Red Cell Antigens Research Articles

Next Generation Sequencing of Red Blood Cell Antigens in Transfusion Medicine: Systematic Review and Meta-Analysis

Molecular analysis of blood groups is important in transfusion medicine, allowing the prediction of red blood cell (RBC) antigens. Many blood banks use single nucleotide variant (SNV) based methods for blood group analysis. While this is a well-established approach, it is limited to the polymorphisms included in genotyping panels. Thus, variants that alter antigenic expression may be ignored, resulting in incorrect prediction of phenotypes. The popularization of next-generation sequencing (NGS) has led to its application in transfusion medicine, including for RBC antigens determination. The present review/meta-analysis aimed to evaluate the applicability of the NGS for the prediction of RBC antigens. A systematic review was conducted following a comprehensive literature search in accordance with the Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines. Studies were selected based on predefined criteria and evaluated using Strengthening the Reporting of Observational studies in Epidemiology guidelines. The characteristics and results of the studies were extracted and meta-analysis was performed to verify the agreement between results from standard molecular methods and NGS. Kell (rs8176058), Duffy (rs2814778, rs12078), or Kidd (rs1085396) alleles were selected as a model for comparisons. Additionally, results are presented for other blood group systems. Of the 864 eligible studies identified, 10 met the inclusion criteria and were selected for meta-analysis. The pooled concordance proportion for NGS compared to other methods ranged from 0.982 to 0.994. The sequencing depth coverage was identified as crucial parameters for the reliability of the results. Some studies reported difficulty in analyzing more complex systems, such as Rh and MNS, requiring the adoption of specific strategies. NGS is a technology capable of predicting blood group phenotypes and has many strengths such as the possibility of simultaneously analyzing hundred individuals and gene regions, and the ability to provide comprehensive genetic analysis, which is useful in the description of new alleles and a better understanding of the genetic basis of blood groups. The implementation of NGS in the routine of blood banks depends on several factors such as cost reduction, the availability of widely validated panels, the establishment of clear quality parameters and access to bioinformatics analysis tools that are easy to access and operate.

Frequency of Rh-e Antigen and reference values of Erythrocyte Sedimentation Rate and Red Cell Indices in an Undergraduate Students’ population in Port Harcourt, Nigeria.

Introduction: Red cell antigens alongside red cell indices provide an essential support to the diagnosis and monitoring of haematological diseases while the erythrocyte sedimentation rate (ESR) indicates and monitor an increase in inflammatory activity within the body. This study aims to determine Rh-e antigen, Erythrocyte Sedimentation Rate and Red cell indices values in apparently healthy undergraduate students of the Rivers State University, Port Harcourt, Nigeria. Material and Methods: One hundred and fifty (150) undergraduate students aged between 17-28years were enrolled in the study and standard venipuncture technique used to collect 5ml of blood. Determination of the Rh-e antigen was carried out using anti-e monoclonal antibodies (Lorne Diagnostics UK), Red cell indices obtained using BC 5000 Mindray Haematology Analyser and ESR by Westergren method. Results: Among the 150 subjects, 130 (86.6%) were positive while 20 (13.3%) were negative for Rh-e antigen. The mean±SD of the mean cell volume (MCV), mean cell haemoglobin (MCH), mean cell haemoglobin concentration (MCHC), red cell distribution width co-efficient of variation (RDW-CV), red cell distribution width-standard deviation (RDW-SD) and erythrocyte sedimentation rate (ESR) were 83.12 ± 10.74, 31.13 ± 3.25, 34.00 ± 3.32, 13.32 ± 1.61, 39.70 ± 2.26 and 30.36 ± 2.15 in the same order, while the reference ranges were 61.64-104.6 for MCV, 24.63-37.63 for MCH, 27.36–40.64 for MCHC, 10.10–16.54 for RDW (CV), 35.18–44.22 for RDW (SD) and 26.06-34.66 for ESR. Gender had no effect on MCV (p=0.3007) and MCHC (p=0.1436) but significant effect on MCH (p=0.030), RDW-CV (p<0.001), RDW-SD (p=0.0005) and ESR (p=0.036) with a perfect positive correlation (r=1) between all the studied parameters. Conclusion: This study revealed a high (86.6%) prevalence for Rh-e antigen, established normal reference ranges for red cell indices and erythrocyte sedimentation rates and showed that gender has significant effects on MCH, RDW-CV, RDW-SD and ESR among healthy undergraduate students of Rivers State University. These findings are of clinical and research relevance.

ABO Red Cell Antigens, von Willebrand Factor, Factor VIII and Platelet counts among Hypertensive Patients In Kaduna Metropolis, Kaduna.

Background: von Willebrand Factor and factor VIII have been implicated in the vulnerability of causing hypertension which is related/common to some of the ABO blood group antigens. However, the precise mechanism/role of the von Willebrand Factor and factor VIII in hypertension is unknown. The study is a comparative study that is aimed to determine the association of ABO red cell antigen, von Willebrand factor, Factor VIII, and Platelets among hypertensive patients in Kaduna, Nigeria. Methods: To determine this association, fifty-five (55) hypertensive patients and 28 controls were recruited. A purposive sampling technique was employed in selecting the study participants. Determination of the ABO blood group, vWF, FVIII, and platelets was carried out to establish the frequency and the association of ABO blood type with hypertension. Results: It was established that blood group O (43%) has the highest distribution followed by A, B, and AB (6%) the least. There was no significant difference in vWF(ng/L), FVIII(pg/ml), and platelet count(109/l) between the patients and the controls (454.9 and 456.2), (242.0 and 228.4) and (238.0 and 213.0) respectively, p>0.05. The correlation studies showed a strong association between vWF and FVIII (r - 0.544, P<0.0001). There was a significant difference between males’ and females’ vWF and FVIII (P=0.0013 and 0.0029 respectively), indicating females had a higher level of vWF and FVIII, and therefore at higher risk of developing hypertension. Women should therefore be screened for these parameters as a matter of routine. Conclusion: The risk of developing hypertension based on the parameters considered in this study is independent of the ABO blood group of an individual. There is a need for further studies, to confirm or rule out these findings.

Assessment of Minor Blood Group System Antigens and Their Phenotype among Voluntary Blood Donors in Ethiopian Blood and Tissue Bank Service, Addis Ababa, Ethiopia.

Red blood cell antigens are numerous in structural and functional diversity; some are proteins while others are carbohydrates. The international society of blood transfusion currently recognized 43 blood group systems containing 349 red cell antigens. It also acknowledged 9 blood group systems (ABO, Rhesus, Kell, Duffy, Kidd, MNS, P, Lewis, and Lutheran) that are clinically significant and associated with hemolytic transfusion reactions as well as hemolytic disease of fetuses and newborns. The objective of this study was to assess the distribution of minor blood group antigens and their phenotype among voluntary blood donors in Ethiopian blood and tissue bank service in Addis Ababa. A cross-sectional study was conducted from January to March 2022 among 260 volunteer blood donors to determine minor blood group antigens and their phenotype at EBTBS, Addis Ababa, Ethiopia. Tests were performed using Galileo Neo Immucor, which is fully automated Immunohematology analyzer. A total of 260 blood donors were screened of which 153 (59%) were males. The antigen frequencies of minor blood group systems were: Fy(a), Fy(b), Jk(a), Jk(b), k, S, s were 33.5%, 43.5%, 97.7%), 40.4%), 100%, 45%, 90%, respectively. Regarding phenotype distribution, the most common phenotypes were: Duffy Fy (a-b+) 36.9%, MNS S-s+ 55% and Kidd Jk (a+b-) 59.6%. This study highlights the frequencies of Fy(a), Fy(b), Jk(a), Jk(b), k, S and s blood group antigens and their phenotypes in volunteer blood donors at EBTBS, Addis Ababa. For the management of alloimmunization cases in transfused patients, knowledge of these minor blood group antigens is relevant.

Frequency and Underlying Causes of Alloimmunization Against Red Blood Cell Antigens in Patients Referred to the Blood Bank of the Tertiary Referral Hospital of Tehran from 2018 to 2020.

Alloimmunization against blood group antigens is an important non-infectious complication of blood transfusion, and early detection of these alloantibodies by antibody screening before transfusion is crucial. Identifying which underlying factors will affect the occurrence of alloimmunization will be necessary to manage this event as accurately as possible. We aimed to assess the prevalence rate and main determinants of RBC alloimmunization among patients referred to a large referral blood bank in Iran. This retrospective cross-sectional study was conducted on all patients referred to a blood bank at Imam Khomeini Hospital between October 2018 and September 2020. Information was collected by referring to the archives of the hospital information system as well as the documents recorded at the blood bank ward and reviewed by two pathologists and completed documents. In total, 39270 cases were cross-matched. Accordingly, the frequency of alloimmunization cases was equal to 220 cases, which indicated a prevalence of 0.56%. The most common alloantibodies were anti-K (43.2%, 95% CI: 36.8‒49.5), anti-E (34%, 95% CI: 27.7‒40.5), and anti-C (16.3%, 95% CI: 11.4‒21.4). Among patients with positive alloimmunization, the most common blood groups were blood group B (34.6%), followed by blood group A (34.1%). Most of these patients were Rh-positive (77.3%). In patients with positive alloimmunization, the frequency of hemoglobinopathy was estimated to be 37.7%. Frequent blood transfusions were found in 42.2%, a history of malignancy in 17.3%, graft history in 11.3%, and a history of pregnancy in 35.0%. Alloimmunization was more prevalent and more predictable among patients with hemoglobinopathies and those receiving recurrent transfusions. Therefore, a history of repeated blood transfusions should be regarded as a risk factor contributing to alloimmunization.

When the available blood supply mismatches the needs of the patient.

Substantial regional differences in the genetic patterns related to blood group have been observed across different continents. This diversity means that the blood supply, as an essential part of patient care, is increasingly impacted by global migration. Consequently, the Austrian blood donor population does not match the immigrant patient population. This mismatch is likely to result in the formation of alloantibodies to red cell antigens in the chronically transfused. Subsequently, major difficulties in providing compatible blood emerge. The study included patients of African origin (n=290) and Caucasians who represent the Austrian donor population (n=1,017). Genetic typing was performed for up to 69 blood group polymorphisms with a multiplex sequence specific primer-PCR including high frequency antigens and antigens for which antisera are not commercially available. By assessing differences in antigen frequencies between the two populations, and using these data for prophylactic matching, we aim to develop tools to increase the quality of patient care. Results indicate various and significant differences (p<0.0001) in antigen frequencies between African patients and the European donor population, especially in the MNS, Duffy, Knops and Rhesus systems. Our data highlight the importance of matching the donor population to the demographics of the patient population. In addition, it underlines the need to recruit donors of African origin and to focus on the upcoming challenges, such as malaria semi-immunity and a significantly higher rate of infectious disease in this population. It is also recommended to apply extended genetic typing to detect rare blood types, and (cryo)storage of rare blood in national and international rare blood banks. Co-operation with regional blood banks should also be encouraged.

Novel GH109 enzymes for bioconversion of group A red blood cells to the universal donor group O

Glycoside hydrolases (GHs) have been employed for industrial and biotechnological purposes and often play an important role in new applications. The red blood cell (RBC) antigen system depends on the composition of oligosaccharides on the surface of erythrocytes, thus defining the ABO blood type classification. Incorrect blood transfusions may lead to fatal consequences, making the availability of the correct blood group critical. In this regard, it has been demonstrated that some GHs may be helpful in the conversion of groups A and B blood types to produce group O universal donor blood. GHs belonging to the GH109 family are of particular interest for this application due to their ability to convert blood from group A to group O. This work describes the biochemical characterisation of three novel GH109 enzymes (NAg68, NAg69 and NAg71) and the exploration of their ability to produce enzymatically converted RBCs (ECO-RBC). The three enzymes showed superior specificity on pNP-α-N-acetylgalactosamine compared to previously reported GH109 enzymes. These novel enzymes were able to act on purified antigen-A trisaccharides and produce ECO-RBC from human donor blood. NAg71 converted type A RBC to group O with increased efficiency in the presence of dextran compared to a commercially available GH109, previously used for this application.

Association of HLA-DRB1 alleles with anti-D alloimmunization in RhD negative pregnant women in India

BackgroundHuman leukocyte antigen (HLA) restriction plays an important role in the susceptibility to alloimmunization against red blood cell (RBC) antigens. The prevalence of anti-D alloimmunization in RhD negative pregnancy is still quite high in our population. Thus, we planned this study to determine the association of HLA-DRB1 alleles with anti-D alloimmunization in RhD negative pregnant women. Material and methodsRBC antibody screen (ABS) was performed for RhD negative pregnant women attending the antenatal clinic our institute. Those with a negative result were included in the ‘non-alloimmunized’ (NAL) group (‘Control’ group), while those with anti-D alloantibody on performing antibody identification were included in the alloimmunized (AL) group of the study (n = 50 each). ABS and identification were done using column agglutination technique. The HLA-DRB1 typing was done by Luminex based reverse sequence specific oligonucleotide probing (SSOP) using commercial kits. The HLA-DRB1 allele frequency was compared in both the groups. ResultsThere was a significant difference between the two groups in terms of gravida (p < 0.001) and history of anti-D immunoprophylaxis (p < 0.001). The frequency of HLA-DRB1*03 and HLA-DRB1*04 alleles was significantly higher in the AL group than the NAL group: 40 % versus 18 % [Odds Ratio (OR): 3.04, 95 % CI: 1.21–7.6; p = 0.015] for HLA-DRB1*03 alleles and 18 % versus 4 % (OR: 5.27, 95 % CI: 1.08–25.78, p = 0.025) for HLA-DRB1*04 alleles. ConclusionThe frequency of HLADRB1*03 and HLADRB1*04 alleles was significantly higher in RhD negative pregnant women alloimmunized with anti-D alloantibody.

The effects of the differentiated macrophages by dexamethasone on the immune responses

The characteristics of M2 macrophages suggest immunotherapeutic approaches for inducing immunological tolerance. The current study aimed to evaluate the effect of Dexamethasone (Dex) treatment on monocytes polarization and its impact on immune responses. The monocytes were extracted from the rat's blood samples. The effects of Dex concentration and treatment duration on monocyte viability, phagocytosis of rabbit red blood cell (RRBC) antigens, and cytokine gene expression were evaluated using MTT, ELISA, and Real-Time PCR analysis, respectively. The monocytes treated with Dex were injected into the rats as an autograft. The effects of the grafted cells were assessed on immune responses, monocyte differentiation, and pathological lesions, in comparison to the control groups.Treatment of monocytes with 10-5 M of Dex for 48 h increased the expression of IL-10 and TGF-β genes, while reducing the expression of TNF-α and IL-1 genes. The monocytes treated with antigen and Dex showed higher CD206 gene expression compared to CD80. The cells that were treated with Dex had the highest concentration of antigens after five days. Administration of the grafted cells to the animals has some significant effects on innate immune responses and no impact on pathological lesions. The group that received cells treated with Dex and antigen experienced a significant decrease in anti-RBC antibody titers. Additionally, there was a significant difference in the expression of cytokine genes and M2 differentiation markers among the groups that were evaluated. The effects of Dex on the viability and differentiation of monocytes depend on the dosage, timing, and duration of the treatment.

Prevalence of Red Blood Cell Alloimmunization Among Pediatric Patients with Sickle Cell Disease in Saudi Arabia

Purpose: Sickle cell disease (SCD) is a common global hereditary hemoglobin disorder. One of the main treatments of sickle cell patients is the requirement of blood transfusions. Post transfusion alloimmunization of red blood cell antigens continue to be a major risk for SCD patients. The study objective is to determine the rate, nature, and risk factors of red cell alloimmunization among pediatric SCD patients in our center and compare our results to published reports from the KSA, regional and some international countries.&#x0D; Methodology: A retrospective study drsign was adopted with record review of SCD patients at King AbdulAziz Medical City-Jeddah (KAMC-J) between 2008-2019 where blood samples were analyzed for alloimmunization using immunohematological techniques. Demographic characteristics and transfusion history were recorded. Data analysis was conducted by SPSS ver. 26. Data are summarized as frequency distribution and chi square test was used to check significance of the difference in the frequency of alloantibodies among subgroups. &#x0D; Findings: Out of all examined sickle cell patients (n=112). Alloantibodies were detected in 21 patients (17.4%), and these were mostly single in 15 patients (71.4%) as anti-K (23.7%), anti-E (19.0%), and anti-S (9.5%). The other six patients (28.6%) had multiple alloantibodies, especially the combination of anti-C and anti-K (9.5%) and the combination of anti-C and anti-E (9.5%). Alloantibodies were significantly higher in patients who had been admitted to the hospital &gt; 5 times annually, those who had an exchange blood transfusion, age groups &gt; 3 years, and for those who received a larger number of blood units (p-value &lt; 0.05).&#x0D; Recommendations: The consequences of red blood cell alloimmunization are highly significant and, therefore, extended RBC antigens to include ABO, RH (D, C, c, E, e), K, Fya, Fyb, Jka and Jkb antigens in the screening panel for donors and recipients is highly recommended to ensure better transfusion practices and avoid transfusion related complications. Our rate of alloimmunization post frequent blood transfusion is considered relatively low compared to other nations.

Antibody-mediated antigen loss switches augmented immunity to antibody-mediated immunosuppression

AbstractAntibodies against fetal red blood cell (RBC) antigens can cause hemolytic disease of the fetus and newborn (HDFN). Reductions in HDFN due to anti-RhD antibodies have been achieved through use of Rh immune globulin (RhIg), a polyclonal antibody preparation that causes antibody-mediated immunosuppression (AMIS), thereby preventing maternal immune responses against fetal RBCs. Despite the success of RhIg, it is only effective against 1 alloantigen. The lack of similar interventions that mitigate immune responses toward other RBC alloantigens reflects an incomplete understanding of AMIS mechanisms. AMIS has been previously attributed to rapid antibody-mediated RBC removal, resulting in B-cell ignorance of the RBC alloantigen. However, our data demonstrate that antibody-mediated RBC removal can enhance de novo alloimmunization. In contrast, inclusion of antibodies that possess the ability to rapidly remove the target antigen in the absence of detectable RBC clearance can convert an augmented antibody response to AMIS. These results suggest that the ability of antibodies to remove target antigens from the RBC surface can trigger AMIS in situations in which enhanced immunity may otherwise occur. In doing so, these results hold promise in identifying key antibody characteristics that can drive AMIS, thereby facilitating the design of AMIS approaches toward other RBC antigens to eliminate all forms of HDFN.

The Incidence of Evanescent Antibodies to Red Blood Cell Antigens in a Tertiary Care Hospital in Northern India

Background and Objectives: The anti-A and anti-B are naturally occurring antibodies in the human body but alloantibodies may be formed in individuals who lacks that corresponding red cell antigen after any sensitising event like blood transfusion or pregnancy. The aim of this study was to find the incidence of evanescenct RBC alloantibodies that may not be detectable at the time of pre-transfusion screening. Methods: This was a retrospective observational study from January 2017 to May 2019 in a tertiary care centre from North India. The data on antibody screening and identification retrieved from the departmental records. The patients were screened for red blood cell antibody and those with a positive screening test were further investigated for antibody identification. Antibody screening was performed by solid phase method using Immucor Capture-R Ready Screen (4 cell). Confirmed positive samples were investigated with advance methods of Antibody ID using Reagent panel Red Blood Cells Capture-R Ready ID (16 Cell) in Automated Analyzer Iris or Neo (Immucor Inc. Nocross, GA, USA). As and when required other advance techniques of adsorption and elution, etc were also performed too. Results: The total number of patient screened during this period were 8071. Amongst them 312 were positive for antibody screening (3.8%), of those 216 (62.9%) cases had alloantibodies and 96 (30.7%) cases had autoantibodies. Among the 216 cases of alloantibody, 147 (68.1%) cases had single alloantibody and 69 (31.9%) cases had multiple alloantibodies. Amongst the patients having single alloantibody, the prevalence was highest for Anti-D 54 (36.7%), followed by Anti-E 27 (18.3%), Anti-C 8 (5.4%), Anti-c 7 (4.7%), Anti-K 9 (6.1%), Anti-Fyb 11 (7.4%), Anti-M 18 (12.2%), Anti-N 4 (2.7%), Anti-Fyb 3 (2%), Anti-Lea 3 (2%), Anti-Cw 2 (1.3%) and Anti-Mia 1 (0.6%). Of the 96 patients with autoantibody 72 had warm autoantibody, 10 had cold autoantibody and there were 8 cases of mixed warm and cold autoantibodies. There were 6 patients with warm autoantibody with underlying alloantibody. Conclusion: In conclusion, the high prevalence of Anti-Rh (Anti-D, E), Anti-M, Anti-Fyb antibodies in patient requiring transfusion reiterates the importance of stringent antibody screening and identification as an essential step in preventing delayed hemolytic transfusion reaction.

Red Cell Alloimmunization and Antibody Specificity in Multigravida Attending Antenatal Clinic at Tertiary Care Centre from Rohilkhand Region

Introduction: Red cell alloimmunization is an immuneresponse to foreign red cell antigens which can occur due totransfusion between a donor and recipient, during pregnancybetween mother and fetus and also in transplant recipients.Such disparity may result in transfusion reactions or may beassociated with hemolytic disease of the fetus and newborn.The current study was undertaken to observe the prevalenceof red cell alloimmunization and antibody specificity inmultigravida patients with respect to epidemiological (age),obstetrical, major blood group systems and transfusion-relatedparameters.Material and Methods: This prospective cross-sectional studywas conducted over a period of 1.5 years from October 2018 toApril 2020, in the patients at risk of exposure to foreign red cellantigens in multigravida patients, in the blood bank of tertiarycare medical institute of North India.Antibody screening and identification was performed on 1055multigravida females using commercially prepared O cells(IMMUCOR, USA). Statistical evaluation by Chi-square testwas performed wherever applicable. p-value of &lt;0.05 wasconsidered statistically significant at 95% confidence interval.Results: Prevalence of red cell alloimmunization inmultigravida females was 1.99% with anti-D being the mostcommon antibody identified. Other less commonly detectedalloantibodies were anti-E, anti-Jkb (Kidds) and anti-Kpa (Kell).A statistically significant association was found between red cellalloimmunization and increase in gravida status, presence ofbad obstetric history, age (&gt;30 years) and Rh-D status. Whencompared with other independent variables such as parityand ABO blood group of the female, no statistical significantassociation was observed.Conclusion: Maternal alloimmunization is associated withanti-D specificity and antibodies against other clinicallysignificant minor blood group antigens such as anti-E andanti-Jkb (Kidd) and anti-Kpa (Kell). Routine antibody screeningof all antenatal females, irrespective of the Rh-D status mustbe adopted by health care system for detection of clinicallysignificant antibodies that may be associated with HDFN ordelayed hemolytic transfusion reaction.

Prevalence of alloantibodies associated with haemolytic disease of the fetus and newborn in pregnant women at the Ekiti State University Teaching Hospital, Ado-Ekiti, Southwest Nigeria.

Haemolytic disease of the fetus and newborn (HDFN) is caused by maternal alloimmunization against red blood cell antigens, which could result in fetal anaemia, hyperbilirubinaemia, kernicterus, and death. This study was designed to determine the prevalence of alloantibodies against erythrocyte antigens in blood samples of pregnant women during the first trimester which may cause HDFN. A total of 123 consenting pregnant women attending the antenatal clinic of Ekiti state University Teaching Hospital, Ado Ekiti participated in the study which lasted three months. The participants were within the ages of 16 to 45 years old across the major ethnic group in Nigeria. ABO/Rh typing, screening and identification of red blood cell alloantibodies were carried out using standard protocols. 15 (12.2%) subjects had detectable antibodies known to cause haemolytic disease of the fetus and newborn (HDFN). The specificity of the antibodies was as follows: anti-K (5, 33%), anti-k (3, 20%), anti- Jsa (2, 13%), anti-C. (3, 20%), and anti-E (2, 13 %). Based on ethnicity, the prevalence of Kell antibodies was highly significant among the Yorubas as well as anti-C and anti-E. The observation was similar in the Igbo and Hausa groups. There is a need to determine these antibodies and monitor their titre in pregnant women to manage or prevent the morbidity and mortality associated with HDFN during routine antenatal care.

The development and application of a novel reagent for fixing red blood cells with glutaraldehyde and paraformaldehyde

ABSTRACTObjectiveThe currently employed red blood cell reagents have a short shelf life. Some hospitals with a small number of specimens will be unable to utilize them within the validity period, resulting in a substantial increase in the purchase price. Therefore, the method of developing long-term red blood cell reagents is a problem worthy of further study.MethodsIn this experiment, the type and concentration of the red blood cell reagent treatment solution were evaluated based on the red blood cell antigen concentration 24 h after treatment. In addition, the qualified glutaraldehyde/paraformaldehyde reagent was stored for six months, and five red blood cell indices were measured every month. At the same time, the detection indices of treated red blood cell reagents and untreated red blood cell reagents were compared.ResultsIt was discovered that treated red blood cells containing 0.005% GA and 0.05% PFA were more suitable for the preservation of red blood cells than other treated concentrations, and the preservation time could reach six months. The test tube method (n = 24) and microcolumn gel card (n = 35) were used to determine the accuracy of the treated blood cells containing 0.005% glutaraldehyde +0.05% paraformaldehyde, with an accuracy of 100%.ConclusionThis experiment resulted in the development of a novel reagent for treating red blood cells with glutaraldehyde/paraformaldehyde fixed solution that can effectively prolong its storage time by two to three times that of red blood cell reagents currently on the market.

Extended red blood cell antigens and phenotypes in Burkina Faso: potential issues to design local population-sourced red blood cell reagent panels.

To date, 43 blood group systems with 349 red blood cell (RBC) antigens have been recognized. The study of their distribution is useful for blood services to improve their supply strategies for providing blood of rare phenotypes, but also to design indigenous RBC panels for alloantibody screening and identification. In Burkina Faso, the distribution of extended blood group antigens is not known. This study aimed to investigate the extended profiles of blood group antigens and phenotypes of this population and to raise limitations and potential strategies for the design of local RBC panels. We conducted a cross-sectional study that included group O blood donors. Extended phenotyping for antigens in the Rh, Kell, Kidd, Duffy, Lewis, MNS, and P1PK systems was performed using the conventional serologic tube technique. The prevalence of each antigen and phenotype combination was determined. A total of 763 blood donors were included. The majority were positive for D, c, e, and k and negative for Fya and Fyb. The prevalence of K, Fya, Fyb, and Cw was less than 5 percent. The most frequent Rh phenotype was Dce, and the most common probable haplotype was R0R0 (69.5%). For the other blood group systems, the K-k+ (99.4%), M+N+S+s- (43.4%), and Fy(a-b-) (98.8%) phenotypes were the most frequent. Antigenic polymorphism of blood group systems by ethnicity and geography argues for the design and evaluation of population-sourced RBC panels to meet specific antibody profiles. However, some of the specificities identified in our study, such as the rarity of double-dose antigen profiles for certain antigens and the cost of antigen phenotyping tests, are major challenges to overcome.

Comparing red cell alloantibody detection and titration by gel microcolumn agglutination method with conventional tube in Rh-negative antenatal cases

BackgroundAlloimmunization to red cell antigens during antenatal period is a serious complication. Antibody titration of maternal blood sample corroborates with severity of disease and helps in planning further management. Conventional Tube Testing (CTT) method is widely accepted for antibody titration in antenatal cases but it can be replaced by Gel Microcolumn Agglutination (GMA) as it offers many advantages. Critical titer levels have been recommended by CTT method, but corresponding levels by GMA are yet to be established due to lack of adequate data. MethodsTotal of 1020 Rh negative antenatal females were evaluated over a period of four years and those found to be positive on antibody screening were further investigated. Antibody titration by CTT and GMA was carried out and the titers were correlated with the outcome of pregnancy. ResultsOut of the 1020 cases screened for antibodies, 112 (10.98%) were detected to be positive by GMA while 40 (3.92%) cases were detected by CTT. Titration was performed by both methods and results were statistically correlated. A moderate correlation was observed where one or more than one antibodies were involved (Pearson’s Coefficient 0.756), while a strong correlation (0.893) was observed between the two methods when single antibody (Anti-D) was involved. Titer values obtained by GMA were also higher than CTT. ConclusionGel microcolumn agglutination (GMA) was found to be more sensitive and precise method for titration. A titer of 512 by GMA (IgG only) mostly corresponded to the values of 16 by CTT and had good correlation with clinical outcome.

Turning universal O into rare Bombay type blood

Red blood cell antigens play critical roles in blood transfusion since donor incompatibilities can be lethal. Recipients with the rare total deficiency in H antigen, the Oh Bombay phenotype, can only be transfused with group Oh blood to avoid serious transfusion reactions. We discover FucOB from the mucin-degrading bacteria Akkermansia muciniphila as an α-1,2-fucosidase able to hydrolyze Type I, Type II, Type III and Type V H antigens to obtain the afucosylated Bombay phenotype in vitro. X-ray crystal structures of FucOB show a three-domain architecture, including a GH95 glycoside hydrolase. The structural data together with site-directed mutagenesis, enzymatic activity and computational methods provide molecular insights into substrate specificity and catalysis. Furthermore, using agglutination tests and flow cytometry-based techniques, we demonstrate the ability of FucOB to convert universal O type into rare Bombay type blood, providing exciting possibilities to facilitate transfusion in recipients/patients with Bombay phenotype.

Live birth prevalence of hemolytic disease of the fetus and newborn in the United States from 1996 to 2010

Hemolytic disease of the fetus and newborn (HDFN) is mediated by maternal alloantibodies, a consequence of immune sensitization during pregnancy with maternal-fetal incompatibility with ABO, Rhesus factor (Rh), and/or other red blood cell antigens. RhD, Kell, and other non-ABO alloantibodies are the primary cause of moderate to severe HDFN, whereas ABO HDFN is typically mild. HDFN live birth prevalence owing to Rh alloimmunization among newborns in the United States was last estimated to be 106 per 100,000 births in 1986. HDFN live birth prevalence owing to all alloantibodies was estimated to be 817 to 840 per 100,000 in Europe. There is a need for updated prevalence estimates in the United States and a better understanding of disease demographics, severity, and treatments. This study aimed to estimate the live birth prevalence of HDFN and the proportion of severe cases of HDFN in the United States, to describe the associated risk factors, and to compare the clinical outcomes and treatments among healthy newborns, newborns with HDFN, and newborns who are sick without HDFN using a nationally representative hospital discharge database. In this retrospective, observational cohort study, we used data from the 1996 to 2010 National Hospital Discharge Survey to identify live births, defined by inpatient visits with the newborn flag, with and without a diagnosis of HDFN across 200 to 500 sampled hospitals (≥6 beds) per year. Patient and hospital characteristics, alloimmunization status, disease severity, treatment, and clinical outcomes were evaluated. Frequencies and weighted percentages were calculated for all variables. Logistic regression was used to compare the characteristics between newborns with HDFN and other newborns using odds ratios. Of 480,245 live births identified, 9810 HDFN cases were recorded. When weighted to the United States population, this corresponded to a live birth prevalence of 1695 per 100,000 live births. Compared with other newborns, newborns with HDFN were more likely to be female, Black, living in the South (vs the Midwest or West), and treated at larger (>100 beds) and government-owned hospitals. ABO and Rh alloimmunization accounted for 78.1% and 4.3% of newborns with HDFN, respectively, whereas HDFN caused by other antigens, such as Kell and Duffy, accounted for 17.6% of the cases. Among newborns with HDFN, 22% received phototherapy, 1% received simple transfusions, and 0.5% received exchange transfusions or intravenous immunoglobulin. Newborns affected by HDFN caused by Rh alloimmunization were more likely to require medical interventions, including simple or exchange transfusions, and more likely to be delivered by cesarean delivery. Overall, HDFN was associated with a longer hospital length of stay in the neonatal intensive care unit when compared with healthy and other sick newborns, a higher rate of cesarean delivery, and a higher rate of nonroutine discharge than healthy newborns. Overall, the live birth prevalence of HDFN was higher than those previously reported, whereas Rh-induced HDFN live birth prevalence was similar to those previously reported. HDFN live birth prevalence owing to Rh alloimmunization decreased over time, likely because of continued Rh immune globulin prophylaxis. Treatment patterns for newborns with HDFN and the comparative clinical outcomes when compared with healthy newborns confirm the continued clinical needs of this population.

Immunostimulatory and Immunorestorative Effects of Leaf Extract and Fractions of Musanga cecropioides on Immunocompetent and Experimentally Immunocompromised Mice

• Musanga cecropioides boosted immune stimulation in immunocompetent animals • M. cecropioides brought about fast rate of restoration of immune status • M. cecropioides stimulated immune response to (sheep red blood cell) SRBC antigen Stimulation of the immune system against disease causing agents and restoration of immune functions in immunodeficiency disease state are essential for maintaining good health. Objective : This study investigated the immunomodulatory effects of the leaf extract and fractions of Musanga cecropioides in immunocompetent and induced immunocompromised animal models. Humoral immune stimulatory effect of the extract and its fractions at 200 and 400 mg∙kg −1 against sheep red blood cells (SRBCs) antigen was determined in both immunocompetent and cyclophosphamide (80 mg∙kg −1 ) immunosuppressed animals. The effect of the most active fraction on leucopoiesis was also determined following high dose cyclophosphamide (300 mg∙kg −1 ) suppression of the immune system. Levamisole at 2.5 mg∙kg −1 was used as the reference drug throughout the study. The extract dose dependently stimulated the humoral immune response to SRBC antigen in immunocompetent animals; however, its stimulatory effect was not significant ( P > 0.05). In the immunosuppressed model, the extract at 400 mg∙kg −1 evoked significant ( P < 0.05) increase in antibody titer value with a corresponding 67% immune-restorative effect. The ethyl acetate fraction (EAF) maintained the most active fraction with significant ( P < 0.05) antibody stimulatory effect in immunocompetent and immunosuppressed animals. Similarly, higher recovery rate was demonstrated by the EAF as shown by steep time recovery curve in high dose immunosuppressed animals. The EAF at 200 and 400 mg∙kg −1 showed above 50% leucopoiesis just like the reference drug (2.5 mg∙kg −1 levamisole) against 33.83% shown by the immune-suppressed control group. M. cecropioides boosted immune stimulation in immunocompetent animals and brought about fast rate of restoration of immune status in immunocompromised animals.