Effect of host Lewis and ABO blood group antigen expression on Helicobacter pylori colonisation density and the consequent inflammatory response

Relationship between ABO Blood Group Alleles and Pancreatic Cancer Is Modulated by Secretor (FUT2) Genotype, but Not Lewis Antigen (FUT3) Genotype

BACKGROUND

In Western populations, pancreatic ductal adenocarcinoma (PDAC) risk has been found to be greater among individuals with non-O blood types than those with O blood type. However, the association has not been fully evaluated with respect to FUT2 (determining secretor status) and FUT3 (determining Lewis antigens) status, two biologically important genes in the expression of ABO blood groups with PDAC.

METHODS

We examined interactions in data from 8,027 cases and 11,362 controls in large pancreatic cancer consortia (PanScan I-III and PanC4) by using genetic variants to predict ABO blood groups (rs505922 and rs8176746), secretor status (rs601338), and Lewis antigens (rs812936, rs28362459, and rs3894326). Multivariable logistic regression was used to estimate ORs and 95% confidence intervals (CI) of the risk of PDAC adjusted for age and sex. We examined multiplicative interactions of ABO with secretor status and Lewis antigens by considering each product term between ABO and secretor and between ABO and Lewis antigens individually.

RESULTS

We found that the increased risk associated with non-O blood groups was somewhat stronger among secretors than nonsecretors [ORs, 1.28 (95% CI, 1.15-1.42) and 1.17 (95% CI, 1.03-1.32) respectively; Pinteraction = 0.002]. We did not find any interactions between ABO and Lewis antigens.

CONCLUSIONS

Our large consortia data provide evidence of effect modification in the association between non-O blood type and pancreatic cancer risk by secretor status.

IMPACT

Our results indicate that the association between ABO blood type and PDAC risk may vary by secretor status, but not by Lewis antigens.

Helicobacter species binding to the human gastric mucosa

Helicobacter pylori infects half of the world population, being associated with several gastric disorders, such as chronic gastritis and gastric carcinoma. The Helicobacter genus also includes other gastric helicobacters, such as H. heilmannii¸ H. ailurogastricus, H. suis, H. felis, H. bizzozeronii, and H. salomonis. These gastric helicobacters colonize both the human and animal stomach. The prevalence of gastric non-Helicobacter pylori Helicobacter (NHPH) species in humans has been described as low, and the in vitro binding to the human gastric mucosa was never assessed. Herein, human gastric tissue sections were used for the evaluation of the tissue glycophenotype and for the binding of gastric NHPH strains belonging to different species. Histopathological evaluation showed that 37.5% of the patients enrolled in our cohort presented chronic gastritis, while the presence of neutrophil or eosinophilic activity (chronic active gastritis) was observed in 62.5% of the patients. The secretor phenotype was observed in 68.8% of the individuals, based on the expression of Lewis B antigen and binding of the UleX lectin. The in vitro binding assay showed that all the NHPH strains evaluated were able to bind, albeit in low frequency, to the human gastric mucosa. The H. heilmannii, H. bizzozeronii, and H. salomonis strains displayed the highest binding ability both to the gastric superficial epithelium and to the deep glands. Interestingly, we observed binding of NHPH to the gastric mucosa of individuals with severe chronic inflammation and intestinal metaplasia, suggesting that NHPH binding may not be restricted to the healthy gastric mucosa or slight chronic gastritis. Furthermore, the in vitro binding of NHPH strains was observed both in secretor and non-secretor individuals in a similar frequency. In conclusion, this study is the first report of the in vitro binding ability of gastric NHPH species to the human gastric mucosa. The results suggest that other glycans, besides the Lewis antigens, could be involved in the bacterial adhesion mechanism; however, the molecular intervenients remain unknown.

Adhesion of Helicobacter Species to the Human Gastric Mucosa: A Deep Look Into Glycans Role

Helicobacter species infections may be associated with the development of gastric disorders, such as gastritis, peptic ulcers, intestinal metaplasia, dysplasia and gastric carcinoma. Binding of these bacteria to the gastric mucosa occurs through the recognition of specific glycan receptors expressed by the host epithelial cells. This review addresses the state of the art knowledge on these host glycan structures and the bacterial adhesins involved in Helicobacter spp. adhesion to gastric mucosa colonization. Glycans are expressed on every cell surface and they are crucial for several biological processes, including protein folding, cell signaling and recognition, and host-pathogen interactions. Helicobacter pylori is the most predominant gastric Helicobacter species in humans. The adhesion of this bacterium to glycan epitopes present on the gastric epithelial surface is a crucial step for a successful colonization. Major adhesins essential for colonization and infection are the blood-group antigen-binding adhesin (BabA) which mediates the interaction with fucosylated H-type 1 and Lewis B glycans, and the sialic acid-binding adhesin (SabA) which recognizes the sialyl-Lewis A and X glycan antigens. Since not every H. pylori strain expresses functional BabA or SabA adhesins, other bacterial proteins are most probably also involved in this adhesion process, including LabA (LacdiNAc-binding adhesin), which binds to the LacdiNAc motif on MUC5AC mucin. Besides H. pylori, several other gastric non-Helicobacter pylori Helicobacters (NHPH), mainly associated with pigs (H. suis) and pets (H. felis, H. bizzozeronii, H. salomonis, and H. heilmannii), may also colonize the human stomach and cause gastric disease, including gastritis, peptic ulcers and mucosa-associated lymphoid tissue (MALT) lymphoma. These NHPH lack homologous to the major known adhesins involved in colonization of the human stomach. In humans, NHPH infection rate is much lower than in the natural hosts. Differences in the glycosylation profile between gastric human and animal mucins acting as glycan receptors for NHPH-associated adhesins, may be involved. The identification and characterization of the key molecules involved in the adhesion of gastric Helicobacter species to the gastric mucosa is important to understand the colonization and infection strategies displayed by different members of this genus.

Core 1-derived mucin-type O-glycosylation protects against spontaneous gastritis and gastric cancer

Core 1-derived mucin-type O-glycans (O-glycans) are a major component of gastric mucus with an unclear role. To address this, we generated mice lacking gastric epithelial O-glycans (GEC C1galt1-/-). GEC C1galt1-/- mice exhibited spontaneous gastritis that progressed to adenocarcinoma with ∼80% penetrance by 1 yr. GEC C1galt1-/- gastric epithelium exhibited defective expression of a major mucus forming O-glycoprotein Muc5AC relative to WT controls, which was associated with impaired gastric acid homeostasis. Inflammation and tumorigenesis in GEC C1galt1-/- stomach were concurrent with activation of caspases 1 and 11 (Casp1/11)-dependent inflammasome. GEC C1galt1-/- mice genetically lacking Casp1/11 had reduced gastritis and gastric cancer progression. Notably, expression of Tn antigen, a truncated form of O-glycan, and CASP1 activation was associated with tumor progression in gastric cancer patients. These results reveal a critical role of O-glycosylation in gastric homeostasis and the protection of the gastric mucosa from Casp1-mediated gastric inflammation and cancer.

FUT2 Variants Confer Susceptibility to Familial Otitis Media

Non-secretor status due to homozygosity for the common FUT2 variant c.461G>A (p.Trp154∗) is associated with either risk for autoimmune diseases or protection against viral diarrhea and HIV. We determined the role of FUT2 in otitis media susceptibility by obtaining DNA samples from 609 multi-ethnic families and simplex case subjects with otitis media. Exome and Sanger sequencing, linkage analysis, and Fisher exact and transmission disequilibrium tests (TDT) were performed. The common FUT2 c.604C>T (p.Arg202∗) variant co-segregates with otitis media in a Filipino pedigree (LOD = 4.0). Additionally, a rare variant, c.412C>T (p.Arg138Cys), is associated with recurrent/chronic otitis media in European-American children (p = 1.2 × 10-5) and US trios (TDT p = 0.01). The c.461G>A (p.Trp154∗) variant was also over-transmitted in US trios (TDT p = 0.01) and was associated with shifts in middle ear microbiota composition (PERMANOVA p < 10-7) and increased biodiversity. When all missense and nonsense variants identified in multi-ethnic US trios with CADD > 20 were combined, FUT2 variants were over-transmitted in trios (TDT p = 0.001). Fut2 is transiently upregulated in mouse middle ear after inoculation with non-typeable Haemophilus influenzae. Four FUT2 variants-namely p.Ala104Val, p.Arg138Cys, p.Trp154∗, and p.Arg202∗-reduced A antigen in mutant-transfected COS-7 cells, while the nonsense variants also reduced FUT2 protein levels. Common and rare FUT2 variants confer susceptibility to otitis media, likely by modifying the middle ear microbiome through regulation of A antigen levels in epithelial cells. Our families demonstrate marked intra-familial genetic heterogeneity, suggesting that multiple combinations of common and rare variants plus environmental factors influence the individual otitis media phenotype as a complex trait.

Gastroduodenal Ulcers and ABO Blood Group: the Japan Nurses' Health Study (JNHS)

Background

Although several studies have shown that blood type O is associated with increased risk of peptic ulcer, few studies have investigated these associations in Japan. We sought to investigate the association between the ABO blood group and risk of gastroduodenal ulcers (GDU) using combined analysis of both retrospective and prospective data from a large cohort study of Japanese women, the Japan Nurses’ Health Study (JNHS; n = 15,019).

Methods

The impact of the ABO blood group on GDU risk was examined using Cox regression analysis to estimate hazard ratios (HRs) and 95% confidence intervals (CI), with adjustment for potential confounders.

Results

Compared with women with non-O blood types (A, B, and AB), women with blood type O had a significantly increased risk of GDU from birth (multivariable-adjusted HR 1.18; 95% CI, 1.04–1.34). Moreover, the highest cumulative incidence of GDU was observed in women born pre-1956 with blood type O. In a subgroup analysis stratified by birth year (pre-1956 or post-1955), the multivariable-adjusted HR of women with blood type O was 1.22 (95% CI, 1.00–1.49) and 1.15 (95% CI, 0.98–1.35) in the pre-1956 and post-1955 groups, respectively.

Conclusion

In this large, combined, ambispective cohort study of Japanese women, older women with blood type O had a higher risk of developing GDU than those with other blood types.

Helicobacter pylori adhesin HopQ engages in a virulence-enhancing interaction with human CEACAMs

Helicobacter pylori specifically colonizes the human gastric epithelium and is the major causative agent for ulcer disease and gastric cancer development. Here, we identify members of the carcinoembryonic antigen-related cell adhesion molecule (CEACAM) family as receptors of H. pylori and show that HopQ is the surface-exposed adhesin that specifically binds human CEACAM1, CEACAM3, CEACAM5 and CEACAM6. HopQ-CEACAM binding is glycan-independent and targeted to the N-domain. H. pylori binding induces CEACAM1-mediated signalling, and the HopQ-CEACAM1 interaction enables translocation of the virulence factor CagA into host cells and enhances the release of pro-inflammatory mediators such as interleukin-8. Based on the crystal structure of HopQ, we found that a β-hairpin insertion (HopQ-ID) in HopQ's extracellular 3+4 helix bundle domain is important for CEACAM binding. A peptide derived from this domain competitively inhibits HopQ-mediated activation of the Cag virulence pathway, as genetic or antibody-mediated abrogation of the HopQ function shows. Together, our data suggest the HopQ-CEACAM1 interaction to be a potentially promising novel therapeutic target to combat H. pylori-associated diseases.

Structural diversity and biological importance of ABO, H, Lewis and secretor histo-blood group carbohydrates

ABO, H, secretor and Lewis histo-blood system genes control the expression of part of the carbohydrate repertoire present in areas of the body occupied by microorganisms. These carbohydrates, besides having great structural diversity, act as potential receptors for pathogenic and non-pathogenic microorganisms influencing susceptibility and resistance to infection and illness. Despite the knowledge of some structural variability of these carbohydrate antigens and their polymorphic levels of expression in tissue and exocrine secretions, little is known about their biological importance and potential applications in medicine. This review highlights the structural diversity, the biological importance and potential applications of ABO, H, Lewis and secretor histo-blood carbohydrates.

Factors that mediate colonization of the human stomach by Helicobacter pylori

Helicobacter pylori (H. pylori) colonizes the stomach of humans and causes chronic infection. The majority of bacteria live in the mucus layer overlying the gastric epithelial cells and only a small proportion of bacteria are found interacting with the epithelial cells. The bacteria living in the gastric mucus may act as a reservoir of infection for the underlying cells which is essential for the development of disease. Colonization of gastric mucus is likely to be key to the establishment of chronic infection. How H. pylori manages to colonise and survive in the hostile environment of the human stomach and avoid removal by mucus flow and killing by gastric acid is the subject of this review. We also discuss how bacterial and host factors may together go some way to explaining the susceptibility to colonization and the outcome of infection in different individuals. H. pylori infection of the gastric mucosa has become a paradigm for chronic infection. Understanding of why H. pylori is such a successful pathogen may help us understand how other bacterial species colonise mucosal surfaces and cause disease.

Association of Helicobacter pylori infection with the Lewis and ABO blood groups in dyspeptic patients

Background:

Helicobacter pylori infection is a basic risk factor for chronic gastritis, and gastric carcinoma. Based on some studies, the reason is binding of H. pylori to H and Le^b antigens in gastric mucosa. However, some other findings have not determined any association between the infection and these antigens. Because of this controversy and the fact that H. pylori infection and gastric adenocarcinoma are common diseases in Iran, the assessment of the association of H. pylori infection with these blood groups could be valuable.

Materials and Methods:

In a cross sectional study on 135 adult dyspeptic patients in Mashhad, Iran, from 2009 to 2010, H. pylori infection was evaluated by using the Heliprobe ¹⁴C-urea breath test and the ABO and Lewis blood group antigens were determined by the tube method. Association between the Lewis and ABO phenotypes with H. pylori infection were analysed by Fisher's exact test. A P ≤ 0.05 was considered to be significant.

Results:

68 (50.4%) patients were positive for H. pylori infection. The frequencies of the ABO, Lewis and secretion phenotypes were not significant in the infected and non-infected patients. We also did not find a significant association between Le^a and Le^b antigens and this infection.

Conclusion:

We could not establish a significant association between the Lewis, ABO and secretion phenotypes with H. pylori infection. Diversity of sequences of blood group antigen b-binding adhesion (babA gene) of H. pylori may be a reason why our findings are different from other studies in other geographic areas.

Evidence of an association between the O blood group and allergic rhinitis

Objective

The aim of this study was to verify if ABO phenotypes are associated with allergic rhinitis.

Methods

168 patients with allergic rhinitis and 168 control individuals from the same geographical region and paired by gender and age were enrolled in the study. ABO phenotypes were identified in red blood cells using the hemagglutination technique. The Fisher exact and chi-squared tests were employed to compare proportions. Statistical significance was set for an alpha error of 5% (p-value < 0.05).

Results

The overall differences in the frequencies of the ABO phenotypes of patients and controls were marginal (χ²: 7.569; degrees of freedom (DF): 3; p-value = 0.055) however the O blood group was associated with allergic rhinitis (χ²: 5.764; DF: 1; p-value = 0.016; OR: 1.735; CI 95%: 1.127-2.673). The differences in the frequencies of the O phenotype in patients and controls were statistically different for men (χ²: 8.520; DF: 1; p-value = 0.003) but not for women (χ²: 0.6375; DF: 1; p-value = 0.4246). The A phenotype was associated with protection (OR: 0.4385; CI 95%: 0.2043-0.9415; p-value = 0.049) and the O phenotype was associated with susceptibility (OR = 2.789; CI 95%: 1.385-5.616; p-value = 0.005) to allergic rhinitis only for men.

Conclusion

The O blood group phenotype is associated with allergic rhinitis in male but not in female patients.

Pancreatic cancer: Helicobacter pylori colonization, N-nitrosamine exposures, and ABO blood group

Thirty years of research with animal models has shown that pancreatic adenocarcinoma is induced by N-nitrosamine carcinogens, which damage DNA through adduct formation. Human risk factors for pancreatic cancer include gastric colonization by Helicobacter pylori, as well as dietary intake of those same N-nitrosamines or of nitrite which forms those N-nitrosamines in the stomach, and cigarette smoking which also contains those N-nitrosamines. Physiologic actions of H. pylori colonization enhance the carcinogenic effect of N-nitrosamines delivered by smoking or dietary sources. This effect is modulated by host inflammatory response to the organism, by various virulence and other properties of the Helicobacter itself, and by host-organism interactions. A recent genome-wide association study identified SNPs within the ABO 9q34 locus as statistically significantly associated with risk of pancreatic cancer. A number of recent and older studies going back 40 yr also support the ABO association. ABO-product antigens are expressed on gastrointestinal epithelium on which H. pylori binds, and ABO genotype is known to be associated with risks of duodenal and gastric ulcer and with risk of gastric cancer, conditions definitively related to Helicobacter colonization. We suspect that ABO genotype/phenotype status influences the behavior of H. pylori which in turn affects gastric and pancreatic secretory function, and these ultimately influence the pancreatic carcinogenicity of dietary- and smoking-related N-nitrosamine exposures, and thus risk of pancreatic cancer. Our study results on the interaction of ABO and H. pylori significantly confirm this hypothesis and together with other existing studies strongly implicate this organism in the disease etiology.

Relation between ABO blood groups and Helicobacter pylori infection in symptomatic patients

Epidemiological studies have demonstrated higher frequencies of the O blood group and the nonsecretor phenotype of ABH antigens among patients suffering from peptic ulcers. Since Helicobacter pylori has been established as the main etiological factor in this disease, controversies about the associations of the ABO and Lewis blood group phenotypes and secretor and nonsecretor phenotypes in relation to susceptibility towards infection by this bacillus have been presented. The aim of this study was to verify the frequencies of ABO and Rhesus (Rh) blood groups in H. pylori seropositive symptomatic patients. The study included (n = 1108) patients with dyspepsia symptoms referred from an outpatient clinic in Erbil city for investigation. Age, sex, and residency were recorded as a routine laboratory framework. Patients underwent SD Bioline (Standard Diagnostics Inc, Kyonggi-do, South Korea) and enzyme-linked immunosorbent assay serologic tests for H. pylori. ABO blood group phenotypes were determined by a standard hemagglutination test. Results showed that 64.8% of patients (n = 718/1108) were seropositive for H. pylori infection, and (35.2%) (n = 390/1108) were seronegative. Of the seropositive patients, 40.8% (n = 293/718) were male and 59.2% (n = 425/718) were female; while of the seronegative patients, 46.7% (n = 182/390) were male and 53.3% (n = 208/390) were female. The mean age for seropositives and seronegatives was (38.0 ± 14.6) years and (37.6 ± 15.7) years respectively. The frequency of the ABO and Rh-positive (Rh+) blood groups among seropositive patients was (A = 32.0%, B = 19.5%, AB = 6.7%, O = 41.8%, and Rh+ = 92.5%) and was (A = 32.3%, B = 28.2%, AB = 8.0%, O = 31.5%, and Rh+ = 92.5%) in seronegatives. The results of this study suggest that ABO blood groups, age, and gender influence seropositivity for H. pylori infection.

Risk of gastric cancer and peptic ulcers in relation to ABO blood type: a cohort study

Blood group A was found to be associated with gastric cancer in the 1950s. Strikingly, for peptic ulcers an increased risk has been shown for blood group O. However, previous investigations have generally been poorly conducted and have failed to take a unifying approach to these observations. Using the Scandinavian Donations and Transfusions (referred to as "SCANDAT") database, the authors established a cohort of Swedish and Danish blood donors with known blood type and followed these for the occurrence of gastric cancer and peptic ulcers through December 31, 2002. Cases were ascertained by using nationwide cancer and hospital registers. Altogether, 1,089,022 donors were followed for up to 35 years, during which 688 gastric cancer cases and 5,667 peptic ulcer cases accrued. Poisson regression analyses confirmed an increased risk of gastric cancer among individuals with blood group A (incidence rate ratio = 1.20, 95% confidence interval: 1.02, 1.42) and conversely that peptic ulcer risk was instead highest among those with blood group O. In this large, population-based cohort study, the authors have confirmed the association between blood group A and gastric cancer. In addition, they give further support to the notion that individuals with blood group O have a higher risk of peptic ulcers than those with other blood groups.

Role of mucin Lewis status in resistance to Helicobacter pylori infection in pediatric patients

BACKGROUND

Helicobacter pylori causes gastritis, peptic ulcer and is a risk factor for adenocarcinoma and lymphoma of the stomach. Gastric mucins, carrying highly diverse carbohydrate structures, present functional binding sites for H. pylori and may play a role in pathogenesis. However, little information is available regarding gastric mucin in children with and without stomach diseases.

MATERIALS AND METHODS

Expression of mucins and glycosylation was studied by immunohistochemistry on gastric biopsies from 51 children with and without H. pylori infection and/or peptic ulcer disease.

RESULTS

In all children, MUC5AC was present in the surface epithelium and MUC6 in the glands. No MUC6 in the surface epithelium or MUC2 was detected in any section. The Le(b) and Le(a) blood group antigens were present in the surface epithelium of 80% and 29% of children, respectively. H. pylori load was higher in Le(b) negative children than in Le(b) positive individuals (mean +/- SEM 17.8 +/- 3.5 vs 10.8 +/- 1.5; p < 0.05), but there was no correlation between Le(a) or Le(b) status and gastritis, nodularity, and gastric or duodenal ulcer (DU). Expression of sialyl-Le(x) was associated with H. pylori infection, and DU.

CONCLUSIONS

Mucin expression and glycosylation is similar in children and adults. However, in contrast to adults, pediatric H. pylori infection is not accompanied by aberrant expression of MUC6 or MUC2. Furthermore, the lower H. pylori density in Le(b) positive children indicates that H. pylori is suppressed in the presence of gastric mucins decorated with Le(b), the binding site of the H. pylori BabA adhesin.

The role of endotoxin in infection: Helicobacter pylori and Campylobacter jejuni

Both Helicobacter pylori and Campylobacter jejuni are highly prevalent Gram-negative microaerophilic bacteria which are gastrointestinal pathogens of humans; H. pylori colonizes the gastroduodenal compartment and C. jejuni the intestinal mucosa. Although H. pylori causes chronic gastric infection leading to gastritis, peptic ulcers and eventually gastric cancer while C. jejuni causes acute infection inducing diarrhoeal disease, the endotoxin molecules of both bacterial species contrastingly contribute to their pathogenesis and the autoimmune sequelae each induces. Compared with enterobacterial endotoxin, that of H. pylori has significantly lower endotoxic and immuno-activities, the molecular basis for which is the underphosphorylation and underacylation of the lipid A component that interacts with immune receptors. This induction of low immunological responsiveness by endotoxin may aid the prolongation of H. pylori infection and therefore infection chronicity. On the other hand, this contrasts with acute infection-causing C. jejuni where overt inflammation contributes to pathology and diarrhoea production, and whose endotoxin is immunologically and endotoxically active. Futhermore, both H. pylori and C. jejuni exhibit molecular mimicry in the saccharide components of their endotoxins which can induce autoreactive antibodies; H. pylori expresses mimicry of Lewis and some ABO blood group antigens, C. jejuni mimicry of gangliosides. The former has been implicated in influencing the development of inflammation and gastric atrophy (a precursor of gastic cancer), the latter is central to the development of the neurological disorder Guillain-Barré syndrome. Both diseases raise important questions concerning infection-induced autoimmunity awaiting to be addressed.

Frequency of ABO blood group in peptic ulcer disease in Iranian subjects

The relationship between ABO blood group distribution and Peptic Ulcer Disease (PUD) has been widely evaluated in the past. But data concerning the same evaluation are very limited in Iran. This study sought to determine the distribution of ABO blood group in patients with PUD in Iranian subjects. Eighty-one patients with PUD (51 male and 30 female; mean age: 49 +/- 18 years) who attended our endoscopy section were enrolled. Blood samples were used for ABO/Rhesus (Rh) blood group antigen typing. The ABO blood group phenotype distribution in subjects was as follows: 37.1% (30/81) for group A, 23.4% (19/81) for group B, 35.6% (28/81) for group O and 4.9% (4/81) for group AB. Rh positivity was found in 63% (51/81) of patients. In local healthy population, ABO/Rh blood group distribution was 33.8, 20.7, 34.7, 8.4 and 89.6% for A, B, O, AB and Rh, respectively. AB blood group distribution in healthy population was higher than PUD (8.4 vs 4.9%). In contrast, Rh positivity of PUD in Iran is lower than healthy subjects (63 vs 89.6%). Variation in the results of studies is related to different study communities. According to these results, probably ABO/Rh blood group has an important role in patients with peptic ulceration. The functional significance of ABO blood group distribution might be associated with biological behavior of PUD. The impact of blood group on PUD may be a focus for further studies.

Blood group O and vWf expression may be involved in development of peptic ulcer disease secondary to Helicobacter pylori infection

Helicobacter pylori is a gram negative organism involved in peptic ulcer disease and has been linked to a number of extra-intestinal diseases. There is a large body of evidence describing the link between blood group O/non-secretor phenotypes with H. pylori infection and the risk of peptic ulcer disease. Blood group O individuals also have a higher risk of bleeding disorders due to low levels of the circulating plasma protein von Willebrand factor (vWf). vWf is one of the main proteins that binds platelets during platelet activation and aggregation. The mechanisms of how ulcers develop during H. pylori infection are not fully understood. There is however recent evidence of vWf involvement in platelet aggregation in H. pylori infection. Our new hypothesis states that H. pylori bacteria present in blood group O/non-secretor individuals are binding the available vWf to promote adhesion and subsequent platelet aggregation within the microvasculature. This in turn may deplete any available vWf for wound repair to take place leading to an increased risk of peptic ulceration and bleeding and eventually leading to an ulcer.

Role of ABO secretor status in mucosal innate immunity and H. pylori infection

The fucosylated ABH antigens, which constitute the molecular basis for the ABO blood group system, are also expressed in salivary secretions and gastrointestinal epithelia in individuals of positive secretor status; however, the biological function of the ABO blood group system is unknown. Gastric mucosa biopsies of 41 Rhesus monkeys originating from Southern Asia were analyzed by immunohistochemistry. A majority of these animals were found to be of blood group B and weak-secretor phenotype (i.e., expressing both Lewis a and Lewis b antigens), which are also common in South Asian human populations. A selected group of ten monkeys was inoculated with Helicobacter pylori and studied for changes in gastric mucosal glycosylation during a 10-month period. We observed a loss in mucosal fucosylation and concurrent induction and time-dependent dynamics in gastric mucosal sialylation (carbohydrate marker of inflammation), which affect H. pylori adhesion targets and thus modulate host–bacterial interactions. Of particular relevance, gastric mucosal density of H. pylori, gastritis, and sialylation were all higher in secretor individuals compared to weak-secretors, the latter being apparently “protected.” These results demonstrate that the secretor status plays an intrinsic role in resistance to H. pylori infection and suggest that the fucosylated secretor ABH antigens constitute interactive members of the human and primate mucosal innate immune system.

The common ABO blood group antigen system was described in the early 20th century. In addition, it has been known for 60 years that the majority of individuals also express the corresponding ABO antigens (carbohydrate identity tags) in their saliva, tears, milk, and mucus secretions in the digestive tract. To this date, however, the biological function of the ABO blood group antigens has remained an enigma. Here, we show that the great majority of Rhesus monkeys are of blood group B and weak-secretors, i.e., are similar to the human populations in South Asia from where these monkeys originate. This observation suggests that an evolutionary adaptation in digestive tract mucosal carbohydrate patterns to local environmental selection has occurred. In addition, we demonstrate that long-term infection by the “peptic ulcer bacterium” Helicobacter pylori induces mucosal carbohydrate patterns that change according to the individual secretor phenotype. The common weak-secretor monkeys were apparently “protected,” as they had stable glycosylation, lower inflammation, and lower bacterial infection load, whereas the less common secretor animals had increased levels of inflammation-associated mucosal carbohydrate patterns and a transient decrease in the ABO blood group system type of carbohydrates. These novel observations suggest that the individual ABO blood group and secretor phenotype are part of human and non-human primate innate immunity against infectious disease.

The Multiple Carbohydrate Binding Specificities of Helicobacter pylori

Persistent colonization of the human stomach by Helicobacter pylori is a risk factor for the development of peptic ulcer disease and gastric cancer. Adhesion of microbes to the target tissue is an important determinant for successful initiation, establishment and maintenance of infection, and a variety of different candidate carbohydrate receptors for H. pylori have been identified. Here the different the binding specifities, and their potential role in adhesion to human gastric epithelium are described. Finally, recent findings on the roles of sialic acid binding SabA adhesin in interactions with human neutrophils and erythrocytes are discussed.

Relevance of fucosylation and Lewis antigen expression in the bacterial gastroduodenal pathogen Helicobacter pylori

Helicobacter pylori is a prevalent bacterial, gastroduodenal pathogen of humans that can express Lewis (Le) and related antigens in the O-chains of its surface lipopolysaccharide. The O-chains of H. pylori are commonly composed of internal Le(x) units with terminal Le(x) or Le(y) units or, in some strains, with additional units of Le(a), Le(b), Le(c), sialyl-Le(x) and H-1 antigens, as well as blood groups A and B, thereby producing a mosaicism of antigenic units expressed. The genetic determination of the Le antigen biosynthetic pathways in H. pylori has been studied, and despite striking functional similarity, low sequence homology occurs between the bacterial and mammalian alpha(1,3/4)- and alpha(1,2)-fucosyltransferases. Factors affecting Le antigen expression in H. pylori, that can influence the biological impact of this molecular mimicry, include regulation of fucosyltransferase genes through slipped-strand mispairing, the activity and expression levels of the functional enzymes, the preferences of the expressed enzyme for distinctive acceptor molecules and the availability of activated sugar intermediates. Le mimicry was initially implicated in immune evasion and gastric adaptation by the bacterium, but more recent studies show a role in gastric colonization and bacterial adhesion with galectin-3 identified as the gastric receptor for polymeric Le(x) on the bacterium. From the host defence aspect, innate immune recognition of H. pylori by surfactant protein D is influenced by the extent of LPS fucosylation. Furthermore, Le antigen expression affects both the inflammatory response and T-cell polarization that develops after infection. Although controversial, evidence suggests that long-term H. pylori infection can induce autoreactive anti-Le antibodies cross-reacting with the gastric mucosa, in part leading to the development of gastric atrophy. Thus, Le antigen expression and fucosylation in H. pylori have multiple biological effects on pathogenesis and disease outcome.

Expression of Lewis antigens and their precursors in gastric mucosa: relationship with Helicobacter pylori infection and gastric carcinogenesis

Lewis (Le)-associated antigens are carbohydrates that are related biochemically to the ABO blood groups, and may have a role in Helicobacter pylori adherence. To evaluate their relationship to clinicopathological outcomes, gastric Le expression, including type 1 precursor, type 1 H, Le(a), Le(b), Le(x), Le(y) and sialylated Le(a) (CA19-9), was evaluated immunohistochemically in 233 gastric biopsy specimens obtained at routine gastroscopy. Expression was also investigated in gastric tissues showing chronic gastritis, intestinal metaplasia, and carcinoma from 42 patients with gastric cancer. A polymerase chain reaction was performed for H. pylori and the bacterial babA2 gene. We identified type 1 precursor expression in 34.3%, type 1 H in 55.8%, Le(a) in 44.2%, Le(b) in 82.0%, Le(x) in 44.2%, Le(y) 56.7%, and CA19-9 in 16.3% of the 233 gastric biopsy specimens. Expression of type 1 H, Le(b), and CA19-9 was significantly associated with H. pylori infection and histological features (p < 0.05), and expression of type 1 H was an independent predictive factor for H. pylori infection by multivariate logistic regression (p = 0.020). Positivity for the babA2 genotype correlated significantly with H. pylori infection and type 1 H expression in gastric biopsy specimens (p < 0.05). The babA2 genotype was more frequent in gastric mucosa from the gastric cancer patients than in gastric biopsy specimens from routine gastroscopy (p = 0.009). In the 42 gastric cancer patients, the frequency of type 1 precursor, Le(a), and Le(x) expression was significantly higher in intestinal metaplasia and carcinoma than in chronic gastritis (p < 0.05), but the frequency of type 1 H and Le(b) expression was significantly lower in intestinal metaplasia and carcinoma (p < 0.05). In conclusion, Le expression, especially that of type 1 H, was significantly associated with clinicopathological features. In gastric cancer patients, Le expression was altered in intestinal metaplasia and carcinoma in comparison with chronic gastritis.

ABH and Lewis antigen distributions in blood, saliva and gastric mucosa and H pylori infection in gastric ulcer patients

AIM: To investigate the ABH and Lewis antigen expression in erythrocytes, saliva and gastric epithelium, as well as the association between H pylori and the presence of gastric epithelial lesions.

METHODS: The distribution of ABH and Lewis blood group antigens in erythrocytes, saliva and gastric mucosa of H pylori-infected gastric ulcer patients was analyzed. Forty-two patients with gastric ulcer were studied, and fifty healthy individuals were used as control group. The blood group antigens were determined by direct hemagglutination, dot-ELISA and immunohistochemical methods in erythrocytes, saliva and gastric mucosa specimens, respectively. Diagnosis for H pylori infection was performed by conventional optical microscopy and ELISA.

RESULTS: A higher seroprevalence of IgG H pylori specific antibodies was observed in gastric ulcer patients (90%) compared to the control group (60%). We observed a significant increase of phenotypes O, A₂ and Lewis b in H pylori-infected patients. The expression of these antigens had progressive alterations in areas of ulcerous lesions and intestinal metaplasia.

CONCLUSION: ABH and Lewis blood group antigens are a good indicator for cellular alterations in the gastric epithelium.

Metastability of Helicobacter pylori bab adhesin genes and dynamics in Lewis b antigen binding

Heterogeneity among Helicobacter pylori strains in gastric epithelial adherence is postulated to contribute to pathogen fitness in the physiologically diverse human population. H. pylori adherence to ABO and Lewis b (Leb) blood group antigens in the human stomach is mediated by the blood group antigen-binding adhesin BabA. Approximately 70% of Swedish and U.S. H. pylori clinical isolates exhibit Leb binding, but here we show that the babA gene is present in each of 10 Leb-nonbinding strains. Fluorescence microscopy identified occasional bacterial cells with a Leb-binding phenotype in populations of Leb-nonbinding strains. Thus, nonbinding seemed to be a metastable phenotype. To model metastable transition into the virulence-associated Leb-binding mode, Leb-binding clones were isolated from nonadherent strains by panning with Leb-magnetic beads and characterized. Strain 17875 has two babA genes, babA1 (silent) and babA2 (expressed). We found that a babA2-cam derivative of strain 17875 regained Leb binding by recombination of the formerly silent babA1 gene into the expressed and partially homologous babB locus. The chimeric BabB/A adhesin binds Leb with an affinity similar to that of wild-type BabA adhesin, but its expression level was lower and was subject to phase variation through slipped-strand mispairing. Equivalent results were obtained with strain NCTC11638. We propose that adhesin metastability and heterogeneity contributes to bacterial fitness and results in some clones having potential for periodic activation and deactivation of virulence appropriate for intensity of the host response to infection.

Lewis enzyme (alpha1-3/4 fucosyltransferase) polymorphisms do not explain the Lewis phenotype in the gastric mucosa of a Portuguese population

The human alpha-1,3/4 fucosyltransferase III (FucT III) catalyses the synthesis of Lewis antigens including Le(b) antigen which is a ligand for Helicobacter pylori adhesion. Several polymorphisms have been described in the FUT3 gene affecting both the transmembrane and catalytic domains, some of which affect the enzyme activity. The aim of the present work was to study the Lewis gene polymorphisms in a Caucasian Portuguese population, with a high rate of H. pylori infection, and to evaluate the implications of mutant enzymes in Le(b) expression in the gastric mucosa. We studied 460 asymptomatic or dyspeptic individuals from northern Portugal. Screening for Lewis gene polymorphisms was performed by SSCP and direct sequencing. Lewis phenotype in gastric mucosa was determined by immunohistochemistry. In 47 individuals with a Lewis negative blood group, we found FUT3 gene polymorphisms that were previously described in other populations: 59T>G, 202T>C, 314C>T, 508G>A and 1067T>A. Among the 47 Lewis negative individuals in blood, only nine were also negative in gastric mucosa, suggesting the existence of another alpha 1-4 fucosyltransferase that is responsible for Le(a) and Le(b) synthesis in gastric mucosa.

Effect of Weissella confusa strain PL9001 on the adherence and growth of Helicobacter pylori

Viable and nonviable Weissella confusa strain PL9001 inhibited the binding of Helicobacter pylori to human gastric-cell line MKN-45 cells by more than 90%. Spent culture supernatant of PL9001 rapidly decreased the viability of H. pylori, rupturing cell walls. The results suggest that PL9001 is a probiotic that can reduce the infectivity and persistence of H. pylori.

Expression of tumor-associated Thomsen-Friedenreich antigen (T Ag) in Helicobacter pylori and modulation of T Ag specific immune response in infected individuals

We tested the hypothesis that the gastric cancer associated bacteria, Helicobacter pylori (H. pylori) express the cancer-related Thomsen-Friedenreich (T) antigen. We also analysed whether infection with H. pylori alters the amount of natural anti-T antibodies in the patients' sera. Cell surface membrane extracts of H. pylori NCTC 11637 strain and clinical isolates of H. pylori (n = 13) were analysed by immunoblotting and cell-ELISA with five different T antigen-specific monoclonal antibodies (MAbs). Two major protein bands of approximately 68 kDa and 58 kDa were immunostained on blots of H. pylori extracts with T specific MAbs but not immunostained with unrelated MAb. The specificity was shown in that immunostaining was blocked with peanut agglutinin (PNA) and rabbit antiserum to T antigen. The binding of T specific MAb to the 58 kDa protein band was also blocked by rabbit antiserum against heat shock proteins of H. pylori. The relative expression of T antigen-related proteins differed among H. pylori strains, with 68 kD associated T antigen expression higher in patients with more severe pathology. The level of IgG antibody to T epitope in patients with gastric cancer (n = 66) and normal blood donors (n = 62) were compared and the level of anti-T Ab in gastric cancer patients was significantly lower than that in normal blood donors. A significant positive correlation between T specific antibody in serum and H. pylori IgG antibody level was found in H. pylori-infected normal blood donors (P < 0.001), but this correlation was not found in H. pylori-infected cancer patients. In summary, the cancer related T epitope is expressed in H. pylori and modulation of T antigen-specific immune response in H. pylori-infected individuals suggests that H. pylori infection may alter natural immune mechanisms against cancer.

Purification and characterization of alpha-L-fucosidases from Streptomyces sp. OH11242

alpha-L-Fucosidases were found in the culture fluid of Streptomyces sp. OH11242 grown with porcine gastric mucin (PGM) as the sole carbon source. The alpha-L-fucosidases were purified by ammonium sulfate precipitation followed by chromatography on Sepharose CL-4B, hydroxyapatite, Resource Q and Mono Q. Two enzyme fractions, termed Fase-I and Fase-II, were obtained, each bearing different substrate specificity. Fase-I hydrolyzed fucose residues from fucose-containing oligosaccharide chains on PGM, but not p-nitrophenyl alpha-L-fucoside (Fucalpha-O-PNP). In contrast, Fase-II cleaved fucose from Fucalpha-O-PNP, but not fucose-containing oligosaccharides on PGM. Fase-I also hydrolyzed the alpha1-2 fucosidic linkage in various oligosaccharides, but not alpha1-3 and alpha1-4 fucosidic linkages. Fase-II was separated into two fractions, Fase-IIa and -IIb by Mono Q chromatography, Fase-IIb hydrolyzed alpha1-3 and alpha1-4 fucosidic linkages, but not alpha1-2 fucosidic linkages, while Fase-IIa hydrolyzed none of them. Fase-I was purified to homogeneity by SDS-polyacrylamide gel electrophoresis, the molecular mass was estimated to be approximately 59000 and 76000 Da by SDS-PAGE and gel-permeation chromatography, respectively. The optimum pH for Fase-I activity was 5.5-6.0. These fucosidases with different substrate specificities might be useful to reveal the physiological role of fucose-containing oligosaccharides in the gastric mucins.

Relationship of anti-Lewis x and anti-Lewis y antibodies in serum samples from gastric cancer and chronic gastritis patients to Helicobacter pylori-mediated autoimmunity

Lewis (Le) antigens have been implicated in the pathogenesis of atrophic gastritis and gastric cancer in the setting of Helicobacter pylori infection, and H. pylori-induced anti-Le antibodies have been described that cross-react with the gastric mucosa of both mice and humans. The aim of this study was to examine the presence of anti-Le antibodies in patients with H. pylori infection and gastric cancer and to examine the relationships between anti-Le antibody production, bacterial Le expression, gastric histopathology, and host Le erythrocyte phenotype. Anti-Le antibody production and H. pylori Le expression were determined by enzyme-linked immunosorbent assay, erythrocyte Le phenotype was examined by agglutination assays, and histology was scored blindly. Significant levels of anti-Le(x) antibody (P < 0.0001, T = 76.4, DF = 5) and anti-Le(y) antibody (P < 0.0001, T = 73.05, DF = 5) were found in the sera of patients with gastric cancer and other H. pylori-associated pathology compared with H. pylori-negative controls. Following incubation of patient sera with synthetic Le glycoconjugates, anti-Le(x) and -Le(y) autoantibody binding was abolished. The degree of the anti-Le(x) and -Le(y) antibody response was unrelated to the host Le phenotype but was significantly associated with the bacterial expression of Le(x) (r = 0.863, r(2) = 0.745, P < 0.0001) and Le(y) (r = 0.796, r(2) = 0.634, P < 0.0001), respectively. Collectively, these data suggest that anti-Le antibodies are present in most patients with H. pylori infection, including those with gastric cancer, that variability exists in the strength of the anti-Le response, and that this response is independent of the host Le phenotype but related to the bacterial Le phenotype.

Molecular mimicry in Campylobacter jejuni and Helicobacter pylori lipopolysaccharides: contribution of gastrointestinal infections to autoimmunity

Molecular mimicry of host structures by the saccharide portion of lipopolysaccharides (LPS) of the gastrointestinal pathogens Campylobacter jejuni and Helicobacter pylori is thought to be associated with the development of autoimmune sequelae. C. jejuni, a leading cause of gastroenteritis, is the most common antecedent infection in Guillain-Barré syndrome (GBS), an inflammatory neuropathy. Chemical analyses of the core oligosaccharides of neuropathy-associated C. jejuni strains have revealed structural homology with human gangliosides. Serum antibodies against gangliosides are found in one third of GBS patients but are generally absent in enteritis cases. Collective data suggest that the antibodies are induced by antecedent infection with C. jejuni, and subsequently react with nerve tissue causing damage. The O-chains of most H. pylori strains express Lewis blood group antigens which are thought to have a role in camouflage of the bacterium as these antigens are also present on human gastric epithelial cells. In chronic H. pylori infections, bacterial expression of Lewis antigens is suggested to be involved in the induction of autoantibodies against the Lewis antigen-expressing gastric proton pump. Many aspects of the autoimmune mechanisms in C. jejuni -associated GBS and H. pylori -induced atrophic gastritis remain unclear, such as the involvement of T cells and the role of host factors.

Favourable effect of an acidified milk (LC-1) on Helicobacter pylori gastritis in man

OBJECTIVE

The supernatant of Lactobacillus johnsonii La1 culture was shown to be bactericidal and to have a partial, acid-independent suppressive effect on Helicobacter pylori in humans. The aim of the present study was to investigate the effect of L. johnsonii La1-acidified milk (LC-1) on H. pylori infection.

DESIGN AND METHODS

Fifty-three volunteers infected with H. pylori as determined by positive 13C-urea breath test and positive serology were randomized to receive either LC-1 or a placebo 180 ml twice a day for 3 weeks. All subjects also received clarithromycin 500 mg bid during the last two weeks of acidified milk therapy. Oesophagogastroduodenoscopy and biopsies were performed at inclusion and repeated 4-8 weeks after the end of the treatment. H. pylori infection was confirmed by urease test and histology. H. pylori density and inflammation were scored using a modified Sydney classification.

RESULTS

LC-1 ingestion induced a decrease in H. pylori density in the antrum (P= 0.02) and the corpus (P= 0.04). LC-1 also reduced inflammation and gastritis activity in the antrum (P= 0.02 and P= 0.01, respectively) and of activity in the corpus (P= 0.02). Clarithromycin eradicated H. pylori in 26% of the subjects; LC-1 did not improve the antibiotic effect.

CONCLUSION

These results suggest that H. pylori infection and gastritis can be down-regulated by LC-1.

Lewis antigens in Helicobacter pylori: biosynthesis and phase variation

The lipopolysaccharides (LPS) of most Helicobacter pylori strains contain complex carbohydrates known as Lewis antigens that are structurally related to the human blood group antigens. Investigations on the genetic determinants involved in the biosynthesis of Lewis antigens have led to the identification of the fucosyltransferases of H. pylori, which have substrate specificities distinct from the mammalian fucosyltransferases. Compared with its human host, H. pylori utilizes a different pathway to synthesize the difucosylated Lewis antigens, Lewis y. and Lewis b. Unique features in the H. pylori fucosyltransferase genes, including homopolymeric tracts mediating slipped-strand mispairing and the elements regulating translational frameshifting, enable H. pylori to produce variable LPS epitopes on its surface. These new findings have provided us with a basis to further examine the roles of molecular mimicry and phase variation of H. pylori Lewis antigen expression in both persistent infection and pathogenesis of this important human gastric pathogen.

Relationship of blood group determinants on Helicobacter pylori lipopolysaccharide with host lewis phenotype and inflammatory response

As Lewis a (Le(a)) and Lewis b (Le(b)) blood group antigens are isoforms of Lewis x (Le(x)) and Lewis y (Le(y)) and are expressed in the gastric mucosa, we evaluated whether the patterns of expression of Le(x) and Le(y) on Helicobacter pylori lipopolysaccharides reflected those of host expression of Le(a) and Le(b). When 79 patients (secretors and nonsecretors) were examined for concordance between bacterial and host Le expression, no association was found (chi(2) = 5.734, 3 df, P = 0.125), nor was there a significant difference between the amount of Le(x) or Le(y) expressed on isolates from ulcer and chronic gastritis patients (P > 0.05). Also, the effect of host and bacterial expression of Le antigens on bacterial colonization and the observed inflammatory response was assessed. In ulcer patients, Le(x) expression was significantly related to neutrophil infiltration (r(s) = 0.481, P = 0.024), whereas in chronic gastritis patients significant relationships were found between Le(x) expression and H. pylori colonization density (r(s) = 0.296, P = 0.03), neutrophil infiltrate (r(s) = 0.409, P = 0. 001), and lymphocyte infiltrate (r(s) = 0.389, P = 0.002). Furthermore, bacterial Le(y) expression was related to neutrophil (r(s) = 0.271, P = 0.033) and lymphocyte (r(s) = 0.277, P = 0.029) infiltrates. Thus, although no evidence of concordance was found between bacterial and host expression of Le determinants, these antigens may be crucial for bacterial colonization, and the ensuing inflammatory response appears, at least in part, to be influenced by Le antigens.

Lack of a relationship between Lewis antigen expression and cagA, CagA, vacA and VacA status of Irish Helicobacter pylori isolates

The cagA gene, vacA gene, CagA (cytotoxin-associated gene A product) and VacA (vacuolating cytotoxin) status of a collection of Helicobacter pylori isolates from the geographically distinct Irish population was determined, the potential association of these traits with Lewis (Le) antigen expression was assessed, and the relationship between these bacterial properties and the pathology associated with H. pylori infection was evaluated. Of the 57 isolates, a higher proportion from ulcer than from non-ulcer patients expressed VacA (71% vs. 53%). H. pylori isolates which were cagA-positive were no more significantly associated with peptic ulcers than non-ulcer disease (71% vs. 67%, P = 0.775), nor were CagA-positive isolates (57% vs. 50%, P = 0.783), but 80% of the isolates from duodenal ulcer patients were cagA-positive. Thirty-seven of the 57 isolates were tested for Le antigen expression. No statistically significant relationship (P > 0.05) was found between the occurrence and level of expression of Le(x) or Le(y) and cagA, vacA, or VacA status. This lack of an association in the Irish H. pylori isolates contrasts with that previously reported for predominantly North American isolates, and may be attributable to the adaptation of H. pylori strains with differing attributes to different human populations.