The prevalence of alloantibodies and ABO RhD blood groups in a cohort of Aboriginal and non-Aboriginal cardiac surgery patients from Australia.

INTRODUCTION: Limited evidence exists on the distribution of ABO RhD blood groups and prevalence and specificity of red blood cell (RBC) alloantibodies in Aboriginal and Torres Strait Islander peoples of Australia. We investigated RBC alloantibody prevalence and ABO RhD groups in Aboriginal patients undergoing cardiac surgery at a South Australian (SA) tertiary hospital, a major cardiac surgical referral centre for Northern Territory (NT) patients METHODS: Retrospective analysis of all consecutive patients undergoing cardiac surgery at Flinders Medical Centre (FMC) between January 2014 and June 2019. ABO and RhD blood groups, and RBC alloantibody prevalence, specificity, and clinical significance in Aboriginal and non-Aboriginal cardiac patients were determined at time of surgery and on follow up to 2021. RESULTS: 2327 patients were included, 588 (25.3 %) were from NT, and 420 (18.0 %) were Aboriginal. Aboriginal patients had a higher prevalence of ABO group O (59.8 % vs 43.9 %) and RhD positive (99.0 % vs 83.8 %). One-hundred-and-eleven patients had 154 RBC alloantibodies, 57/420 (13.6 %) Aboriginal versus 54/1907 (2.8 %) non-Aboriginal (p < 0.0001). There were higher numbers of IgM alloantibodies in Aboriginal patients (59/77, 76.6 %), with Lewis, P1 and M more common. Sixty patients had antibodies detected at time of surgery, 14 NT patients with previously detected alloantibodies, prior to surgery, presented with a negative antibody screen and 37 had new antibodies detected after cardiac surgery. CONCLUSION: A high prevalence of IgM alloantibodies was found in Aboriginal compared to non-Aboriginal cardiac surgery patients. The clinical significance of these IgM alloantibodies in Aboriginal peoples requires further investigation.

Blood group AB is associated with reduced blood loss but also elevated cardiovascular mortality in aortocoronary bypass surgery.

Patient blood group (BG) is predictive for von-Willebrand-factor (VWF) and Factor VIII variation. The clinical impact of this ABO-effect on blood loss, cardiovascular complications and outcome has been described for several patient cohorts. The aim of this study was to investigate the impact of patient BG on blood loss and outcome after coronary artery bypass surgery (CABG). Patient records, intraoperative data and perioperative transfusion records of 5713 patients receiving an on-pump CABG procedure between 05/2004 and 12/2018 were analyzed. A logistic regression model for death due to perioperative myocardial ischaemia (PMI) was developed from initially 24 variables by using an univariate and multivariate selection process. BG AB patients required less blood transfusions as compared to the other blood groups, especially in case of emergency operations. However, BG AB patients also had a higher mortality which was due to secondary cardiovascular complications. The impact of blood type on the rate of cardiovascular mortality was confirmed in the logistic regression model. BG AB patients have a worse outcome after CABG surgery due to an increased incidence of fatal cardiovascular complications. As perioperative myocardial ischemia due to graft occlusion appears to be the most likely explanation, stricter anticoagulation for BG AB patients should be discussed.

Comparison of serum alkaline phosphatase levels between two measurement methods in chronic hemodialysis patients in Japan: involvement of ABO blood group system and relationship with mortality risk.

BACKGROUND: Elevated serum alkaline phosphatase (ALP) levels are a risk factor for all-cause mortality in hemodialysis patients. Traditionally in Japan, ALP measurements were conducted using the JSCC method, which yields higher ALP measurement values than the IFCC method, mainly due to its increased sensitivity to intestinal ALP. METHODS: Serum total ALP levels before and after switching the assay method from JSCC to IFCC were compared among different blood types in 521 hemodialysis patients (Study 1). The association between ALP levels measured by the JSCC method and 7-year mortality was analyzed, including blood types and liver function parameters as covariates, in 510 hemodialysis patients (Study 2). RESULTS: ALP levels measured by the JSCC method were approximately three times higher than those measured by the IFCC method, with significant elevation in patients with blood types B and O compared to those with blood types A and AB. Similarly, ALP levels measured by the IFCC method were significantly higher in patients with blood types B and O compared to those with blood types A and AB (Study 1). The highest tertile of ALP levels showed a significantly increased risk of all-cause mortality, even after adjusting for patient background. However, this significance disappeared when serum liver function-related or inflammatory markers were included as covariates (Study 2). CONCLUSION: ALP levels measured by the JSCC method are associated with life prognosis, but caution should be exercised due to their elevation in patients with blood types B and O and in those with hepatic dysfunction or inflammation.

Recipient blood group does not affect hepatocellular carcinoma recurrence after living donor liver transplantation in Korea.

PURPOSE: This study assessed whether or not the ABO blood type affects the incidence of HCC recurrence after living donor liver transplantation (LDLT). METHODS: This retrospective observational study included 856 patients with hepatocellular carcinoma (HCC) who underwent LDLT between January 2006 and December 2016 at the Asan Medical Center. RESULTS: This study included 324 patients (37.9%) with blood type A, 215 (25.1%) with blood type B, 210 (24.5%) with blood type O, and 107 (12.5%) with blood type AB. ABO-incompatible LT was performed in 136 (15.9%) patients. The independent risk factors for the disease-free survival (DFS) were maximal tumor diameter, microvascular invasion, and Milan criteria. The only independent risk factor for the overall survival (OS) was microvascular invasion. The ABO blood group did not affect the DFS (P = 0.978) or OS (P = 0.261). The DFS according to the ABO blood group did not differ significantly between the ABO-compatible (p = 0.701) and ABO-incompatible LDLT recipients (p = 0.147). The DFS according to the ABO blood group did not differ significantly between patients within the Milan criteria (p = 0.934) and beyond the Milan criteria (p = 0.525). The DFS did not differ significantly between recipients with and without type A blood (p = 0.941). CONCLUSIONS: This study demonstrated that the ABO blood group system had no prognostic impact on the oncological outcomes of patients undergoing LT for HCC.

Blood group is a long-term cardiovascular risk factor after carotid endarterectomy.

BACKGROUND: ABO blood group system has been clinically related to an increased incidence of cardiovascular diseases. Preliminary data relating Rhesus (Rh) factor and these outcomes also have been published. Our aim was to analyse the impact of blood group on the short and long-term outcomes after carotid endarterectomy (CEA). MATERIALS AND METHODS: From 2012 to 2019, patients from a referral centre who underwent CEA for atherosclerotic carotid stenosis were prospectively followed. Our primary outcomes were long-term major adverse cardiovascular events (MACEs) and all-cause mortality. Secondary outcomes were perioperative complications and myocardial injury after non-cardiac surgery (MINS). Median follow-up was 50 months (interquartile range 21-69). Time-to-event analysis was used to determine the effect of ABO and Rh groups in long-term outcomes. RESULTS: One hundred and eighty-four patients were included, with a mean age of 70.1 ± 9.1 years. Eighteen (25.7%) patients with O type and 48 (42.1%) patients with non-O type presented coronary artery disease (odds ratio [OR]: 2.313, 5-95% confidence interval (CI) 1.245-4.297, p = .008). Patients Rh+ presented significantly more congestive heart failure, 23 (14.7%), p = .03. The incidence of MACE in the long-term was higher in non-O patients (adjusted hazard ratio: 2.034; CI: 1.032-4.010, p = .040). Rh- patients, presented a higher incidence of perioperative MINS. However, there was no statistically significant association with long-term risk of MACE. CONCLUSION: The incidence of MACE in long-term analysis was higher in non-O blood type and 30-day MINS was significantly more common amongst Rh- patients. The benefit from a more complete preoperative cardiac study in these patients should be performed.

[Distribution of ABO and Rh Blood Groups in Tibetan and Han Populations With Cleft Lip and Palate in a Tertiary Hospital in Western China]. / ä¸­å›½è¥¿éƒ¨æŸä¸‰ç”²åŒ»é™¢è—æ—ä¸Žæ±‰æ—å”‡è ­è£‚æ‚£è€ ABO血型及Rhè¡€åž‹åˆ†å¸ƒç ”ç©¶.

Objective: Congenital cleft lip and palate is a common birth defect that seriously affects the lives of the afflicted children and their families. Previously, no research has been done to investigate the pathogenic characteristics of cleft lip and palate among ethnic minorities, for example, Tibetans, a minority ethnic group with a large population in China. This study aims to investigate the relationship between the occurrence of cleft lip and palate in Tibetans and Han Chinese in western China and the distribution of ABO blood groups and Rh blood groups to provide a theoretical basis for the precise prevention and treatment of cleft lip and palate. Methods: In this study, statistics on Tibetan patients with cleft lip and palate, some Han patients with cleft lip and palate, and normal controls from western China were retrospectively collected. All participants were patients from West China Stomatology Hospital, Sichuan University. All patients with cleft lip and palate received treatment at the hospital between January 2016 and September 2023. The normal controls were outpatients or inpatients who did not have cleft lip and palate, and who received treatment at the hospital between January 2020 and October 2023. Information on the A, B, O, and AB blood groups and Rh positive and negative blood groups of the patients was collected and compared with that of the normal controls. The incidence of different phenotypes, including cleft lip alone, cleft palate alone, and cleft lip with cleft palate, in patients of blood groups A, B, O and AB were statistically analyzed by Chi-square test. Results: A total of 1227 Tibetan patients with cleft lip and palate, 4064 Han patients with cleft lip and palate, and 5360 normal controls were included in the study. Among all the patients with cleft lip and palate, 1863 had cleft lip alone, 1425 had cleft palate alone, and 2003 had cleft lip with cleft palate. The ABO blood group distribution of Tibetan patients with cleft lip and palate was characterized as O>B>A>AB, with Rh positive blood group accounting for 100%, blood type O accounting for 41.15%, and blood type B accounting for 30.64%. The blood group distribution of the Han patients with cleft lip and palate was characterized as O>A>B>AB, with Rh positive blood group accounting for 99.58%, blood type O accounting for 35.78%, and type A accounting for 30.54%. There was a significant difference in ABO blood groups between Tibetan and Han patients with cleft lip and palate (P<0.005), but no significant difference in Rh blood groups. The ABO blood group distribution of the Tibetan patients with cleft lip and palate showed an obvious difference from that of the control group, while those of the Han patients with cleft lip and cleft palate and the control group did not show obvious differences. In the analysis of the subtypes, it was found that the blood group distribution in the subtypes of cleft lip alone, cleft palate alone, and cleft lip with cleft palate in the Tibetan population was O>B>A>AB, while that in the Han Chinese population was O>A>B>AB. There were differences in blood group distribution between Tibetans and Hans of the subtypes of cleft lip alone and cleft lip with cleft palate (P<0.001), but there was no difference in blood group distribution in the population of cleft palate-only subtype. The proportion of blood type O in Tibetan patients with cleft lip and palate was significantly higher than that in the Han patients with cleft lip and palate. The blood group distribution of Tibetan patients with cleft lip and palate in Sichuan Province, Xizang Autonomous Region, and Qinghai Province was always O>B>A>AB. Tibetan patients from Shiqu County and Baiyu County, Ganzi Tibetan Autonomous Prefecture and Chaya County, Qamdo City were predominantly of blood type B, and those from other regions were mainly of blood type O. Conclusion: There were significant differences in the phenotype composition and ABO blood group distribution between the Tibetan and Han populations with cleft lip and palate in western China. The distribution of blood group O in the population with cleft lip and palate was higher than that in the normal population, and the same trend was observed for different phenotypes. However, differences between Tibetan and Han populations in ABO blood group distribution were only found in the phenotypes of cleft lip only and cleft lip with palate. Tibetans with blood type O are more prone to cleft lip deformity than Han people, and the effect in the phenotype of cleft lip with palate is less pronounced than that in the phenotype of cleft lip only.

Impact of ABO-blood group type on haemorrhagic and thromboembolic complications after resection of intracranial meningiomas.

OBJECTIVE: Recent studies have suggested an impact of the ABO-blood group type on thromboembolic and haemorrhagic events following trauma and surgical procedures. However, only limited data are available on the impact of ABO-blood group types in neurosurgical patients. The goal of the present study was to evaluate the role of the ABO-blood group type on the frequency of thromboembolic and haemorrhagic complications in patients treated surgically for intracranial meningiomas at our institution. METHODS: We retrospectively analysed the medical records of consecutive patients undergoing resection of intracranial meningiomas at our institution during a period of 12.5 years (2006-2018). Clinical characteristics, modalities of surgical treatment, histopathological results and the postoperative course of patients were analysed with specific focus on ABO-blood group typing results, need for transfusion of blood products, events of postoperative thromboembolism and intracranial re-haemorrhage requiring surgical revision, as well as in-hospital mortality. RESULTS: A total of 1,782 patients were included in this study. Based on the ABO-blood group type, patients were subdivided into four categories, corresponding to their ABO-blood group: Blood group A (n = 773; 43%); blood group B (n = 222; 12%); blood group AB (n = 88; 5%); and blood group O (n = 699; 39%). Intracranial re-haemorrhage requiring re-craniotomy and haematoma evacuation occurred in a total of 49 patients (2.7%). Thromboembolic events such as pulmonary embolism occurred in a total of 27 patients (1.5%). Statistical analysis showed no significant differences regarding the ABO-blood group type in patients suffering from re-haemorrhage or thromboembolism compared with patients with uneventful course after surgery. The overall in-hospital mortality rate was 0.17% (n = 3). CONCLUSION: Our findings suggest a lack of relevance of the ABO-blood group type regarding haemorrhagic and thromboembolic complications in patients undergoing neurosurgical meningioma resection.

Assessment of post-partum haemorrhage risk among women with moderate thrombocytopenia.

It is unknown whether moderate thrombocytopenia represents a risk factor for post-partum haemorrhage (PPH). We assessed PPH risk among women with a platelet count of between 100 and 50 × 109 /l and stratified the risk for O/non-O blood group. We included consecutive women undergoing vaginal delivery or caesarean section with moderate thrombocytopenia. Women with >150 × 109 /l platelets at delivery were selected as controls and matched for age, type of birth and ethnicity. Odds ratios (ORs) with their 95% confidence intervals (95% CIs) were calculated as risk estimates. A total of 94 thrombocytopenic women and 94 controls were included in the study. The rate of PPH was significantly higher in thrombocytopenic women than in controls (37% vs. 10%, p < 0.001); there was a higher risk of PPH in the thrombocytopenic group when compared to the control group (adjusted OR 4.7, 95% CI 2.1-10.8, p < 0.01) and this association was stronger in blood group O carriers (adjusted OR 11.0, 95% CI 2.4-49.6, p < 0.01). In conclusion, our study shows that a moderate thrombocytopenia is a risk factor for PPH, especially in blood group O carriers.

ABO blood group and link to COVID-19: A comprehensive review of the reported associations and their possible underlying mechanisms.

ABO blood group is long known to be an influencing factor for the susceptibility to infectious diseases, and many studies have been describing associations between ABO blood types and COVID-19 infection and severity, with conflicting findings. This narrative review aims to summarize the literature regarding associations between the ABO blood group and COVID-19. Blood type O is mostly associated with lower rates of SARS-CoV-2 infection, while blood type A is frequently described as a risk factor. Although results regarding the risk of severe outcomes are more variable, blood type A is the most associated with COVID-19 severity and mortality, while many studies describe O blood type as a protective factor for the disease progression. Furthermore, genetic associations with both the risk of infection and disease severity have been reported for the ABO locus. Some underlying mechanisms have been hypothesized to explain the reported associations, with incipient experimental data. Three major hypotheses emerge: SARS-CoV-2 could carry ABO(H)-like structures in its envelope glycoproteins and would be asymmetrically transmitted due to a protective effect of the ABO antibodies, ABH antigens could facilitate SARS-CoV-2 interaction with the host' cells, and the association of non-O blood types with higher risks of thromboembolic events could confer COVID-19 patients with blood type O a lower risk of severe outcomes. The hypothesized mechanisms would affect distinct aspects of the COVID-19 natural history, with distinct potential implications to the disease transmission and its management.

A historical overview of advances in molecular genetic/genomic studies of the ABO blood group system.

In 1990, 90 years after the discovery of ABO blood groups by Karl Landsteiner, my research team at the Molecular Biology Laboratory of the now-defunct Biomembrane Institute elucidated the molecular genetic basis of the ABO polymorphism. Henrik Clausen, Head of the Immunology Laboratory, initiated the project by isolating human group A transferase (AT), whose partial amino acid sequence was key to its success. Sen-itiroh Hakomori, the Scientific Director, provided all the institutional support. The characterization started from the 3 major alleles (A1, B, and O), and proceeded to the alleles of A2, A3, Ax and B3 subgroups and also to the cis-AB and B(A) alleles, which specify the expression of A and B antigens by single alleles. In addition to the identification of allele-specific single nucleotide polymorphism (SNP) variations, we also experimentally demonstrated their functional significance in glycosyltransferase activity and sugar specificity of the encoded proteins. Other scientists interested in blood group genes later characterized more than 250 ABO alleles. However, recent developments in next-generation sequencing have enabled the sequencing of millions of human genomes, transitioning from the era of genetics to the era of genomics. As a result, numerous SNP variations have been identified in the coding and noncoding regions of the ABO gene, making ABO one of the most studied loci for human polymorphism. As a tribute to Dr. Hakomori's scientific legacy, a historical overview in molecular genetic/genomic studies of the human ABO gene polymorphism is presented, with an emphasis on early discoveries made at his institute.

High titers of anti-A1 and anti-B antibodies among Peruvian group O platelet donors.

Critical antibody titers have been described as factors associated with hemolysis in ABO plasma-incompatible platelet (PLT) transfusions. This study was carried out to describe the frequency of high-titers anti-A and antiB IgM and IgG antibodies in group O apheresis platelet donors, and to explore differences according to the donor characteristics. A cross-sectional study was carried out at the Blood Bank of a National Hospital in Peru from January to March 2019. IgM and IgG antibodies against A1 and B antigens were quantified in 339 platelet donors using the direct hemagglutination technique and the solid-phase adherence technique, respectively. For analysis purposes, two cut-off points; ≥128 and ≥64, were used to define a critical titer for IgM due to a lack of consensus. An IgG titer of ≥256 was also defined as critical. Of the donors, 22.1 % had critical IgM titers when the cut-off point was defined as ≥128. However, when the IgM cut-off was ≥64, the frequency of platelet donors with critical titers increased to 54.0 %. The frequency of donors with critical IgG titers was 23.5 %. Higher IgG titers were associated with female donors while higher IgM titers were negative associated with age. One in two or three platelet donors, depending on the cutoff point used to define a critical IgM titer, had at least one critical titer of anti-A or anti-B antibodies. Early identification of platelet donors with critical antibody titers could prevent passive transfusion of ABO antibodies to non-isogroup recipients.

The effect of probiotic use on ABO antibody titers.

The use of probiotics brings numerous benefits to the immune system, including an increase in antibody production. The development of ABO antibodies may occur naturally due to the bacteria of the intestinal microbiota. However, high titers of ABO antibodies can lead to hemolytic disease of the fetus and newborn and can cause immune transfusion reactions. In this context, this study aimed to evaluate the effect of probiotic consumption on ABO antibody titers in humans. ABO blood group, ABO antibody titer, and fecal pH and Bifidobacteria concentration were determined for 126 healthy individuals before and after daily consumption of yogurt containing Lactobacillus acidophilus and Bifidobacterium lactis over a 1-month period. No changes in fecal pH were observed after probiotic consumption, regardless of ABO blood group. There was, however, an increase in the fecal concentration of Bifidobacteria in individuals with blood group A but not for those with group B or O. A decrease in the titer of anti-B was observed, despite the increase in the concentration of Bifidobacteria in feces being unrelated to fecal pH, in blood group A individuals. Our study, therefore, sought to understand the relationship between probiotics and the antibody titer of the ABO blood system. Despite our findings, further human studies are needed with other probiotic strains and molecular analyses of the intestinal microbiota.

The critical role of therapeutic plasma exchange in ABO-incompatible liver transplantation.

BACKGROUND: The shortage of donor liver restricts liver transplantation (LT). Nowadays, donor liver with ABO blood group incompatibility between donor and recipient has become an option to expand the source of donor liver. Although it is now possible to perform ABO-incompatible (ABO-I) LT, antibody-mediated rejection (AMR) has been recognized as the primary cause of desperate outcomes after ABO-I LT. Anti-A/B antibody is the trigger of immune response to ABO-I LT graft injury. Therapeutic plasma exchange (TPE) can quickly reduce the titer of plasma antibodies and effectively inhibit humoral immunity. DATA SOURCES: We searched PubMed and CNKI databases using search terms "therapeutic plasma exchange", "ABO-incompatible liver transplantation", "ABO-I LT", "liver transplantation", "LT", "antibody-mediated rejection", and "AMR". Additional publications were identified by a manual search of references from key articles. The relevant publications published before September 30, 2020 were included in this review. RESULTS: Different centers have made different attempts on whether to use TPE, when to use TPE and how often to use TPE. However, the control standard of lectin revision level is always controversial, the target titer varies significantly from center to center, and the standard target titer has not yet been established. TPE has several schemes to reduce antibody titers, but there is a lack of clinical trials that provide standardized procedures. CONCLUSIONS: TPE is essential for ABO-I LT. Hence, further research and clinical trials should be conducted to determine the best regimen for TPE to remove ABO antibodies and prevent AMR.

[Clinical Analysis of ABO-Incompatible Living-Donor Liver Transplantation in Children].

Objective: To evaluate the safety and clinical efficacy of ABO-incompatible living-donor liver transplantation (LDLT) in children. Methods: The clinical data of 62 children who underwent for the first time living donor liver transplantation in our hospital from April 2019 to July 2020 were retrospectively analyzed. According to the blood type matching of donor and recipient, the patients were divided into 3 groups, ABO-identical (ABO-Id, n=33), ABO-compatible (ABO-C, n=10) and ABO-incompatible (ABO-In, n=19), the median age of recipients in the three groups being 5 months. In the ABO-In group, 4 recipients whose condition was combined with liver failure and 2 recipients who had blood group antibody titers≥1∶32 received preoperative plasma exchange. All ABO-incompatible recipients had preoperative blood group antibody titers<1∶32. All recipients in the three groups underwent piggyback liver transplantation and received immunosuppressive and anticoagulation therapy. Postoperative follow-up was 5 to 20 months, the median being 12 months, measured until December 31, 2020 or until the date of death. Baseline clinical data, postoperative survival, and postoperative complications of recipients in the three groups were analyzed. Results: There were no significant differences in age, gender, underlying disease, operation history, Child Pugh score, donor age, graft to recipient weight ratio (GR/WR), cold ischemia time, warm ischemia time, duration of surgery, intraoperative blood loss and the use of immunosuppressants among the recipients in the three groups (all P>0.05). There was one death in the perioperative period and two deaths in the postoperative period in the ABO-Id group. There was one death in the postoperative period in the ABO-C group. There was one death in the perioperative period and one death in the postoperative period in the ABO-In group. There was no significant difference in the overall cumulative survival rate among the three groups ( P>0.05). There were no significant differences in the incidence of postoperative infection, acute rejection, biliary anastomotic stenosis and vascular complications among the three groups ( P>0.05). Conclusion: ABO-In LDLT is an effective and safe treatment option that can effectively expand the pool of live donors for liver transplantation and save the life of children with end-stage liver disease.

Prediction of Covid-19 infection severity using ABO blood group types and Rh factor.

Background & Objective: Biological markers for the prediction of acquiring Covid-19 risk are deficient and there is a dire need of immediate research data. The objective of the study was to predict the link of ABO blood group types along with Rh factor distribution with the severity of Covid-19. Methods: This was an observational cross-sectional survey conducted in medicine department of Pakistan Ordnance Factory Hospital, Wah Cantt Pakistan, from August 2020 to December 2020 after approval of IRB. Participants tested positive for presence of Covid-19 infection by polymerase chain reaction (PCR) were included in the study. Covid-19 infection severity was measured through mild, moderate and severe disease categories and analyzed. ABO blood group and Rh subgroups data for all the Covid-19 infected patients were obtained from the laboratory section of the hospital and analyzed. Data was entered in SPSS v 26 and analyzed. Cox regression model was used to find out the severity of Covid-19. Results: Total 248 patients were included; 75% patients were male and 25% were females. The mean age of the patients was 52.77±15.58 years. A very significant association was found between ABO blood group types, Rh factor antigen and severity of Covid-19 (p=0.001). When stratified ABO, Rh antigen blood group with health status of all patients there was a very significant association between them (p=0.013). An insignificant association between male and female odds ratio of ABO blood group types but blood group B, Rh positive antigen was more susceptible in Covid-19 positive patients. Conclusion: There is a link between ABO blood group types along with Rh factor antigen (B+ and O+) with the severity of Covid-19 positive patients. ABO blood group types and Rh factor can be used as a potential marker/tool to predict the susceptibility of acquiring Covid-19 infection as well as for severity of the infection.

Toward universal donor blood: Enzymatic conversion of A and B to O type.

Transfusion of blood, or more commonly red blood cells (RBCs), is integral to health care systems worldwide but requires careful matching of blood types to avoid serious adverse consequences. Of the four main blood types, A, B, AB, and O, only O can be given to any patient. This universal donor O-type blood is crucial for emergency situations where time or resources for typing are limited, so it is often in short supply. A and B blood differ from the O type in the presence of an additional sugar antigen (GalNAc and Gal, respectively) on the core H-antigen found on O-type RBCs. Thus, conversion of A, B, and AB RBCs to O-type RBCs should be achievable by removal of that sugar with an appropriate glycosidase. The first demonstration of a B-to-O conversion by Goldstein in 1982 required massive amounts of enzyme but enabled proof-of-principle transfusions without adverse effects in humans. New α-galactosidases and α-N-acetylgalactosaminidases were identified by screening bacterial libraries in 2007, allowing improved conversion of B and the first useful conversions of A-type RBCs, although under constrained conditions. In 2019, screening of a metagenomic library derived from the feces of an AB donor enabled discovery of a significantly more efficient two-enzyme system, involving a GalNAc deacetylase and a galactosaminidase, for A conversion. This promising system works well both in standard conditions and in whole blood. We discuss remaining challenges and opportunities for the use of such enzymes in blood conversion and organ transplantation.

Blood group O is a risk factor for delayed post-polypectomy bleeding.

BACKGROUND: Blood group O of ABO blood group system is considered as a risk factor for various bleeding events, but the relationship with endoscopic treatment-associated bleeding has yet to be investigated. This study aimed to evaluate whether blood group O is associated with delayed bleeding after colorectal endoscopic resection. METHODS: This was a retrospective observational study based on medical records at four university hospitals in Japan. We reviewed the records for consecutive patients who underwent colorectal endoscopic resection from January 2014 through December 2017. The primary outcome was the incidence of delayed bleeding, defined as hematochezia or melena, requiring endoscopy, transfusion, or any hemostatic intervention up to 28 days after endoscopic resection. Multivariate logistic regression analysis was performed to adjust the impact of blood group O on the delayed bleeding. RESULTS: Among 10,253 consecutive patients who underwent colorectal endoscopic resection during the study period, 8625 patients met the criteria. In total, delayed bleeding occurred in 255 patients (2.96%). The O group had significantly more bleeding events compared with the non-O group (A, B, and AB) (relative risk, 1.62 [95% confidence interval, 1.24-2.10]; P < 0.001). In multivariate logistic regression analysis, blood group O remained an independent risk factor for the bleeding (adjusted odds ratio, 1.60 [95% confidence interval, 1.18-2.17]; P = 0.002). CONCLUSIONS: Blood group O was associated with an increased risk of delayed bleeding in patients undergoing colorectal endoscopic resection. Preoperative screening for ABO blood group could improve risk assessments.

Systematic review and meta-analysis of the susceptibility of ABO blood group to COVID-19 infection.

BACKGROUND: Numerous studies investigate the association between the ABO blood groups and the occurrence of COVID-19 infection; discordant findings were reported. Therefore, the purpose of this meta-analysis was to evaluate the existing evidence on the susceptibility of the ABO blood group to COVID-19 infection. METHODS: Systematically searched published articles in PubMed, Google Scholar, Scopus, and EMBASE between 1 st January 2020 and 21 st March 2021. After quality control and the exclusion of irrelevant studies, 16 studies were included in the final analysis. RESULTS: Although the random-effect meta-analysis revealed a large heterogeneity among studies, I 2 = 99.197 %. The pooled event rates and (95 % CIs) for A, O, B, and AB blood group were 0.459 (95 %CI: 0.358-0.441), 0.342 (95 %CI: 0.298-0.374), 0.180 (95 %CI: 0.150-0.214), and 0.076 (95 %CI: 0.055-0.127), respectively. These results indicated that the COVID-19 infection rate was higher in persons with blood group A > O > B > AB. Overall, the ABO blood group's vulnerability to COVID-19 infection was statistically significant (pooled p -value<0.001). CONCLUSION: This meta-analysis offers a further indication of blood group A individuals' vulnerability to COVID-19 infection, and blood type AB are linked to a lower risk of COVID-19 infection.

ABO blood group is related to bleeding in cardiac surgery.

BACKGROUND: Increased bleeding and blood product transfusions during cardiac surgery are associated with poor outcomes. The patient's ABO blood group is related to hemostatic balance, although it is unclear whether this influences bleeding during cardiac surgery. This study aimed to evaluate whether ABO blood group is related to bleeding during cardiac surgery. METHODS: This retrospective study evaluated data from 17,058 cardiac surgical procedures that were performed in four Danish cardiosurgical centers. Data regarding chest tube drainage and transfusion volumes were retrieved from a clinical database and combined with information regarding ABO group. The primary outcome was chest tube drainage volume and the secondary outcomes were transfused volumes of various blood products. RESULTS: Blood group O had the largest chest tube drainage volume (mean: 745 mL, 95% CI: 720-771 mL) and blood group AB had the smallest volume (mean: 664 mL, 95% CI: 598-731 mL). The inter-group difference in the mean drainage volume was 81 mL (95% CI: 8-154 mL, P < .05). Patients with blood group A or blood group B had mean drainage volumes that were between the volumes for groups AB and O. Relative to group O, group AB received smaller mean volumes of all blood products. The most pronounced difference was in platelet concentrates, with mean values of 170 mL for group O (95% CI: 157-184 mL) and 63 mL for group AB (95% CI: 34-92 mL). CONCLUSION: The patient's ABO group appears to be related to volumes of chest tube drainage and transfused blood products during cardiac surgery.

ABO and Rhesus D blood groups in the Northern Territory of Australia.

BACKGROUND: There are no contemporary published data on the frequency of the ABO and Rhesus D (RhD) blood groups in the Northern Territory (NT) of Australia, particularly for the large Aboriginal population. AIMS: To establish the frequencies of ABO and RhD blood groups in the NT Aboriginal and non-Aboriginal populations in order to aid transfusion inventory management and clinical practice. METHODS: Retrospective data were collected from 1 January 2012 to 31 December 2012. All patients with a blood group sample processed by the NT public hospital laboratories and a recorded ABO and RhD report were included. Results were analysed using Stata 14. RESULTS: The Aboriginal and non-Aboriginal populations had significantly different ABO and RhD distributions (P < 0.001). For Aboriginal individuals, 955/1686 (56.6%) were group O and 669/1686 (39.7%) were group A. In non-Aboriginal individuals, 1201/2657 (45.2%) were group O and 986/2657 (37.1%) were group A. We found that 1646/1686 (97.6%) of Aboriginal individuals were RhD positive, compared with 2225/2657 (83.7%) of non-Aboriginal individuals. Only 62/1686 (3.7%) of Aboriginal individuals were group B or AB, compared with 470/2657 (17.7%) of non-Aboriginal individuals. In Aboriginal individuals we found that group O was more common than A in the 'Northern' NT, whereas there was similar distribution of the groups in 'Central Australia'. CONCLUSIONS: We found a significant difference in ABO and RhD blood groups between Aboriginal and non-Aboriginal individuals in the NT (P < 0.001). These findings will aid transfusion inventory management, allowing us to plan supply of blood products and reduce waste.