Non-O blood types are associated with a greater risk of large artery atherosclerosis stroke and dysregulation of cholesterol metabolism: an observational study.

BACKGROUND: Previous research on ABO blood types and stroke has been controversial, predominantly suggesting heightened risk of stroke in non-O blood types. Nonetheless, investigations into the correlation and underlying mechanisms between ABO blood groups and stroke subtypes, especially within Chinese cohorts, remain limited. METHODS: The ABO blood types of 9,542 ischaemic stroke (IS) patients were inferred using two ABO gene loci (c.261G > del; c.802G > A). The healthy population was derived from the 1000 Genomes Project. Patients were classified by the causative classification system (CCS). Volcano plot and gene ontology (GO) analysis were employed to explore protein differential expression among blood types. Additionally, HT29 and SW480 cell lines with downregulated ABO expression were generated to evaluate its impact on cholesterol uptake and efflux. RESULTS: A greater proportion of stroke patients had non-O blood types (70.46%) than did healthy individuals (61.54%). Notable differences in blood type distributions were observed among stroke subtypes, with non-O blood type patients mainly classified as having large artery atherosclerosis (LAA). Clinical baseline characteristics, such as the low-density lipoprotein cholesterol level, activated partial thromboplastin time and thrombin time, varied significantly among blood types. A volcano plot revealed 17 upregulated and 42 downregulated proteins in the O blood type. GO term analysis indicated that downregulated proteins were primarily associated with lipid metabolism pathways. In vitro experiments revealed that reducing ABO gene expression decreased cholesterol uptake and increased cholesterol efflux. CONCLUSIONS: This study revealed that the non-O blood type increased the risk of LAA stroke through cholesterol metabolism.

ABO blood type and thromboembolic complications after intracerebral hemorrhage: An exploratory analysis.

BACKGROUND AND PURPOSE: Non-O blood types are known to be associated with thromboembolic complications (TECs) in population-based studies. TECs are known drivers of morbidity and mortality in intracerebral hemorrhage (ICH) patients, yet the relationships of blood type on TECs in this patient population are unknown. We sought to explore the relationships between ABO blood type and TECs in ICH patients. METHODS: Consecutive adult ICH patients enrolled into a prospective observational cohort study with available ABO blood type data were analyzed. Patients with cancer history, prior thromboembolism, and baseline laboratory evidence of coagulopathy were excluded. The primary exposure variable was blood type (non-O versus O). The primary outcome was composite TEC, defined as pulmonary embolism, deep venous thrombosis, ischemic stroke or myocardial infarction, during the hospital stay. Relationships between blood type, TECs and clinical outcomes were separately assessed using logistic regression models after adjusting for sex, ethnicity and ICH score. RESULTS: Of 301 ICH patients included for analysis, 44% were non-O blood type. Non-O blood type was associated with higher admission GCS and lower ICH score on baseline comparisons. We identified TECs in 11.6% of our overall patient cohort. . Although TECs were identified in 9.9% of non-O blood type patients compared to 13.0% in O blood type patients, we did not identify a significant relationship of non-O blood type with TECs (adjusted OR=0.776, 95%CI: 0.348-1.733, p=0.537). The prevalence of specific TECs were also comparable in unadjusted and adjusted analyses between the two cohorts. In additional analyses, we identified that TECs were associated with poor 90-day mRS (adjusted OR=3.452, 95% CI: 1.001-11.903, p=0.050). We did not identify relationships between ABO blood type and poor 90-day mRS (adjusted OR=0.994, 95% CI:0.465-2.128, p=0.988). CONCLUSIONS: We identified that TECs were associated with worse ICH outcomes. However, we did not identify relationships in ABO blood type and TECs. Further work is required to assess best diagnostic and prophylactic and treatment strategies for TECs to improve ICH outcomes.

Association between ABO blood groups and SARS-CoV-2 infection in blood donors of Puglia region.

This is an observational multicentric cross-sectional study aiming at assessing the association between ABO blood groups and SARS-CoV-2 seroprevalence among the blood donors in Puglia region. Data on ABO and Rh blood groups and demographic characteristics were obtained from Blood Bank Information System. All donors were screened for SARS-CoV-2 IgG antibodies. Comparison of seroprevalence among blood groups and the association between the recorded variables and seroprevalence were evaluated. A total of 35,709 donors from 22 centers were included, with a seroprevalence of 6.8%. The distribution of ABO phenotypes was blood type O (46.8%), A (34.0%), B (14.7%), and AB (4.5%). Among the 2416 donors reactive for SARS-CoV-2 IgG, the prevalent phenotype was blood type O (43.1%), followed by A (37.7%), B (14.2%), and AB (5%). The seroprevalence of phenotype A and AB was 7.5%, followed by B (6.5%) and O (6.2%). According to the adjusted analysis, there was an increase in seroprevalence in groups A and AB, compared to group O, and an increase in males compared to females. A possible effect modification was observed after stratifying for sex (p = 0.0515). A significantly lower prevalence of blood type O was found compared to A and AB, whereas no association was observed between Rh factor and seroprevalence. We hypothesized that the A antigen present in blood type A and AB can play a role in the binding of SARS-CoV-2 to ACE2 receptors, resulting in an increased risk of infection. Furthermore, natural anti-A/anti-B antibodies produced in group O could block viral adhesion to cells and explain a lower risk of infection.

Association between ABO blood type and type I endometrial cancer: a retrospective study.

This study aimed to assess the association between ABO blood type and incident of type I endometrial cancer (EC), as well as the stage and differentiation. 213 patients with type I EC and 300 healthy controls were included. As a result, the frequencies of A, B, O, and AB blood types among patients with type I EC were 51 (23.9%), 59 (27.7%), 93 (43.7%) and 10 (4.7%), respectively. There were no significant differences in age, body mass index, and other baseline covariates between groups of ABO blood types (p > .05). Logistic regression model showed that women with blood type O was more likely to develop type I EC than those with type A (odds ratio (OR): 1.66, 95% confidence interval (CI): 1.05-2.63). However, there was no significant association of ABO blood type with stage and differentiation of type I EC (p > .05). In conclusion, blood type O was the most prevalent ABO blood type among patients with type I EC and was associated with increased risk of type I EC, while ABO blood type was not significantly associated with stage or differentiation of type I EC.IMPACT STATEMENTWhat is already known on this subject? Previous studies have produced inconsistent findings on association of ABO blood type with EC. Those studies also did not explore the relationship between ABO blood type and stage or differentiation of type I EC.What the results of this study add? The present study showed that women with blood type O was more likely to develop type I EC than those with type A and there was no significant association of ABO blood type with stage or differentiation of type I EC.What the implications are of these findings for clinical practice and/or further research? Gynaecologists should pay more attention to women with blood type O, who should undergo more active EC screening.

SARS-CoV-2 and mutation RT-qPCR test positivity correlation with ABO and Rh blood types.

Studies show that there may be a relationship between ABO blood type and SARS-CoV-2 transmission. It was aimed to determine by investigating the blood type of patients whose one-step reverse transcription and real-time polymerase chain reaction (RT-qPCR) test were positive for SARS-CoV-2. ABO and Rh blood types of individuals whose RT-qPCR test was positive for SARS-CoV-2 were examined and an evaluation was made to identify whether there was a relationship between them or not. The blood type data of 44.928 SARS-CoV-2 positive RT-qPCR test results have been obtained. 17.656 (39.29%) were delta, 8048 (17.91%) were alpha, 800 (1.78%) were beta, and 3000 (6.67%) were omicrons while 15.424 (34.33%) SARS-CoV-2 positive mutation was found to be negative. Our study suggests that O and Rh (-) blood types may provide protection against delta, AB and Rh (+) blood types may hinder omicron infection while A and Rh (+) blood types may be more vulnerable to alpha and delta while B and Rh (+) are more sensitive to beta mutation. The molecular mechanism underlying the relationship between blood types and SARS-CoV-2 infection needs further molecular studies and multi-centered studies.

Mechanistic Studies for the Rational Design of Multivalent Glycodendrimers.

We have synthesized B-antigen-displaying dendrimers (16-mers) with different sizes and evaluated their affinity to their IgM antibody in order to investigate which design features lead to effective multivalency. Unexpectedly, the smallest dendrimer, which cannot chelate the multiple binding sites of IgM, clearly exhibited multivalency, together with an affinity similar to or higher than those of the larger dendrimers. These results indicate that the statistical rebinding model, which involves the rapid exchange of clustered glycans, significantly contributes to the multivalency of glycodendrimers. Namely, in the design of glycodendrimers, high-density glycan presentation to enhance statistical rebinding should be considered in addition to the ability to chelate multiple binding sites. This notion stands in contrast to the currently prevailing scientific consensus, which prioritizes the chelation model. This study thus provides new and important guidelines for molecular design of glycodendrimers.

Role of ABO blood system in COVID-19: Findings from a southern Italian study.

BACKGROUND: COVID-19 is a worldwide infection caused by SARS-CoV-2 and infects humans by binding to the ACE2 receptor. Blood group ABO glycoproteins can influence the binding of the virus to ACE2. The role of ABO blood system in the susceptibility to infection as well as in the clinical outcome of infected patients is still controversial and needs to be clarified. METHODS: We conducted a retrospective study of 167 patients positive for SARS-CoV-2 who underwent nasopharyngeal swab, and of a control group represented by 891 subjects negative for SARS-CoV-2, to assess the association between ABO and Rh blood system and occurrence of SARS-CoV-2 infection, clinical presentation, and outcome of disease. RESULTS: In the cohort of patients positive for SARS-CoV-2, no statistically significant difference in the distribution of ABO blood types compared with controls was observed. Patients with blood type A had a higher risk of developing symptomatic disease (p = 0.002; odds ratio [OR = 3.592]; 95% confidence interval [CI] = 1.576-8.187) compared to patients with blood types B, AB, and O. Patients with blood types B (p = 0.021; OR = 0.293; 95%CI = 0.099-0.869) and O (p = 0.018; OR = 0.417; 95%CI = 0.199-0.871) showed a lower risk in comparison to the other groups. The clinical progression to mild/moderate and severe/critical disease and the mortality showed no association. Moreover, no relationship with Rh blood type was found. CONCLUSIONS: Our findings support a role of ABO blood type in the development of symptomatic disease with a higher risk in subjects with blood type A and a protective effect of blood types B and O. Blood types do not seem, however, to play a role in susceptibility, progression to severe disease, and death.

ABO genotypes and the risk of esophageal and gastric cancers.

BACKGROUND: Blood type has been associated with the risk of gastric cancer, but few studies have examined the association with esophageal squamous cell carcinoma (ESCC). METHODS: We conducted a case-control study using genotyping data of Chinese individuals, including cases of 2022 ESCC, 1189 gastric cardia adenocarcinoma, 1161 gastric noncardia adenocarcinoma, and 2696 controls. Genetic blood type was imputed using three single nucleotide polymorphisms. We used logistic regression to examine the association between blood type and the risk of each cancer. RESULTS: Compared to blood type O, the risk of ESCC was significantly elevated for blood type B and AB, with the highest risk for type AB (OR, 95%CI: 1.34, 1.07-1.67). Analysis of genotype suggested that the association of ESCC was from carrying the B allele. Similarly, blood type was significantly associated with gastric noncardia adenocarcinoma (P < 0.001) with risk significantly elevated in type A (1.37, 1.14-1.65) and AB (1.44, 1.10-1.89) compared to type O. Blood type was not associated with gastric cardia adenocarcinoma (P = 0.13). CONCLUSIONS: This study provides novel insights into the association between blood type and the risk of ESCC and restricted previously observed association to only gastric noncardia cancer, providing important evidence to clarify the pattern of association and suggesting mechanisms of action.

Associations of ABO blood type and galactose-deficient immunoglobulin A1 with adverse outcomes in patients with IgA nephropathy.

BACKGROUND: Both ABO blood group antigens and pathogenic immunoglobulin A1 (IgA1) in patients with IgA nephropathy (IgAN) are influenced by modifications of N-acetylgalactosamine and galactose. The purpose of this study was to assess whether ABO blood type is associated with galactose-deficient IgA1 (Gd-IgA1) in the progression of kidney disease in patients with IgAN. METHODS: We enrolled 1313 IgAN patients with a median of 44 months follow-up and measured the plasma Gd-IgA1 levels. Multivariate Cox regression models were used to estimate the association between all variables and adverse outcomes. Using the propensity score matching method, 718 IgAN patients with blood type either A or B were selected, and their data were used to assess the association of blood type and Gd-IgA1/serum complement 3 (sC3) with outcomes. RESULTS: We found that the risk of adverse outcomes was significantly higher in patients with blood type A than in those with type B (hazard ratio = 1.82, 95% confidence interval 1.23-2.71; P = 0.003) after multivariate adjustment. The Gd-IgA1 levels showed trends similar to the multivariate-adjusted event-free curves for the blood types. However, this higher risk of adverse outcomes in type A than in type B patients was no longer significant after the addition of Gd-IgA1/sC3 to the model. CONCLUSIONS: IgAN patients with blood type A had a higher risk of adverse outcomes than those with type B, and this risk was associated with Gd-IgA1/sC3. Thus, the ABO blood type may provide a reference for the prognostic factors for individuals with IgAN.

Investigation of risk factors associated with erythrocyte engraftment after ABO-incompatible hematopoietic stem cell transplantation.

ABO-incompatible hematopoietic stem cell transplantations (HSCTs) are widely practiced; however, the delay in erythrocyte engraftment can be problematic. While erythrocyte engraftment is usually indicated by an increase in reticulocyte levels without the need for erythrocyte transfusions, the disappearance of recipient-derived anti-A/B isoagglutinin and detection of donor-derived A/B antigens can also be used as other parameters. We conducted a retrospective analysis of 68 ABO-incompatible HSCTs, focusing on major and bidirectional mismatch. We analyzed known clinical risk factors associated with delayed erythrocyte engraftment using the three parameters (disappearance of anti-A/B isoagglutinin in recipient, detection of donor-derived A/B antigen, and reticulocyte levels >1%). Although the three parameters were well correlated, the results showed heterogeneity when analyzing the associated risk factors for delayed erythrocyte engraftment. In the analysis of all cases, the requirement for an HLA-matched platelet transfusion was a common risk factor. Furthermore, erythrocyte engraftment was slower in adults than in children. In adults, cytomegalovirus antigenemia was a risk factor for two parameters; however, in children, underlying disease was a common risk factor for all parameters. There is a complex relationship between erythrocyte engraftment and various factors related to HSCTs. Our results suggest that greater accuracy is possible by using analysis methods other than the measurement of reticulocyte levels.

The impact of ABO blood type on the prevalence of portal vein thrombosis in patients with advanced chronic liver disease.

BACKGROUND AND AIMS: Non-O blood type (BT) is a risk factor for thromboses, which has been attributed to its effects on von Willebrand factor (VWF)/factor VIII (FVIII) levels. Although high VWF/FVIII may be risk factors for portal vein thrombosis (PVT) in patients with advanced chronic liver disease (ACLD), the impact of BT on PVT is unknown. We aimed to assess (I) whether non-O-BT is a risk factor for PVT and (II) whether non-O-BT impacts VWF/factor VIII in patients with ACLD. METHODS: Retrospective analysis comprising two cohorts: (I) "US" including all adult liver transplantations in the US in the MELD era and (II) "Vienna" comprising patients with a hepatic venous pressure gradient (HVPG) ≥6 mmHg. RESULTS: (I) The "US cohort" included 84 947 patients (non-O: 55.43%). The prevalence of PVT at the time of listing (4.37% vs 4.56%; P = .1762) and at liver transplantation (9.56% vs 9.33%; P = .2546) was similar in patients with O- and non-O-BT. (II) 411 patients were included in the "Vienna cohort" (non-O: 64%). Mean HVPG was 18(9) mmHg and 90% had an HVPG ≥10 mmHg. Patients with non-O-BT had slightly increased VWF levels (318(164)% vs 309(176)%; P = .048; increase of 23.8%-23.9% in adjusted analyses), but this difference was driven by patients with less advanced disease. However, non-O-BT explained only 1% of the variation in VWF and had no effect on FVIII. CONCLUSIONS: Although non-O-BT impacts VWF in patients with early stage ACLD, its contribution to VWF variation is considerably smaller than in the general population. Moreover, non-O-BT had no impact on FVIII. These findings may explain the absence of an association between non-O-BT and PVT in patients with advanced cirrhosis.

Genome-wide association study identifies seven novel loci associating with circulating cytokines and cell adhesion molecules in Finns.

BACKGROUND: Inflammatory processes contribute to the pathophysiology of multiple chronic conditions. Genetic factors play a crucial role in modulating the inflammatory load, but the exact mechanisms are incompletely understood. OBJECTIVE: To assess genetic determinants of 16 circulating cytokines and cell adhesion molecules (inflammatory phenotypes) in Finns. METHODS: Genome-wide associations of the inflammatory phenotypes were studied in Northern Finland Birth Cohort 1966 (N=5284). A subsequent meta-analysis was completed for 10 phenotypes available in a previous genome-wide association study, adding up to 13 577 individuals in the study. Complementary association tests were performed to study the effect of the ABO blood types on soluble adhesion molecule levels. RESULTS: We identified seven novel and six previously reported genetic associations (p<3.1×10-9). Three loci were associated with soluble vascular cell adhesion molecule-1 (sVCAM-1) level, one of which was the ABO locus that has been previously associated with soluble E-selectin (sE-selectin) and intercellular adhesion molecule-1 (sICAM-1) levels. Our findings suggest that the blood type B associates primarily with sVCAM-1 level, while the A1 subtype shows a robust effect on sE-selectin and sICAM-1 levels. The genotypes in the ABO locus associating with higher soluble adhesion molecule levels tend to associate with lower circulating cholesterol levels and lower cardiovascular disease risk. CONCLUSION: The present results extend the knowledge about genetic factors contributing to the inflammatory load. Our findings suggest that two distinct mechanisms contribute to the soluble adhesion molecule levels in the ABO locus and that elevated soluble adhesion molecule levels per se may not increase risk for cardiovascular disease.

Challenge to ABO blood type barrier in living donor liver transplantation.

ABO incompatible living donor liver transplantation has the potential to expand the donor pool for patients with end stage liver diseases on the expense of challenges to overcome immunological barriers across blood type. There is a profound impact of age on incidence and severity of antibody mediated rejection (AMR). Even children older than 1 year have chances of AMR; children aged 8 years or older have risks of hepatic necrosis similar to adult liver recipients. The mechanism of AMR is based on circulatory disturbances secondary to inflammation and injury of the vascular endothelium caused by an antibody-antigen-complement reaction. The strategy to overcome ABO blood type barrier is based on both pre-transplant desensitization and adequate treatment of this phenomenon. Nowadays, rituximab is the standard means of desensitization but unfortunately an insufficient aid to treat AMR. Because of low incidence (less than 5% in the rituximab era), in practice of AMR only some case reports about the treatment of clinical AMR are available in the literature. Initial experiences revealed that the proteasome inhibitor, bortezomib might be a promising treatment based on its capacity to deplete plasma cell agents. Although ABO blood type barrier has been counteracted in 95% of patients by applying "rituximab-desensitization", many issues, such as prediction of high-risk patients of infection and AMR and secure treatment strategies for evoked AMR, remain to be resolved.

Effect of ABO blood group on asymptomatic, uncomplicated and placental Plasmodium falciparum infection: systematic review and meta-analysis.

BACKGROUND: Malaria clinical outcomes vary by erythrocyte characteristics, including ABO blood group, but the effect of ABO blood group on asymptomatic, uncomplicated and placental Plasmodium falciparum (P. falciparum) infection remains unclear. We explored effects of ABO blood group on asymptomatic, uncomplicated and placental falciparum infection in the published literature. METHODS: A systematic review and meta-analysis was performed using the preferred reporting items for systematic reviews and meta-analyses guidelines. Articles in Pubmed, Embase, Web of Science, CINAHL and Cochrane Library published before February 04, 2017 were searched without restriction. Studies were included if they reported P. falciparum infection incidence or prevalence, stratified by ABO blood group. RESULTS: Of 1923 articles obtained from the five databases (Embase = 728, PubMed = 620, Web of Science = 549, CINAHL = 14, Cochrane Library = 12), 42 met criteria for systematic review and 37 for meta-analysis. Most studies (n = 30) were cross-sectional, seven were prospective cohort, and five were case-control studies. Meta-analysis showed similar odds of uncomplicated P. falciparum infection among individuals with blood group A (summary odds ratio [OR] 0.96, 15 studies), B (OR 0.89, 15 studies), AB (OR 0.85, 10 studies) and non-O (OR 0.95, 17 studies) as compared to those with blood group O. Meta-analysis of four cohort studies also showed similar risk of uncomplicated P. falciparum infection among individuals with blood group non-O and those with blood group O (summary relative risk [RR] 1.03). Meta-analysis of six studies showed similar odds of asymptomatic P. falciparum infection among individuals with blood group A (OR 1.05), B (OR 1.03), AB (OR 1.23), and non-O (OR 1.07) when compared to those with blood group O. However, odds of active placental P. falciparum infection was significantly lower in primiparous women with non-O blood groups (OR 0.46, 95% confidence interval [CI] 0.23 - 0.69, I2 0.0%, three studies), particularly in those with blood group A (OR 0.41, 95% CI 0.003 - 0.82, I2 1.4%, four studies) than those with blood group O. CONCLUSIONS: This study suggests that ABO blood group may not affect susceptibility to asymptomatic and/or uncomplicated P. falciparum infection. However, blood group O primiparous women appear to be more susceptible to active placental P. falciparum infection.

Myelopathy due to human T-cell leukemia virus type-1 from the donor after ABO-incompatible liver transplantation.

We report the case of a 53-year-old-man who developed human T-cell leukemia virus type-1-associated myelopathy (HAM) after ABO-incompatible liver transplantation for alcoholic liver cirrhosis. The living donor was seropositive for human T-cell leukemia virus type-1 (HTLV-1) and the recipient was seronegative for HTLV-1 before transplantation. After transplantation, the recipient developed steroid-resistant acute cellular rejection, which was successfully treated using anti-thymocyte globulin, and he was eventually discharged. He underwent spinal surgery twice after the transplantation for the treatment of cervical spondylosis that had been present for a period of 9 months before the transplantation. The surgery improved his gait impairment temporarily. However, his gait impairment progressed, and magnetic resonance imaging revealed multiple sites of myelopathy. He was diagnosed with HAM 16 months after the transplantation. Pulse steroid therapy (1000mg) was administered over a period of 3 days, and his limb paresis improved. Presently, steroid therapy is being continued, with a plan to eventually taper the dose, and he is being carefully followed up at our institution. Our case suggests that liver transplantation involving an HTLV-1-positive living donor carries the risk of virus transmission and short-term development of HAM after transplantation.

Serum amylase activity altered by the ABO blood group system in Chinese subjects.

OBJECTIVE: The underlying interactions between ABO blood group antigens and pancreatic exocrine tissue have been demonstrated, and serum amylase was synthesized by pancreatic ductal cells. Thus, we investigated the link between ABO blood type and serum amylase activity in Chinese subjects. METHODS: Our study included 343 relatively healthy Chinese individuals, and the data were retrieved from electronic medical record database. RESULTS: A increased trend was observed for serum amylase activity in ABO blood type distribution, and we found that serum amylase activity was remarkable increased in subjects with O blood type compared to those with non-O blood type (P = 0.013). Logistic regression analysis indicated that serum amylase was independently associated with individuals with O blood group (adjusted odds ratio 1.574; 95% CI, 1.022-2.425, P = 0.039). CONCLUSIONS: The present evidence suggests a significant link between serum amylase activity and ABO blood type in the study population, indicating ABO blood type may be associated with the susceptibility of pancreatic disease.

ABO Blood Type and Hematoma Expansion After Intracerebral Hemorrhage: An Exploratory Analysis.

BACKGROUND/PURPOSE: Blood type has become an increasingly recognized risk factor for coagulopathy. We explored the association between blood type and hematoma expansion (HE) after intracerebral hemorrhage (ICH). METHODS: Spontaneous ICH patients prospectively enrolled in an ongoing ICH cohort study at Columbia University Irving Medical Center from 2009 to 2016 were evaluated. Primary ICH patients with admission blood type testing were evaluated for HE differences, defined as > 33% relative HE. The association of blood type with radiographic HE outcomes was assessed using multivariable logistic regression models. The association of blood type and poor clinical outcomes using modified Rankin Scale (mRS 4-6) was additionally explored. RESULTS: Of 272 ICH patients with blood type data and neuroimaging available to determine HE, there were 146 (54%) type-O, 82 (30%) type-A, 34 (13%) type-B, and 10 (3%) type-AB patients. No significant baseline demographic, clinical, or radiographic differences were noted between blood types. Type-B blood was associated with more HE compared to other blood types (OR 2.82; 95% CI 1.23-6.45) after adjusting for known covariates of HE (anticoagulant use, time to admission computed tomography scan, and baseline hematoma volume). No associations with blood type and poor 3 month mRS were identified, but these analyses were limited secondary to our smaller cohort. CONCLUSIONS: There may be differences in HE after ICH in patients with different blood types. Further work is required to replicate these findings and identify the pathophysiologic mechanisms behind coagulopathy between blood types after ICH.

Association between response to rituximab and antibody-mediated rejection in ABO-incompatible living kidney transplantation.

OBJECTIVES: To examine the association of response to rituximab and the incidence of antibody-mediated rejection in preconditioning of rituximab and plasma exchange without post-transplant plasmapheresis in patients undergoing ABO-incompatible living kidney transplantation. METHODS: A total of 115 patients who underwent ABO-incompatible living kidney transplantation at Tokyo Women's Medical University Hospital, Tokyo, Japan, were divided into two groups based on the response to rituximab: good response (n = 75) or poor response (n = 40). The rituximab good response and poor response patients were defined as patients whose CD19+ cells were non-detected (0%) and detected on the day of transplantation (2-5 days, median 3 days, after rituximab administration), respectively. RESULTS: Rituximab response and anti-A/B blood antibody titer after plasmapheresis were significant risk factors for antibody-mediated rejection (P = 0.036, 0.045, respectively). The occurrence of antibody-mediated rejection was higher in the poor response group than in the good response group (22.5% vs 8.0%; P = 0.028). The 14-day, 3-month and 1-year cumulative incidence of antibody-mediated rejection was 2.7%, 5.3% and 8.0% in the good response group, and 17.5%, 20.0% and 22.5% in the poor response group after ABO-incompatible living kidney transplantation. The patient survival was not significantly different between the two groups. However, graft survival 1 month after transplantation was lower in the poor response group. There is no significant difference in graft function and in the incidence of complications, including infection, after transplantation between the two groups. CONCLUSIONS: Antibody-mediated rejection after ABO-incompatible living kidney transplantation was significantly associated with the response to rituximab in our preconditioning protocol.

The impact of blood type O on mortality of severe trauma patients: a retrospective observational study.

BACKGROUND: Recent studies have implicated the differences in the ABO blood system as a potential risk for various diseases, including hemostatic disorders and hemorrhage. In this study, we evaluated the impact of the difference in the ABO blood type on mortality in patients with severe trauma. METHODS: A retrospective observational study was conducted in two tertiary emergency critical care medical centers in Japan. Patients with trauma with an Injury Severity Score (ISS) > 15 were included. The association between the different blood types (type O versus other blood types) and the outcomes of all-cause mortality, cause-specific mortalities (exsanguination, traumatic brain injury, and others), ventilator-free days (VFD), and total transfusion volume were evaluated using univariate and multivariate competing-risk regression models. Moreover, the impact of blood type O on the outcomes was assessed using regression coefficients in the multivariate analysis adjusted for age, ISS, and the Revised Trauma Score (RTS). RESULTS: A total of 901 patients were included in this study. The study population was divided based on the ABO blood type: type O, 284 (32%); type A, 285 (32%); type B, 209 (23%); and type AB, 123 (13%). Blood type O was associated with high mortality (28% in patients with blood type O versus 11% in patients with other blood types; p <  0.001). Moreover, this association was observed in a multivariate model (adjusted odds ratio = 2.86, 95% confidence interval 1.84-4.46; p <  0.001). The impact of blood type O on all-cause in-hospital mortality was comparable to 12 increases in the ISS, 1.5 decreases in the RTS, and 26 increases in age. Furthermore, blood type O was significantly associated with higher cause-specific mortalities and shorter VFD compared with the other blood types; however, a significant difference was not observed in the transfusion volume between the two groups. CONCLUSIONS: Blood type O was significantly associated with high mortality in severe trauma patients and might have a great impact on outcomes. Further studies elucidating the mechanism underlying this association are warranted to develop the appropriate intervention.

Non-O blood group and outcomes of in vitro fertilization.

PURPOSE: Retrospective and cross-sectional studies suggested that non-O blood group may be associated with failures of in vitro fertilization (IVF), but data remain controversial. The aim of this observational cohort study was to prospectively evaluate the effect of non-O blood type on clinical outcomes of IVF. METHODS: Women < 40 years who underwent IVF and had ABO blood type recorded as part of the routine workup were eligible. The primary study outcome was live birth. Secondary outcomes included spontaneous abortion, positive pregnancy test, and clinical pregnancy. RESULTS: A total of 497 women with a mean age of 34.6 (standard deviation 3.2) years were included. The mean number of embryos transferred was 2.3 (standard deviation 0.6). The most common ABO blood types were O (n = 213, 42.9%) and A (n = 203, 40.8%), while 63 (12.7%) and 18 (3.6%) women had the B and AB blood types, respectively. Differences in live birth (21.8 vs. 24.3%, odds ratio [OR] 1.17; 95% confidence intervals [CI], 0.76 to 1.78), positive pregnancy test (37.9 vs. 36.6%, OR 0.96; 95% CI, 0.66 to 1.38), clinical pregnancy (35.1 vs. 33.8%, OR 0.95; 95% CI, 0.66 to 1.39), and spontaneous abortion (12.3 vs. 9.2%, OR 0.72; 95% CI, 0.41 to 1.29) between women with O and non-O blood type were not statistically significant. CONCLUSIONS: In a prospective cohort study, we confirmed the lack of a significant association between non-O blood type and clinical outcomes of IVF. Further studies are needed to clarify whether non-O blood group has any prognostic relevance in women undergoing IVF.