Red Cell Alloimmunization Research Articles

Trends of Erythrocyte Alloimmunization in Transfused Women.

Objectives: To identify the trends of red cell alloimmunization in multi transfused females using red blood cell panels. Study Design: Prospective Cross sectional study. Place and Duration of Study: Army Medical College and Armed Forces Institute of Transfusion with collaboration of Military hospital Rawalpindi. Study duration was 8 months, from Jan 2018 - Aug 2018. Methodology: Consent from Institutional Ethical Committee was acquired. Blood samples of 75 females with prior history of blood transfusion were collected from MH Rawalpindi, selected by non-probability consecutive sampling technique. After pilot diagnostic tests for ABO and Rh D blood grouping, samples were screened by 3 cell panel to identify presence of RBCs alloimmunization. Positive results were further recognized by 11 cell panel following company’s directions. Results: Seventy-five women with previous history of at least one blood transfusion were selected for screening of red cell alloimmunization. The frequency of alloantibodies in transfused women was 1(1.3%). Only alloantibody identified was anti-e, which is a rare alloantibody. Conclusion: Study confirmed that Rh alloantibodies are most prevalent antibodies, regardless of age, ABO blood grouping, Rh grouping and ethnicity. Our study also confirmed that multiple transfusions have strong association of development of red cell alloimmunization.

RhD alloimmunization – diagnostics, therapy and prophylaxis

Introduction: The success in preventing and treating Rh D alloimmunization is a major accomplishment in modern obstetrics. The widespread use of Rh D immune globulin has led to a decline in red cell alloimmunization. Despite evidence of its effectiveness, many cases of Rh D alloimmunization persist due to non-compliance with established protocols. Implementing routine anti-D prophylaxis (RAADP) during the third trimester is well-established but requires more careful. Aim of study: The aim of the study is to summarize the available knowledge about alloimmunization in pregnancy and methods of prophylaxis. The definition, patomechanism, methods of treatment and prophylaxis were summarized and described. Materials and methods: The literature available in PubMed database was reviewed using following keywords: “alloimmunization in pregnancy”, “serological conflict”, “fetal anemia”, “HDFN”, “prophylaxis of alloimmunization”. Conclusion: Advancements in diagnosing, treating, and preventing hemolytic disease of the fetus and newborn are notable. Quick, non-invasive diagnostics have facilitated more efficient treatment implementation. Prevention methods include specific and nonspecific prophylaxis, which can start during or after pregnancy. Numerous guidelines and studies exist regarding immunoglobulin use in pregnancy. However, medical staff education on managing hemolytic disease during pregnancy is crucial.

Alloimmunization in Pregnancy: Implications for the Fetus and Neonate.

Blood group or red cell alloimmunization occurs when a pregnant patient has produced antibodies to a blood group antigen possessed by the fetus and not possessed by the pregnant patient. Maternal antibodies are usually produced as an immune response to fetal-maternal bleeding or blood product transfusion. Prevention remains the most important strategy to avoid the formation of maternal antibodies or alloimmunization. Maternal alloimmunization may result in transplacental passage of these antibodies into the fetal circulation and the potential for fetal or neonatal hemolysis and anemia. Red cell alloimmunization can result in significant perinatal morbidity and mortality. Management of alloimmunization in pregnant patients should be protocol-driven. Current strategies for assessment and therapies allow for more thorough and less invasive management with risks to mother and fetus.

Red blood cell alloimmunization in transfused patients with hereditary hemorrhagic telangiectasia: A single centre retrospective study

BackgroundHereditary hemorrhagic telangiectasia (HHT) is a genetic blood vessel disorder which may lead to chronic bleeding and red blood cell (RBC) transfusions. Data on transfusion requirements and complications in HHT patients are sparse. Study Design and MethodsRetrospective chart review was conducted at St. Michael’s Hospital (SMH) in Toronto, Canada. All adults with a definite clinical diagnosis of HHT AND inpatient hospital visits between January 1, 2011 and December 31, 2020 AND had undergone transfusion compatibility testing at SMH, were identified. Data were abstracted from electronic medical records. Simple descriptive statistics were used to analyze data. Institutional Research Ethics Board approval was obtained. Results63 HHT patients underwent compatibility testing and were subsequently transfused at SMH. Median patient age at data abstraction was 70 years (Interquartile Range [IQR]: 18) and 35 (56 %) were female. RBC alloantibodies were found in 23 transfused patients (36.5 %) and were predominantly directed against Rh and Kell antigens: Anti-E (65 %), Anti-K (39 %) and Anti-c (22 %) were most common. Excluding an outlier who received 611 RBC units during the study period, the mean number of RBC units transfused per HHT patient at SMH was 22.1 units (Standard Deviation: 40.9, IQR: 17). Six (9.5 %) transfused patients experienced at least one transfusion reaction. ConclusionRBC alloimmunization rate was 36.5 % in our cohort of transfused HHT patients; this is much higher than described in the general population and another transfused HHT cohort. The most commonly observed alloantibodies were Rh and Kell, supporting our policy of prophylactic phenotypic matching for these antigens for all transfused patients with HHT.

Frequency of red blood cell allo-immunization in transfused patients with sickle cell disease in Africa: a systematic review with meta-analysis

Background and Objectives: Blood transfusion is an effective and proven treatment for some severe complications of sickle cell disease. Recurrent transfusions have put patients with sickle cell disease at risk of developing antibodies against the various antigens they were exposed to. This study aims to investigate the frequency of red blood cell alloimmunization in patients with sickle disease in Africa. Materials and Methods: This is a systematic review of peer-reviewed and published literature. The review was conducted consistent with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist.Data sources for the review include MEDLINE, PubMed, AJOL, CINAHL, Psych-Info and Academic Search Complete. Included in this review are articles that reported the frequency/prevalence of red blood cell alloimmunization in sickle cell disease patients in Africa. Eligible studies were subjected to independent full-text screening and data extraction. Risk of bias assessment was conducted with the aid of the mixed method appraisal tool. We employed a random-effects model of meta-analysis to estimate the pooled prevalence. We computed Cochrane’s Q statistics and I2 and prediction interval to quantify heterogeneity in effect size. Results: The prevalence estimates range from 2.6% to 29%. Pooled prevalence was estimated to be 12.1% (95% CI 8.1 to 17.7), with significant heterogeneity (I2= 91.83; PI = 2 to 54%). Conclusion: The frequency of red cell alloantibody varies considerably in Africa. Keywords: Systematic review; red blood cell; alloimmunization; sickle cell disease; Africa.

Blended Phenotypes From a SERPINA 11 Pathogenic Variant Over Underlying Immune Fetal Hydrops: A Rare Case Report and Literature Review

Abstract Fetal hydrops can stem from immune or nonimmune causes. Immune causes often involve red cell alloimmunization, whereas nonimmune causes encompass structural malformations, aneuploidy, infections, lymphatic system disorders, genetic syndromes, and more. In a rare and complex case, we encountered a fetal hydrops presentation characterized by blended phenotypes, indicating both a genetic and an underlying immune etiology. The mother, Rhesus negative, presented with a history of adverse obstetric events. At 21 weeks, the current fetus was diagnosed with hydrops. Maternal blood tests unveiled Rhesus alloimmunization, featuring a positive indirect Coombs test at a 1:512 dilution and the presence of anti-D, anti-C, and anti-E antibodies. Fetal blood sampling revealed an O-positive blood group with a hemoglobin level of 10 gm/dL. Despite administering intrauterine transfusion to the fetus, there was no improvement; instead, the fetal hydrops worsened, accompanied by the emergence of nuchal and axillary masses. Exome sequencing of fetal DNA revealed the fetus was homozygous for a pathogenic variant in the SERPINA11 gene and compound heterozygous for a pathogenic variant in the PIEZO1 gene. Furthermore, the combination of pathogenic variants in SERPINA11 and PIEZO1 genes has not been described in cases of fetal hydrops before. This case posed significant challenges in management due to the concurrent presence of both immune and nonimmune hydrops. We describe some of the diagnostic challenges faced in clinical management of this case.

Increased Intrauterine Transfusion Blood Volume Needed to Correct Fetal Anemia due to Placental Chorioangioma

Introduction: To compare the blood volume transfused for fetal anemia in cases of placental chorioangioma versus red blood cell (RBC) alloimmunization in patients matched for gestational age (GA) and hydrops. Methods: Study patients had intrauterine transfusions and were obtained from 3 sources: group (1) placental chorioangioma patients treated at our center (2016–2023); group (2) placental chorioangioma patients reported in the medical literature; and group (3) RBC alloimmunization patients treated for fetal anemia at our center (2016–2023) matched (2:1) to patients in groups 1 and 2 by GA at procedure and presence of hydrops. The expected volume (cc) of transfusion was calculated for all patients based on a formula commonly used for fetal anemia in cases of RBC alloimmunization that includes the GA at procedure, pre-transfusion hemoglobin, donor hemoglobin, and target hemoglobin. The ratio of the volume actually transfused to the expected volume was calculated for each group and for groups 1 and 2 combined; comparisons were made using nonparametric testing. Results: By group, the patients studied included: (1) 7 treated chorioangioma patients, (2) 8 chorioangioma patients described in the literature, and (3) 30 matched RBC alloimmunization patients. The median (range) GA at procedure for groups 1, 2, and 3 was 29.6 (22.7–32.7), 27.0 (24.0–30.0), 28.4 (22.7–34.3) weeks. The median pre-procedure hemoglobin for each group was 8.5 (5.8–12.5), 6.7 (5.6–12.0), and 5.3 (2.2–10.7) g/dL, and the median post-procedure hemoglobin for each group was 12.9 (11.5–14.0), 12.7 (9.6–14.7), and 13.6 (8.0–15.7) g/dL. The median (range) ratio of the actual to the expected volume transfused for each group was 2.50 (1.79–8.33), 1.64 (1.11–3.85), and 1.10 (0.69–1.86) (p < 0.001). When groups 1 and 2 were combined, the median ratio was 1.89 (1.11–8.33), which remained statistically significant when compared to group 3 (p < 0.001). Conclusion: Intrauterine transfusion for fetal anemia in cases of large placental chorioangiomas appeared to require nearly twice the blood volume that was normally anticipated for cases of RBC alloimmunization, although the actual amount transfused varied widely.

The development and evanescence of red blood cell antibodies after transfusion: A multi-institutional prospective study in Japan.

Despite several reports on red blood cell (RBC) alloimmunization, the actual prevalence and factors contributing to RBC alloimmunization in transfused patients remain poorly investigated. We examined the association between clinical factors and the development and evanescence of RBC antibodies after transfusion. Each participating institution performed antibody screens before and after RBC transfusion. A survey including patient characteristics, results of antibody screen and identification, antibody screen methods, total amount of RBC transfused, and adverse reactions, was conducted. Between October 2018 and March 2023, 1194 patients were registered at five institutions. Overall, 958 patients underwent at least one follow-up RBC antibody screen after transfusion, revealing new antibody development in 44 (4.6%). Anti-E was identified in 25 patients, anti-Jka in 5, and anti-c in 4. The number of RBC units transfused was significantly associated with antibody development after transfusion (p < .001). Among 55 patients in whom antibodies were identified after transfusion, including historical antibodies, antibodies evanesced in 18 (33%); anti-E in 7, anti-Jka in 4, and anti-Lea in 2. Evanescent antibodies were identified more frequently by saline and/or enzyme methods than persistent antibodies (p = .012). The number of RBC units transfused can impact antibody development, and antibodies identified only by saline and/or enzyme methods, deemed clinically insignificant, are likely to have a high evanescence rate. Antibody screen should be carefully performed, especially in those receiving a large number of RBC units. Confirming previous antibody screen results should be performed to prevent omitting evanesced antibodies regardless of clinical relevance.

Risk factors for red blood cell alloimmunization in patients with hematologic malignancy.

Patients with hematologic malignancy have a higher risk of developing red blood cell (RBC) alloimmunization which can delay blood transfusion. Information on the risk factors for alloimmunization in this group is still limited. This study aimed to determine the prevalence and predictors of RBC alloimmunization among these patients. Electronic medical records of the patients with acute myeloid leukaemia (AML), acute lymphoid leukaemia (ALL), multiple myeloma (MM) and lymphoma from a tertiary care hospital between January 2018 and December 2022 were retrospectively reviewed. Clinical, demographic and transfusion history data of the included patients were analysed. Of the 983 patients with hematologic malignancy, 798 were included in the study. The prevalence of RBC alloantibodies in this population was 4.8% (38 patients). The alloimmunization rate of each subgroup was as followed: AML 9.1%, ALL 2.9%, MM 3.8% and lymphoma 2.5%. The most common alloantibodies were anti-Mia, anti-E and anti-Lea. The majority (29/38, 76.3%) of alloimmunization had a single alloantibody. RBC autoantibody was detected in 10 patients. The detection of autoantibodies and having AML were independently associated with RBC alloimmunization (adjusted odds ratio [aOR] 13.41, 95% confidence interval [CI] 2.00-89.72, p = 0.007 and aOR 11.44, 95% CI 2.02-64.72, p = 0.006, respectively). The prevalence of RBC alloimmunization in the patients with hematologic malignancy was 4.8%. The alloimmunization rate of the AML subgroup was higher than those of other hematologic malignancies. The detection of autoantibodies and the AML diagnosis were identified as potential risk factors for RBC alloimmunization.

“When less is more and more is less” red cell alloimmunization in multitransfused patients attending a medical institution with a newly developed blood center in North India: A multifactorial study

Abstract: INTRODUCTION: Multiple blood transfusions with one or more nonself, genetically mismatched donor red blood cells (RBCs) may result in the production of alloantibodies, complicating future transfusions and increasing patient morbidity. This could be averted if adequate prophylactic measures are implemented in the vulnerable group. Due to the paucity of data in our region, we planned this study to identify the alloimmunization pattern in relation to clinical and demographic patient factors. MATERIALS AND METHODS: A prospective observational study was carried out in a newly developed Medical Institution of National importance in Northern India, for 1 year. The red cell antibody screening and identification were done for 770 patients receiving two or more transfusions. The patient and transfusion-related factors were statistically compared between alloimmunized and nonalloimmunized cases. RESULTS: The overall seroprevalence of RBC alloimmunization among the multi-transfused patients was 4.02% (31/770). Thirty-six alloantibodies were identified in the 31 alloimmunized patients, which comprised 13 different alloantibody specificities. Most of them belonged to the Rh system (38.8%), followed by MNS (25%) and Lewis (27.7%) blood group systems. On Multivariate logistic regression analysis, the highest risk was found to be associated with recipients having more than three transfusions with an odds ratio of 8.4. CONCLUSIONS: The highest alloimmunization risk was found in multi-transfused patients receiving more than three transfusions and with female gender. Rh blood group system was found to be predominating the alloantibody specificity pattern. This highlights the need for the provision of extended Rh (DCcEe) matched packed red cells for susceptible patients.

Management of Red Cell Alloimmunization in Pregnancy.

Rhesus immune globulin has resulted in a marked decrease in the prevalence of RhD alloimmunization in pregnancy; however, antibody formation to other red cell antigens continues to occur. Evaluation for the presence of anti-red cell antibodies should be routinely undertaken at the first prenatal visit. If anti-red cell antibodies are detected, consideration of a consultation or referral to a maternal-fetal medicine specialist with experience in the monitoring and treatment of these patients is warranted. Cell-free DNA can be used to determine fetal red cell antigen status to determine whether the pregnancy is at risk of complications from the red cell antibodies. First-time sensitized pregnancies are followed up with serial maternal titers, and, when indicated, serial Doppler assessment of the peak systolic velocity in the middle cerebral artery should be initiated by 16 weeks of gestation. When there is a history of an affected fetus or neonate, maternal titers are less predictive of fetal risk; if the fetus is antigen positive, serial peak systolic velocity in the middle cerebral artery measurements should be initiated by 15 weeks of gestation because intraperitoneal intrauterine blood transfusions can be used at this gestation if needed. The mainstay of fetal therapy involves intrauterine transfusion through ultrasound-directed puncture of the umbilical cord with the direct intravascular injection of red cells. A perinatal survival rate exceeding 95% can be expected at experienced centers. Neonatal phototherapy and "top-up" transfusions attributable to suppressed reticulocytosis often are still required for therapy after delivery.

The prevalence of erythrocyte alloimmunization in clinical practice: A hospital-based study

Abstract BACKGROUND: One of the complications of blood transfusion is the development of red cell alloimmunization. Little published literature on the prevalence and actual significance of red cell alloantibodies among nonregularly transfused patients and the general population. OBJECTIVES: This study aimed to estimate red cell alloantibodies’ prevalence, specificity, and clinical significance in obstetric and medical practice in Iraq. MATERIALS AND METHODS: A cross-sectional hospital-based study involving internal medicine patients and ladies in obstetric wards of Baghdad Teaching Hospital in Baghdad/Iraq, from January 2022 to May 2022. Demographic data were collected along with detailed medical, obstetric, and transfusion history. Alloantibody screening was performed, and samples with positive results were subjected to antibody titration and identification. RESULTS: A total of 200 patients were enrolled. Indirect antiglobulin test was positive in 15% of patients in internal medicine wards and 23% of ladies in obstetric wards, with most of the identified alloantibodies being clinically significant, against Kidd and Duffy antigen groups. Blood transfusion of more than four units to patients at internal medical wards showed a significant association as a risk for developing red cell alloantibodies (P = 0.025). For ladies in obstetric wards, there was a significant association between pregnancy loss at the time of screening and alloimmunization (P = 0.0164). CONCLUSION: High prevalence of red cell alloantibodies in comparison to what is published worldwide. Transfusion of more than four units of blood and pregnancy loss at the time of screening were statistically significant risks for alloimmunization of the medical and obstetric populations, respectively.

Red cell Alloimmunization and its Correlation with Clinical Spectrum &amp; Transfusion Profile in Pediatric Thalassemia Major Patients: Experience from a Tertiary Care Pediatric Center in Northern India

Red cell Alloimmunization and its Correlation with Clinical Spectrum &amp; Transfusion Profile in Pediatric Thalassemia Major Patients: Experience from a Tertiary Care Pediatric Center in Northern India

Prevalence of red blood cell alloantibodies in pregnant women with sickle cell disease in Bamako.

Pregnancy in women with sickle cell disease (SCD) is associated with severe complications. Red blood cell (RBC) alloimmunisation is a worrying situation in pregnant women with SCD. This could increase the difficulty in finding a pheno-compatible red blood product. Our study aimed to determine the prevalence of RBC alloantibodies in pregnant women with SCD and to determine the risk factors for alloantibodies formation. We conducted a prospective study at the "Centre National de Transfusion Sanguine de Bamako" from August 2022 to January 2023. For each participant, we collected important information, including obstetrical and transfusion histories. We performed ABO group, Rh and Kell phenotyping, and antibody screening in all study participants. We performed statistical analysis. We recruited 95 pregnant women with SCD. In our study, 62% of our participant had a history of blood transfusion. Only 23% of our pregnant women with SCD had a history of miscarriage. The prevalence of RBC alloantibodies was 14%. The main antibodies detected were anti-E (38%) and pan-agglutinins (23%). Miscarriage history, blood transfusion history, and pregnancy number were the main risk factors for RBC alloimmunisation. The care of pregnant women with SCD is complex and requires collaboration between haematologists, clinicians and gynaecologists. National guidelines should be implemented to make ABO and D typing, Rh and Kell phenotyping and antibody screening routine for all pregnant women. This would facilitate early detection of high-risk situations. Particular attention should be paid to SCD pregnant women with miscarriage and blood transfusion histories.

Red blood cell alloimmunization in transfused patients with myelodysplastic syndromes: a retrospective study from northern China.

Alloimmunization against red blood cell (RBC) antigen is an important concern in myelodysplastic syndromes (MDSs) patients with chronic transfusion, causing potential risk for hemolytic reaction and limited supply of compatible blood. However, there is little data addressing RBC alloimmunization in this patient cohort among the Chinese population. This study aims to evaluate the incidence, specificity of antibodies, and RBC units transfused before antibody formation and its significance in a population of patients consistently receiving RhD-matched RBC units. We retrospectively reviewed the transfusion and clinical information of all transfused patients with MDS enrolled in our hospital from 2012 to 2022. The cumulative incidence of alloimmunization was analyzed by a Kaplan-Meier plot. Alloimmunization incidence was compared based on different transfused RBC units using the log-rank test. A total of 103 patients with MDS were included in this study; alloantibody formed in 8 (7.8%) patients. Before reaching 32 RBC units, 87.5% of the alloimmunized patients had developed their alloantibodies. All but 1 of the alloantibodies developed were antibodies to Rh antigens. The RBC transfusion intensity and frequency were significantly higher following alloimmunization in the alloimmunized patients (P=.008, P=.008, respectively). The antibodies detected mostly involve the Rh system among MDS patients in China. The alloimmunization tended to occur early prior to reaching 32 RBC units in patients with MDS. Rh antigen matching should be considered early in the patient's transfusion history and completed before receiving 32 RBC units.

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.

A genome-wide association study of alloimmunization in the TOPMed OMG-SCD cohort identifies a locus on chromosome 12.

Red cell alloimmunization after exposure to donor red cells is a very common complication of transfusion for patients with sickle cell disease (SCD), resulting frequently in accelerated donor red blood cell destruction. Patients show substantial differences in their predisposition to alloimmunization, and genetic variability is one proposed component. Although several genetic association studies have been conducted for alloimmunization, the results have been inconsistent, and the genetic determinants of alloimmunization remain largely unknown. We performed a genome-wide association study (GWAS) in 236 African American (AA) SCD patients from the Outcome Modifying Genes in Sickle Cell Disease (OMG-SCD) cohort, which is part of Trans-Omics for Precision Medicine (TOPMed), with whole-genome sequencing data available. We also performed sensitivity analyses adjusting for different sets of covariates and applied different sample grouping strategies based on the number of alloantibodies patients developed. We identified one genome-wide significant locus on chr12 (p = 3.1e-9) with no evidence of genomic inflation (lambda = 1.003). Further leveraging QTL evidence from GTEx whole blood and/or Jackson Heart Study PBMC RNA-Seq data, we identified a number of potential genes, such as ARHGAP9, STAT6, and ATP23, that may be driving the association signal. We also discovered some suggestive loci using different analysis strategies. We call for the community to collect additional alloantibody information within SCD cohorts to further the understanding of the genetic basis of alloimmunization in order to improve transfusion outcomes.

Hemoglobin Electrophoresis versus Kleihauer-Betke to Determine Bone Marrow Suppression in Fetuses Undergoing Intrauterine Transfusion.

Mainstay therapy for fetuses affected by maternal red cell alloimmunization is serial intrauterine transfusion (IUT). Testing to determine when fetal red cells have been replaced with donor cells historically involves the use of the Kleihauer-Betke (KB) test. Hemoglobin (Hgb) electrophoresis testing may be more rapid with a reduced cost of analysis. We aimed to determine the correlation between fetal Hgb electrophoresis versus the traditional KB test. This is a retrospective analysis of all alloimmunized singleton pregnancies undergoing IUT between January 1, 2021, and July 1, 2023. Maternal and fetal characteristics were collected along with the indication for IUT. A final fetal blood sample was obtained at the conclusion of each transfusion and sent for KB testing and Hgb electrophoresis. The primary outcome was the assessment of these parameters in their ability to predict the replacement of the fetal circulating red cell population with donor cells. Linear regression analysis and repeated measures analysis of variance were performed, and p-values less than 0.05 were considered significant. A total of 56 IUTs were performed in 16 patients. There were 39 (69.6%) final KB test values collected and compared with 30 (53.6%) final Hgb electrophoresis values. Hgb electrophoresis when compared with the KB test demonstrated a significant correlation (R 2 = 0.93; 95% confidence interval, 0.61-0.76; p < 0.001). This same finding held true when examining the correlation at each individual IUT as well. The final KB test and Hgb electrophoresis values significantly decreased with each transfusion (p = 0.003). A predominance of adult donor blood was noted by the third transfusion for both laboratory indices. Fetal Hgb electrophoresis obtained at the time of IUT demonstrates a significant correlation with the traditional KB test. · Fetal Hgb electrophoresis following IUT is underexplored. · Hgb electrophoresis is an automated evaluation. · The traditional KB test is a manual evaluation. · These two tests demonstrate significant correlation.

Red Cell Alloimmunisation Among Sickle Cell Disease and Thalassemia Patients Following Rh- and K-Matched Red Cell Transfusion in Southwestern Saudi Arabia: A Multicenter Study.

Alloimmunisation remains a major consequence of blood transfusion among sickle cell disease (SCD) and thalassemia patients due to the exposure to non-self-red blood cell (RBC) antigen. The complication is associated with transfusion reactions and delayed transfusion procedure because of the difficulty of finding compatible blood. This study aims to determine the prevalence of alloimmunisation to RBC and alloantibody specificities among SCD and thalassemia patients in, an endemic area of SCD and thalassemia, Jazan province of Saudi Arabia, from three major hospitals. This is a retrospective, multicenter cross-sectional study conducted on 1027 patients with SCD and thalassemia, which received Rh/K matched transfusions in 2019 in the three centers. Demographic data and medical records of participants from three transfusion institutions were collected and analysed. A total of 1027 were enrolled in the cohort; 906 (88.2%) and 121 (11.8%) patients with SCD and thalassemia, respectively. There were 483 (47%) males and 544 (53%) females with median age of 15 (range 1-48). Among the studied population, 78 were alloimmunised with an overall alloimmunisation rate of 7.6%. These patients developed a total of 108 alloantibodies, and anti-E was the most detected antibody (25.9%) followed by anti-K (24.1%). The overall rate of alloimmunisation to RBC antigen among the studied population in Jazan was low compared to other areas in the country. Most alloantibodies detected were against E and K antigens. The knowledge of most encountered alloantibodies in our population will aid in selecting the most appropriate antigen-negative red cells. Further research, however, is needed to explore factors associated with residual risk of alloimmunisation in these patients.

Red Blood Cell Alloimmunization in Pregnancy: A Review of the Pathophysiology, Prevalence, and Risk Factors.

This review paper provides an overview of the risk factors and laboratory testing for red blood cell (RBC) alloimmunization in pregnancy. RBC alloimmunization is a significant medical issue that can cause haemolytic disease of the fetus and newborn (HDFN), leading to neonatal morbidity and mortality. Current HDFN prophylaxis targets only Rhesus D (RhD) alloimmunization, with no effective measures to prevent alloimmunization to other RBC antigen groups. Several factors can increase the risk of developing RBC alloimmunization during pregnancy, including fetomaternal haemorrhage, RBC and maternal genetic status, and previous transfusions. Identifying these risk factors is essential to execute the appropriate management strategies to minimize the risk of HDFN. The review also discusses the laboratory methods and overview of pregnancy management. The paper highlights the importance of identifying and managing the risk factors for RBC alloimmunization in pregnancy to minimize the risk of HDFN and improve neonatal outcomes.