated destruction of transfused red cells.

Alloimmunization in multitransfused liver disease patients: Impact of underlying disease

Introduction:

Transfusion support is vital to the management of patients with liver diseases. Repeated transfusions are associated with many risks such as transfusion-transmitted infection, transfusion immunomodulation, and alloimmunization.

Materials and Methods:

A retrospective data analysis of antibody screening and identification was done from February 2012 to February 2014 to determine the frequency and specificity of irregular red-cell antibodies in multitransfused liver disease patients. The clinical and transfusion records were reviewed. The data was compiled, statistically analyzed, and reviewed.

Results:

A total of 842 patients were included in our study. Alloantibodies were detected in 5.22% of the patients. Higher rates of alloimmunization were seen in patients with autoimmune hepatitis, cryptogenic liver disease, liver damage due to drugs/toxins, and liver cancer patients. Patients with alcoholic liver disease had a lower rate of alloimmunization. The alloimmunization was 12.7% (23/181) in females and 3.17% (21/661) in males. Antibodies against the Rh system were the most frequent with 27 of 44 alloantibodies (61.36%). The most common alloantibody identified was anti-E (11/44 cases, 25%), followed by anti-C (6/44 cases, 13.63%).

Conclusion:

Our findings suggest that alloimmunization rate is affected by underlying disease. Provision of Rh and Kell phenotype-matched blood can significantly reduce alloimmunization.

Impact of antigenic exposures and role of molecular blood grouping in enhancing transfusion safety in chronically transfused thalassemics

Background:

Red cell alloimmunization is an acknowledged complication of blood transfusion. Current transfusion practices for thalassemia do not cater to this risk. Serological phenotyping is usually not reliable in these cases unless performed before the first transfusion. Under such circumstances, molecular blood grouping is an effective alternative.

Aim:

To perform molecular blood group genotyping in chronically transfused thalassemia patients and assess the risk of antigenic exposure and incidence of alloimmunization with current transfusion protocols.

Materials and Methods:

Molecular blood group genotyping was performed for 47 chronically transfused thalassemia patients. Their 1-year transfusion records were retrieved to assess the antigenic exposure and the frequency thereof.

Results:

Of 47 patients, 6 were already alloimmunized (3 with anti-E and 3 with anti-K) and were receiving the corresponding antigen negative units. We observed that random selection of ABO and Rh D matched units resulted in 57.7% ±8.26% chance of Rh and Kell phenotype matching also. Forty-four patients had received one or more antigenic exposures at least once. The 6 already alloimmunized patients were further exposed to antigens other than the ones they were immunized to. During the study period, only one patient developed an alloantibody, anti-E with exposure to antigens C (92%) and/or E (32%) at each transfusion.

Conclusion:

Several factors apart from mere antigen exposure may influence the development of alloimmunization as most of our patients received antigenic exposures but not alloimmunized. Our data provide an impetus for future large-scale studies to understand the development of alloimmunization in such patients.

Partial matching of blood group antigens to reduce alloimmunization in Western India

Red blood cell alloimmunization occurs due to the genetic disparity of red cell antigens between donor and recipient. In the present study, we report a spectrum of red cell alloantibodies characterized in patients with different clinical conditions in a reference center in India. Majority of the antibodies identified were against the blood group antigens c, D, E, M, N, S, s and Jka. Hence, apart from ABO and RhD, we recommend partial antigen matching between donor and patients for other Rh (C, c, E, e) and MNS blood group antigens to potentially reduce the risk of alloimmunization by 75%. Matching of Kell antigen is not recommended in Western India.

Study of alloimmunization and autoimmunization in Iranian β-thalassemia major patients

Background:

Thalassemia is one of the most common monogenic disorders characterized by reduced production of globin chains. Although regular red blood cell (RBC) transfusion support is the main treatment for these patients, it may be associated with complications such as RBC alloimmunization.

Aim:

The study aimed to determine the incidence of alloimmunization and autoimmunization to RBC antigens in β-thalassemia major patients from Zanjan, Zanjan Province, Iran.

Materials and Methods:

A total of 49 β-thalassemia major patients comprising 24 females and 25 males (mean age: 18.59 ± 8.16 years; range: 2-40 years) from Northwest Iran were included in a cross-sectional study. Alloantibody screening and identification were done using 3-cell and 10-cell reagent red blood cells, respectively. Autoantibody detection was performed using direct Coomb's test.

Results:

The incidence of alloimmunization was 16.32% with 10 alloantibodies identified in 8 patients. The most common clinically significant alloantibody identified in alloimmunized patients was anti-Kell (K-antigen) (60%) followed by anti-Rhesus (Rh) (E, c-antigens). The rate of alloimmunization was significantly lower in patients transfused with leukoreduced RBCs compared with those transfused with nonleukoreduced RBCs (9.53% vs 57.14%, P = 0.001). There was no significant correlation between alloantibody formation and the age, gender, hemoglobin levels, number of transfused units, and splenectomy.

Conclusion:

Transfusion of leukoreduced and phenotypically matched red blood cells for Kell (K) and Rh (E, c) antigens may help reduce the alloimmunization rate in Iranian β-thalassemia major patients. Moreover, autoimmunization to RBC antigens was rare in our patients.

Can the interval between antibody identifications be increased for alloimmunized patients?

BACKGROUND

New alloantibody formation is unpredictable in patients who have been previously alloimmunized. Pretransfusion testing is designed to detect these antibodies while antibody identification (ABI) techniques are designed to identify the specificity of the antibody. Pretransfusion testing intervals are prescribed by regulatory and accrediting agencies, intervals for ABI in alloimmunized patients are not. Our institution evaluated the safety of increasing the interval from every 72 hours to 14 days. The current 72-hour interval was chosen at our institution to align with AABB Standard 5.14.3.2, which requires a pretransfusion specimen drawn within 3 days of the scheduled transfusion for potentially immunized patients.

STUDY DESIGN AND METHODS

Over 2 years, all ABI entries in the laboratory information system were screened. All cases of alloimmunized patients with an additional antibody specificity that developed within 14 days of a previous ABI were reviewed and confirmed by four transfusion medicine physicians.

RESULTS

Initially, 8948 entries were screened. Thirty patients were identified to have formed 33 newly identified clinically significant alloantibodies within 14 days. After further categorization, only 13 antibodies (0.15% of all ABIs, 0.47% of alloimmunized patients examined) were deemed to be newly formed clinically significant antibodies that would have led to a change in transfusion practice.

CONCLUSION

Retrospective analysis of ABI results over a 2-year period revealed that 0.47% of previously alloimmunized patients that have samples for pretransfusion testing develop a new clinically significant alloantibody in 14 days or less. While there would be significant resource advantages to increasing the duration between repeat ABI, it does not outweigh the risk of a potential hemolytic transfusion reaction.

Human leucocyte antigen alloimmunisation in repeatedly transfused thalassemic Egyptian children and its relation to febrile non-haemolytic transfusion reactions

OBJECTIVES

To document the incidence of lymphocytotoxic antibodies (LCA) in chronically transfused children with β thalassemia major and the relationship between alloimmunisation and febrile non-haemolytic transfusion reactions. We also compared the effect of leucoreduced-packed red blood cells (RBCs) by bed-side filtration and washed RBCs in preventing FNHTRs and in inducing haemoglobin rise.

BACKGROUND

Alloimmunisation to human leucocytic antigens is one of the common complications of transfusions, particularly in chronically transfused patients as those with thalassemia major, a common disease in Northern Egypt.

METHODS/MATERIALS

LCA were screened for in 45 chronically transfused β thalassemia major children (group I), 20 splenectomised ones (group II) and 20 healthy controls (group III), using qualitative lymphocytotoxic antibody (LCA) enzyme-linked immunosorbent assay (ELISA) kit.

RESULTS

Nine out of 65 thalassemic children (∼14%) were positive for LCA antibodies. Frequency of transfusions and LCA positivity were significantly higher in group I than group II (p = 0.036 and 0.014). There was no statistically significant difference between LCA positive and negative cases regarding age of starting transfusion, frequency of transfusions or FNHTRs. There was no statistically significant difference between washed and filtered RBCs in reducing FNHTRs (p = 1.000) and in inducing haemoglobin rise in positive LCA cases (p = 0.409).

CONCLUSION

Human leukocyte antigen (HLA) alloimmunisation was only 14% in the children with β thalassemia major we studied. Surprisingly FNHTRs were not more common in those with HLA antibodies. Splenectomy plays a role in reducing the frequency of transfusion and HLA alloimmunisation. Washed and filtered RBCs are comparable in reducing FNHTRs and in inducing haemoglobin rise.

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

Introduction. Red blood cell (RBC) alloimmunization and autoimmunization remain a major problem in transfusion dependent thalassemic patients. There is a paucity of data on the incidence of RBC alloimmunization and autoimmunization in thalassemic patients from eastern part of India, as pretransfusion antibody screening is not routinely performed. Aims. To assess the incidence of RBC alloimmunization and autoimmunization in transfusion dependent thalassemic patients in eastern India. Materials and Methods. Total 500 thalassemia cases were evaluated. The antibody screening and identification were performed with commercially available panel cells (Diapanel, Bio-rad, Switzerland) by column agglutination method. To detect autoantibodies, autocontrol and direct antiglobulin tests were carried out using polyspecific coombs (IgG + C3d) gel cards in all patients. Results. A total of 28 patients developed RBC alloimmunization (5.6%) and 5 patients had autoantibodies (1%). Alloantibody against c had the highest incidence (28.57%) followed by E (21.42%). Five out of 28 (17.85%) patients had developed antibodies against both c and E. Conclusion. Data from this study demonstrate that the RBC alloantibody and autoantibody development rates are significant in our region. Thus, pretransfusion antibody screening needs to be initiated in eastern India in order to ensure safe transfusion practice.

Prevalence and Specificity of RBC Alloantibodies in Indian Patients Attending a Tertiary Care Hospital

Background. Red blood cell (RBC) alloimmunization results from genetic disparity of RBC antigens between donor and recipients. Data about alloimmunization rate in general patient population is scarce especially from resource limited countries. We undertook this study to determine prevalence and specificity of RBC alloantibodies in patients admitted in various clinical specialties at a tertiary care hospital in North India. Methods. Antibody screening was carried out in 11,235 patients on automated QWALYS 3 platform (Diagast, Loos, France). Antibody identification was carried out with an 11-cell identification panel (ID-Diapanel, Diamed GmbH, Switzerland). Results. The overall incidence of RBC alloimmunization in transfused patients was 1.4% (157/11235), with anti-E being the most common specificity (36.3%), followed by anti-D (16%), anti-c (6.4%), anti-c + E (6.4%), anti-C + D (5.1%), and anti-K (4.5%). The highest incidence of alloimmunization was observed in hematology/oncology patients (1.9%), whereas in other specialties the range was 0.7–1%. Conclusion. As alloimmunization complicates the transfusion outcomes, authors recommend pretransfusion antibody screening and issue of Rh and Kell matched blood to patients who warrant high transfusion requirements in future.