Red Cell Blood Group Research Articles

Genetic Polymorphism of Antigens in Twelve Rare Blood Group Systems of Li Nationality in Hainan Province

To explore the distribution characteristics of main antigen gene frequencies of Duffy,Diego,Kidd,Dombrock,MNS,Lutheran,Kell,Colton,Scianna,Yt,Knops and Indian in red blood cell blood group system of Li nationality in Hainan Province. Antigens in twelve rare blood group systems of 214 Li people in Hainan Province were genotyped and analyzed by polymerase chain reaction-sequence specific primers (PCR-SSP). The gene frequency of antigens in twelve rare blood group systems of 214 Li people in Hainan Province including: the gene frequency of Duffy blood group system: fya=0.9556，fyb=0.0444；the gene frequency of Diego blood group system: Dia=0.0678，Dib=0.9322；the gene frequency of Kidd blood group system：JKa=0.4533，JKb=0.5467；the gene frequency of Dombrock blood group system：DOa=0.1051，DOb=0.8949；the gene frequency of MNS blood group system：M=0.8131，N=0.1869,S=0.0327，s=0.9673，Mur+=0.5748，Mur-=0.4252；the gene frequency of Lutheran blood group system：AUa=0.8318，AUb=0.1682；the Kell, Colton, Scianna, Yt, Knops and Indian blood type systems showed a monomorph and the genotype was kk, coacoa, Sc1Sc1, YtaYta, KnaKna and InbInb. The observed and expected genotype values in twelve rare blood group systems of Li nationality in Hainan province were obeyed by the Hardy-Weinberg genitic rules. The difference between the observed and expectated values of the Kidd blood group system showed significant differences（χ2=17.1946，P=0.0002）. The genetic distribution and genetic status in twelve rare blood group systems of Li nationality in Hainan Province are relatively stable. The gene distribution of Duffy, Diego, Kidd, Drombrock, MNS and Lutheran blood group systems are polymorphic and show unique distribution characteristics compared with other regions and different nationalities. The gene frequency distribution of Kell、Colton、Scianna、Yt、Knops、Indian blood group systems are monomorphic.

Application Value of Blood Types Gene Detection in Blood Transfusion of Patients with ABO Blood Type Identification Difficulty

The human red blood cell blood group system plays an extremely important role in blood transfusion medicine and the ABO blood group system is of great significance in clinical blood transfusion, organ transplantation, forensic medicine and genetics research. The aim of this study was to study the application of genotyping technology in difficult ABO blood types identification. A total of 12 patients were selected in our hospital from August 2019 to August 2020. Among them, 1 patient with peptic ulcer, 1 patient with chronic kidney disease stage V, 2 patients with diabetes, 1 patient with infertility, 3 patients with anemia, 1 patient with primary liver cancer, 2 patients with leukemia and 1 patient with systemic lupus erythematosus. Polymerase chain reaction-sequence specific primers genotyping method was used to detect these patients with difficult ABO blood type antigens and statistical method was used to analyze the correlation of ABO genotypes and difficult ABO blood types. The specific distribution of ABO genotypes in 12 patients were detected as follows: 6 cases of A/B, 3 cases of A/O and 3 cases of B/O. The genotype detected by polymerase chain reaction-sequence specific primers was consistent with serological phenotype. As an auxiliary method, ABO genotyping can be used to detect difficult ABO blood types.

Blood group systems

Blood group systems

Effect of Red Blood Cell Storage Duration on Outcomes of Isolated Traumatic Brain Injury.

BackgroundThe aim of this study was to investigate the effects of red blood cell (RBC) storage duration on the outcomes of adult isolated traumatic brain injury (iTBI) patients after transfusion.Material/MethodsA total of 1252 adult iTBI patients who received the fresh RBCs (stored for ≤14 days) or old RBCs (stored for >14 days) were finally enrolled in this study. The primary outcome was 90-day mortality. The secondary outcomes were in-hospital mortality, nosocomial infection, and complications.ResultsBy 90 days after RBC transfusion, 89 patients (17.0%) had died in the fresh RBC group, and 107 had died (14.7%) in the old RBC group, with no significant difference in 90-day mortality between the 2 groups (OR=1.192, 95% CI: 0.877–1.620, P=0.261). According to ISS score, no differences were discovered in mild injury (OR=1.079, 95% CI: 0.682–1.707, P=0.746), severe injury (OR=1.055, 95% CI: 0.634–1.755, P=0.838), and more severe injury (OR=1.940, 95% CI: 0.955–3.943, P=0.064). For GCS score, there were no differences in mild injury (OR=1.546, 95% CI: 0.893–2.676, P=0.118), moderate injury (OR=0.965, 95% CI: 0.616–1.513, P=0.877), and severe injury (OR=1.332, 95% CI: 0.677–2.620, P=0.406). We also observed no significant differences in secondary outcomes.ConclusionsUse of old RBCs did not increase the 90-day mortality in adult iTBI patients.

Inter-donor variability in deformability of red blood cells in blood units.

This study aimed to examine the donor-to-donor variability in the deformability of red blood cells (RBCs) from freshly collected blood donations (F-RBC) and packed RBCs. Packed RBCs are supplied for transfusion by the first-in-first-out (FIFO) criterion, assuming that their quality is the same for packed RBCs with equal storage duration. To challenge this notion, we determined the deformability of F-RBC and packed RBCs stored for different durations. Three RBC groups were employed: A. 79 samples of F-RBC; B. 76 samples of packed RBC units, randomly used for transfusion at different storage durations; and C. 65 samples of outdated packed RBCs stored for 35 to 37 days. All packed RBC units were non-leukofiltrated and stored in Citrate-phosphate-dextrose solution with adenine (CPDA-1). RBC deformability was determined using a computerised cell-flow properties analyser, which monitors the shape change of cells directly visualised in a narrow-gap flow chamber and provides the cells' deformability distribution in a large RBC population. The F-RBC deformability exhibited a wide-range inter-donor variability. The cold storage of packed RBCs exerted a mild reduction of deformability, which became significant, compared to the initial inter-donor variability, only after 3 weeks of storage. Packed RBCs are generally supplied for transfusion by the FIFO criterion based on the assumption that the storage duration is a key factor of RBC quality. This study demonstrates that the deformability of red blood cells is significantly different in donors, and substantial variability persists throughout the entire process of their storage. Therefore, the FIFO criterion is not sufficient for assessing the RBC deformability, which should, therefore, be specifically characterised for each unit.

A Predictive Model for Hemoglobin Change before and after Collection of Apheresis Autologous Red Blood Cells in Patients

To analyze the affecting factors of hemoglobin changes in apheresis red blood cells (RBCs), and to establish a predictive model for the evaluation of apheresis. The clinical data of 130 patients undergoing selective surgery for apheresis autologous RBCs from January 2017 to December 2018 were collected. The change of hemoglobin and its affecting factors before and after apheresis were analyzed. The predictive model of the hemoglobin change was established by machine learning algorithm and compared with the theoretical predictive model. The average Hb level in the 300 ml autologous RBC group decreased by 22.61±8.85 g/L, and the average Hb in 400 ml group decreased by 29.08±7.25 g/L. The change of Hb was mainly affected by Hb level before apheresis and peripheral circulation blood volume (P＜0.05). Sex, age, and the interval time between blood collection and operation not significantly influenced Hb change (P＞0.05). The initially established predictive model by the machine learning (MAE 6.27) is superior to the theoretical predictive model (MAE 8.11). The predictive model established by the machine learning can provide a reference for more accurate evaluation of apheresis autologous red blood cells.

The Kg‐antigen, RhAG with a Lys164Gln mutation, gives rise to haemolytic disease of the newborn

The Kg-antigen was first discovered in an investigation of a mother whose infant had haemolytic disease of the newborn (HDN). The antibody against the Kg-antigen is believed to be responsible for HDN. The Kg-antigen is provisionally registered under the number 700045, according to the Red Cell Immunogenetics and Blood Group Terminology. However, the molecular nature of the Kg-antigen has remained a mystery for over 30years. In this study, a monoclonal antibody against the Kg-antigen and the recombinant protein were developed that allowed for the immunoprecipitation analysis. Immunoprecipitants from the propositus' red blood cell ghosts were subjected to mass spectrometry analysis, and DNA sequence analysis of the genes was also performed. A candidate for the Kg-antigen was molecularly isolated and confirmed to be a determinant of the Kg-antigen by cell transfection and flow cytometry analyses. The Kg-antigen and the genetic mutation were then screened for in a Japanese population. The molecular nature of the Kg-antigen was shown to be RhAG with a Lys164Gln mutation. Kg phenotyping further clarified that 0.22% of the Japanese population studied was positive for the Kg-antigen. These findings provide important information on the Kg-antigen, which has been clinically presumed to give rise to HDN.

IMMUNE ANTIBODIES IN MOKSHA AND ERZYA ETHNIC GROUPS OF THE REPUBLIC OF MORDOVIA

ABO system's immune antibodies are common, but not as persistent as natural anti-A and anti-B antibodies. They are the result of hyper immunization of an iso- or heteroimmune nature and belong to the IgG class. The study of serum for the presence of immune antibodies of the ABO, Rh system is necessary for the diagnosis of hemolytic disease cases of newborns with ABO, Rh-conflict pregnancy. Clinically significant immune antibodies of erythrocyte systems capable to cause in vivo destruction of red blood cells are of great importance in transfusiology and immunohematology. The most common cause of their occurrence is alloimmunization with red blood cell antigens during childbirth. The aim of this study was to determine the characteristics of the immune anti-erythrocyte antibodies in residents of the Republic of Mordovia belonging to the ethnic groups of Moksha and Erzya. Methods. The cross-sectional study involved 294 people from the Moksha and 387 people and Erzya ethnic groups, randomly selected in 7 districts of the Republic of Mordovia. Detection of IgG anti-A, anti-B ABO systems was performed by inactivation of disulfide bonds in IgM molecules using a 5 % unitiol solution and then by direct agglutination method at indoor temperature with standard red blood cells of group O(I), A(II), and B(III). The study of incomplete anti-erythrocyte antibodies of other systems was performed by indirect Coombs' test using gel technology. Results. The study of immune antibodies of the ABO system revealed from 10.61 to 16.00 % of anti-A antibodies and from 2.27 to 6.38 % of anti-B antibodies in both men and women Moksha and Erzya. We studied immune anti-erythrocyte antibodies: anti-D 0.34 % in Moksha and anti-D 0.26% and anti-Kell 0.26 % antibodies in Erzya. The scale of immunogenicity of red blood cell antigens in the studied groups: A>, B>, D> and K>. The alloimmunization index of transfusion-hazardous antigens was calculated as 0.34 for Moksha and 0.52 for Erzya. Conclusions. Physiologically, the immune system in Moksha and Erzya actively reacts with antibody's production and it is sensitive to immunization by the group of antigens.

Immediate effects of systemic administration of normal and high O2-affinity haemoglobin vesicles as a transfusion alternative in a rat pneumonectomy model

BackgroundHaemoglobin vesicles (HbVs) are red blood cell (RBC) substitutes with a phospholipid bilayer membrane and a polyethylene modified surface (diameter=250 nm; P50=28 Torr). They can be preserved for years and...

Red cell alloantibodies in beta-thalassaemia major patients' blood referring to the regional blood transfusion center of Tehran, Iran.

Introduction: Thalassemia is associated with a genetic decline in the rate of synthesis of one or more types of natural hemoglobin polypeptide chains. One of the major complications in thalassemia patients is alloimmunization, which is antibody production by the patient against transfused red blood cells (RBCs). These RBCs are unknown by the recipient and the formed antibodies against them are called alloantibodies. This study aimed to evaluate the frequency of alloantibodies against RBCs in beta-thalassemia patients referred to Tehran Regional Blood Transfusion Center. Methods: In this study, antibody screening tests (Dia-cell I, II, and III) were performed on 184 thalassemia patients. An identification test by the Dia panel consisting of 11 different O RBCs groups to examine sera with Dia cells (I, II, or III) was performed. Results: In our study, males and females patients comprised 66 (35.87%) and 118 (64.13%), respectively, of whom 116 (63%) had alloimmunization. In addition, 68 thalassemia subjects (37%) lacked alloantibodies. Among 184 patients with beta-thalassemia major, anti-K (Kell system), anti-D, and anti-E (Rhesus system) had the most abundant alloantibody variants with an incidence of 24 (13%), 11 (5.98%), and 10 (5.4%), respectively. Conclusion: Before RBC transfusion, regular RBC antigen phenotypes, as well as problem-solving of alloantibody production by receiving compatible blood for Kell and RH subgroups, are suggested for all cases of transfusion-derived thalassemia.

Hemoglobin and erythrocyte count are independently and positively associated with arterial stiffness in a community-based study.

The association of blood hemoglobin (Hb) concentration and red blood cell (RBC) count with arterial stiffness is not well-defined. Herein, we examined the associations of brachial-ankle pulse wave velocity (baPWV) and augmentation index (AI) with Hb level and RBC count from a population cohort in and around Beijing, China. A total of 3994 participants (57.1 ± 8.8 years old) were included in our analysis. Blood routine examination, baPWV, and possible covariates were examined. The mean Hb, RBC count, AI corrected for a heart rate of 75 bpm (AIP75), and baPWV were 131.4 ± 17.1 g/l, 4.2 ± 0.5 1012/l, 80.2 ± 12.0%, and 1665.3 ± 377.1 cm/s, respectively, consistent with previously described cohorts. RBC counts and Hb levels were positively associated with baPWV (β for 1012/l RBC: 50.08 cm/s, 95% confidence interval [CI]: 30.54-69.63, p < 0.001; β for 10 g/l Hb: 9.05 cm/s, 95% CI: 3.35-14.76, p = 0.002) and AIP75 (β for 1012/l RBC: 1.33%, 95% CI: 0.55-2.12, p < 0.001; β for 10 g/l Hb: 0.34%, 95% CI: 0.12-0.57, p = 0.003), despite adjustment for covariates. The average levels of baPWV in the third-fourth quartile RBC groups were higher than in the first quartile (Q1) group (p < 0.001 for all). The average levels of baPWV in the fourth quartile Hb groups were higher than in the Q1 Hb group (p = 0.038). Mean AIP75 levels in the third-fourth RBC and Hb groups were higher than in the Q1 groups (p < 0.05 for all). In conclusion, circulating blood Hb levels and RBC counts are positively associated with arterial stiffness in our community-based study.

Improved Hemodynamic Stability in Experimental Trauma/Hemorrhagic Shock by Red Blood Cell‐containing Resuscitation Fluids Secondary to Preserved Diastolic Blood Pressure

ObjectiveFluid resuscitation with blood products is standard of care in the current management of trauma/hemorrhagic shock (T/HS). However, the availability of whole blood is rare in civilian prehospital care, and thus blood component therapy and other fluid replacement options are required. This study sought to differentiate and compare the effects of lactated Ringer’s solution (LR), plasma, washed red blood cells (RBC), and whole blood (Control) as resuscitation fluids for hemodynamic restoration after T/HS.MethodsWister male rats (400g) were randomly divided into four groups: LR, Plasma, RBC, and Control, anesthetized with isoflurane and subjected to experimental T/HS. A mid‐line laparotomy incision was made, and blood was slowly withdrawn to maintain a mean arterial blood pressure (MAP) of 35–40 mmHg for 90 minutes. After the 90‐min shock period, intravenous fluids corresponding to the experimental group were started with the goal of achieving a MAP ≥ 65 mmHg, the clinical target for adequate pressure. Animals were monitored for 120 minutes following start of reperfusion. Vital signs were continuously measured, as well as arterial blood gases, lactate, and hemoglobin.ResultsMAP in animals that received RBCs was similar to that of the whole‐blood Control group (70.4 ± 4.0 mmHg vs 83.0 ± 5.8 mmHg, RBC vs Control, NS), and significantly greater than MAPs of Plasma (59.9 ± 4.4 mmHg, p=0.03) and LR (45.6 ± 4.8 mmHg, p&lt;0.001) groups. As systolic blood pressure (SBP) was not significantly different between RBC, Plasma and Control groups, the higher MAP seen in the RBC group compared to Plasma was due to increased diastolic blood pressure (DBP) (55.5 ± 3.1 mmHg vs 38.6 ± 3.2 mmHg, RBC vs Plasma, p=0.01). The RBC and Control groups were able to achieve a higher MAP with decreased volume resuscitation percentage (RBC: 50.7 ± 13.6%; Control: 39.3 ± 5.1%) compared to the Plasma and LR groups (81.1 ± 4.4% and 190.5 ± 10.6%, respectively). Animals given blood products also displayed significantly lower lactate levels compared to those given LR (Control: 2.3 ± 1.2 mM; Plasma: 4.8 ± 0.9 mM, RBC: 4.3 ± 1.3 mM, vs LR: 10.7 ± 3.5 mM, p=0.004 all groups compared to LR). Ending hemoglobin in RBC animals was significantly greater than in other groups (p&lt;0.001 compared to all groups). However, blood gas analysis revealed that the RBC group also had the lowest O2 saturation (88.3 ± 0.5% vs. LR: 93.9 ± 4.7%, Plasma: 94.8 ± 0.6%, WB: 93.5 ± 4.5%), yet PaO2 was comparable between groups.ConclusionIn our model of experimental T/HS, reperfusion fluids carrying red blood cells substantially improved hemodynamic stability by returning the mean arterial blood pressure to survivable values. The efficacy of RBC and whole blood resuscitation may be largely the result of improvements in diastolic blood pressure, suggesting increased contribution from systemic vascular resistance in these groups.Support or Funding InformationDOD W81XWH‐17‐2‐0047

Normothermic machine perfusion of ischaemically damaged porcine kidneys with autologous, allogeneic porcine and human red blood cells.

In porcine kidney auto-transplant models, red blood cells (RBCs) are required for ex-vivo normothermic machine perfusion (NMP). As large quantities of RBCs are needed for NMP, utilising autologous RBCs would imply lethal exsanguination of the pig that is donor and recipient-to-be in the same experiment. The purpose of this study was to determine if an isolated porcine kidney can also be perfused with allogeneic porcine or human RBCs instead. Porcine kidneys, autologous and allogeneic blood were obtained from a local slaughterhouse. Human RBCs (O-pos), were provided by our transfusion laboratory. Warm ischaemia time was standardised at 20 minutes and subsequent hypothermic machine perfusion lasted 1.5–2.5 hours. Next, kidneys underwent NMP at 37°C during 7 hours with Williams' Medium E and washed, leukocyte depleted RBCs of either autologous, allogeneic, or human origin (n = 5 per group). During perfusion all kidneys were functional and produced urine. No macroscopic adverse reactions were observed. Creatinine clearance during NMP was significantly higher in the human RBC group in comparison with the allogeneic group (P = 0.049) but not compared to the autologous group. The concentration of albumin in the urine was significantly higher in the human RBC group (P <0.001) compared to the autologous and allogeneic RBC group. Injury marker aspartate aminotransferase was significantly higher in the human RBC group in comparison with the allogeneic group (P = 0.040) but not in comparison with the autologous group. Renal histology revealed glomerular and tubular damage in all groups. Signs of pathological hyperfiltration and microvascular injury were only observed in the human RBC group. In conclusion, perfusion of porcine kidneys with RBCs of different origin proved technically feasible. However, laboratory analysis and histology revealed more damage in the human RBC group compared to the other two groups. These results indicate that the use of allogeneic RBCs is preferable to human RBCs in a situation where autologous RBCs cannot be used for NMP.

Effect of phase-change material blood containers on the quality of red blood cells during transportation in environmentally-challenging conditions

BackgroundThe effect of phase-change material blood containers on the quality of stored red blood cells (RBCs) transported in the Qinghai-Tibet Plateau remains to be studied.Study design and methodsRBCs stored in a phase-change material blood container were transported from Chengdu to Tibet and then back to Chengdu. The detection time points were the 1st day of fresh-collected RBCs (group 1), the 14th day of resting refrigerated storage (group 2), and the 14th day of plateau transportation under refrigerated storage in the container (group 3). RBC counts, hemoglobin (HGB) content, free hemoglobin (FHb) content, blood biochemical indexes, hemorheologic indexes and 2,3-DPG content were detected.ResultsCompared with group 2, RBC counts and HGB were decreased, and the mean corpuscular volume (MCV), FHb and K+ content were increased in group 3. The glucose consumption and lactic acid production were significantly increased in groups 2 and 3. Compared with group 2, the 2,3-DPG content and whole blood viscosity were decreased in group 3. After resting refrigerated storage and plateau transportation, the RBC quality still met the national standard (GB18469-2012 whole blood and component blood quality requirements).ConclusionThe phase-change material blood container can be maintained at a constant temperature under plateau environmental conditions, ensuring that the quality of the stored RBCs is compliant with GB18469-2012 whole blood and component blood quality requirements.

Detection of red cell alloantibodies in thalassaemia patients

Background: β-thalassaemia patients receive regular blood transfusion to thrive. Due to antigen disparity between the blood donors and these patients they develop red cell alloantibodies due to alloimmunization. The objective of this study is to predict the frequency of red cell alloimmunization amongst β-thalassaemia major patients receiving regular blood transfusion.Methods: This study including 106 patients with β-thalassaemia was conducted in the department of Transfusion Medicine, S. C. B. Medical College, Cuttack for a period of 12 months. Alloantibodies to different red cell blood group antigens in multi-transfused thalassaemia patients were detected using the glass bead technology for blood group serology in the present study.Results: Out of 106 β-thalassaemia major patients included in the study, 7.5% of patients developed alloantibodies, all being clinically significant. The alloantibodies were anti-E, anti c, anti e and anti-D. The rate of incidence of these alloantibodies was 3.8%, 1.9%, 0.9% and 0.9% respectively. There was a significant association between alloantibody formation with number of transfused packed red cells (Mann-Whitney Test: p value = 0.035) and age at first transfusion (p value = 0.001). The factors having no association with alloimmunization to red cell antigens are age and gender.Conclusions: Alloimmunization to various erythrocyte blood group antigens is a common problem in multi-transfused β-thalassaemia patients. There is an association between number of transfused packed red cells and age at first transfusion with alloantibody formation in the study.

Cell‐free fetalDNAand fetal blood group genotyping: non‐invasive prenatal testing

In transfusion medicine and clinical immunology, cell‐free fetalDNA(cffDNA) is analysed from maternal plasma of pregnant women to predict fetal blood groups with the purpose of (1) assessing the risk of haemolytic disease of the fetus and newborn (HDFN) in immunized women and (2) guiding targeted Rh prophylaxis in non‐immunized RhD‐negative women. National programmes for guiding prophylaxis are now implemented in around 6–7 European countries; assay accuracy is very high, with sensitivities of 99·9%. Sensitivity is challenged by low quantities of cffDNA, especially in early pregnancy. Specificity is challenged by the polymorphic Rh blood group system, where careful attention is needed to navigate among the manyRHDvariants that may complicate cffDNAanalysis and interpretation of results, especially in populations with mixed ethnicities. However, fetalRHDtesting is feasible when implemented with careful attention to these issues. The success of predicting fetal RhD and its successful clinical implementation should encourage widespread implementation. For blood groups that are determined bySNPs, such asKELor Rhc, novel techniques such as next‐generation sequencing and droplet digitalPCRare now providing accurate non‐invasive prediction of these fetal blood groups. Future work on non‐invasive prenatal testing of fetal blood groups determined bySNPs may consolidate the application for cell‐freeDNAtesting for such targets. AtISBT, the newly formed cfDNAsubgroup of the Red Cell Immunogenetics and Blood Group Terminology Working Party will work to facilitate clinical applications, implementation and evaluation of cell‐freeDNAtesting.

Genetic Variants Within the Erythroid Transcription Factor, KLF1, and Reduction of the Expression of Lutheran and Other Blood Group Antigens: Review of the In(Lu) Phenotype.

Erythroid-specific Krüppel-like factor 1, or KLF1, is an integral transcriptional activator for erythropoiesis. Genetic variants within KLF1 can result in a range of erythropoietic clinical phenotypes from benign to significant. The In(Lu) phenotype refers to changes in the quantitative expression of blood group-associated red cell surface molecules due to KLF1 variants which are otherwise clinically benign. These clinically benign KLF1 variants are associated with a reduced expression of 1 or more red cell membrane proteins/carbohydrates that carry blood group antigens for the LU (Lutheran), IN (Indian), P1PK, LW (Landsteiner-Wiener), KN (Knops), OK, RAPH, and I blood group systems. This is of significance during routine serologic blood typing when expression falls below the test sensitivity and therefore impacts on the ability to accurately detect the presence of affected blood group antigens. This is of clinical importance because the transfusion requirements for individuals with the In(Lu) phenotype differ from those of individuals that have a true Lunull phenotype. With this review, we summarize the current body of knowledge with regard to the In(Lu) phenotype and associated KLF1 variants. Our review also highlights discordant reports and provides insights for future research and management strategies. Serological heterogeneity in blood group expression of In(Lu) individuals has been shown, but studies are limited by the low prevalence of the phenotype and therefore the small numbers of samples. They are further limited by availability and inconsistent application of serological reagents and varying test algorithms. With the advent of genome sequence-based testing, an increasing list of In(Lu)-associated KLF1 variants is being revealed. The spectrum of effects on blood group expression due to these variants warrants further attention, and a consistent methodological approach of studies in larger cohorts is required. We propose that a recently reported testing framework of standardized serological studies, flow cytometry, and variant analysis be adopted; and that the international databases be curated to document KLF1 variability and the resultant In(Lu) red cell blood group expression. This will provide better classification of KLF1 variants affecting blood group expression and allow for phenotype prediction from genotype, accurate typing of In(Lu) individuals, and better transfusion management of related challenging transfusion scenarios.

Altered Expression Levels of CD59, but Not CD55, on Red Blood Cells in Stored Blood

Objective: Red blood cells (RBCs) in storage undergo structural and biochemical changes that may cause functional effects. Studies exploring structural changes affecting the expression levels of CD55 and CD59 on RBCs are limited. The aim of this study was to investigate the pattern of CD55 and CD59 expression on RBCs in stored blood from Arab donors. Materials and Methods: Flow-cytometric analysis was performed on RBCs from 92 packed RBC (PRBC) units, stored for varying times, and from 56 nonstored RBC from healthy controls using the commercial REDQUANT kit. Results: The proportions of CD55- and CD59-deficient RBCs from stored PRBC units did not significantly differ when compared with those from healthy controls; however, the mean fluorescent intensity (MFI) of CD59 expression, but not MFI of CD55 expression, on RBCs from stored PRBC units was significantly reduced when compared to the expression of RBCs from healthy controls (p = 0.02). MFI of CD55 expression on RBCs from PRBC units did not significantly differ among the 3 groups of stored RBC; however, there was a statistically significant time-dependent preferential decline in MFI of CD59 expression on RBCs from stored PRBC units (p < 0.01). Conclusion: There is a preferential time-dependent decline in the expression of CD59, but not of CD55, on stored RBCs, the in vivo significance of which in relation to the response to PRBC transfusion needs further investigation.

International Society of Blood Transfusion Working Party on Red Cell Immunogenetics and Blood Group Terminology: Report of the Dubai, Copenhagen and Toronto meetings.

The International Society of Blood Transfusion (ISBT) Working Party for Red Cell Immunogenetics and Blood Group Terminology meets in association with the ISBT congress and has met three times since the last report: at the international meetings held in Dubai, United Arab Emirates, September 2016 and Toronto, Canada, June 2018; and at a regional congress in Copenhagen, Denmark, June 2017 for an interim session. As in previous meetings, matters pertaining to blood group antigen nomenclature and classification were discussed. New blood group antigens were approved and named according to the serologic and molecular evidence presented. Fifteen new blood group antigens were added to eight blood group systems. One antigen was made obsolete based on additional data. Consequently, the current total of blood group antigens recognized by the ISBT is 360, of which 322 are clustered within 36 blood groups systems. The remaining 38 antigens are currently unassigned to a known system. Clinically significant blood group antigens continue to be discovered, through serology/sequencing and/or recombinant or genomic technologies.

The role of genomics in transfusion medicine.

To summarize recent advances in red blood cell (RBC) blood group genotyping, with an emphasis on advances in the use of NGS next generation sequencing (NGS) to detect clinically relevant blood group gene variation. Genetic information is useful in predicting RBC blood group antigen expression in several clinical contexts, particularly, for patients at high-risk for allosensitization, such as multiple transfused patients. Blood group antigen expression is directed by DNA variants affecting multiply genes. With over 300 known antigens, NGS offers the attractive prospect of comprehensive blood group genotyping. Recent studies from several groups show that NGS reliably detects blood group gene single nucleotide variants (SNVs) with good correlation with other genetic methods and serology. Additionally, new custom NGS methods accurately detect complex DNA variants, including hybrid RH alleles. Thus, recent work shows that NGS detects known and novel blood group gene variants in patients, solves challenging clinical cases, and detects relevant blood group variation in donors. New work shows that NGS is particularly robust in identifying SNVs in blood group genes, whereas custom genomic tools can be used to identify known and novel complex structural variants, including in the RH system.