Rh Blood Research Articles

DNA Reference Reagents for Genotyping RH Variants

Patients who carry RH blood group variants may develop Rh alloantibodies requiring matched red cell transfusions. Serologic reagents for Rh variants often fail to specifically identify variant Rh antigens and are in limited supply. Therefore, red cell genotyping assays are essential for managing transfusions in patients with clinically relevant Rh variants. Well-characterized DNA reference reagents are needed to ensure quality and accuracy of the molecular tests. Eight lyophilized DNA reference reagents, representing 21 polymorphisms in RHD and RHCE, were produced from an existing repository of immortalized B-lymphoblastoid cell lines at CBER/U.S. FDA. The material was validated through an international collaborative study involving 17 laboratories that evaluated each DNA candidate using molecular assays to characterize RHD and RHCE alleles including commercial platforms and laboratory developed testing such as Sanger sequencing, next generation sequencing, and third generation sequencing. The genotyping results showed 99.4% agreement with the expected results for the target RH polymorphisms and 87.9% for RH allele agreement. Most of the discordant RH alleles results were explained by a limited polymorphism coverage in some genotyping methods. Results of stability and accelerated degradation studies support the suitability of these reagents for use as reference standards. The collaborative study results demonstrate the qualification of these eight DNA reagents for use as reference standards for RH blood group genotyping assay development and analytical validation.

Variation of ABO phenotypes, Rhesus factor and salivary secretor status in chronic periodontitis patients with and without type II diabetes mellitus: A cross sectional study

Introduction and Aim: While numerous studies have explored the connection between ABO blood groups and disease incidence in various medical contexts, there has been a scarcity of research dedicated to examining the relationship between ABO blood groups and the occurrence of oral diseases with a specific focus on those with and without Type II diabetes mellitus. Understanding the patient’s blood group and salivary secretor status might help to create a new qualitative personalized approach in preclinical diagnosis and to develop preventive measures. Hence, this study delves into the correlation between ABO phenotypes, Rhesus factor, and salivary secretor status in chronic periodontitis patients, with and without Type 2 Diabetes Mellitus Materials and Methods: The study sample comprised 120 subjects aged between 35 and 60 years. Participants were categorized into three groups: Group A, consisting of patients with only chronic periodontitis; Group B, including patients with only Type II Diabetes Mellitus; and Group C, comprising individuals with both chronic periodontitis and Type II Diabetes Mellitus. Salivary secretor status was determined using the absorption elution method. Results: Group B showed the highest percentage of salivary secretors (97.5%), followed by group A (95%) and group C showed the least percentage of secretors (92.5%). Group B showed the least percentage of non-secretors (2.5%), Group A showed 5% and group C showed the highest percentage of non-secretors (7.5%). The common blood groups in Study Group A were O>B>A>AB. Similarly in Group B, the blood groups were B>O=A>AB and finally in Study Group C, the common blood groups were B>A>O>AB. Majority of the individuals were Rh Positive. Conclusion: The current study has identified a correlation between ABO phenotype, Rh phenotype, and secretor status among individuals with periodontitis, both with and without type 2 diabetes.

ASSOCIATION BETWEEN BLOOD GROUPS AND COVID-19 OUTCOME CROSS SECTIONAL STUDY

Background: Coronavirus disease 2019 (COVID-19) first started as an epidemic in Wuhan city – China in 2019 then became a pandemic. Certain viral infections showed linkage with certain antigenic determinants of ABO blood groups and Rh factor. Aim of the study: determine the association between blood groups and Rh factor with COVID19 infection in a sample of Iraqi patients. Patients and methods: This cross-sectional retrospective study was conducted among 580 students of a variety of colleges mainly in Baghdad from 6th of December 2021 to 18th of January 2022. An online questionnaire using Google forms was used to collect the data. Results: A total of 580 samples were collected during the study with 358 (61.7%) females samples and 222 (38.3%) males and there was a significant difference between them (P=0.0001). The mean age of the participants was 20.20± 2.716 years. Of the 580 COVID-19 infected samples collected 289 ( 49.8%) were blood group O. 133 (22.9%) were blood Group A then 108(18.6%) were blood group B, and 50 (8.6%) blood group AB while with significant difference (P=0.). About 508 (87.5%) of the samples were Rh + who had COVID-19 infection and the remaining 72(12.5%) were Rh – (P=0.0001). Conclusions: There was an association between Blood group O+ and COVID-19 infection who did not required hospitalization and the blood group AB+ were less susceptible to infection

An overview of serology and molecular biology of the Rh blood group system

An overview of serology and molecular biology of the Rh blood group system

Adverse pregnancy outcome and its association with the various determinants of current pregnancy in a district hospital, urban Bengaluru, India

Background: Maternal health is a crucial aspect of public health, directly influencing pregnancy outcomes. Adverse outcomes, such as miscarriage, stillbirth, cesarean delivery, and abortion, reflect poor maternal health and contribute to maternal mortality and infant mortality rates. Antenatal care (ANC) and institutional delivery are pivotal strategies to mitigate maternal and fetal complications. However, the escalating rates of cesarean sections in India, surpassing the WHO-recommended threshold, present a severe public health challenge. Methods: This retrospective cross-sectional study, conducted in urban Bengaluru from January to July 2023, aimed to identify adverse pregnancy outcomes and their determinants among women aged 15 to 49 in India. Data from maternal birth and labor records were analyzed, encompassing sociodemographic factors, obstetric characteristics, and adverse outcomes. Results: The study revealed a 20.8% magnitude of adverse pregnancy outcomes. It was found to be higher among women in the age group above 30 years, multigravida, have low blood pressure (BP) both systolic and diastolic, B blood group, positive Rh type, a male baby. In bivariate analysis, higher odds were observed among women in the 30-49 age group, body mass index overweight category, active management of the third stage of labor, and delayed cord clamping were found to be statistically significant. Conclusions: The study underscores the urgency for an expanded action plan to enhance maternal healthcare in India. While governmental initiatives exist, there remains a pressing need to address unnecessary caesarean deliveries and associated complications. The findings advocate for heightened awareness, community health worker training, and stringent guidelines on the necessity of caesarean sections.

Sex-Dependent Changes to the Intestinal and Hepatic Abundance of Drug Transporters and Metabolizing Enzymes in the SOD1G93A Mouse Model of Amyotrophic Lateral Sclerosis.

Amyotrophic lateral sclerosis (ALS) is characterized by death and dysfunction of motor neurons that result in a rapidly progressing loss of motor function. While there are some data on alterations at the blood-brain barrier (BBB) in ALS and their potential impact on CNS trafficking of drugs, little is reported on the impact of this disease on the expression of drug-handling proteins in the small intestine and liver. This may impact the dosing of the many medicines that individuals with ALS are prescribed. In the present study, a proteomic evaluation was performed on small intestine and liver samples from postnatal day 120 SOD1G93A mice (a model of familial ALS that harbors a human mutant form of superoxide dismutase 1) and wild-type (WT) littermates (n = 7/genotype/sex). Untargeted, quantitative proteomics was undertaken using either label-based [tandem mass tag (TMT)] or label-free [data-independent acquisition (DIA)] acquisition strategies on high-resolution mass spectrometric instrumentation. Copper chaperone for superoxide dismutase (CCS) was significantly higher in SOD1G93A samples compared to the WT samples for both sexes and tissues, therefore representing a potential biomarker for ALS in this mouse model. Relative to WT mice, male SOD1G93A mice had significantly different proteins (Padj < 0.05, |fold-change|>1.2) in the small intestine (male 22, female 1) and liver (male 140, female 3). This included an up-regulation of intestinal transporters for dietary glucose [solute carrier (SLC) SLC5A1] and cholesterol (Niemann-Pick c1-like 1), as well as for several drugs (e.g., SLC15A1), in the male SOD1G93A mice. There was both an up-regulation (e.g., SLCO2A1) and down-regulation (ammonium transporter rh type b) of transporters in the male SOD1G93A liver. In addition, there was both an up-regulation (e.g., phosphoenolpyruvate carboxykinase) and down-regulation (e.g., carboxylesterase 1) of metabolizing enzymes in the male SOD1G93A liver. This proteomic data set identified male-specific changes to key small intestinal and hepatic transporters and metabolizing enzymes that may have important implications for the bioavailability of nutrients and drugs in individuals with ALS.

Prevalence of fetomaternal Rhesus incompatibility at the tertiary care hospital: a cross-sectional study.

Fetomaternal Rhesus incompatibility is a medical condition that affects the pregnant woman [of blood group (A, B, AB, O) and a negative Rhesus] and the foetus (of positive Rhesus). The objective of this study is to determine the prevalence and to present the clinical characteristics of fetomaternal Rhesus incompatibility in a tertiary care hospital. The authors conducted a retrospective cross-sectional study and 37 participants were recorded during the study period of 4 years. A total of 11898 pregnant women admitted to the maternity and 37 of them (women with blood groups A, B, AB or O and with a negative Rhesus) participated in our study, including a frequency of 0.31%. Thirty cases of fetomaternal Rhesus incompatibility were recorded in new-borns. 27 (73%) of the women are from the urban region and the age group between 21 and 25 is the most affected with 37.8%. Twenty-two (59.5%) of pregnant women have blood group O (and negative Rhesus) and primiparous women are the most affected with 64.9%. For the discovery of allo-immunization, 43.2% of women discovered it during the second pregnancy and 48.7% women received a single infusion of Anti-D serum during the first pregnancy. Twelve (40%) new-borns developed jaundice as a perinatal prognosis. Fetomaternal Rhesus incompatibility remains a major problem of maternal health because it is likely to lead to the formation of antibodies in women, which by crossing the placental barrier, they destroy red blood cells and thus cause serious complications.

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

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

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

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

Detection of ABO Blood Groups From Dentin and Pulp by Using the Absorption-Elution Technique: A Forensic Cross-Sectional Study Among the Population of the Al Jouf Province, Saudi Arabia.

Background and objective Human teeth have a significant forensic importance. As they are the hardest of all human tissues, they are not just chemically stable but also their characteristics are maintained for a long time after death even in the most harsh environmental conditions. Despite the advances made in DNA analysis, fingerprinting, etc., ABO blood grouping still plays a significant role in the forensic practice in the field of personal identification, paternity disputes, and several other scenarios including the identification of mass disaster victims. The term blood groups refers to inherited antigens on the surface of red blood cells (RBCs) detected by specific antibodies. Since tooth pulp contains numerous blood vessels, blood group antigens are most certainly bound to be present in tooth pulp. Various studies have shown that blood group antigens in the pulp and dentin are preserved as long as up to two years after the demise of an individual. Absorption-elution technique has been proven to be the most sensitive, reliable, and consistent method to determine the ABO blood group from both the pulp and dentine.This study aimed toascertain the ABO blood group from both the hard (dentin) as well as the soft tissue (pulp) of the tooth by using the absorption-elution (AE) technique and also to determine if there are any variations in identifying the blood groups from the teeth based on age and gender. Material and methods After obtaining due consent, we included patients of both genders aged between 16-60 years visiting the outpatient department (OPD) clinics at the College of Dentistry for periodontal or orthodontic extractions.One patient's blood type was determined by using the slide agglutination technique before any capillary blood extraction was performed; this patient served as a control. For this investigation, we used the pulp and powdered dentin samples taken from the dental extractions to test for the presence of ABO and Rhesus (Rh) factor antigens by using the AE method. The study samples were compared with the control for blood group determination. Statistical analysis was carried out using the chi-square test with Monte Carlo (MC) simulation to check for any correlation of blood grouping with age and gender. Results The dentin and pulp were shown to have positive blood group antigens for the ABO and Rh factors.While neither pulp nor dentin performed significantly differently in identifying the blood group antigens, pulp showed marginally higher accuracy.There was no discernibledifference regarding gender or age in the dentin or pulp of any of the 45 samples studied. Conclusions For determining an individual's blood type and Rh factor, both the hard (dentin) and soft (pulp) tissues of a tooth are valid sources. This is particularly helpful in forensic medicine cases where teeth are the onlyremains that can be viably used to find out a person's identity.

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

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

Investigating the Association Between ABO Blood Groups and Rhesus Factors with Dengue and Chikungunya Virus Infections During the 2017 Outbreak in Bangladesh.

This retrospective study was conducted in 2017 during the dual dengue and chikungunya outbreak in Bangladesh. Febrile participants underwent blood tests for chikungunya, dengue, and ABO groups and rhesus (Rh) factors. Blood grouping information was gathered from healthy donors. Males and those aged between 18 and 49 years had a higher risk of contracting dengue and chikungunya. Blood group O exhibited the highest infection rates at ∼50%, whereas group AB had the lowest at ∼9% among the participants in the study. Yet, when considering the general population's blood group distribution, the combined odds of infection were 2.0, 3.5, and 1.4 times higher in groups B, O, and AB, respectively, than in group A. Infection rates were greater in Rh-negative people. Blood groups B, O, and AB showed higher susceptibility than blood group A according to adjusted odds ratios. Blood groups ABO and Rh factor hold significance in disease susceptibility and vaccine effectiveness. Keeping these implications in mind, further investigations are necessary to understand the mechanisms underlying these connections and their effects on the efficacy of dengue and chikungunya vaccines.

Hemolytic Disease in Newborn Due to Jka Antibody: A Unique Clinical Presentation

Hemolytic disease in newborn results from alloimmune-mediated destruction of fetal or neonatal red blood cells caused by maternal alloantibodies. While ABO and Rh (D) incompatibilities are common causes, other minor antigenic mismatches such as Kidd are relatively infrequent. Here, we report a case of a female infant displaying conjugated hyperbilirubinemia and hepato-splenomegaly. Lab tests revealed both mother’s and baby’s blood groups as A positive, along with elevated reticulocyte count and a positive direct antiglobulin test. An abdominal ultrasound unveiled inspissated bile syndrome, likely due to calcium bilirubin sludge, leading to the conjugated hyperbilirubinemia. Further assessment revealed the infant and the father had a JKa-positive RBC phenotype, while the mother had a JKa-negative phenotype. This case highlights the significance of blood group antigen beyond the Rh system as a potential cause of hemolytic disease in newborn.

Distribution of ABO and Rhesus (D) blood group antigens among the Indian Kami population from the Sub-Himalayan region of West Bengal and Sikkim, India

Abstract BACKGROUND: Limited information is available regarding the distribution of ABO and Rhesus (Rh) blood groups among the populations from the sub-Himalayan regions. The present study was undertaken to understand the phenotypic, genotypic, and allelic frequencies of ABO and Rh antigens among the Kami population. METHODS: A total of 1420 Kami individuals were included in the study from the sub-Himalayan region of West Bengal and Sikkim. The ABO and RhD blood groups were determined among 158 individuals by standard slide agglutination method, and from 1262 individuals blood group, data were collected who had undergone routine blood group tests in diagnostic laboratories. RESULTS: The frequency of blood group O (31.06%) was found to be the highest followed by B (29.15%), A (27.54%), and AB (12.25%). A total of 97.89% individuals were Rh (D) positive and 2.11% were Rh (D) negative. The allele frequencies of ABO were found to be 0.200 for IA (p), 0.243 for IB (q), and 0.557 for IO (r). For Rh (D), the calculated gene frequencies were 0.855 for Rh positive (ID) and 0.145 for Rh negative (Id). Among the subcaste of Kami population, a significantly high frequency of blood group A was observed among Baraily and Lamgade, O among Sashankar, Dural, Diyali, and Dutraj, and B among Ramudamu, Koirala, and Silal. CONCLUSION: The study is the first of its kind to comprehensively describe the ABO blood group distribution among the Kami population which shows the same trend as the general Indian population.

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

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

Blood Transfusion cross match on the basis of Phenotype &amp; Rh Antigen in Donors and Receivers and Analysis of Variations

Background: In brief, knowing the local Rh blood group system frequency helps develop a donor pool for patients who need numerous transfusions and alloantibody-compatible antigen negative blood. Patients have been matched for component blood transfusions using ABO and Rh phenotypes since 2020. Our detection of all blood transfusion-needy patients began. Aim: Our department began To detect C, E, c, and e Rh-specific antigens in multi-transfused patients in 2020. Methods: For the aim of this investigation, 2300 patient samples were obtained from patients who required clinical blood transfusions at our hospital between March 2020 and October 2022. These samples were gathered for the purpose of this investigation. One patient was counted as a single sample even though they required repeated blood transfusions. 1900blood donor samples were provided by the Blood Centre of (duplicated samples were removed based on the identification numbers that were provided by the Blood Centre once they were identified). Results: The study obtained 4200 samples, including 1900donor and 2300patient samples. The allele frequency distribution of blood group antigens in the studied population was compared with the prevalence observed in the present study. The D antigen exhibited a frequency of 99.34% in the studied population, slightly lower than the prevalence observed in the present study at 98.9% (95% CI: 98.5 - 99.0). Conversely, the C antigen was found in 93.1% of the studied population, with a slightly higher prevalence observed in the present study at 99.1% (95% CI: 92.0 - 99.2). Implication: The study suggests serological testing is a cost-effective method for blood transfusion management, identifying Rh phenotypes. Compiling a database of donor Rh genotypes simplifies transfusion selection, reducing unfavorable responses. Pre-transfusion Rh phenotype examination is crucial for matching patient blood type with donor blood, reducing adverse reactions, and improving patient safety. Conclusion: In transfusion applications, serological testing are cost-effective for Rh phenotype identification but not genotypes. Creating a database of blood donors' Rh phenotypes and evaluating each patient before their initial transfusion should lessen adverse reactions and speed up antigen-negative blood availability, saving more patients. Keywords: Blood transfusion, phenotype, Rh antigen, donors, receivers, analysis of variations

Distribution and Frequency of ABO and Rhesus blood groups among donors at Chughtai Institute of Pathology, Lahore

Aim: To assess the demographic background of blood donors in a referral institution located in Lahore, as well as the distribution of blood groups among those who donate blood. Additionally, the study will investigate the distribution of blood groups among those who donate blood. Study design: A cross-sectional study Place of Study: Chughtai Institute of Pathology, Lahore Study duration: March to June 2023 Results: Among the participants, blood group O was most common 202(49.26%), followed by A 110(27.1%), B 82(20%) and AB 15(3.65%). Blood group O was most common. Blood group O was the least common among participants. The least common blood group was AB, with 3.65% of male participants and 1.7% of female participants. A statistical analysis found no significant difference between gender and blood type (χ2 = 2.9932, P value =0.912). All blood groups except AB had Rh-negative antigens. A comparison of blood types found no changes in RH (χ2 = 2.112, P value = 0.698). Conclusion: For the functioning of a national health service, it is crucial to possess current information on the prevalence of blood types in various local settings. Currently, there is a lack of information on this important subject. Our research provides detailed information on the blood type and demographic characteristics of donors. Additional research and mobilisation are needed nationwide to adhere to the World Health Organization's suggestions regarding voluntary blood donation. Keywords: Rhesus factor, ABO, blood donation, and transfusion medicine

Serological Characteristics and Clinical Significance of Irregular Antibodies in Pregnant Women

To understand the serological characteristics of irregular antibodies in pregnant women and explore their clinical significance. From January 2017 to March 2022, 151 471 pregnant women in Women and Children's Hospital of Chongqing Medical University were enrolled in this study, microcolumn gel card test was used for irregular antibody screening, and antibody specificity identification was further performed in some antibody-positive subjects. The positive rate of irregular antibody screening in the enrolled pregnant women was 0.91% (1 375/151 471), 0.23% (355/151 471) was detected in the first trimester, 0.05% (71/151 471) in the second trimester, and 0.63% (949/151 471) in the third trimester. The positive rate of irregular antibody screening in the third trimester was significantly higher than that in the first and second trimester, and a significant increase in the number of positive cases was found in the third trimester than that in the second trimester. The analysis of agglutination intensity of 1 375 irregular antibody screening positive results showed that the weakly positive agglutination intensity accounted for 50.11% (689/ 1 375), which was the highest, the suspicious positive was 18.69% (257/1 375), and the positive was 31.20% (429/1 375). The significant difference in distribution of agglutination intensity was not observed between the first trimester group and the second trimester group, however, in the third trimester, the proportion of suspicious positive and weakly positive was lower than the first trimester, while, the proportion of positive was higher than the first trimester, and the difference was statistically significant (P < 0.001). Among the irregular antibody screening positive pregnant women, the proportion of pregnant women with pregnancy number ≥ 2 was significantly higher than that with pregnancy ≤ 1. Among 60 pregnant women who underwent antibody identification, the distributions of the antibodies were as follows: Rh blood group system accounted for 23.33% (14/60), Lewis system 43.33% (26/60), Kidd system 3.33% (2/60), MNS system 16.67% (10/60), P1PK system 1.67% (1/60), autoantibodies 1.67% (1/60), and 4 cases was unable to identify (6.67%, 4/60). Among specific antibodies, the anti-Lea was the most common (30.00%), followed by anti-E (16.67%) and anti-M (16.67%). The differences of irregular antibody serological characteristics exist in pregnant women from different regions with different genetic backgrounds, understanding the characteristics of irregular antibody in local pregnant women is of great significance for ensuring transfusion safety in pregnant women and preventing hemolytic disease of newborn.

Distribution pattern of abo and rhesus blood group among voluntary blood donors in Abakaliki

ABO and Rhesus (Rh) blood group antigens are hereditary characters and are useful in population genetic studies, in resolving medico-legal issues and more importantly in compatibility test in blood transfusion practice. The aim of this work is to determine the distribution pattern of ABO and Rh (D) blood group among voluntary blood donors in Abakaliki. Blood groups and rhesus were tested in 500 subjects comprising of 446 male donors and 54 female donors. Cell and serum grouping technique was carried out using standard procedures respectively. The overall distribution of ABO cell and serum grouping, and Rh (D) groups result shows that A, B, AB and O are 87(17%), 63(13%), 5(1%) and 345(69%) respectively. For the Rh group, 473 (95%) of the donors were Rh (D) positive and 27(5%) were Rh D negative. The reduction in number of female donors is due to religious belief of some, menstrual flow, fear of needle prick, Low PCV etc. In Conclusion, this work could help health institutions to identify where they can obtain blood products necessary for medical interventions. Moreover, this piece of information contributes to the knowledge of the genetic structure of the Abakaliki population which could have significant implications in different fields of biomedicine.

RH genotypes and red cell alloimmunization rates in chronically transfused patients with sickle cell disease: A multisite study in the USA.

Red cell alloimmunization remains a challenge for individuals with sickle cell disease (SCD) and contributes to increased risk of hemolytic transfusion reactions and associated comorbidities. Despite prophylactic serological matching for ABO, Rh, and K, red cell alloimmunization persists, in part, due to a high frequency of variant RH alleles in patients with SCD and Black blood donors. We compared RH genotypes and rates of alloimmunization in 342 pediatric and young adult patients with SCD on chronic transfusion therapy exposed to >90,000 red cell units at five sites across the USA. Genotyping was performed with RHD and RHCE BeadChip arrays and targeted assays. Prevalence of overall and Rh-specific alloimmunization varied among institutions, ranging from 5% to 41% (p = .0035) and 5%-33% (p = .0002), respectively. RH genotyping demonstrated that 33% RHD and 57% RHCE alleles were variant in this cohort. Patients with RHCE alleles encoding partial e antigens had higher rates of anti-e identified than those encoding at least one conventional e antigen (p = .0007). There was no difference in anti-D, anti-C, or anti-E formation among patients with predicted partial or altered antigen expression compared to those with conventional antigens, suggesting that variant Rh on donor cells may also stimulate alloimmunization to these antigens. These results highlight variability in alloimmunization rates and suggest that a molecular approach to Rh antigen matching may be necessary for optimal prevention of alloimmunization given the high prevalence of variant RH alleles among both patients and Black donors.