Non-secretion of ABO antigens predisposing to infection by Neisseria meningitidis and Streptococcus pneumoniae

Genome-wide association study of chronic sputum production implicates loci involved in mucus production and infection

BACKGROUND

Chronic sputum production impacts on quality of life and is a feature of many respiratory diseases. Identification of the genetic variants associated with chronic sputum production in a disease agnostic sample could improve understanding of its causes and identify new molecular targets for treatment.

METHODS

We conducted a genome-wide association study (GWAS) of chronic sputum production in UK Biobank. Signals meeting genome-wide significance (p<5×10-8) were investigated in additional independent studies, were fine-mapped and putative causal genes identified by gene expression analysis. GWASs of respiratory traits were interrogated to identify whether the signals were driven by existing respiratory disease among the cases and variants were further investigated for wider pleiotropic effects using phenome-wide association studies (PheWASs).

RESULTS

From a GWAS of 9714 cases and 48 471 controls, we identified six novel genome-wide significant signals for chronic sputum production including signals in the human leukocyte antigen (HLA) locus, chromosome 11 mucin locus (containing MUC2, MUC5AC and MUC5B) and FUT2 locus. The four common variant associations were supported by independent studies with a combined sample size of up to 2203 cases and 17 627 controls. The mucin locus signal had previously been reported for association with moderate-to-severe asthma. The HLA signal was fine-mapped to an amino acid change of threonine to arginine (frequency 36.8%) in HLA-DRB1 (HLA-DRB1*03:147). The signal near FUT2 was associated with expression of several genes including FUT2, for which the direction of effect was tissue dependent. Our PheWAS identified a wide range of associations including blood cell traits, liver biomarkers, infections, gastrointestinal and thyroid-associated diseases, and respiratory disease.

CONCLUSIONS

Novel signals at the FUT2 and mucin loci suggest that mucin fucosylation may be a driver of chronic sputum production even in the absence of diagnosed respiratory disease and provide genetic support for this pathway as a target for therapeutic intervention.

Maternal H-antigen secretor status is an early biomarker for potential preterm delivery

OBJECTIVE

Pre-pregnancy or first trimester biomarkers predicting preterm delivery are lacking. The purpose of this study was to determine whether maternal H-antigen (secretor status) is a potential biomarker for preterm delivery.

METHODS

This cohort study examined maternal saliva samples and birth data gathered by the National Children's Study Vanguard pilot phase (2009-2014) and included 300 women who were ≥18 years old and provided birth data and saliva samples. The maternal secretor status phenotype was determined by quantifying H-antigen in saliva using enzyme-linked immunoassay. Mothers were stratified by secretor status and multivariable analysis estimated adjusted associations with preterm delivery.

RESULTS

Maternal lack of H-antigen production was an independent risk factor for preterm delivery after adjusting for known confounders (aOR 4.53; 95% CI: 1.74, 11.81; P = 0.002).

CONCLUSIONS

Maternal H-antigen may be a biomarker identifying women at-risk for preterm delivery. Prospective cohort studies validating these findings are needed.

The role of the blood group-related glycosyltransferases FUT2 and B4GALNT2 in susceptibility to infectious disease

The glycosylation profile of the gastrointestinal tract is an important factor mediating host-microbe interactions. Variation in these glycan structures is often mediated by blood group-related glycosyltransferases, and can lead to wide-ranging differences in susceptibility to both infectious- as well as chronic disease. In this review, we focus on the interplay between host glycosylation, the intestinal microbiota and susceptibility to gastrointestinal pathogens based on studies of two exemplary blood group-related glycosyltransferases that are conserved between mice and humans, namely FUT2 and B4GALNT2. We highlight that differences in susceptibility can arise due to both changes in direct interactions, such as bacterial adhesion, as well as indirect effects mediated by the intestinal microbiota. Although a large body of experimental work exists for direct interactions between host and pathogen, determining the more complex and variable mechanisms underlying three-way interactions involving the intestinal microbiota will be the subject of much-needed future research.

Intestinal α1-2-Fucosylation Contributes to Obesity and Steatohepatitis in Mice

BACKGROUND & AIMS

Fucosyltransferase 2 (Fut2)-mediated intestinal α1- 2-fucosylation is important for host-microbe interactions and has been associated with several diseases, but its role in obesity and hepatic steatohepatitis is not known. The aim of this study was to investigate the role of Fut2 in a Western-style diet-induced mouse model of obesity and steatohepatitis.

METHODS

Wild-type (WT) and Fut2-deficient littermate mice were used and features of the metabolic syndrome and steatohepatitis were assessed after 20 weeks of Western diet feeding.

RESULTS

Intestinal α1-2-fucosylation was suppressed in WT mice after Western diet feeding, and supplementation of α1-2-fucosylated glycans exacerbated obesity and steatohepatitis in these mice. Fut2-deficient mice were protected from Western diet-induced features of obesity and steatohepatitis despite an increased caloric intake. These mice have increased energy expenditure and thermogenesis, as evidenced by a higher core body temperature. Protection from obesity and steatohepatitis associated with Fut2 deficiency is transmissible to WT mice via microbiota exchange; phenotypic differences between Western diet-fed WT and Fut2-deficient mice were reduced with antibiotic treatment. Fut2 deficiency attenuated diet-induced bile acid accumulation by altered relative abundance of bacterial enzyme 7-α-hydroxysteroid dehydrogenases metabolizing bile acids and by increased fecal excretion of secondary bile acids. This also was associated with increased intestinal farnesoid X receptor/fibroblast growth factor 15 signaling, which inhibits hepatic synthesis of bile acids. Dietary supplementation of α1-2-fucosylated glycans abrogates the protective effects of Fut2 deficiency.

CONCLUSIONS

α1-2-fucosylation is an important host-derived regulator of intestinal microbiota and plays an important role for the pathogenesis of obesity and steatohepatitis in mice.

Can the FUT2 Non-secretor Phenotype Associated With Gut Microbiota Increase the Children Susceptibility for Type 1 Diabetes? A Mini Review

The global toll of type 1 diabetes (T1D) has steadily increased over the last decades. It is now widely acknowledged that T1D pathophysiology is more complex than expected. Indeed, a multifaceted interplay between genetic, metabolic, inflammatory and environmental factors exists that leads to heterogeneous clinical manifestations across individuals. Children with non-secretor phenotype and those affected by T1D share low abundance of bifidobacteria, low content of short-chain fatty acids, intestinal phosphatase alkaline and a high incidence of inflammatory bowel diseases. In this context, host-gut microbiota dyad may represent a relevant contributor to T1D development and progression due to its crucial role in shaping host immunity and susceptibility to autoimmune conditions. The FUT2 gene is responsible for the composition and functional properties of glycans in mucosal tissues and bodily secretions, including human milk. FUT2 polymorphisms may profoundly influence gut microbiota composition and host susceptibility to viral infections and chronic inflammatory disease. In this minireview, the possible interplay between mothers' phenotype, host FUT2 genetic background and gut microbiota composition will be discussed in perspective of the T1D onset. The study of FUT2-gut microbiota interaction may add a new piece on the puzzling T1D etiology and unveil novel targets of intervention to contrast T1D development and progression. Dietary interventions, including the intake of α-(1, 2)-fucosyl oligosaccharides in formula milk and the use of specific prebiotics and probiotics, could be hypothesized.

The landscape of host genetic factors involved in immune response to common viral infections

BACKGROUND

Humans and viruses have co-evolved for millennia resulting in a complex host genetic architecture. Understanding the genetic mechanisms of immune response to viral infection provides insight into disease etiology and therapeutic opportunities.

METHODS

We conducted a comprehensive study including genome-wide and transcriptome-wide association analyses to identify genetic loci associated with immunoglobulin G antibody response to 28 antigens for 16 viruses using serological data from 7924 European ancestry participants in the UK Biobank cohort.

RESULTS

Signals in human leukocyte antigen (HLA) class II region dominated the landscape of viral antibody response, with 40 independent loci and 14 independent classical alleles, 7 of which exhibited pleiotropic effects across viral families. We identified specific amino acid (AA) residues that are associated with seroreactivity, the strongest associations presented in a range of AA positions within DRβ1 at positions 11, 13, 71, and 74 for Epstein-Barr virus (EBV), Varicella zoster virus (VZV), human herpesvirus 7, (HHV7), and Merkel cell polyomavirus (MCV). Genome-wide association analyses discovered 7 novel genetic loci outside the HLA associated with viral antibody response (P < 5.0 × 10-8), including FUT2 (19q13.33) for human polyomavirus BK (BKV), STING1 (5q31.2) for MCV, and CXCR5 (11q23.3) and TBKBP1 (17q21.32) for HHV7. Transcriptome-wide association analyses identified 114 genes associated with response to viral infection, 12 outside of the HLA region, including ECSCR: P = 5.0 × 10-15 (MCV), NTN5: P = 1.1 × 10-9 (BKV), and P2RY13: P = 1.1 × 10-8 EBV nuclear antigen. We also demonstrated pleiotropy between viral response genes and complex diseases, from autoimmune disorders to cancer to neurodegenerative and psychiatric conditions.

CONCLUSIONS

Our study confirms the importance of the HLA region in host response to viral infection and elucidates novel genetic determinants beyond the HLA that contribute to host-virus interaction.

Breaking the Glyco-Code of HIV Persistence and Immunopathogenesis

PURPOSE OF REVIEW

Glycoimmunology is an emerging field focused on understanding how immune responses are mediated by glycans (carbohydrates) and their interaction with glycan-binding proteins called lectins. How glycans influence immunological functions is increasingly well understood. In a parallel way, in the HIV field, it is increasingly understood how the host immune system controls HIV persistence and immunopathogenesis. However, what has mostly been overlooked, despite its potential for therapeutic applications, is the role that the host glycosylation machinery plays in modulating the persistence and immunopathogenesis of HIV. Here, we will survey four areas in which the links between glycan-lectin interactions and immunology and between immunology and HIV are well described. For each area, we will describe these links and then delineate the opportunities for the HIV field in investigating potential interactions between glycoimmunology and HIV persistence/immunopathogenesis.

RECENT FINDINGS

Recent studies show that the human glycome (the repertoire of human glycan structures) plays critical roles in driving or modulating several cellular processes and immunological functions that are central to maintaining HIV infection. Understanding the links between glycoimmunology and HIV infection may create a new paradigm for discovering novel glycan-based therapies that can lead to eradication, functional cure, or improved tolerance of lifelong infection.

FUT2 secretor genotype and susceptibility to infections and chronic conditions in the ALSPAC cohort

Background: The FUT2 (fucosyltransferase-2) gene determines blood group secretor status. Being homozygous for the inactive "non-secretor" rs601338(A) allele confers resistance to certain infections (e.g. Norovirus, Rotavirus) and susceptibility to others (e.g. Haemophilus influenza, Streptococcus pneumonia). Non-secretors also have an increased risk of type 1 diabetes and inflammatory bowel disease. We examined FUT2 genotype, infections and chronic conditions in a population-based cohort. Methods: We studied 7,582 pregnant women from the ALSPAC pregnancy cohort. Infections (measles, mumps, chicken pox, whooping cough, meningitis, herpes, gonorrhea and urinary infections) and chronic conditions (kidney disease, hypertension, diabetes, rheumatism, arthritis, psoriasis, hay fever, asthma, eczema and allergies) were self-reported. FUT2 secretor status was determined from the rs601338 genotype. ABO blood type was obtained from clinical records. Results: Overall, 1920 women (25.3%) were homozygous for the non-secretor allele (AA). Secretor status was associated with mumps, with 68% of non-secretors experiencing this infection, compared to 48% of secretors (RR, 1.40; 95% CI, 1.34-1.46). A weaker association was observed for measles infection (76% vs. 72%; RR, 1.05; 95% CI, 1.02-1.09). Non-secretors also experienced an increased risk of kidney disease (5.4% vs. 3.9%; RR, 1.39; 95% CI, 1.11-1.75). Independent of secretor status, AB blood type was a risk factor for mumps (RR 1.15; 95%CI, 1.03, 1.28 compared to type O). We found no evidence of interaction between secretor status and blood type.  For some conditions, including asthma and arthritis, FUT2 heterozygosity (GA) appeared to confer an intermediate phenotype. There was no strong evidence of association between secretor status and other infections or chronic conditions, although statistical power was limited for rare outcomes. Conclusion: Our results identify an association between FUT2 secretor status and self-reported kidney disease, and confirm a recently reported association with susceptibility to mumps infection. The clinical implications of these associations warrant further investigation.

FUT2 secretor genotype and susceptibility to infections and chronic conditions in the ALSPAC cohort

Background: The FUT2 (fucosyltransferase 2) gene encodes alpha (1,2) fucosyltransferase, which determines blood group secretor status. Being homozygous for the inactive "non-secretor" rs601338(A) allele appears to confer resistance to certain infections (e.g. Norovirus, Rotavirus and Helicobacter pylori) and susceptibility to others (e.g. Haemophilus influenza and Streptococcus pneumonia). Non-secretors also have an increased risk of type 1 diabetes and inflammatory bowel disease. We aimed to determine the association of the FUT2 secretor genotype with infections and chronic conditions in the population-based Avon Longitudinal Study of Parents and Children (ALSPAC). Methods: This study included 7,582 pregnant women from the ALSPAC pregnancy cohort. Personal history of infections (measles, mumps, chicken pox, whooping cough, cold sores, meningitis, genital herpes, gonorrhea and urinary infections) and chronic conditions (kidney disease, hypertension, diabetes, rheumatism, arthritis, psoriasis, hay fever, asthma, eczema and various allergies) were self-reported by standardized questionnaire. FUT2 secretor status was determined from the rs601338 genotype. Results: Overall, 1920 women (25.3%) were homozygous for the FUT2 non-secretor allele (AA). Secretor status was associated with mumps, with 68% of non-secretors experiencing this infection, compared to 48% of secretors (RR, 1.40; 95% CI, 1.34-1.46; p<0.0001). A weaker association was observed for measles infection (76% vs. 72%; RR, 1.05; 95% CI, 1.02-1.09; p=0.0008). Non-secretors also experienced a 39% increased risk of kidney disease (5.4% vs. 3.9%; RR, 1.39; 95% CI, 1.11-1.75; p=0.004). For some conditions, including gonorrhea and arthritis, FUT2 heterozygosity (GA) appeared to confer an intermediate phenotype. There was no strong evidence of association between FUT2 secretor status and other infections or chronic conditions, although statistical power was limited for rare outcomes. Conclusion: Our results identify an association between FUT2 secretor status and kidney disease, and confirm a recently reported association with susceptibility to mumps infection. The clinical implications of these associations warrant further investigation.

Infection's Sweet Tooth: How Glycans Mediate Infection and Disease Susceptibility

Glycans form a highly variable constituent of our mucosal surfaces and profoundly affect our susceptibility to infection and disease. The diversity and importance of these surface glycans can be seen in individuals who lack a functional copy of the fucosyltransferase gene, FUT2. Representing around one-fifth of the population, these individuals have an altered susceptibility to many bacterial and viral infections and diseases. The mediation of host-pathogen interactions by mucosal glycans, such as those added by FUT2, is poorly understood. We highlight, with specific examples, important mechanisms by which host glycans influence infection dynamics, including by: acting as pathogen receptors (or receptor-decoys), promoting microbial stability, altering the physical characteristics of mucus, and acting as immunological markers. We argue that the effect glycans have on infection dynamics has profound implications for many aspects of healthcare and policy, including clinical management, outbreak control, and vaccination policy.

Genetic susceptibility to infectious diseases: Current status and future perspectives from genome-wide approaches

Genome-wide association studies (GWASs) have been widely applied to identify genetic factors that affect complex diseases or traits. Presently, the GWAS Catalog includes > 2800 human studies. Of these, only a minority have investigated the susceptibility to infectious diseases or the response to therapies for the treatment or prevention of infections. Despite their limited application in the field, GWASs have provided valuable insights by pinpointing associations to both innate and adaptive immune response loci, as well as novel unexpected risk factors for infection susceptibility. Herein, we discuss some issues and caveats of GWASs for infectious diseases, we review the most recent findings ensuing from these studies, and we provide a brief summary of selected GWASs for infections in non-human mammals. We conclude that, although the general trend in the field of complex traits is to shift from GWAS to next-generation sequencing, important knowledge on infectious disease-related traits can be still gained by GWASs, especially for those conditions that have never been investigated using this approach. We suggest that future studies will benefit from the leveraging of information from the host's and pathogen's genomes, as well as from the exploration of models that incorporate heterogeneity across populations and phenotypes. Interactions within HLA genes or among HLA variants and polymorphisms located outside the major histocompatibility complex may also play an important role in shaping the susceptibility and response to invading pathogens.

•

Relatively few GWASs for infectious diseases were performed.

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Phenotype heterogeneity and case/control misclassification can affect GWAS power.

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Adaptive and innate immunity loci were identified in several infectious disease GWASs.

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Unexpected loci (e.g., lncRNAs) were also associated with infection susceptibility.

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GWASs should integrate host and pathogen diversity and use complex association models.

FUT2 genotype influences lung function, exacerbation frequency and airway microbiota in non-CF bronchiectasis

OBJECTIVE

To assess whether FUT2 (secretor) genotype affects disease severity and airway infection in patients with non-cystic fibrosis bronchiectasis.

PARTICIPANTS

Induced sputum samples were obtained from 112 adult patients with high-resolution CT scan-proven bronchiectasis and at least two exacerbations in the previous year, as part of an unrelated randomised control trial.

OUTCOME MEASURES

Presence of null FUT2 polymorphisms were determined by gene sequencing and verified by endobronchial biopsy histochemical staining. Outcome measures were FEV1% predicted, exacerbation frequency, and bacterial, fungal and viral components of the microbiota (measured by culture independent approaches).

RESULTS

Patients were grouped by FUT2 loss-of-function genotype; categorised as non-secretors (n=27, sese), heterozygous secretors (n=54, Sese) or homozygous secretors (n=31, SeSe). FEV1% was significantly lower in SeSe patients compared with sese patients (mean 61.6 (SD 20.0) vs 74.5 (18.0); p=0.023). Exacerbation frequency was significantly higher in SeSe (mean count 5.77) compared with sese (4.07; p=0.004) and Sese (4.63; p=0.026) genotypes. The time until first exacerbation was significantly shorter in SeSe compared with Sese (HR=0.571 (95% CI 0.343 to 0.950); p=0.031), with a similar trend for sese patients (HR=0.577 (0.311 to 1.07); p=0.081). sese had a significantly reduced frequency of Pseudomonas aeruginosa-dominated airway infection (8.7%) compared with Sese (31%; p=0.042) and SeSe (36%; p=0.035). In contrast, fungal, viral and non-dominant bacterial components of the microbiome were not significantly different between FUT2 genotypes.

CONCLUSIONS

FUT2 genotype in patients with non-cystic fibrosis bronchiectasis was significantly associated with disease outcomes, with homozygous secretors exhibiting lower lung function, higher exacerbation number and a higher frequency of P. aeruginosa-dominated infection.

TRIAL REGISTRATION NUMBER

ACTRN12609000578202 (anzctr.org.au); Pre-results.

Epithelial glycosylation in gut homeostasis and inflammation

Intestinal epithelial cells apically express glycans, especially α1,2-fucosyl linkages, which work as a biological interface for the host-microbe interaction. Emerging studies have shown that epithelial α1,2-fucosylation is regulated by microbes and by group 3 innate lymphoid cells (ILC3s). Dysregulation of the gene (FUT2) encoding fucosyltransferase 2, an enzyme governing epithelial α1,2-fucosylation, is associated with various human disorders, including infection and chronic inflammatory diseases. This suggests a critical role for an interaction between microbes, epithelial cells and ILC3s mediated via glycan residues. In this Review, using α1,2-fucose and Fut2 gene expression as an example, we describe how epithelial glycosylation is controlled by immune cells and luminal microbes. We also address the pathophysiological contribution of epithelial α1,2-fucosylation to pathogenic and commensal microbes as well as the potential of α1,2-fucose and its regulatory pathway as previously unexploited targets in the development of new therapeutic approaches for human diseases.

ABO blood group antigen mismatch has an impact on outcome after allogeneic peripheral blood stem cell transplantation

ABO blood group antigen incompatibility (ABO mismatch) is not an obstacle to allogeneic stem cell transplantation (allo-SCT). However, the impact on clinical outcome after allo-SCT remains controversial. We analyzed 512 patients after allogeneic peripheral blood SCT (allo-PBSCT) for an association of ABO mismatch with transfusion requirements, myeloid and platelet engraftment, the incidence of GvHD, relapse, transplant-related mortality (TRM), and overall survival (OS). A total of 260 patients underwent ABO-mismatched transplantation and the control group consisted of 252 patients with ABO-matched allo-PBSCT. We found a significant association between major-0 ABO mismatch (group 0 recipient/group A, B, or AB donor) and increased red blood cell (RBC) and platelet transfusion requirements (both P<.001) as well as delayed platelet engraftment (P<.001). Minor-A (group A recipient/group 0 donor) and minor-AB (group AB recipient/group 0, A, or B donor) ABO mismatch was significantly associated with an increased TRM after allo-PBSCT (P=.001 and P=.02). In multivariate analysis performed using Cox regression, minor ABO mismatch appeared as independent risk factor for TRM after allo-PBSCT. No association was found for ABO mismatch with the incidence of GvHD, relapse, and OS. Our results suggest that ABO blood group mismatch has a significant impact on the outcome and that minor-A and minor-AB ABO mismatch represents a risk factor for increased TRM after allo-PBSCT.

Blood group antigen expression is involved in C. albicans interaction with buccal epithelial cells

Human blood group polymorphisms are known to be determined by the expression of A, B or H antigens and the Lewis antigens. Protection against microbial infections has been associated with inheritance of polymorphisms in genes encoding and regulating the expression of ABH and Lewis antigens in bodily secretions and epithelial tissue surfaces, subsequently resulting in the presentation of different glycosylated terminal antigens on the cell surface. We investigated the role of blood group antigens in diversifying the glycosylation of buccal epithelial cells (BEC) that line the oral cavity. Specifically, we characterized and statistically evaluated the expression of histo-blood group (A, B, O) antigens on N-and O-linked glycans from BEC membrane proteins of various individuals that represented different blood group type and secretor status using a porous graphitic carbon liquid chromatography electrospray ionization mass spectrometry (PGC-LC-ESI-MS) based glycomics approach. From these BEC membrane proteins a total of 77 N-glycan and 96 O-glycan structures were structurally characterized from 19 individuals and relatively quantitated. The N-glycans from the secretor individuals did not express any A/B blood group determinants, but contained several terminal H-antigens. Apart from the non-secretors, the N-glycan profiles of BEC from all blood groups displayed similar glycan types, while varying in their relative intensities between individuals. However, multivariate analysis of the O-glycans from individuals displayed segregation patterns clearly associated with their blood group type and secretor status. In adhesion assays the oral pathogen Candida albicans showed a significantly higher interaction to blood group O type BECs relative to other blood groups.

A genome-wide association meta-analysis of diarrhoeal disease in young children identifies FUT2 locus and provides plausible biological pathways

More than a million childhood diarrhoeal episodes occur worldwide each year, and in developed countries a considerable part of them are caused by viral infections. In this study, we aimed to search for genetic variants associated with diarrhoeal disease in young children by meta-analyzing genome-wide association studies, and to elucidate plausible biological mechanisms. The study was conducted in the context of the Early Genetics and Lifecourse Epidemiology (EAGLE) consortium. Data about diarrhoeal disease in two time windows (around 1 year of age and around 2 years of age) was obtained via parental questionnaires, doctor interviews or medical records. Standard quality control and statistical tests were applied to the 1000 Genomes imputed genotypic data. The meta-analysis (N = 5758) followed by replication (N = 3784) identified a genome-wide significant association between rs8111874 and diarrhoea at age 1 year. Conditional analysis suggested that the causal variant could be rs601338 (W154X) in the FUT2 gene. Children with the A allele, which results in a truncated FUT2 protein, had lower risk of diarrhoea. FUT2 participates in the production of histo-blood group antigens and has previously been implicated in the susceptibility to infections, including Rotavirus and Norovirus Gene-set enrichment analysis suggested pathways related to the histo-blood group antigen production, and the regulation of ion transport and blood pressure. Among others, the gastrointestinal tract, and the immune and neuro-secretory systems were detected as relevant organs. In summary, this genome-wide association meta-analysis suggests the implication of the FUT2 gene in diarrhoeal disease in young children from the general population.

Histo-blood group glycans in the context of personalized medicine

BACKGROUND

A subset of histo-blood group antigens including ABO and Lewis are oligosaccharide structures which may be conjugated to lipids or proteins. They are known to be important recognition motifs not only in the context of blood transfusions, but also in infection and cancer development.

SCOPE OF REVIEW

Current knowledge on the molecular background and the implication of histo-blood group glycans in the prevention and therapy of infectious and non-communicable diseases, such as cancer and cardiovascular disease, is presented.

MAJOR CONCLUSIONS

Glycan-based histo-blood groups are associated with intestinal microbiota composition, the risk of various diseases as well as therapeutic success of, e.g., vaccination. Their potential as prebiotic or anti-microbial agents, as disease biomarkers and vaccine targets should be further investigated in future studies. For this, recent and future technological advancements will be of particular importance, especially with regard to the unambiguous structural characterization of the glycan portion in combination with information on the protein and lipid carriers of histo-blood group-active glycans in large cohorts.

GENERAL SIGNIFICANCE

Histo-blood group glycans have a unique linking position in the complex network of genes, oncodevelopmental biological processes, and disease mechanisms. Thus, they are highly promising targets for novel approaches in the field of personalized medicine. This article is part of a Special Issue entitled "Glycans in personalised medicine" Guest Editor: Professor Gordan Lauc.

A Genetic Modifier of the Gut Microbiome Influences the Risk of Graft-versus-Host Disease and Bacteremia After Hematopoietic Stem Cell Transplantation

The human gut microbiome is involved in vital biological functions, such as maintenance of immune homeostasis and modulation of intestinal development and enhanced metabolic capabilities. Disturbances of the intestinal microbiota have been associated with development and progression of inflammatory conditions, including graft-versus-host disease (GVHD). The fucosyltransferase 2 (FUT2) gene produces an enzyme that is responsible for the synthesis of the H antigen in body fluids and on the intestinal mucosa. FUT2 genotype has been shown to modify the gut microbiome. We hypothesized that FUT2 genotype influences risk of GVHD and bacterial translocation after allogeneic hematopoietic stem cell transplantation (HSCT). FUT2 genotype was determined in 150 consecutive patients receiving allogeneic HSCT at our center. We abstracted clinical characteristics and outcomes from the transplantation database. Cumulative risk of any acute GVHD varied by FUT2 genotype, with decreased risk in those with A/A genotype and increased risk in those with G/G genotype. In contrast, the cumulative incidence of bacteremia was increased in those with A/A genotype. We conclude that the FUT2 genotype influences risk of acute GVHD and bacteremia after HSCT. We hypothesize that the mechanisms involve altered intestinal surface glycosylation and microbial composition but this requires additional study.

IL-10-producing CD4(+) T cells negatively regulate fucosylation of epithelial cells in the gut

Fucosylated glycans on the surface of epithelial cells (ECs) regulate intestinal homeostasis by serving as attachment receptors and a nutrient source for some species of bacteria. We show here that epithelial fucosylation in the ileum is negatively regulated by IL-10-producing CD4⁺ T cells. The number of fucosylated ECs was increased in the ileum of mice lacking T cells, especially those expressing αβ T cell receptor (TCR), CD4, and IL-10. No such effect was observed in mice lacking B cells. Adoptive transfer of αβTCR⁺ CD4⁺ T cells from normal mice, but not IL-10-deficient mice, normalized fucosylation of ECs. These findings suggest that IL-10-producing CD4⁺ T cells contribute to the maintenance of the function of ECs by regulating their fucosylation.

Intestinal fucose as a mediator of host-microbe symbiosis

Fucose is an L-configuration sugar found abundantly in the mammalian gut. It has long been known to be induced there by the presence of bacteria, but only recently have some of the molecular mechanisms behind this process been uncovered. New work suggests that fucose can have a protective role in both gut-centered and systemic infection and inflammation. This review highlights recent studies showing that, in addition to acting as a food source for beneficial gut symbionts, host fucose can suppress the virulence of pathogens and pathobionts. The relevance of gut fucosylation to human diseases also is discussed.

Fucosyltransferase 2: a genetic risk factor for primary sclerosing cholangitis and Crohn's disease--a comprehensive review

Fucosyltransferase 2 (FUT2) mediates the inclusion of fucose in sugar moieties of glycoproteins and glycolipids. ABO blood group antigens and host-microbe interactions are influenced by FUT2 activity. About 20 % of the population has a "non-secretor" status caused by inactivating variants of FUT2 on both alleles. The non-sense mutation G428A and the missense mutation A385T are responsible for the vast majority of the non-secretor status in Caucasians, Africans, and Asians, respectively. Non-secretor individuals do not secrete fucose-positive antigens and lack fucosylation in epithelia. They also appear to be protected against a number of infectious diseases, such as Norovirus and Rotavirus infections. In recent years, genome-wide association studies (GWAS) identified inactivating variants at the FUT2 locus to be associated with primary sclerosing cholangitis (PSC), Crohn's disease (CD), and biochemical markers of biliary damage. These associations are intriguing given the important roles of fucosylated glycans in host-microbe interactions and membrane stability. Non-secretors have a reduced fecal content of Bifidobacteria. The intestinal bacterial composition of CD patients resembles the one of non-secretors, with an increase in Firmicutes and decreases in Proteobacteria and Actinobacteria. Non-secretor individuals lack fucosylated glycans at the surface of biliary epithelium and display a different bacterial composition of bile compared to secretors. Notably, an intact biliary epithelial glycocalix is relevant for a stable 'biliary HCO3 (-) umbrella' to protect against toxic effects of hydrophobic bile salt monomers. Here, the biology of FUT2 will be discussed as well as hypotheses to explain the role of FUT2 in the pathophysiology of PSC and Crohn's disease.

Reduced coffee consumption among individuals with primary sclerosing cholangitis but not primary biliary cirrhosis

BACKGROUND & AIMS

Coffee consumption has been associated with decreased risk of liver disease and related outcomes. However, coffee drinking has not been investigated among patients with cholestatic autoimmune liver diseases, primary biliary cirrhosis (PBC), or primary sclerosing cholangitis (PSC). We investigated the relationship between coffee consumption and risk of PBC and PSC in a large North American cohort.

METHODS

Lifetime coffee drinking habits were determined from responses to questionnaires from 606 patients with PBC, 480 with PSC, and 564 healthy volunteers (controls). Patients (those with PBC or PSC) were compared with controls by using the Wilcoxon rank sum test for continuous variables and c(2) method for discrete variables. Logistic regression was used to analyze the estimate of the effects of different coffee parameters (time, frequency, and type of coffee consumption) after adjusting for age, sex, smoking status, and education level.

RESULTS

Patients with PBC and controls did not differ in coffee parameters. However, 24% of patients with PSC had never drunk coffee compared with 16% of controls (P < .05), and only 67% were current drinkers compared with 77% of controls (P < .05). Patients with PSC also consumed fewer lifetime cups per month (45 vs 47 for controls, P < .05) and spent a smaller percentage of their lifetime drinking coffee (46.6% vs 66.7% for controls, P < .05). These differences remained significant in a multivariate model. Among PSC patients with concurrent ulcerative colitis, coffee protected against proctocolectomy (hazard ratio, 0.34; P < .001).

CONCLUSIONS

Coffee consumption is lower among patients with PSC, but not PBC, compared with controls.

Fut2 genotype is a risk factor for dominant stenosis and biliary candida infections in primary sclerosing cholangitis

BACKGROUND

A recent genome-wide association study identified the FUT2 secretor status and genotype defined by the single-nucleotide polymorphism rs601338 as potential genetic risk factor in primary sclerosing cholangitis (PSC), which significantly influences biliary bacterial composition.

AIM

To determine the impact of the rs601338-FUT2 genotype on frequency of biliary infections, development of dominant stenosis and liver-transplantation-free survival in patients with PSC.

METHODS

Cohort study of 215 patients with PSC treated at our tertiary care centre with respect to their rs601338-FUT2 genotype. Results of endoscopic retrograde cholangiography and bile culture were analysed; 639 biliary samples were obtained, cultured and subjected to microbial analysis. Clinical and laboratory data were analysed using chart reviews.

RESULTS

For the rs601338-FUT2 genotype, 69 patients (32.1%) were found to be wildtype (GG), 97 (45.1%) patients were heterozygous (AG) and 49 patients (22.8%) were homozygous-mutated (AA). In addition to alterations in the bacterial pattern, especially in heterozygous carriers, patients with mutated alleles had a marked increase in the frequency of biliary Candida infections (P = 0.025). Further, patients with mutated alleles showed an increased frequency of episodes of cholangitis (P = 0.0025), development of dominant stenosis (P < 0.002) and a reduced actuarial transplantation-free survival (P = 0.044). Levels of biliary Ca19-9 were significantly elevated in the homozygous-mutated patients.

CONCLUSIONS

The rs601338-FUT2 genotype is strongly associated with episodes of cholangitis, fungobilia and the incidence of dominant stenosis, which are three clinical hallmarks of PSC; FUT2 is thus an important genetic risk factor for host-microbial diversity and disease progression in PSC.

2'-fucosyllactose: an abundant, genetically determined soluble glycan present in human milk

Lactose is the preeminent soluble glycan in milk and a significant source of energy for most newborn mammals. Elongation of lactose with additional monosaccharides gives rise to a varied repertoire of free soluble glycans such as 2'-fucosyllactose (2'-FL), which is the most abundant oligosaccharide in human milk. In infants, 2'-FL is resistant to digestion and reaches the colon where it is partially fermented, behaving as soluble prebiotic fiber. Evidence also suggests that portions of small soluble milk glycans, including 2'-FL, are absorbed, thus raising the possibility of systemic biological effects. 2'-FL bears an epitope of the Secretor histo-blood group system; approximately 70-80% of all milk samples contain 2'-FL, since its synthesis depends on a fucosyltransferase that is not uniformly expressed. The fact that some infants are not exposed to 2'-FL has helped researchers to retrospectively probe for biological activities of this glycan. This review summarizes the attributes of 2'-FL in terms of its occurrence in mammalian phylogeny, its postulated biological activities, and its variability in human milk.

A novel role for inducible Fut2 in angiogenesis

RATIONALE

Angiogenesis plays an important role in wound healing and tumor growth. Fucosyltransferases synthesize fucosylated glycans and may play a major role in vascular biology.

OBJECTIVE

To examine the role of an alpha(1,2) fucosyltransferase (Fut2) in angiogenesis.

METHODS AND RESULTS

We found that Fut2 mRNA and protein expression is inducible in human dermal microvascular endothelial cells (HMVECs). After finding that Fut2 is inducible in HMVECs, we examined if Fut2 contributes to angiogenesis. We found that Fut2 null endothelial cell (EC) migration and tube formation were significantly less compared to wild type (wt) ECs. Angiogenesis was impaired in Fut2 null compared to wt mice in the mouse Matrigel plug and the sponge granuloma angiogenesis assays. To assess the characteristics of Fut2 null ECs in vivo, we performed Matrigel plug angiogenesis assays in wt mice using Fut2 null and wt mouse ECs. We found a significant decrease in Fut2 null EC incorporation in neoangiogenesis compared to wt ECs. ERK1/2 activation, fibroblast growth factor receptor2, and vascular endothelial growth factor expression were less in Fut2 null ECs, suggesting a possible mechanism of impaired angiogenesis when Fut2 is lacking.

CONCLUSIONS

These data suggest a novel role for Fut2 as a regulator of angiogenesis.

FUT2 nonsecretor status links type 1 diabetes susceptibility and resistance to infection

OBJECTIVE

FUT2 encodes the α(1,2) fucosyltransferase that determines blood group secretor status. Homozygotes (A/A) for the common nonsense mutation rs601338A>G (W143X) are nonsecretors and are unable to express histo-blood group antigens in secretions and on mucosal surfaces. This mutation has been reported to provide resistance to Norovirus and susceptibility to Crohn's disease, and hence we aimed to determine if it also affects risk of type 1 diabetes.

RESEARCH DESIGN AND METHODS

rs601338A>G was genotyped in 8,344 patients with type 1 diabetes, 10,008 control subjects, and 3,360 type 1 diabetic families. Logistic regression models were used to analyze the case-control collection, and conditional logistic regression was used to analyze the family collection. RESULTS The nonsecretor A/A genotype of rs601338A>G was found to confer susceptibility to type 1 diabetes in both the case-control and family collections (odds ratio for AA 1.29 [95% CI 1.20-1.37] and relative risk for AA 1.22 [95% CI = 1.12-1.32]; combined P = 4.3 × 10(-18)), based on a recessive effects model.

CONCLUSIONS

Our findings linking FUT2 and type 1 diabetes highlight the intriguing relationship between host resistance to infections and susceptibility to autoimmune disease.

Fucosyltransferase 2 (FUT2) non-secretor status is associated with Crohn's disease

Genetic variation in both innate and adaptive immune systems is associated with Crohn's disease (CD) susceptibility, but much of the heritability to CD remains unknown. We performed a genome-wide association study (GWAS) in 896 CD cases and 3204 healthy controls all of Caucasian origin as defined by multidimensional scaling. We found supportive evidence for 21 out of 40 CD loci identified in a recent CD GWAS meta-analysis, including two loci which had only nominally achieved replication (rs4807569, 19p13; rs991804, CCL2/CCL7). In addition, we identified associations with genes involved in tight junctions/epithelial integrity (ASHL, ARPC1A), innate immunity (EXOC2), dendritic cell biology [CADM1 (IGSF4)], macrophage development (MMD2), TGF-beta signaling (MAP3K7IP1) and FUT2 (a physiological trait that regulates gastrointestinal mucosal expression of blood group A and B antigens) (rs602662, P=3.4x10(-5)). Twenty percent of Caucasians are 'non-secretors' who do not express ABO antigens in saliva as a result of the FUT2 W134X allele. We demonstrated replication in an independent cohort of 1174 CD cases and 357 controls between the four primary FUT2 single nucleotide polymorphisms (SNPs) and CD (rs602662, combined P-value 4.90x10(-8)) and also association with FUT2 W143X (P=2.6x10(-5)). Further evidence of the relevance of this locus to CD pathogenesis was demonstrated by the association of the original four SNPs and CD in the recently published CD GWAS meta-analysis (rs602662, P=0.001). These findings strongly implicate this locus in CD susceptibility and highlight the role of the mucus layer in the development of CD.

The relationship between blood groups and disease

The relative contribution of founder effects and natural selection to the observed distribution of human blood groups has been debated since blood group frequencies were shown to differ between populations almost a century ago. Advances in our understanding of the migration patterns of early humans from Africa to populate the rest of the world obtained through the use of Y chromosome and mtDNA markers do much to inform this debate. There are clear examples of protection against infectious diseases from inheritance of polymorphisms in genes encoding and regulating the expression of ABH and Lewis antigens in bodily secretions particularly in respect of Helicobacter pylori, norovirus, and cholera infections. However, available evidence suggests surviving malaria is the most significant selective force affecting the expression of blood groups. Red cells lacking or having altered forms of blood group-active molecules are commonly found in regions of the world in which malaria is endemic, notably the Fy(a-b-) phenotype and the S-s- phenotype in Africa and the Ge- and SAO phenotypes in South East Asia. Founder effects provide a more convincing explanation for the distribution of the D- phenotype and the occurrence of hemolytic disease of the fetus and newborn in Europe and Central Asia.

Genetic basis of host resistance to norovirus infection

Noroviruses have emerged as a major cause of acute gastroenteritis in humans of all ages and are responsible for 200,000 deaths every year, mainly in developing countries. Despite high infectivity and lack of long-term immunity, authentic and volunteer studies have shown existence of inherited protective factors. Recent studies have shown that secretor status controlled by the α1,2-fucosyltransferase gene located on chromosome 19 determines susceptibility to most, if not all, norovirus infections, with individuals homozygous for the G428A nonsense mutation (nonsecretors) representing 20% of the highly protected European population.

Mendelian resistance to human norovirus infections

Noroviruses have emerged as a major cause of acute gastroenteritis in humans of all ages. Despite high infectivity of the virus and lack of long-term immunity, volunteer and authentic studies has suggested the existence of inherited protective factors. Recent studies have shown that histo-blood group antigens (HBGAs) and in particular secretor status controlled by the α1,2fucosyltransferase FUT2 gene determine susceptibility to norovirus infections, with nonsecretors (FUT2−/−), representing 20% of Europeans, being highly resistant to symptomatic infections with major strains of norovirus. Moreover, the capsid protein from distinct strains shows different HBGA specificities, suggesting a host–pathogen co-evolution driven by carbohydrate–protein interactions.

Distribution of H type 1-4 chains of the ABO(H) system in different cell types of human respiratory epithelium

We used three anti-H monoclonal antibodies (MAbs) specific for H Type 1, H Type 2, and H Type 3/4 antigens to investigate the distribution of H Type 1-H Type 4 chains of the ABO(H) histo-blood group in the human respiratory system. Strong staining of H Type 1 chain and weak staining of H Type 2 chain were observed in mucous cells of submucosal glands of bronchial epithelium, which were dependent on the secretor status. No H Type 3/4 chains were detected in mucous cells. Serous cells of submucosal glands of respiratory system showed no staining by three anti-H antibodies. H Type 1 and H Type 3/4 antigens were detected heterogeneously in apical surfaces of bronchial epithelium from secretors but not from nonsecretors. In contrast, basal cells of bronchial epithelium expressed H Type 2 irrespective of the secretor status, probably regulated by the H gene. Some alveolar Type II cells contained only H Types 3/4, which were dependent on the secretor status, whereas alveolar Type I cells had no H antigens. Our results indicated that different cell types in respiratory epithelium expressed different types of carbohydrate chains of histo-blood group antigens under the control of the H or the Se gene.

Pathogenesis of urinary tract infection. Role of host defenses

In the last decade, there have been modest strides made in our understanding of the pathogenesis of urinary tract infections (UTIs). Matching the advances achieved in unraveling the complexities of bacterial virulence factors using molecular-genetic techniques has been a parallel increase in knowledge of host defense mechanisms. Host susceptibility to UTI in the past has been predominantly studied in patients with structural (obstruction) or functional abnormalities (diabetes mellitus); however, most patients with UTIs have no such demonstrable abnormalities, hence attention has now focused on host behavioral factors in addition to genetically determined cellular mechanisms that predispose to sporadic and recurrent UTI.

Genetics of infectious disease resistance

The identification of large numbers of candidates genes and the introduction of methodologies for whole-genome screening have provided new opportunities for elucidating the molecular basis of variable susceptibility to major infectious diseases. 12 genes have been implicated in variable susceptibility to malaria and susceptibility/resistance genes for several other infectious diseases are beginning to be identified. Recent work suggests that large-scale family linkage and population association studies will be a more successful route to human disease genes than extrapolation from mouse models of infection.

Inhibitory effect of saliva from secretors and non-secretors on binding of meningococci to epithelial cells

Carriage of Neisseria meningitidis B:4:P1.15 was higher among non-secretors during a school outbreak of meningitis; non-secretors had lower levels of anti-meningococcal salivary IgM. Flow cytometry was used to assess effects of secretor and non-secretor saliva on binding of B:4:P1.15 to buccal epithelial cells: (1) to assess inhibition by IgA and IgM; and (2) to assess contributions of salivary antibodies to inhibitory activities. Greater inhibition was obtained with secretor saliva: pooled (P = 0.049); fresh (P = 0.0001). Purified IgA (P = 0.02) and IgM (P = 0.03) were equally inhibitory. After absorption of anti-meningococcal antibodies, there was still significant inhibitory activity in the pools: secretors (P = 0.018); non-secretors (P = 0.005). These results indicate that both secretory immunoglobulins and other factors contribute to protection against colonisation by meningococci and might explain the increased carriage of B:4:1.15 in this population.

Secretor status and oral cancer

A prospective study was undertaken of 100 Sri Lankan patients with oral cancer and an equal number of age and sex matched control individuals. Each subject's secretor status was established from samples of appropriately prepared whole saliva using a haemagglutination technique. No significant differences were recorded in the distribution of secretors or non-secretors between the patient and control groups. In contrast to studies of Caucasians with potentially malignant oral lesions such as candidal leukoplakia in which non-secretor status predominates, secretor status does not appear to be an associated risk marker for the development for oral cancer in a selected Sri Lankan population.

Detection of microbial surface antigens that bind Lewis(a) antigen

There is evidence that the Lewis(a) blood group antigen is one of the receptors for a number of potentially pathogenic microorganisms. To determine how widely distributed the microbial adhesins are that bind this antigen, anti-idiotypic antibodies produced against monoclonal anti-Lewis(a) were used in coagglutination assays to screen a variety of species. The following were agglutinated: 7/7 strains of Staphylococcus aureus; 10/19 (53%) strains of Neisseria meningitidis; 8/13 (62%) strains of Haemophilus influenzae; 1/3 strains of Helicobacter pylori; 1/2 strains of Neisseria gonorrhoeae; 1/2 strains of Candida albicans. The application of the anti-idiotypic antibodies to studies of host cell receptors, isolation of adhesins and development of new epidemiological typing reagents is discussed.

Smoking, the environment and meningococcal disease: a case control study

This case control study investigated environmental factors in 74 confirmed cases of meningococcal disease (MD). In children aged under 5, passive smoking in the home (30 or more cigarettes daily) was associated with an odds ratio (OR) of 7.5 (95% confidence interval (CI) 1.46-38.66). ORs increased both with the numbers of cigarettes smoked and with the number of smokers in the household, suggesting a dose-response relationship. MD in this age group was also significantly associated with household overcrowding (more than 1.5 persons per room) (OR 6.0, 95% CI 1.10-32.8), with kisses on the mouth with 4 or more contacts in the previous 2 weeks (OR 2.46, 95% CI 1.09-5.56), with exposure to dust from plaster, brick or stone in the previous 2 weeks (OR 2.24, 95% CI 1.07-4.65); and with changes in residence (OR 3.0, 95% CI 1.0-8.99), marital arguments (OR 3.0, 95% CI 1.26-7.17) and legal disputes in the previous 6 months (OR 3.10, 95% CI 1.24-7.78). These associations were independent of social class. Public health measures to lower the prevalence of cigarette smoking by parents of young children may reduce the incidence of MD. The influence of building dust and stressful life events merits further investigation.

ABH secretor status, as judged by the Lewis phenotypes, in Norwegian survivors from meningococcal disease

Survivors from meningococcal disease (serogroups B and C) and a control series (blood donors) were examined for their ability to secrete ABH blood group substance. The examination was done indirectly by determining their Lewis phenotypes. There was no significant difference in the secretor status between the two groups.

Secretor status and humoral immune responses to Neisseria lactamica and Neisseria meningitidis

Non-secretors of ABO blood group antigens are over-represented among patients with meningococcal diseases. Lower levels of secretory IgA reported for non-secretors have been suggested to compromise mucosal defences. Total serum and salivary IgG, IgA and IgM and levels of these isotypes specific for Neisseria lactamica and five isolates of meningococci were determined by ELISA for 357 pupils and staff of a secondary school in which an outbreak of meningitis occurred. There were no differences in total or specific levels of serum IgG, IgA or IgM or salivary IgG or IgA of secretors compared with non-secretors. Non-secretors had significantly lower levels of salivary IgM (P = 0.022). A similar pattern was observed for levels of IgM specific for N. lactamica and five meningococcal isolates. The significance of these results is discussed with reference to the role of secretory IgM in protection of mucosal surfaces in infants.

Factors affecting carriage of Neisseria meningitidis among Greek military recruits

Greek military recruits (993) were examined for carriage of meningococci during July 1990. Blood, saliva and throat swab specimens were obtained and each recruit answered a questionnaire providing information on age, education (a measure of socioeconomic level), place of residence, smoking habits and recent infections. The overall carriage rate was 25% but differed between the two camps: 79/432 (18%) in Camp A and 168/561 (30%) in Camp B (P less than 0.0005). In Camp B, there were significantly higher proportions of recruits who were non-secretors (P less than 0.0005), and/or heavy smokers (P less than 0.0005). They were also younger (less than 19 years old) (P less than 0.001), and on the whole had fewer years of education (P less than 0.0005). By univariate analysis, carriage was significantly associated with smoking. By multiple logistic regression analysis, carriage was associated with smoking (P less than 0.001), age (P less than 0.01) and the camp in which the recruits were based (P less than 0.01). Among recruits in Camp B, 15/38 (40%) of those with recent viral infections were carriers compared with 30% for the camp in general.

Blood group non-secretors have an increased inflammatory response to urinary tract infection

The aim of this study was to assess the possible relationship between secretor state and the inflammatory response to urinary tract infection (UTI). Girls with recurrent UTI were prospectively studied. They included 61 secretor and 23 non-secretor individuals with 604 episodes of recurrent UTI. The response to each UTI episode was measured as the levels of C-reactive protein, erythrocyte sedimentation rate and the body temperature as well as renal concentrating capacity and pyuria. The levels of C-reactive protein, erythrocyte sedimentation rate and the body temperature were significantly higher in non-secretors than in secretors (p less than 0.04). As a consequence, non-secretors had an increased probability of being assigned a diagnosis of acute pyelonephritis rather than asymptomatic bacteriuria (p less than 0.05). The higher inflammatory response in non-secretors was independent of the Gal alpha 1-4Gal beta adhesin expression of the infecting Escherichia coli strains. The increased inflammatory response to UTI in non-secretors might explain the accumulation of these individuals among patients with renal scarring.

Association between secretor status and respiratory viral illness

OBJECTIVE

To determine whether non-secretion of blood group antigens is associated with respiratory virus diseases.

DESIGN

Study of secretor status in patients with respiratory virus diseases determined by an enzyme linked immunosorbent assay (ELISA) developed to identify Lewis (Le) blood group antigen phenotypes (Le(a) non-secretor; Le(b) secretor).

SUBJECTS

Patients aged 1 month to 90 years in hospital with respiratory virus diseases (584 nasal specimens).

MAIN OUTCOME MEASURES

Criteria for validation of ELISA (congruence between results on ELISA testing of 1155 saliva samples from a previous study and previously established results on haemagglutination inhibition (HAI) testing, proportions of Le(a), Le(b), and Le- phenotypes in 872 samples of nasal washings from a previous study compared with the normal population). Secretor status of patients determined by ELISA and viruses isolated.

RESULTS

Agreement between HAI and ELISA for 1155 saliva samples was 97%. Lewis antigens were detected by ELISA in 854 (97.9%) of nasal washings (Le(a) 233 (26.7%), Le(b) 621 (71.2%), and Le- 18 (2.1%)) in proportions predicted for a northern European population. Secretors were significantly overrepresented among patients from whom influenza viruses A and B (55/64, 86%; p less than 0.025), rhinoviruses (63/72, 88%; p less than 0.01), respiratory syncytial virus (97/109, 89%; p less than 0.0005), and echoviruses (44/44, p less than 0.0005) had been isolated compared with the distribution of secretors in the local population.

CONCLUSION

Secretion of blood group antigens is associated with respiratory virus diseases.

Cell surface carbohydrates are markers of differentiation in human oral epithelium

Carbohydrates of the epithelial cell membrane are involved in cell-cell and cell-substrate interaction, and changes are seen in relationship to cell differentiation and neoplastic transformation. The terminal part of carbohydrate structures carried on oral epithelial cells often expresses antigens of the ABO and Lewis blood group systems. The expression of these antigens are in oral mucosa genetically regulated by the A, B, H, Lewis, and secretor genes with subsequent correspondence between the blood group antigens expressed on erythrocytes and on oral epithelial cells. Variation in expression of carbohydrates is also seen in relationship to terminal differentiation in that blood group antigens and their immediate precursor structures are sequentially expressed on cells during their pathway through the epithelium. Various organs and tissues differ in their expression of cell surface carbohydrates. In oral mucosa, a close relationship is seen between the type of tissue differentiation and expression of blood group antigen; keratinized, nonkeratinized, and junctional epithelium all show different patterns of carbohydrate expression.

Denture stomatitis and ABO blood types

To determine the interrelation between ABO blood types of denture wearers, denture plaque accumulation, and denture stomatitis, 442 denture wearers were studied using a simplified culture method, which is convenient to use in the dental office. The degree of plaque accumulation and the occurrence of denture stomatitis varied depending on the blood type of the patients. Especially in blood group O compared with other types, both denture plaque accumulation and denture stomatitis were found to be higher or more severe. These results suggest that the ABO blood group is one of the etiologic factors of denture stomatitis and that denture wearers of blood group O are more susceptible to denture stomatitis.

Pseudomonas colonization in cystic fibrosis: lack of correlation with secretion of ABO blood group antigens

In cystic fibrosis, a majority of patients develop persistent lifelong respiratory tract colonisation with pseudomonas aeruginosa while a minority do not appear to become colonised. There is some evidence that non-secretion of ABO Blood Group antigens into body secretions is a marker for susceptibility to certain gram negative infections. Therefore, we studied 47 adult patients with cystic fibrosis to identify an association, if any, between secretor status and the presence or absence of pseudomonas aeruginosa in their sputum. Overall, we found no difference between the prevalence of non-secretors in our patient group and in the normal population. Furthermore, there was no association between secretor status and presence or absence of pseudomonas aeruginosa in sputum. We conclude that secretor status is unlikely to play a major role in susceptibility to pseudomonas aeruginosa infection in patients with cystic fibrosis.