Blood Group Polymorphisms Research Articles

Connection of genetic blood markers with the level of fatty acids in the intramuscular fat of pigs

Using large white, Kemerovo, Duroc, Landrace, and Pietrain pigs, an analysis was carried out of the relationship between the level of fatty acids in the intramuscular fat of pigs and the polymorphism of blood groups by conducting an experiment and reviewing studies by scientists from different countries. The concentration of saturated (SFA), monounsaturated (MUFA), and polyunsaturated (PUFA) fatty acids were studied. A difference in the frequency of blood genotypes in animals with different levels of fatty acids was revealed. Thus, a significant difference was noted in the EA B system between the genotypes EA Ba/a and EA Ba/b in the content of arachidic C20:0 and heptadecenoic C17:1 fatty acid. In the EA D system, a similar difference was found between genotypes EA Da/b and EA Db/b in arachidic C20:0 and eicosandienoic C20:2 fatty acids. In the EA E system, an increased concentration of eicosadienoic C20:2 fatty acid was noted in pigs with the EA genotype E edg/edf, stearic C18:0, arachidic C20:0, palmitoleic C16:1, linoleic C18:2 – in pigs with the EA genotype Eaeg/edg. The EA G system contained significantly less arachidic C20:0 and eicosadienoic C20:2 fatty acids in individuals with the EA Ga/a genotype. A comparison of correlation coefficients allows us to state a high degree of positive correlation between margaric and heptadecenoic acids (r=+0.79), and a high degree of negative correlation was found between oleic and linoleic fatty acids (r= -0.94). The strength of the influence of blood group genotypes on the variability of several fatty acids ranges from 0.2 to 0.6. It is comparable to the effect of the breed factor on the variability of the assessed traits. These data can be used in breeding as candidates for genetic markers for selecting and selecting animals to improve the herd.

Alloimmunization and hyperhemolysis in sickle cell disease.

Alloimmunization against red blood cell antigens and delayed hemolytic transfusion reaction (DHTR) are major barriers to transfusion in sickle cell disease (SCD). In SCD, DHTR is a potentially life-threatening. Blood group polymorphism in SCD patients, who are of African ancestry and frequently exposed to antigens they do not carry; an inflammatory clinical state; and occasional transfusion in acute situations are risk factors for alloimmunization and DHTR. In patients at risk, the transfusion indication must be balanced against the risk of developing DHTR. However, when transfusion is absolutely necessary, protocols combining the prevention of exposure to immunogenic antigens with immunosuppressive treatments must be implemented, and patients should be carefully monitored during posttransfusion follow-up. This close monitoring makes it possible to diagnose hyperhemolysis as soon as possible; to avoid retransfusion, which can exacerbate hemolysis; and to administer specific treatments, such as anticomplement therapy, in severe cases. Finally, in patients with severe disease, hematopoietic stem cell transplantation may be indicated. However, transfusion is also required in this context, and its management is complex because these risks must be taken into account.

Polymorphism of yak blood groups depending on coat color and collection

Yaks of the Republic of Tyva are characterised by high biological diversity, expressed by a wide range of body colours and polymorphism of blood groups. According to the distribution of colour and polymorphic blood systems in bulls and yak dams, the most characteristic colours are black, black-and-white, and brown; their frequency in the population is 0.403, 0.148 and 0.118, respectively. Animals of other colour patterns were encountered with a frequency ranging from 0.004 to 0.091. Differentiation of yak bulls and dams by the presence or absence of horns showed that in polled bulls and dams, the frequency of markers Q, L', F of the blood systems B, C, F-V is higher (from 0.250 to 0.846) than in horned ones (0.100–0.500). Blood markers R2, W, X1, U' systems C, and S were identified in polled bulls and dams with a frequency of 0.018–0.143, not found in horned bulls and dams. The frequency of blood antigens G2, T2, I2, E'2, Y', J2 of systems B, J is higher in horned bulls and dams (from 0.200 to 0.800) than in polled individuals (0.054–0.464), and S1 of blood system S was detected only in horned queens. Blood markers I1, Y2, R2, W, X1, and U' systems B, C, and S were undetected in horned bulls and dams. In polled and horned bulls, the frequency of genes E'2, E, X2, V, Z of blood systems B, C, F-V, and Z is higher; they are detected with a frequency of 0.333 to 1.000, regardless of colour. Polled bulls of grey colour do not have markers A2, G2, I1, O2, Y', Y2, Q', Y', X1 blood systems A, B, C, and brown colour - A2, O2, Q', F, U, U' blood systems A, B, F-V, S. Still, in polled bulls with black and brown colours, blood antigens I1, X1 were identified, which are absent in horned individuals of different colours. In yaks, statistically significant differences were noted in colour, polledness and antigens A2, G2, I1, I2, Q, T2, E'2, I', Y', R2, W, X1, X2, L', F, V, J2, H', U, U', Z.

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.

Acceleration of the selection process in the population of Black and Spotted cattle by using genetic markers

Genetic researches of cattle breeds in the western region of Ukraine are ecologically necessary, and they also become the most actual in connection with the formation of breed associations. In addition, the research of the genetic characteristics of various breeds for use in agricultural production is an attempt to identify the most common genetically determined characteristics in the herd. The choice of such economically valuable characteristics is determined by modern methods of research in agriculture by selecting herds with such a gene pool in which this characteristic is the most typical. The genetic structure was evaluated by genetically determined polymorphism of blood groups and genetic-biochemical systems. Experiments were carried out on erythrocytes and blood plasma. Blood from the animals was taken from the jugular vein in a test tube with heparin. Polymorphism of proteins and enzymes was evaluated using the method of electrophoretic separation of proteins in 13 % starch gel in horizontal chambers followed with subsequent histochemical staining. Group erythrocyte antigens were determined according to the generally accepted methodology based on hemolytic tests using 48 reagents of 9 genetic systems. The genetic structure of this breed is characterized by the following features: the transferrin locus is characterized by the greatest heterozygosity – 0.729, but according to the Hardy-Weinberg law, this locus is in a balanced state (Р – 0.104). The dominant frequency of occurrence is the allele Tf A – 0.438, mainly as a result of AD1 and AD2 heterozygotes. The amylase locus (AM-l) is in an unbalanced state – there are not enough heterozygotes and too many homozygotes (Р – 0.013). The frequencies of occurrence of two alleles Am-l B and Am-l C are the same and amount to 0.500. Hemoglobin is monomorphic in all investigated animals (hemoglobin AA). For purine nucleoside phosphorylase (NP), there are no significant differences within the studied group of animals.The higher frequency of occurrence of the Np L allele is 0.872, but the Np H allele occurs less often, its frequency is 0.128, the heterozygosity of this locus is 0.225. As for blood groups, the vast majority of antigens detected with the help of 48 specific antisera are found in the antigenic spectrum of the investigated Black and Spotted dairy breed. However, the frequency of some antigens (less than 0.057) is extremely low (I1, Q, T1, T2, P1, P2, Y, R, U, I', B'', H''), others (J, B ', U') is slightly higher (0.082-0.099), and some (A2, G2, G3, B2, I2, O1, O2, Y2, D', G', E'2, O', Q', G'', C1, C2, E, W, X2, L, F, S, H'', Z) was sufficiently high (from 0.11 to 0.888). The Black and Spotted dairy breed has a unique genetic structure based on the investigated loci.

Frequency and characterization of RHD and RHCE variants in the Noir Marron population from French Guiana.

The RH system is one of the most polymorphic blood group systems due to the proximity and opposite orientation of RHD and RHCE genes. Numerous alleles are described and can affect Rh protein expression. This complexity is especially evident in populations of African origin. We performed RHD and RHCE genotyping of the Noir Marron population in French Guiana. This population belongs to the Maroon community who are direct descendants of African slaves, who escaped from Dutch plantations, in the current day Suriname, during the 17th century. They represent an original ethnic group with highly blended culture. A total of 89 DNA samples were collected from four different ethnic groups of the Noir Marron population of French Guiana. RHD and RHCE genotyping was performed using DNA microarray and/or sequencing. Significant allelic diversity was shown, with 45% of individuals presenting an RHD gene variant (most common: RHD*DAU, RHD*DIVa, and RHD*DIIIa allele) and 9.4% with a partial D phenotype. Likewise, 85% presenting an RHCE gene variant and 9% a partial RH2 antigen. One original allele was identified in two D+ Noir Marron individuals: a hybrid RHD*DIIIa-CE(9)-D allele, encoding probably a partial D antigen and associated with an RHCE*ce(48C,733G,1006T) allele. The African diversity of RHD and RHCE genes is found in this population with preserved genetic but mixed cultural backgrounds. These data allow us to describe the characteristics of the RH system antigen and highlights a significant number of partial antigens with a risk of alloimmunization.

Genetic background of anti-Xga producers in Japanese blood donors.

The Xg blood group is composed of two antigens, Xga (XG1) and CD99 (XG2 and MIC2). The XG and CD99 are homologous genes located on pseudoautosomal region 1 of the X and Y chromosomes. The expressions of Xga and CD99 are co-regulated by a single nucleotide polymorphism (rs311103) in the GATA-1 binding region. Another mechanism of the Xg(a-) phenotype is the genomic deletion of approximately 114 kb, including the XG gene. Anti-Xga seems to be naturally occurring by detection in males who have never been transfused. In this study, we identified 23 anti-Xga producers among 580,115 donors (0.004%). Additional 12 anti-Xga producers were also identified from a separate cohort. All 35 anti-Xga producers were male. Genomic DNA was obtained from 34 of 35 producers, and all 34 producers were confirmed to carry the XG-gene-deficient allele (XGdel). The breakpoints of all 34 producers were identical. The XGdel was also identified in 12 non-producers of anti-Xga among 860 donors who have no antibodies against RBCs, and the breakpoints were also identical with the anti-Xga producers. Our results will serve as the basis for a more complete understanding of Xg blood group polymorphisms.

Systematic review and meta-analysis of the effect of ABO blood group on the risk of SARS-CoV-2 infection.

We have been experiencing a global pandemic with baleful consequences for mankind, since the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) was first identified in Wuhan of China, in December 2019. So far, several potential risk factors for SARS-CoV-2 infection have been identified. Among them, the role of ABO blood group polymorphisms has been studied with results that are still unclear. The aim of this study was to collect and meta-analyze available studies on the relationship between SARS-CoV-2 infection and different blood groups, as well as Rhesus state. We performed a systematic search on PubMed/MEDLINE and Scopus databases for published articles and preprints. Twenty-two studies, after the removal of duplicates, met the inclusion criteria for meta-analysis with ten of them also including information on Rhesus factor. The odds ratios (OR) and 95% confidence intervals (CI) were calculated for the extracted data. Random-effects models were used to obtain the overall pooled ORs. Publication bias and sensitivity analysis were also performed. Our results indicate that blood groups A, B and AB have a higher risk for COVID-19 infection compared to blood group O, which appears to have a protective effect: (i) A group vs O (OR = 1.29, 95% Confidence Interval: 1.15 to 1.44), (ii) B vs O (OR = 1.15, 95% CI 1.06 to 1.25), and (iii) AB vs. O (OR = 1.32, 95% CI 1.10 to 1.57). An association between Rhesus state and COVID-19 infection could not be established (Rh+ vs Rh- OR = 0.97, 95% CI 0.83 to 1.13).

Examination of the Relationship between the ABO Blood Group and Susceptibility to SARS-CoV-2 Infection Risk

The ABO blood group system has been linked with multiple infectious and non-infectious diseases and disorders such as, hepatitis B, dengue haemorrhagic fever, cancer, cardiovascular diseases, hematologic disorders, metabolic diseases, malaria, etc. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is the virus that causes COVID-19 (Coronavirus disease 2019), a respiratory infectious disease that has become a global pandemic. Several reports have investigated the role of ABO blood groups in susceptibility/resistance to various infectious Diseases, and have proposed that ABO blood group polymorphism may be linked with COVID-19 susceptibility and clinical outcomes, however, the results were questionable. It has been suggested that blood type O may have a protective role against COVID-19 infection, as blood group O individuals were found COVID-19 positive in lower levels. This could emonstrate that those Individuals are less susceptible to infection, or are asymptomatic in higher proportions, or may be associated with a slightly lower risk for severe COVID-19 disease. It has been hypothesized that the mentioned association can be probably explained by the configuration of distribution of the sialic acid-containing receptors on host cell surfaces induced by ABO antigens through carbohydrate-carbohydrate interactions, that could maximize or minimize the SARS-CoV-2 virus spike protein (S) binding to the host cell. The classical viral entry through the ACE-2 receptors can be prevented by the anti-A antibodies that are produced from O and B blood group individuals. Experimental models based on cellular lines suggested a possible explanation for blood type configuration of infection showing that S protein/ACE-2-dependent adhesion to ACE 2-expressing cells was especially inhibited by natural or monoclonal human anti-A antibodies. Consequently, non-A blood groups individuals, mainly O, or B blood group, that produce anti-A antibodies, may have a lesser degree of susceptible to SARS-CoV-2 infection due to the inhibitory effects of anti-A antibodies. Therefore, it is possible that individuals with group A are more susceptible to SARS-CoV-2 infection and/or manifestation of a severe status.

Using whole-genome sequencing to characterize clinically significant blood groups among healthy older Australians

AbstractThere have been no comprehensive studies of a full range of blood group polymorphisms within the Australian population. This problem is compounded by the absence of any databases carrying genomic information on chronically transfused patients and low frequency blood group antigens in Australia. Here, we use RBCeq, a web server–based blood group genotyping software, to identify unique blood group variants among Australians and compare the variation detected vs global data. Whole-genome sequencing data were analyzed for 2796 healthy older Australians from the Medical Genome Reference Bank and compared with data from 1000 Genomes phase 3 (1KGP3) databases comprising 661 African, 347 American, 503 European, 504 East Asian, and 489 South Asian participants. There were 661 rare variants detected in this Australian sample population, including 9 variants that had clinical associations. Notably, we identified 80 variants that were computationally predicted to be novel and deleterious. No clinically significant rare or novel variants were found associated with the genetically complex ABO blood group system. For the Rh blood group system, 2 novel and 15 rare variants were found. Our detailed blood group profiling results provide a starting point for the creation of an Australian blood group variant database.

RBCeq: A robust and scalable algorithm for accurate genetic blood typing.

SummaryBackgroundWhile blood transfusion is an essential cornerstone of hematological care, patients requiring repetitive transfusion remain at persistent risk of alloimmunization due to the diversity of human blood group polymorphisms. Despite the promise, user friendly methods to accurately identify blood types from next-generation sequencing data are currently lacking. To address this unmet need, we have developed RBCeq, a novel genetic blood typing algorithm to accurately identify 36 blood group systems.MethodsRBCeq can predict complex blood groups such as RH, and ABO that require identification of small indels and copy number variants. RBCeq also reports clinically significant, rare, and novel variants with potential clinical relevance that may lead to the identification of novel blood group alleles.FindingsThe RBCeq algorithm demonstrated 99·07% concordance when validated on 402 samples which included 29 antigens with serology and 9 antigens with SNP-array validation in 14 blood group systems and 59 antigens validation on manual predicted phenotype from variant call files. We have also developed a user-friendly web server that generates detailed blood typing reports with advanced visualization (https://www.rbceq.org/).InterpretationRBCeq will assist blood banks and immunohematology laboratories by overcoming existing methodological limitations like scalability, reproducibility, and accuracy when genotyping and phenotyping in multi-ethnic populations. This Amazon Web Services (AWS) cloud based platform has the potential to reduce pre-transfusion testing time and to increase sample processing throughput, ultimately improving quality of patient care.FundingThis work was supported in part by Advance Queensland Research Fellowship, MRFF Genomics Health Futures Mission (76,757), and the Australian Red Cross LifeBlood. The Australian governments fund the Australian Red Cross Lifeblood for the provision of blood, blood products and services to the Australian community.

Genetic structure of population of the Kalmyk breed cattle

Blood groups, due to their irremovability and independence from gender, age, feeding conditions and maintenance, are widely used in animal breeding. The purpose of this study was to identify genetic markers of economically valuable traits of cattle of Kalmyk breed. Analysis of polymorphism of blood groups of Kalmyk cattle during the study period showed that there are antigens in the allelofond with a high concentration and frequency of occurrence: А1, A2, D', W, V, and Z, while G2I', C2 remain with low one. Analysis of the genetic status of different breeds revealed that there are obvious differences in frequencies. Antigens A1,A2,E’3,Z can serve as genetic markers of Kalmyk cattle purebred. The highest index of genetic distance was 0.1931 between the Kalmyk breed of the Republic of Kazakhstan and the Kazakh white-headed breed. The smallest genetic distance was found between the Simmental breed and the Kalmyk AO and is equal to 0.1166. The identification of the most effective method of selection, taking into account the index of genetic similarity, revealed the smallest number of parent pairs in the low (0.0-0.30) and high (0.61-0.90) indices of antigenic similarity and amounted to: “Agrofirma Aduchi” LLC – 24 pairs (16%) and 48 pairs (32%), “Sarpa” AO – 17 pairs (11%) and 21 pair (14%), A. A. Chapchayev AO PZ – 15 pairs (10%) and 9 pairs (6%), “Agribusiness” LLC – 8 pairs (5%) and 7 pairs (5%), respectively. When selecting parent pairs with an antigenic similarity index of 0.31-0.60, it allows to get bullheads with the highest live weight. Antigens marking the index value of 0,31-0,60, А1, А2, G2, E’3, C2, Z are considered genetic markers of the reproductive ability of Kalmyk breed cattle.

Prevalence of Lewis Blood Group Polymorphisms in Southern Thai Blood Donors

Objective: To determine the frequencies of five of the most common (59T&gt;G, 202T&gt;C, 314C&gt;T, 508G&gt;A and 1067T&gt;G) single nucleotide polymorphisms (SNPs) of the FUT3 gene in Thai blood donors and examine their associations with the presence or absence of Lewis antigens on red blood cells.Material and Methods: A total of 364 donor specimens from Songklanagarind Hospital and Regional Blood Centre XII Songkhla, Thailand, were recruited for the study. Molecular analysis of each SNP was performed by polymerase chain reaction amplification with sequence-specific primers (PCR-SSP). The Lewis phenotype was investigated in 159 individuals using the standard hemagglutination test.Results: The frequencies of the SNPs were 32.0% (59T&gt;G), 46.6% (202T&gt;C), 21.7% (314C&gt;T), 37.9% (508G&gt;A), and 25.0% (1067T&gt;A). The prevalences of the Lewis phenotype were 61.0% for Le(a-b+), 7.6% for Le(a+b-), 11.3% for Le(a+b+), and 20.1% for Le(a-b-). The Lewis-negative phenotype was significantly associated with homozygosity in 59T&gt;G and 1067T&gt;A (χ2 =49.873, and χ2 =44.520, respectively).Conclusion: Our findings suggest that le59,1067 is largely responsible for the Lewis-negative phenotype in our southern Thai population. Genetic variations in FUT3 polymorphisms may be used as molecular markers for ethnicity and to help understand the roles of the Lewis blood group in infections or clinical diseases.

Impact of Extended Molecular RBC Antigen Matching between Blood Donors and Patients with Hematological Diseases

Background: Programs to prevent alloimmunization against red RBC antigens aims to provide antigen-compatible blood transfusions for patients with hematological diseases. Recently, there is an emerging role of molecular methods in donor-receptor compatibility for major blood group polymorphisms and for Rh variants to improve transfusion safety.Aims: We aimed to determine the genotype and allele frequencies of major blood-group systems and RHD and RHCE variants in blood donors and patients with SCD, Myelodysplastic Syndromes (MDS), Acute Myeloid Leukemia (AML) or Autoimmune Hemolytic Anemia (AIHA) to verify if the genotyping results are in concordance with serologic typing results and to perform molecular compatibility between donors and patients.Methods: Samples from 198 blood donors were phenotyped for five clinically relevant blood-group system antigens (RH, KEL, JK, FY and MNS). Samples from 158 patients with hematological diseases (101 with SCD, 14 with MDS, 26 with AIHA and 17 with AML) and from 198 blood donors were evaluated molecularly for 18 blood-group systems alleles (RH, CO, CROM, DI, DO, FY, GE, IN, JK, KEL, KN, LE, LU, LW, MNS, OK, SC and YT) using the Blood-MLPA assay (Multiplex Ligation-dependent Probe Amplification). RHD and/or RHCE exon-specific sequencing was performed to discriminate RHD and RHCE subtypes not distinguished by MLPA. Computerized molecular matching was performed between all patients and donors for ABO, RH, MNS, KEL, FY, JK and DI blood-group systems (Level 1). Afterwards, we extended the matching degree [ABO, RH (further variants), MNS, KEL, FY, JK and DI (Level 2)] for patients who inherit clinically relevant RHD and/or RHCE genotypes predicting partial Rh antigens.Results: We found statistically significant differences in the frequencies of the blood group alleles MNS, FY, JK, DO, CO, GE and RH (RHD*DAU0, RHCE*ceVS.01, RHCE*Ce and RHCE*CE) between donors and patients with hematological diseases. The allelic profile of AML patients was the most similar to the allelic profile of donors, while that of SCD patients was the most different. Eight donors and nine patients had clinically relevant RHD genotypes, while 14 donors and 22 patients had clinically relevant RHCE genotypes. There was 99.2% concordance between the results of the serologic typing and the results of the predicted phenotypes by the blood-MLPA. Considering the Level 1 matching It would be possible to find at least one compatible blood donor for 91.1% patients with hematological diseases. From recently transfused patients (i.e., those transfused up to one year prior to participation in the study), 70.3% would have enough blood units for an annual transfusion cycle. The MDS patient group were the least attended with matched blood (55.6%) and the one with the lowest number of compatible donors (85.7%). Taking into consideration the Level 2 matching the average number of available donors per patient reduced from 19.7 to 3.5 when the degree of matching was extended (i.e., from Level 1 to Level 2). Besides, the number of compatible donors was not sufficient to fulfil the transfusion needs of patients with Rh variants.Conclusion: We reliably determine the genotype and allele frequencies of clinically relevant blood-group systems in donors and in patients using molecular methods. It would be possible to meet the transfusion needs of most patients with hematological diseases through molecular compatibility, but the current donor population would not fill the transfusion requirements of patients with Rh variants. Molecular RBC matching increases the safety of patients with SCD, MDS, AML and AIHA by providing more accurate compatibility with genotyped donors and by reducing the risk of transfusion reactions. DisclosuresNo relevant conflicts of interest to declare.

SARS-CoV-2 Infection Susceptibility of Pregnant Patients at Term Regarding ABO and Rh Blood Groups: A Cohort Study.

Background and Objectives: The susceptibility of pregnant patients at term to SARS-CoV-2 infection regarding the ABO and Rh blood group polymorphism was analyzed in this study. Materials and Methods: In this prospective study, 457 patients admitted for delivery at term in our hospital, between 1 April 2020 and 31 December 2020 were studied. There were 46 positive and 411 SARS-CoV-2 negative patients. Their values for RT-PCR, ABO, and Rh blood group analyses, which were determined upon admittance, were studied. Results: A slightly higher percentage of infected pregnant patients at term belonged to the A blood group compared with the percentage belonging to the other blood groups; this was also true for the healthy control group. For the Rh-negative pregnant patients at term, the odds of being infected with SARS-CoV-2 was OR = 1.22 compared with Rh-positive patients where OR = 1. In our study, the highest risk was found among BIII Rh-negative pregnant patients at term (OR = 3). None of the above differences were statistically significant. Conclusions: No significant difference was found between the percentage of ABO or Rh blood groups in SARS-CoV-2 positive patients when compared with SARS-CoV-2 negative patients (p = 0.562).

The role of balancing selection in maintaining human RhD blood group polymorphism: A preregistered cross‐sectional study

Maintenance of genetic polymorphism remains one of the big questions of evolutionary biology, which for a long time tended to be explained by balancing selection. This explanation was later criticized, but now is again accepted as an important mechanism in evolution. Human blood group systems seem affected by balancing selection especially strongly. In this preregistered study, we focused on stable coexistence of RhD-positive and RhD-negative subjects in a population. This is an evolutionary conundrum, because carriers of the less frequent negative allele suffer from lower fecundity due to haemolytic disease of the newborn affecting RhD-positive infants born to RhD-negative women. One explanation of persisting stability of RhD polymorphism points to heterozygote advantage. Over the past decade, numerous studies demonstrated that RhD-positive subjects score better than RhD-negative homozygotes in psychomotor tests and physical health-related variables. Still, evidence of better health and performance of heterozygotes is scarce and merely indirect. We compared the physical and mental health of 2,539 subjects whose RhD genotype was estimated based on their and their parents' RhD phenotype. We confirmed that RhD-negative homozygotes fare worse in terms of physical and mental health than subjects with RhD-positive phenotype and that RhD-positive heterozygotes enjoy better health than both homozygotes. For the first time, we demonstrated that RhD-positive homozygotes might suffer from worse health than RhD-negative homozygotes. Our results strongly support the hypothesis that RhD polymorphism is maintained by heterozygote advantage and that balancing selection may have played an important role in human evolution in this context and in general.

Blood group typing from whole-genome sequencing data.

Many questions can be explored thanks to whole-genome data. The aim of this study was to overcome their main limits, software availability and database accuracy, and estimate the feasibility of red blood cell (RBC) antigen typing from whole-genome sequencing (WGS) data. We analyzed whole-genome data from 79 individuals for HLA-DRB1 and 9 RBC antigens. Whole-genome sequencing data was analyzed with software allowing phasing of variable positions to define alleles or haplotypes and validated for HLA typing from next-generation sequencing data. A dedicated database was set up with 1648 variable positions analyzed in KEL (KEL), ACKR1 (FY), SLC14A1 (JK), ACHE (YT), ART4 (DO), AQP1 (CO), CD44 (IN), SLC4A1 (DI) and ICAM4 (LW). Whole-genome sequencing typing was compared to that previously obtained by amplicon-based monoallelic sequencing and by SNaPshot analysis. Whole-genome sequencing data were also explored for other alleles. Our results showed 93% of concordance for blood group polymorphisms and 91% for HLA-DRB1. Incorrect typing and unresolved results confirm that WGS should be considered reliable with read depths strictly above 15x. Our results supported that RBC antigen typing from WGS is feasible but requires improvements in read depth for SNV polymorphisms typing accuracy. We also showed the potential for WGS in screening donors with rare blood antigens, such as weak JK alleles. The development of WGS analysis in immunogenetics laboratories would offer personalized care in the management of RBC disorders.

The association between ABO blood group and SARS-CoV-2 infection: A meta-analysis.

At present, existing evidence about the association between SARS-CoV-2 infection and ABO blood group polymorphism is preliminary and controversial. In this meta-analysis we investigate this association and determine SARS-CoV-2 positive individuals’ odds of having a specific blood group compared to controls. We performed a systematic search on MEDLINE and LitCovid databases for studies published through July 15, 2020. Seven studies met inclusion criteria for meta-analysis, including a total of 13 subgroups of populations (7503 SARS-CoV-2 positive cases and 2962160 controls). We analysed the odds of having each blood group among SARS-CoV-2 positive patients compared with controls. Random-effects models were used to obtain the overall pooled odds ratio (OR). Subgroup and sensitivity analyses were performed in order to explore the source of heterogeneity and results consistency. The results of our meta-analysis indicate that SARS-CoV-2 positive individuals are more likely to have blood group A (pooled OR 1.23, 95%CI: 1.09–1.40) and less likely to have blood group O (pooled OR = 0.77, 95%CI: 0.67–0.88). Further studies are needed to investigate the mechanisms at the basis of this association, which may affect the kinetics of the pandemic according to the blood group distribution within the population.

RHD and RHCE molecular analysis in weak D blood donors and in patients with Rh antibodies against their own corresponding Rh antigen.

The Rh system is the largest and most polymorphic blood group system. The existence of a large number of RH alleles results in variant phenotypes that often complicate blood donor phenotyping and the distinction between auto- and allo-antibodies in recipients who have anti-Rh antibodies in the presence of their own corresponding Rh antigen. Knowledge of these variants is necessary in order to make blood transfusion safer. Samples from 48 blood donors with serological weak D and from 29 patients who had anti-Rh antibody in the presence of their own corresponding Rh antigen were evaluated molecularly for RHD and RHCE alleles using a blood-multiplex ligation-dependent probe amplification assay and Sanger sequencing. Rh variants were found in 45 of the 48 blood donors: 24/45 (53%) were weak D, 2/45 (4%) partial D and 19/45 (42%) were weak and partial D. The remaining three donors (6%) did not show a mutation in the RHD allele. Among the 29 patients, 13/29 had anti-e, of whom 4/13 had genotypes that predicted a partial e antigen; 11/29 had anti-D, with 6/11 being identified as partial D; 2/29 had anti-c, of whom 1/2 was predicted to express partial c antigen; 4/29 who had anti-E and 4/29 who had anti-C did not show mutations in RHCE*C or RHCE*E. It was possible to find individuals with clinically significant Rh phenotypes due to the weak reactivity of the D antigen, detected through serological tests in blood donors. In patients, when found with the anti-Rh antibody in the presence of the same Rh antigen, it is difficult to distinguish an auto-antibody from an allo-antibody by serological tests; in these cases, molecular methods (genotyping) can help us to determine whether there are changes in the RH alleles and to discover the nature of the antibody (allo or auto).

An unusual variant glycophorin expressing protease‐resistant M antigen encoded by the GYPB‐E(2‐4)‐B hybrid gene

MNS is a highly polymorphic blood group comprising 49 antigens recognized by International Society of Blood Transfusion, some of which may have been generated by genomic recombination among the closely linked genes GYPA, GYPB and GYPE. The GYPE gene has an almost identical sequence to GYPA*01 allele in exon 2 (99% homology), which accounts for M antigen. We investigated an unusual glycophorin molecule with protease-resistant M antigen. Blood samples were screened by an automated blood typing system (PK7300) using bromelain-treated red blood cells (RBCs) and murine monoclonal anti-M. The M-positive RBC samples were analysed by immunoblotting using anti-M as the primary antibody. GYPA, GYPB and GYPE genes were analysed by polymerase chain reaction (PCR), cloning and sequencing using reticulocyte mRNA and genomic DNA. Serological tests and immunoblotting revealed that 103 of the 193009 individuals (0·0534%) expressed protease-resistant M-active glycophorin having a molecular weight of 20kDa. All the 103 individuals were S+s- or S-s+. When reticulocyte mRNA from the individuals with M-active glycophorin (20kDa) was examined by PCR and cloning followed by sequencing, a novel GYPE-B hybrid transcript was identified. Long-range PCR and sequencing using genomic DNA revealed that the individuals had a GYPB-E(2-4)-B hybrid gene. This hybrid gene was predicted to encode a 59-amino-acid mature glycoprotein that expresses no S or s antigens CONCLUSIONS: The prevalence of the M-active glycophorin (20kDa) in the Japanese population is 0·0534%. This glycophorin is predicted to be a 59 amino acids polypeptide encoded by the novel GYPB-E(2-4)-B hybrid gene.