Basophil-bound and serum immunoglobulin E directed against Helicobacter pylori in patients with chronic gastritis

Genetic Evidence for a Causal Relationship Between Innate Leukocytes and the Risk of Digestive System Cancers in East Asians and Europeans

Background

Peripheral traditional immune cell disorder plays an important role in cancer onset and development. The causal relationships between leukocytes prior to cancer and the risk of digestive system cancer remain unknown. This study assesses the causal correlations between leukocytes and digestive system cancer risk in East Asians and Europeans.

Methods

Summary-level data on leukocyte-related genetic variation were extracted from Biobank Japan (107,964 participants) and a recent large-scale meta-analysis (563,946 participants). Summary-level data for the cancers were obtained from Biobank Japan (212,978 individuals) and the FinnGen consortium (178,802 participants). Univariable and multivariable Mendelian randomization (MR) analyses were performed on East Asians and Europeans separately.

Results

Univariable MR analysis demonstrated the significant association between circulating eosinophil counts and risk of colorectal cancer (CRC) in East Asians (odds ratio (OR) = 0.80, 95% confidence interval (CI): 0.69 - 0.92, P = 0.002) and a suggestive relationship in the European population (OR = 0.86, 95% CI: 0.77 - 0.97, P = 0.013). An inverse suggestive association was observed between levels of basophils and the risk of gastric cancer (GC) in East Asians (OR = 0.83, 95% CI: 0.72 - 0.97, P = 0.019). The multivariable MR analysis showed the independent causal effect of eosinophil count on CRC risk in East Asians (OR = 0.72, 95% CI: 0.57 - 0.92, P = 0.009) and Europeans (OR = 0.80, 95% CI: 0.70 - 0.92, P = 0.002). Circulating basophils served as the negative causal factor in GC risk in East Asians (OR = 0.80, 95% CI: 0.67 - 0.94, P = 0.007).

Conclusions

Our MR analyses revealed a genetic causal relationship between reduced blood eosinophils and an increased CRC risk in both Europeans and East Asians. Furthermore, our results suggested a causal association between decreased basophils and an elevated GC risk specifically in East Asians.

Relationship of the Difficulty of Helicobacter pylori Eradication with Drinking Habits and Allergic Disease

Eradication of Helicobacter pylori (H. pylori) is crucial to reduce the risk of developing gastric ulcers and gastric cancer. Although immunoglobulin E (IgE) levels and alcohol consumption have been shown to influence the failure of H. pylori eradication, the relationship between these factors and the mechanism of failure has not been clarified. Because high IgE levels are associated with eradication failure, the purpose of this study was to clarify the factors leading to high IgE levels. Completed questionnaires and blood test data were collected from patients who visited a university hospital for H. pylori eradication. Logistic regression analysis was per-formed to examine the relationship between high IgE levels and allergic diseases. We also examined the relationship between alcohol intake and high IgE levels. Linear regression analysis was performed on the relationship between the amount of alcohol consumed and IgE measurements. The results showed that patients with allergic diseases and those with high alcohol intake had significantly higher IgE levels. High IgE levels are a risk factor for failure of H. pylori eradication that is associated with drinking habits and alcohol consumption, and our results suggest that daily alcohol consumption should be avoided even in non-allergic patients.

Association Between Patients' Immunoglobulin E Levels and Difficulty Eradicating Helicobacter pylori

Background

Helicobacter pylori is a cause of gastric cancer, and thus the eradication of this bacterium is very important. The success rate of primary eradication has been dramatically increased by the introduction of potassium-competitive acid blockers. However, H. pylori cannot be eradicated in all patients, and the contributing factors need to be clarified.

Aim

Because allergy status may be a factor and considering research linking hay fever with eradication failure, the purpose of this study was to examine blood immunoglobulin E levels as a contributing factor in patients who were unable to eradicate H. pylori in a single eradication treatment and who underwent multiple eradication attempts.

Methods

Questionnaire data were collected from 250 patients who visited the Department of Gastroenterology, Hamamatsu University School of Medicine, for H. pylori eradication. In addition, non-specific IgE levels in the blood were measured and analyzed with one-way analysis of variance. Multinomial logistic regression analysis was performed to examine the association between the number of eradication attempts and the IgE level (< 500 vs ≥ 500 IU/mL).

Results

The mean IgE values were 188.4, 211.9, and 744.0 IU/mL in patients with one, two, and three or more eradication attempts, respectively (P < 0.05). The results of multinomial logistic regression analysis showed that attempting eradication three or more times was significantly associated with high levels of IgE, even after consideration of antibiotic sensitivity.

Conclusion

H. pylori eradication was less likely in patients with high IgE. It is thus necessary to study the appropriate regimen for patients with high IgE levels.

Food Allergy and Helicobacter pylori Infection: A Systematic Review

Introduction: Based on the hygiene hypothesis, a low prevalence of Helicobacter pylori (H. pylori) infection may explain the recent high prevalence of allergic diseases including food allergy. However, there are very few studies that investigate the relationship between H. pylori and food allergy.

Summary: We searched for PubMed, Ovid Medline and the Cochrane library for relevant articles published in English from inception to November 2015. The inverse relationship between H. pylori and food allergy remains unproven because of contradictory and limited evidence at the moment. Likewise, only limited studies have examined the relationship between CagA; one of H. pylori virulence factor and food allergy. On the other hand, in vitro evidence seems to point out a role of H. pylori in the causation of food allergy. The inconsistent results from epidemiological data may be due to small sample size, heterogeneous populations and unstandardised methods or food allergens.

Conclusion: Available studies do not support the role of H. pylori in food allergy.

Correlation between Helicobacter pylori infection, IgE hypersensitivity, and allergic disease in Korean adults

BACKGROUND

The correlation between allergic disease and Helicobacter pylori infection is still controversial in endemic areas. The aim of this study was to determine whether H. pylori infection is related to allergic disease and/or immunoglobulin E (IgE) hypersensitivity in Korean adults.

MATERIALS AND METHODS

Consecutive Korean adults who visited our center for a routine checkup were enrolled. All subjects completed a questionnaire that was designed to ascertain their medical history pertaining to physician-diagnosed allergic disease, allergy treatments, and H. pylori eradication therapy. Blood was sampled for serum anti-H. pylori IgG antibody. IgE hypersensitivity was measured using a commercially available ImmunoCAP(®) Phadiatop (Phadia AB, Uppsala, Sweden).

RESULTS

Of the 3376 Korean adults who were enrolled, 62 did not answer to the questionnaires adequately and were thus excluded. The proportion of noninfected subjects (p < .001) and the prevalence of IgE-related allergic disease (p < .001) were both highest among those aged <40 years, while the prevalence of non-IgE-related allergic disease was highest among those aged ≥70 years (p < .001). Logistic regression analysis revealed that being younger than 40 years was significantly related to the absence of H. pylori infection (OR = 2.507, 95% CI = 1.621-3.878, p < .001).

CONCLUSIONS

The statuses of H. pylori infection, IgE hypersensitivity, and allergic diseases differ with age group, there being a higher prevalence of IgE-related allergic disease and a lower H. pylori infection rate among young adults. The hygiene hypothesis might explain these findings in young Koreans, due to the rapid development and improvements in sanitation in Korea.

Mast cell plasticity and sphingosine-1-phosphate in immunity, inflammation and cancer

Mast cells (MC) are found in all vascularized tissues at homeostasis and, until recently, were viewed only as effector cells of allergic reactions via degranulation, the canonical process through which MC release mediators, including histamine and pre-formed proteases and cytokines such as TNF. Cross-linking of IgE bound to surface high affinity receptors for IgE (FcɛRI) by a specific antigen (Ag) triggers signaling events leading to degranulation. We and others have reported the concomitant production and export of an influential multifaceted sphingolipid mediator, sphingosine-1-phosphate (S1P) transported outside of MC by ATP-binding cassettes (ABC) transporters, i.e., independently of degranulation. Indeed, the MC horizon expanded by the discovery of their unique ability to selectively release mediators depending upon the stimulus and receptors involved. Aside from degranulation and transporter usage, MC are also endowed with piecemeal degranulation, a slower process during which mediator release occurs with minor morphological changes. The broad spectrum of pro- and anti-inflammatory bioactive substances MC produce and release, their amounts and delivery pace render these cells bona fide fine-tuners of the immune response. In this viewpoint article, MC developmental, phenotypic and functional plasticity, its modulation by microRNAs and its relevance to immunity, inflammation and cancer will be discussed.

Alzheimer's Disease: APP, Gamma Secretase, APOE, CLU, CR1, PICALM, ABCA7, BIN1, CD2AP, CD33, EPHA1, and MS4A2, and Their Relationships with Herpes Simplex, C. Pneumoniae, Other Suspect Pathogens, and the Immune System

Alzheimer's disease susceptibility genes, APP and gamma-secretase, are involved in the herpes simplex life cycle, and that of other suspect pathogens (C. pneumoniae, H. pylori, C. neoformans, B. burgdorferri, P. gingivalis) or immune defence. Such pathogens promote beta-amyloid deposition and tau phosphorylation and may thus be causative agents, whose effects are conditioned by genes. The antimicrobial effects of beta-amyloid, the localisation of APP/gamma-secretase in immunocompetent dendritic cells, and gamma secretase cleavage of numerous pathogen receptors suggest that this network is concerned with pathogen disposal, effects which may be abrogated by the presence of beta-amyloid autoantibodies in the elderly. These autoantibodies, as well as those to nerve growth factor and tau, also observed in Alzheimer's disease, may well be antibodies to pathogens, due to homology between human autoantigens and pathogen proteins. NGF or tau antibodies promote beta-amyloid deposition, neurofibrillary tangles, or cholinergic neuronal loss, and, with other autoantibodies, such as anti-ATPase, are potential agents of destruction, whose formation is dictated by sequence homology between pathogen and human proteins, and thus by pathogen strain and human genes. Pathogen elimination in the ageing population and removal of culpable autoantibodies might reduce the incidence and offer hope for a cure in this affliction.

Plasticity in mast cell responses during bacterial infections

Mast cells (MCs) have been implicated in orchestrating the host's early innate immune and adaptive immune responses in several models of acute bacterial infections. Most of this activity results in early clearance of the bacteria and timely resolution of infection. However, during chronic infections because of the prolonged nature of MC-bacterial interactions, the role of the MC in determining the fate of infection is markedly more complex. Depending on the nature of the pathogen, severity of infection, and its association with a preexisting inflammatory disease, MCs may promote rather than contain chronic infections and exacerbate their pathological sequellae.

Interleukin-2 gene polymorphisms associated with increased risk of gastric atrophy from Helicobacter pylori infection

BACKGROUND

Gastric atrophy induced by Helicobacter pylori is thought to predispose patients to noncardiac gastric cancer development. However, the host genetic factors that influence the progression of gastric atrophy have not been elucidated. In this study, we examined the effects of cytokine polymorphisms on H. pylori-induced gastric atrophy.

METHODS

Blood samples were taken from 454 Japanese subjects. The interleukin-2 (IL-2; T-330G), IL-4 (C-33T), and IL-13 (C-1111T) polymorphisms were genotyped by polymerase chain reaction with confronting two-pair primers (PCR-CTPP). Anti-H. pylori IgG antibody and pepsinogen I and II were measured to diagnose H. pylori infection and atrophic gastritis.

RESULTS

The odds ratios (ORs) for the association between IL-2 polymorphism [OR = 2.78, 95% CI (confidence interval) = 1.26-6.17 (T/T to G/G)] or IL-4 polymorphism [OR = 2.22, 95% CI = 1.01-4.89 (T/C to C/C)] were increased significantly with gastric atrophy, whereas the corresponding OR of IL-13 polymorphism was decreased with gastric atrophy [OR = 0.61, 95% CI = 0.39-0.96 (C/T and T/T to C/C)]. There were no significant H. pylori seropositivity-related differences between these polymorphisms. We examined the relationship between these polymorphisms and gastric atrophy separately in H. pylori-seropositive and -seronegative groups. In the H. pylori-seropositive group, the IL-2 T/T (OR = 2.78, 95% CI = 1.12-6.93) had a significant association with gastric atrophy.

CONCLUSIONS

These results reveal that the IL-2 gene polymorphism is associated with an increased risk of gastric atrophy induced by H. pylori infection and might predispose to gastric cancer.

Chronic urticaria and infections

PURPOSE OF REVIEW

The pathogenesis of chronic urticaria is multifactorial and a specific treatment is lacking. In acute urticaria there is no doubt of a causal relationship with infections and all chronic urticaria must start as the acute form. However, in the chronic form a primary role for infection is controversial, although it is undeniable that concurrent infections exacerbate the condition. This is the first English language review based on a detailed analysis of current peer-reviewed publications dealing with infections and chronic urticaria.

RECENT FINDINGS

In chronic urticaria there is a lot of evidence for different infections, but randomized controlled trials are missing. The prevalence of infections is not increased but in susceptible patients the immune response may lead to the development of chronic urticaria. Interestingly, there is evidence for an infection-associated autoreactive response at least in the subgroup with a positive autologous serum skin test. A variety of mechanisms have been invoked to explain these observations, including molecular mimicry.

SUMMARY

Actually the arguments for an important role of underlying causal infections in chronic urticaria are weak, from an evidence-based viewpoint, but there are data suggesting a link. Moreover, an association with underlying or precipitating infectious causes is difficult to establish because there is no possibility for challenge and the number of other urticarial triggers is vast. For the future it will be necessary to reveal the link between urticaria, autoreactivity, non-immunoglobulin E-mediated hypersensitivity reactions and infections to find attractive and specific therapeutic interventions for urticarial symptomatology.

Mast cells and IgE-containing cells in gastric mucosa of Helicobacter pylori infected and non-infected patients with chronic urticaria

BACKGROUND

Several studies have indicated that antibiotic therapy aimed at eradication of Helicobacter pylori has effects on symptoms of chronic urticaria (CU) patients. However, the possible connections and pathomechanism by which H. pylori might be linked to CU have remained largely unknown. The IgE-mediated pathway might be a possible link between H. pylori infection and CU. We therefore clarified the role of H. pylori as an inducer of IgE response.

MATERIALS AND METHODS

Gastroscopy was performed and mucosal biopsy specimens were taken to evaluate the histology, as well as the presence of H. pylori bacteria, mast cells and IgE-containing cells in the antral mucosa, in 21 CU patients. Controls (n = 48) included 19 patients with lichen planus, nine patients with atopic dermatitis and 20 patients with no skin or allergic disease.

RESULTS

The mean densities of IgE-containing cells were significantly higher in H. pylori-infected patients and in patients with skin disease compared to non-H. pylori-infected patients with no skin or allergic disease. No significant difference was found in the number of IgE-containing cells between H. pylori-infected and non-infected patients with CU. There was no significant difference in the mean densities of mast cells in the different patient groups.

CONCLUSIONS

Our findings suggest that H. pylori gastritis leads to increased IgE production. However, we could not show a significant difference in IgE staining between H. pylori-infected and non-infected patients with CU.

Basophils Infiltrate Human Gastric Mucosa at Sites of Helicobacter pylori Infection, and Exhibit Chemotaxis in Response to H. pylori-derived Peptide Hp(2–20)

Basophils, which are normally confined to the circulation, can migrate to sites of allergic inflammation. Using the specific mAb, BB1, we detected basophil infiltration of the gastric mucosa of Helicobacter pylori-infected patients affected by moderate and severe gastritis. Basophils were not found in H. pylori-free individuals or in subjects with mild gastritis. The H. pylori-derived peptide, Hp(2-20), was a potent basophil chemoattractant in vitro, whereas the control peptide, Hp1, was ineffective. Basophils from peripheral blood of healthy volunteers expressed mRNA for the formyl peptide receptors, N-formyl-peptide receptor (FPR), FPR-like (FPRL)1, and FPRL2. Preincubation of basophils with FMLP or Hp(2-20) caused complete desensitization to a subsequent challenge with homologous stimulus. Incubation of basophils with a low concentration of FMLP, which binds with high affinity to FPR, but not to FPRL1 or FPRL2, did not affect the chemotactic response to Hp(2-20). In contrast, a high concentration of FMLP, which binds to FPRL1 and FPRL2, reduced the chemotactic response to Hp(2-20). The FPR antagonist, cyclosporin H, prevented chemotaxis induced by FMLP, but not by Hp(2-20). Hp(2-20) could be responsible, at least in part, for basophil infiltration of the gastric mucosa of H. pylori-infected patients presumably through the interaction with FPRL1 and FPRL2.

Helicobacter pylori infection in skin diseases: a critical appraisal

More than 50% of the human population have long-term Helicobacter pylori infection, causing, in some cases, severe diseases such as peptic ulcers and stomach cancer. In the last few years several extra-gastrointestinal disorders have been associated with H. pylori infection. This review summarized the current medical literature, identified through hand searching and MEDLINE research, including our own studies, with regard to H. pylori and skin diseases. From the literature it can be seen that the role of H. pylori in skin diseases is still a controversial subject. Randomized controlled trials with adequate masking and sample sizes are still lacking. The best evidence comes from studies investigating chronic urticaria in which chronic urticaria disappeared in many patients with H. pylori infection after careful eradication of the H. pylori. Moreover, there are promising recent reports of beneficial H. pylori eradication in Behçet's disease, pruritus cutaneus, prurigo chronica, prurigo nodularis and in some patients with lichen planus, but not in rosacea or psoriasis. Before any conclusions with respect to other skin diseases such as atopic dermatitis, Schoenlein-Henoch Purpura, Sweet's syndrome, Sjögren syndrome or systemic sclerosis may be drawn, additional randomized, double-blinded and placebo-controlled studies including adequate diagnostic schedules, sufficient eradication treatment protocols, confirmation of eradication and adequate control groups are needed. The cutaneous pathology of H. pylori is far from being clear, but it is speculated that the systemic effects may involve increased mucosal permeability to alimentary antigens, immunomodulation, an autoimmune mechanism or the impairment of vascular integrity.

Chronic pruritus associated with Helicobacter pylori

BACKGROUND

Helicobacter pylori is an established cause of gastritis and has been implicated in extradigestive diseases.

OBJECTIVE

To investigate the role of H. pylori in patients with unexplained refractory pruritus.

METHODS

Ten patients with severe pruritus unresponsive to conventional therapy were evaluated for active H. pylori infection by H. pylori serology followed by either esophagogastroduodenoscopy (EGD) or urea breath test. Of the 10 patients, 8 were found to have active infection. All 10 received anti-H. pylori antibiotic therapy and were reevaluated for relief of pruritus.

RESULTS

Of 8 patients with active H. pylori infection, 87.5% (7/8) had some type of pruritus relief after triple therapy. Of these, 62.5% (5/8) had complete relief and 25% (2/8) had temporary relief of pruritus. The remaining 12.5% (1/8) did not respond. Two control patients without active H. pylori infection had no relief of pruritus with therapy.

CONCLUSIONS

We have identified a population of patients with refractory pruritus and active H. pylori infection whose pruritus resolved after eradication of H. pylori.

Chronic Pruritus Associated with Helicobacter Pylori

Background:

Helicobacter pylori is an established cause of gastritis and has been implicated in extradigestive diseases.

Objective:

To investigate the role of H. pylori in patients with unexplained refractory pruritus.

Methods:

Ten patients with severe pruritus unresponsive to conventional therapy were evaluated for active H. pylori infection by H. pylori serology followed by either esophagogastroduodenoscopy (EGD) or urea breath test. Of the 10 patients, 8 were found to have active infection. All 10 received anti- H. pylori antibiotic therapy and were reevaluated for relief of pruritus.

Results:

Of 8 patients with active H. pylori infection, 87.5% (7/8) had some type of pruritus relief after triple therapy. Of these, 62.5% (5/8) had complete relief and 25% (2/8) had temporary relief of pruritus. The remaining 12.5% (1/8) did not respond. Two control patients without active H. pylori infection had no relief of pruritus with therapy.

Conclusions:

We have identified a population of patients with refractory pruritus and active H. pylori infection whose pruritus resolved after eradication of H. pylori.

IgE-containing cells in gastric mucosa with and without Helicobacter pylori infection

Gastric mucosa responds with inflammation to Helicobacter pylori (H. pylori) infection. While numerous reports have shown that the immune system produces specific IgG, IgA, and IgM isotype anti H. pylori antibodies, IgE-mediated pathways of H. pylori-associated gastritis are mostly unknown. Our aim was to evaluate whether an increased presence of IgE in the antral gastric mucosa is responsible for the severity of the H. pylori-associated gastritis. The number of IgE-containing cells was estimated in formalin-fixed, paraffin-embedded antral gastric biopsy specimens using immunohistochemistry in three groups of patients: (i) 20 H. pylori-positive cases with moderate inflammation, (ii) 19 H. pylori-negative cases with moderate inflammation, and (iii) 19 H. pylori-negative cases with normal mucosa. In chronic gastritis, the number of IgE-positive cells increased significantly as compared to normal mucosa. In gastritic patients, H. pylori positivity was accompanied by a significant accumulation of IgE-positive cells, mainly plasma cells. These data suggest that IgE-mediated immune response probably plays an important role in the development of H. pylori-associated gastritis.

Eosinophils and Mast Cells in Helicobacter Pylori Infected Gastric Mucosa

Although Helicobacter pylori (HP) is frequently associated with chronic active gastritis and peptic ulcers, its exact pathogenic role or the pathomechanism is still unclear. Here, we describe a striking, statistically significant increase of eosinophils in HP infected gastric mucosa compared to HP negative gastritis with similar activity. In both cases, the mean number of the mast cells in the mucosa was comparable, although the individual values showed wide distribution. The source and role of eosinophilia in HP infected mucosa, the potential link between the degree of eosinophilia and the clinical progression, as well as between eosinophils and mast cells require further study.

Helicobacter pylori alters exogenous antigen absorption and processing in a digestive tract epithelial cell line model

To study the influence of Helicobacter pylori on epithelial barrier function, bacteria, bacterial sonicates, or broth culture supernatants were incubated for 24 h with HT29-19A intestinal cells grown as monolayers. Subsequently, the monolayers were mounted in Ussing chambers, and electrical resistance (R), fluxes of 22Na (JNa) and 14C-mannitol (JMan) (markers of the paracellular pathway), and fluxes of horseradish peroxidase (HRP) in total (J3H-HRP), intact (JHRPi), and degraded forms were measured. H. pylori did not induce any modification of the paracellular pathway (R = 148 +/- 10 versus 174 +/- 16 Omega. cm2; JNa = 4.16 +/- 0.44 versus 3.51 +/- 0.41 microEq/h. cm2; JMan = 0.081 +/- 0.01 versus 0.058 +/- 0.009 micromol/h. cm2), nor did it modify J3H-HRP (2,201 +/- 255 versus 2, 110 +/- 210 ng/h. cm2 for H. pylori-infected and control cells, respectively). However, in the presence of H. pylori, we observed a significant increase in JHRPi (520 +/- 146 versus 171 +/- 88 ng/h. cm2). This effect was not dependent of the cag status of the strain and was not reproduced by the sonicates or the culture supernatants. It was related to the presence of urease, since a urease-negative mutant of H. pylori did not induce this effect. Ammonia and bafilomycin A1, two agents known to increase the endolysosomal pH, reproduced the increase in JHRPi. In conclusion, H. pylori does not affect directly the integrity of intercellular junctions of epithelial cells in vitro, but it increases the passage of intact HRP, probably by inhibition of the intralysosomal degradation due to the release of ammonia. The increased transport of intact macromolecules may contribute to the induction and maintenance of gastric inflammation by H. pylori.

Number, fixation properties, dye-binding and protease expression of duodenal mast cells: comparisons between healthy subjects and patients with gastritis or Crohn's disease

There is an accumulation of evidence to suggest that mast cells may play a key role in gastrointestinal inflammation. We have investigated the numbers and heterogeneity in staining properties of mast cells in biopsies of the duodenum of normal subjects (n = 10), and of normal duodenum from patients with Crohn's disease of the ileum and/or colon (n = 7) or with Helicobacter-associated gastritis of the antrum/corpus (n = 6). In normal donors, two subsets of mast cells, one located in the duodenal mucosa and the other in the submucosa, were clearly distinguished by their morphology and dye-binding properties. Whereas submucosal mast cells stained metachromatically with Toluidine Blue after neutral formalin fixation and emitted a yellow fluorescence after staining with Berberine sulphate, those in the mucosa were invisible using these stains. In patients with gastritis or Crohn's disease, there were marked changes in the numbers of mucosal mast cells compared with control subjects even though the duodenal biopsies were from apparently uninvolved tissue. Gastritis was associated with increased mucosal mast cell numbers (controls: 187 +/- 23 cells mm-2; gastritis: 413 +/- 139 cells mm-2; p = 0.0004), but mean mucosal mast cell counts in the uninvolved duodenum of Crohn's patients were actually decreased (34 +/- 30 cells mm-2, p = 0.0147). The clear differentiation between mucosal and submucosal mast cells on the basis of metachromasia with Toluidine Blue was not seen in biopsies from the patients with gastritis or Crohn's disease. Previous studies which have suggested that there are no distinct mucosal and submucosal mast cell subsets in the human intestine may, therefore, have been affected by the use of tissue from diseased subjects. Heterogeneity in the expression of mast cell tryptase and chymase was seen by immunohistochemistry using specific antibodies, but the relative numbers of mast cell subsets were critically dependent on the methods used. Using a sensitive staining procedure, the majority of mucosal mast cells stained positively for chymase as well as for tryptase, an observation confirmed by immunoelectron microscopy and immunoabsorption studies. Our findings suggest that early stages in intestinal inflammation may be reflected in changes in mast cell numbers and in their staining properties, and call for a reappraisal of mast cell heterogeneity in the human intestinal tract.

Blood leukocyte differential in Helicobacter pylori infection

Helicobacter pylori causes a chronic infection in gastric mucosa, but its systemic effects are largely unknown. Our aim was to characterize the effect of H. pylori infection and gastric mucosal inflammation on the peripheral blood leukocyte count. An endoscopic series of 96 patients (40 men and 56 women), with a mean age of 62 years (range 49-80) was studied. Endoscopy with eight stepwise biopsies was performed and the occurrence of H. pylori was studied from sections stained with Warthin-Starry. The severity of inflammation in antral and body mucosa was estimated. The peripheral blood leukocyte count and differential count were determined by the automatic flow cytometric method. The total number of blood leukocytes and the numbers of lymphocytes and basophils were significantly increased in H. pylori-positive patients (N = 58), as compared with H. pylori-negative ones (N = 38). The total number of blood leukocytes correlated with the numbers of neutrophils, eosinophils, and mononuclear cells in the gastric mucosa. The number of basophils correlated with the number of mucosal neutrophils and mononuclear inflammatory cells. The results show that mucosal inflammation due to H. pylori infection is reflected in the amount of peripheral blood leukocytes. Basophilia suggests involvement of allergic mechanisms in H. pylori gastritis.

Immune and inflammatory responses to Helicobacter pylori infection

The gastroduodenal response to chronic Helicobacter pylori infection is characterized by the infiltration of plasma cells, lymphocytes, neutrophils and monocytes into the mucosa. Eradication studies have shown that this inflammatory response represents a specific reaction to the presence of H. pylori. As well as stimulating specific local T and B cell responses and a systemic antibody response, H. pylori infection also induces a local pro-inflammatory cytokine response. Interleukin-8 (IL-8), which is expressed and secreted by gastric epithelial cells, may be an important host mediator inducing neutrophil migration and activation. IL-8 mRNA and protein secretion in gastric epithelial cell lines can be up-regulated by the cytokines tumour necrosis factor-alpha and IL-1 and also by type I strains of H. pylori (expressing the vacuolating toxin and cytotoxin-associated protein, CagA). The gastric epithelium thus plays an active role in mucosal defence. Neutrophil activation and the production of reactive oxygen metabolites will be induced directly by bacterial factors and indirectly via host-derived cytokines, products of complement activation and bioactive lipids. Strain variation in the induction of both IL-8 from epithelial cells and the oxidative burst in neutrophils may be an important factor determining the extent of mucosal injury. There is now increasing evidence from both in vivo and in vitro studies that type I strains induce an enhanced inflammatory response and mucosal damage. An understanding of the bacterial mediators of mucosal inflammation is important in elucidating the role of chronic H. pylori infection in the pathogenesis of gastroduodenal disease.

The role of gastric mast cells, enterochromaffin-like cells and parietal cells in the regulation of acid secretion

The idea presented here is that, in gastric mucosa, two independent regulatory systems use the same transmitter: histamine molecules. The IgE/mast cell system is dispersed throughout the body, while the other regulates the gastric acid secretion. IgE molecules in gastric mucosa are attached to the mast cells. Mast cells release histamine molecules after the antigen has been recognized by IgE. These molecules normally act on vascular H1 receptors to promote extravasation and chemotaxy. Gastrin molecules are released from antral G cells to stimulate gastric acid secretion. Their influence on parietal cells is indirectly augmented by gastrin governed release of histamine molecules from enterochromaffin-like cells. These histamine molecules normally act on H2 receptors of parietal cells to promote gastric acid secretion. Chronic infection of gastric mucosa (i.e. with Helicobacter pylori), autoimmune disorders or repetitive mucosal exposure to the same antigen, can develop chronic inflammation of gastric mucosa. Gastric acid secretion is diminished with secondary hypergastrinemia and increased release of histamine from enterochromaffin-like cells in an attempt to stimulate the few remaining parietal cells. Hypothetically, increased concentrations of released histamine in gastric mucosa might activate the vascular H1 receptors with extravasation and aggravated inflammation. This can further decrease the number of active parietal cells, reduce gastric acid secretion and potentiate hypergastrinemia. In this hypothetical setting, H1 blockers might reduce the damage by abolishing the vascular reactions. The prolonged antigen load on gastric mucosa can promote production of specific IgE antibodies. Further exposures to the same antigen degranulate sensitized mucosal mast cells. Liberated histamine can produce extravasation through the vascular H1 receptor and, hypothetically, local hyperacidity through the parietal cell H2 receptors. The result would be hyperacidity and hypogastrinemia with possible ulcer disease. Some individuals are more predisposed to IgE production or have increased numbers of mast cells that might explain why only some people develop ulcer disease after H. pylori infection.

Gastric mucosal histamine storing cells. Evidence for different roles of mast cells and enterochromaffin-like cells in humans

Gastric mucosal histamine content, enterochromaffin-like cell density, and mast cell density were studied in 13 subjects under omeprazole therapy, 13 partially gastrectomized subjects with a Billroth II reconstruction, 10 partially gastrectomized subjects with a Roux-en-Y reconstruction, and 9 control subjects. Histamine content was significantly greater both in the subjects with higher gastrinemic levels (omeprazole-treated subjects) and those with more abundant enterogastric reflux (Billroth II subjects) than in controls. Enterochromaffin-like cell density was significantly greater in the omeprazole subjects than in each of the other groups. Mast cell density was significantly greater in Billroth II subjects than in controls. Serum gastrin levels, mucosal histamine content, and enterochromaffin-like cell density were positively correlated. Gastrin was not correlated to mast cell density. These results support the existence of different control pathways for enterochromaffin-like and mast cells. Moreover, they suggest that enterochromaffin-like cells and mast cells are involved in the regulation of gastric secretion and in gastric mucosal injury-repair mechanisms, respectively, due to histamine release.

Review article: new insights into prostaglandins and mucosal defence

A role for prostaglandins in maintaining mucosal integrity in the gastrointestinal tract is well documented. While traditionally the effects of prostaglandins on mucosal blood flow and epithelial function have been regarded as critical in the mechanism of action of these fatty acids, recent evidence that mucosal ulceration is almost invariably associated with mucosal inflammation has caused a re-evaluation of the role of prostaglandins in mucosal defence. This review focuses on the ability of prostaglandins to exert anti-inflammatory, and therefore anti-ulcerogenic, effects in the gastrointestinal tract. These effects of prostaglandins are attributable to their ability to suppress the release of inflammatory mediators and reactive oxygen metabolites from a number of immunocytes, stromal cells and inflammatory cells. There is emerging evidence for cooperative interactions between prostaglandins and nitric oxide in maintaining mucosal integrity. Recent work on the inducible isoform of prostaglandin synthase as it pertains to mucosal defence is also reviewed.

Helicobacter pylori-associated gastritis. Evolution of histologic changes over 10 years

BACKGROUND

Helicobacter pylori seems to be the commonest cause of chronic gastritis, but the natural course of H. pylori-associated gastritis is largely obscure.

METHODS

We present a histologic follow-up of 39 patients with H. pylori-positive gastritis. Gastroscopies with stepwise biopsies were performed in all the patients at an interval of 10 years.

RESULTS

Of the patients 87% (34/39) had a persistent infection and showed a significant decrease in the grades of antral gastritis, eosinophilic granulocytes, corpus eosinophilic granulocytes, and foveolar hyperplasia and a significant increase in the grade of corpus neutrophilic granulocytes. The quantities of H. pylori as estimated histologically did not change significantly during the follow-up period in patients with a persistent infection. In the five other patients (13%) the H. pylori infection had apparently disappeared spontaneously, and this was accompanied by decreases in the amount of inflammatory cells in the gastric mucosa.

CONCLUSIONS

H. pylori infection in the gastric mucosa is chronic and may be associated with both regressive and progressive histologic changes. Spontaneous healing of H. pylori infection is possible and is associated with partial resolution of the inflammatory changes in the gastric mucosa.

Lipopolysaccharide induces Ca(2+)-independent nitric oxide synthase activity in rat gastric mucosal cells

Ca(2+)-independent nitric oxide synthase was detected in gastric mucosal cells isolated from rats injected 4 h previously with Escherichia coli lipopolysaccharide (3 mg/kg i.v.). Induced nitric oxide synthase was located in an elutriated cell fraction of intermediate size which contained epithelial cells, but was absent from the parietal cell fraction. Administration of dexamethasone (2 mg/kg i.p.) 1 h before lipopolysaccharide inhibited the appearance of Ca(2+)-independent nitric oxide synthase, and prevented the observed reduction in cell viability (trypan blue exclusion). Ca(2+)-independent nitric oxide synthase activity can thus be induced in certain cells of the gastric mucosa, and may contribute to gastric pathologies where there is activation of the immune system.

Distinct profiles of gastritis in dyspepsia subgroups. Their different clinical responses to gastritis healing after Helicobacter pylori eradication

BACKGROUND

A contribution of Helicobacter pylori gastritis to the pathogenesis of non-ulcer dyspepsia (NUD) remains uncertain.

METHODS

Administration of an appropriate clinical questionnaire followed by endoscopy allowed us to select, among 139 outpatients with dyspepsia, 87 non-ulcer dyspepsia patients with more severe and group-distinctive symptoms, 35 of whom were classified as having ulcer-like (ULD). 38 as dysmotility-like (DLD), and 14 as reflux-like dyspepsia (RLD). Biopsy specimens were evaluated for H. pylori gastritis in accordance with the Sydney system. The 70 H. pylori-positive cases were treated with omeprazole, 20 mg twice daily, and amoxycillin, 1 g three times daily for 2 weeks.

RESULTS

Higher rates of H. pylori colonization were found histologically in the gastric mucosa of ULD (91%) and RLD (86%) than in that of DLD (68%) or asymptomatic (42%) patients. ULD differed from RLD patients in their higher score of antritis activity. Three and 6 months after H. pylori eradication ULD (but not DLD) showed significant regression of dypspetic symptoms scores.

CONCLUSIONS

It seems likely that H. pylori gastritis, with special reference to active antritis, is among causative factors of ULD. Its role in the pathogenesis of RLD and DLD needs further investigation.

Helicobacter pylori potentiates histamine release from rat serosal mast cells induced by bile acids

In the present study we have experimentally addressed the effects of Helicobacter pylori on the bile acid capability of histamine release. Bile acids alone were confirmed to be able to induce in vitro histamine release from rat serosal and mucosal mast cells. On the contrary, no significant histamine release was obtained when incubating any Helicobacter pylori preparations alone with mast cells. However, histamine release induced by bile acids was significantly enhanced, without any significant increase in lactate dehydrogenase activity, when whole washed or formalin-killed bacterial cells or crude cell walls were incubated with mast cells in the presence of cholic (0.3 mM), deoxycholic (0.3 mM), or lithocholic (0.3 mM) acids, chenodeoxycholylglycine (0.3 mM), and deoxycholyltaurine (3 mM). The electron microscopic features of mast cells incubated with Helicobacter pylori were consistent with an exocytotic secretion. The release of histamine induced by 0.3 mM deoxycholic acid in the presence of Helicobacter pylori was inhibited by the preincubation of the cells with dimaprit (an H2 agonist) and potentiated by the H2 antagonist, ranitidine. The current results suggest a link between human Helicobacter pylori infection and histamine release and a possible involvement of gastric mucosal mast cells in the pathogenesis of Helicobacter pylori-associated gastritis.

Helicobacter pylori potentiates histamine release from serosal rat mast cells in vitro

Helicobacter pylori seems to be involved in the etiology of peptic ulcer and chronic gastritis. Histamine is fundamental in gastric secretion modulation, and some features of H. pylori-associated gastritis (edema, vasodilatation, inflammatory cell infiltration) are typical of the histamine-mediated response. This in vitro study has been undertaken as a preliminary step, in order to find a possible link between H. pylori and histamine release. H. pylori isolated from gastric biopsies has been tested as whole washed bacterium, whole formalin-killed bacterium, and crude cell wall preparation with serosal mast cells obtained by density gradient centrifugation or elutriation from peritoneal and pleural washings of male Wistar albino rats. Histamine release was assayed fluorimetrically. No significant histamine release was obtained by testing the various bacterial preparations alone with mast cells. On the contrary, whole washed cells, whole formalin-killed cells and crude cell walls from H. pylori have been found to potentiate compound 48/80 or calcium ionophore A23187-induced histamine release. Crude cell walls showed the highest activity, whereas filtered supernatants from broth cultures constantly appeared inactive. The enhancement in histamine release differed between the different strains. The present in vitro study, which shows the potentiating effect of H. pylori on histamine release, may prove interesting; however, at present, clinical implications cannot be inferred and further studies as well as in vivo demonstrations are needed.