The human gut symbiont Ruminococcus gnavus shows specificity to blood group A antigen during mucin glycan foraging: Implication for niche colonisation in the gastrointestinal tract

The human gut symbiont Ruminococcus gnavus displays strain-specific repertoires of glycoside hydrolases (GHs) contributing to its spatial location in the gut. Sequence similarity network analysis identified strain-specific differences in blood-group endo-β-1,4-galactosidase belonging to the GH98 family. We determined the substrate and linkage specificities of GH98 from R. gnavus ATCC 29149, RgGH98, against a range of defined oligosaccharides and glycoconjugates including mucin. We showed by HPAEC-PAD and LC-FD-MS/MS that RgGH98 is specific for blood group A tetrasaccharide type II (BgA II). Isothermal titration calorimetry (ITC) and saturation transfer difference (STD) NMR confirmed RgGH98 affinity for blood group A over blood group B and H antigens. The molecular basis of RgGH98 strict specificity was further investigated using a combination of glycan microarrays, site-directed mutagenesis, and X-ray crystallography. The crystal structures of RgGH98 in complex with BgA trisaccharide (BgAtri) and of RgGH98 E411A with BgA II revealed a dedicated hydrogen network of residues, which were shown by site-directed mutagenesis to be critical to the recognition of the BgA epitope. We demonstrated experimentally that RgGH98 is part of an operon of 10 genes that is overexpresssed in vitro when R. gnavus ATCC 29149 is grown on mucin as sole carbon source as shown by RNAseq analysis and RT-qPCR confirmed RgGH98 expression on BgA II growth. Using MALDI-ToF MS, we showed that RgGH98 releases BgAtri from mucin and that pretreatment of mucin with RgGH98 confered R. gnavus E1 the ability to grow, by enabling the E1 strain to metabolise BgAtri and access the underlying mucin glycan chain. These data further support that the GH repertoire of R. gnavus strains enable them to colonise different nutritional niches in the human gut and has potential applications in diagnostic and therapeutics against infection.

Association of ABO blood group with COVID-19 severity, acute phase reactants and mortality

Introduction Coronavirus disease 2019 (COVID-19) is the ongoing pandemic with multitude of manifestations and association of ABO blood group in South-East Asian population needs to be explored. Methods It was a retrospective study of patients with COVID-19. Blood group A, B, O, and AB were identified in every participant, irrespective of their RH type and allotted groups 1, 2,3, and 4, respectively. Correlation between blood group and lab parameters was presented as histogram distributed among the four groups. Multivariate regression and logistic regression were used for inferential statistics. Results The cohort included 1067 patients: 521 (48.8%) participants had blood group O as the prevalent blood type. Overall, 10.6% COVID-19-related mortality was observed at our center. Mortality was 13.9% in blood group A, 9.5% in group B, 10% in group C, and 10.2% in AB blood group (p = 0.412). IL-6 was elevated in blood group A (median [IQR]: 23.6 [17.5,43.8]), Procalcitonin in blood group B (median [IQR]: 0.54 [0.3,0.7]), D-dimers and CRP in group AB (median [IQR]: 21.5 [9,34]; 24 [9,49], respectively). Regarding severity of COVID-19 disease, no statistical difference was seen between the blood groups. Alteration of the acute phase reactants was not positively associated with any specific blood type. Conclusion In conclusion, this investigation did not show significant association of blood groups with severity and of COVID-19 disease and COVID-19-associated mortality.

AB0 and rhesus blood groups as a risk factor for ARVI COVID-19

The frequency of AB0 and Rhesus blood groups was studied in 12120 patients with COVID-19, 5180 convalescent plasma donors and 118801 healthy donors from Moscow, Smolensk, Yakutsk, Minsk and Gomel. In infected individuals, the frequency of blood group A was significantly higher than in uninfected individuals (41,54 % and 34,39 % respectively, p<0,05), and the frequency of blood group 0, on the contrary, was significantly lower (27,69 % and 36,71 %, p<0,05). The frequency of blood group A was particularly high among patients who died from ARVI COVID-19 - 45,51 % vs. 34,39 %, p=0,008. In some groups of patients, there was a decrease in the frequency of Rh-negative individuals (2,23 % vs. 8,30 %, p<0,001).

Frequency of ABO and Rhesus blood groups in Saudi healthy blood donors versus non-Saudi in a retrospective study in Makkah City

Purpose: to assess the frequency of ABO and Rh blood groups among Saudi and non-Saudi healthy blood donors and to compare between them. Methods: A retrospective study was conducted; in Makkah City, Saudi Arabia. It included 15,365 participants of 44 nationalities who have attended the blood bank of King Abdul Aziz Hospital. The collected data were age, sex, nationality, ABO, and Rhesus blood groups. Results: 46.8 % of the participants were O, 28.8 % A, 19.5 % B, and 4.9% AB. The nationalities with a higher frequency of blood group O were Saudi, Mauritanian, Yemeni, Thai, Malian, Sudanese, Jordanian, Indian, Moroccan, Somali, Malaysian, Indonesian, Myanmar, Nigerian, Pakistani, Bangladeshi, Algerian, Djibouti, Burkinabe, Eritrean, Ghanaian, Bahraini, Bosnian, Canadian, Gambian, Iraqi, and Sri Lankan. Those with a higher frequency of blood group A were Turkish, Palestinian, Syrian, Lebanese, Egyptian, Afghan, Chadian, French, Tunisian, Cameroonian, Ethiopian, and British. Those with a higher frequency of B were Nigerien, American, Nepalese, and two nationalities with higher AB frequency Filipino and Chinese. 91.6 % of all populations were Rh-positive, and 8.4% were Rh-negative. The Saudi participants were like some nationalities and differed from others. Conclusion: In Makkah city, the higher frequency of ABO blood group in Saudi and non -Saudi people is O followed by A, then B, and AB. The Rh-positive is predominant, and 8.4% of the participants are negative. The ABO and Rh blood groups' identifications are essential for providing suitable blood storage for individuals in need.

Red blood cell blood group A antigen level affects the ability of heparin and PfEMP1 antibodies to disrupt Plasmodium falciparum rosettes

Background The histo-blood group ABO system has been associated with adverse outcomes in COVID-19, thromboembolic diseases and Plasmodium falciparum malaria. An integral part of the severe malaria pathogenesis is rosetting, the adherence of parasite infected red blood cells (RBCs) to uninfected RBCs. Rosetting is influenced by the host’s ABO blood group (Bg) and rosettes formed in BgA have previously been shown to be more resilient to disruption by heparin and shield the parasite derived surface antigens from antibodies. However, data on rosetting in weak BgA subgroups is scarce and based on investigations of relatively few donors. Methods An improved high-throughput flow cytometric assay was employed to investigate rosetting characteristics in an extensive panel of RBC donor samples of all four major ABO Bgs, as well as low BgA expressing samples. Results All non-O Bgs shield the parasite surface antigens from strain-specific antibodies towards P. falciparum erythrocyte membrane protein 1 (PfEMP1). A positive correlation between A-antigen levels on RBCs and rosette tightness was observed, protecting the rosettes from heparin- and antibody-mediated disruption. Conclusions These results provide new insights into how the ABO Bg system affects the disease outcome and cautions against interpreting the results from the heterogeneous BgA phenotype as a single group in epidemiological and experimental studies. Graphical Abstract

The Correlation Between The COVID-19 Infection Severity and ABO Blood Groups in Sulaimaniyah City, Iraq

Background ABO blood group types are among the risk factors of COVID-19 infection in many recent studies. Thus, the objective of this study is to find the relations between ABO types and COVID-19 infection as well as to find out the riskier group that is associated with hospitalization and the need for O2 support. Methods This observational cross-sectional study was done to identify the risk and relations between ABO blood groups and Rh factor of 530 Iraqi-Kurdish patients affected with COVID-19 infection. Among them, 184 patients were severe cases that needed hospitalization while 346 patients were mild to moderate cases that were treated at home. The diagnosis of COVID-19 infection was based on Real-Time Polymerase Chain Reaction (RT-PCR) test, high-resolution Chest CT scan, strong clinical suspicion plus history of the close home or job contact with COVID-19 confirmed patient. Results There were no significant differences in the distribution of ABO blood grouping in the total COVID-19 cases, however, the severity in form of hospitalization and O2 demand was higher in blood group A whereas the lowest in group B. Male patient were significantly older than females with more prolonged illness duration. The duration of COVID-19 illness, the need for plasma, and the rate of mortality were very significantly higher among hospitalized COVID-19 patients than non-hospitalized. In 37.2% of the patient, the initial presentation was a combination of more than one symptom. In 28% of cases, myalgia was the 1st mono-symptomatic presentation. Conclusions Blood group A is associated with the highest rate of hospitalization and O2 demand, besides, the duration of illness and rate of mortality in males were more than females.

INFLUENCE ANTIOMOTOXIC PREPARATIONS ON UNSPECIFIC REACTION OF ADAPTATION OF ORGANISM

Effectiveness of Heel firm antihomotoxic preparation on unspecific adaptation reactions of organism was studied in this work. The main work was being done on the base of Georgian LLS of Physical Culture and on the base of Center of Treatment, Tbilisi. 57 patients 19-58 of age were taken for the investigation. They were divided into two groups. Group A (30 person) was prescribed antiohomotoxic preparations dosage according to general rules of usage of Heel firm preparation. Control and correction of the dosage of Heel firm preparation was making of croup B (27 persons) once a week. By its phone parameters of white blood group A and B didn’t have truthfully differences (p˃0,05). The possibility to model the resistance of organism with putting an antihomotoxic preparation was established with using of parameters of white blood. The new approach to individual dosage of antihomotoxic preparation was worked out in treatment of such diseases as gastritis, colitis, cystitis, adnexitis, thrombophlebitis, bronchial asthma, arthritis.

INFLUENCE ANTIOMOTOXIC PREPARATIONS ON UNSPECIFIC REACTION OF ADAPTATION OF ORGANISM

Effectiveness of Heel firm antihomotoxic preparation on unspecific adaptation reactions of organism was studied in this work. The main work was being done on the base of Georgian LLS of Physical Culture and on the base of Center of Treatment, Tbilisi. 57 patients 19-58 of age were taken for the investigation. They were divided into two groups. Group A (30 person) was prescribed antiohomotoxic preparations dosage according to general rules of usage of Heel firm preparation. Control and correction of the dosage of Heel firm preparation was making of croup B (27 persons) once a week. By its phone parameters of white blood group A and B didn’t have truthfully differences (p˃0,05). The possibility to model the resistance of organism with putting an antihomotoxic preparation was established with using of parameters of white blood. The new approach to individual dosage of antihomotoxic preparation was worked out in treatment of such diseases as gastritis, colitis, cystitis, adnexitis, thrombophlebitis, bronchial asthma, arthritis.

Genetic Contributions to Early and Late Onset Ischemic Stroke

Objective: To determine the contribution of common genetic variants to risk of early onset ischemic stroke (IS). Methods: We performed a meta-analysis of genome-wide association studies of early onset IS, ages 18-59, using individual level data or summary statistics in 16,927 cases and 576,353 non-stroke controls from 48 different studies across North America, Europe, and Asia. We further compared effect sizes at our most genome-wide significant loci between early and late onset IS and compared polygenic risk scores for venous thromboembolism between early versus later onset IS. Results: We observed an association between early onset IS and ABO, a known stroke locus. The effect size of the peak ABO SNP, rs8176685, was significantly larger in early compared to late onset IS (OR 1.17 (95% C.I.: 1.11-1.22) vs 1.05 (0.99-1.12); p for interaction = 0.008). Analysis of genetically determined ABO blood groups revealed that early onset IS cases were more likely to have blood group A and less likely to have blood group O compared to both non-stroke controls and to late onset IS cases. Using polygenic risk scores, we observed that greater genetic risk for venous thromboembolism, another prothrombotic condition, was more strongly associated with early, compared to late, onset IS (p=0.008). Conclusion: The ABO locus, genetically predicted blood group A, and higher genetic propensity for venous thrombosis are more strongly associated with early onset IS, compared with late onset IS, supporting a stronger role of prothrombotic factors in early onset IS.

Contemplating SARS-CoV-2 infectivity with respect to ABO blood groups

COVID-19 is a disease that is caused by SARS-CoV-2 and very speedily spreading all over the world. The blood group’s effect on COVID-19 is not clear. The main aim of this article is to determine the relationship between sensitivity of COVID-19 and ABO blood group. For this study we have observed that the individuals with blood group A are at higher risk of getting COVID-19 because they contain the higher concentration of Angiotensin-converting enzyme-2 that provide the site to virus for entry. But in other blood groups the natural Anti A antibodies block the interaction between host receptor and virus and disturb their interaction. Certain studies show that the infectivity and mortality rate in covid patients is not affected by AB blood group system. But according to research, increased ventilator usage, ICU stay was observed in critically ill patients with AB blood group than of other blood groups. O blood group has proved to be protective against SARS-CoV-2 due to the presence of both anti-A and anti-B antibodies as they prevent the binding of the spike protein S of the virus with the ACE2 receptors which are present on the surface of cells. Moreover, furin also plays a major role in penetration of virus in the host cells. Furin is required for the activation of the spike protein S of the virus and due to the low efficiency of furin cleavage in blood group O it is protected from SARS-CoV-2 and other chronic diseases. Mortality rate of covid 19 depends upon the environmental factors, number of people living in the area and also some economic factors. The different strains of COVID-19 effect the different people differently and as the time passes the strain of COVID-19 has changed and thus according to this the mortality rate of different provinces and areas varies due to environmental factors. Pregnant women have no any kind of transportation of covid to their fetuses but mostly patients of blood group A are being affected by COVID-19 and hence their fetuses are somehow effected. And those pregnant women having blood group O does not have any risk of COVID-19 of severe stages.