Reduced risk of atopic disorders in adults with Helicobacter pylori infection

Impact of local human microbiota on the allergic diseases: Organ-organ interaction

The homogeneous impact of local dysbiosis on the development of allergic diseases in the same organ has been thoroughly studied. However, much less is known about the heterogeneous influence of dysbiosis within one organ on allergic diseases in other organs. A comprehensive analysis of the current scientific literature revealed that most of the relevant publications focus on only three organs: gut, airways, and skin. Moreover, the interactions appear to be mainly unidirectional, that is, dysbiotic conditions of the gut being associated with allergic diseases of the airways and the skin. Similar to homogeneous interactions, early life appears to be not only a crucial period for the formation of the microbiota in one organ but also for the later development of allergic diseases in other organs. In particular, we were able to identify a number of specific bacterial and fungal species/genera in the intestine that were repeatedly associated in the literature with either increased or decreased allergic diseases of the skin, like atopic dermatitis, or the airways, like allergic rhinitis and asthma. The reported studies indicate that in addition to the composition of the microbiome, also the relative abundance of certain microbial species and the overall diversity are associated with allergic diseases of the corresponding organs. As anticipated for human association studies, the underlying mechanisms of the organ-organ crosstalk could not be clearly resolved yet. Thus, further work, in particular experimental animal studies are required to elucidate the mechanisms linking dysbiotic conditions of one organ to allergic diseases in other organs.

Helicobacter pylori infection

Helicobacter pylori infection causes chronic gastritis, which can progress to severe gastroduodenal pathologies, including peptic ulcer, gastric cancer and gastric mucosa-associated lymphoid tissue lymphoma. H. pylori is usually transmitted in childhood and persists for life if untreated. The infection affects around half of the population in the world but prevalence varies according to location and sanitation standards. H. pylori has unique properties to colonize gastric epithelium in an acidic environment. The pathophysiology of H. pylori infection is dependent on complex bacterial virulence mechanisms and their interaction with the host immune system and environmental factors, resulting in distinct gastritis phenotypes that determine possible progression to different gastroduodenal pathologies. The causative role of H. pylori infection in gastric cancer development presents the opportunity for preventive screen-and-treat strategies. Invasive, endoscopy-based and non-invasive methods, including breath, stool and serological tests, are used in the diagnosis of H. pylori infection. Their use depends on the specific individual patient history and local availability. H. pylori treatment consists of a strong acid suppressant in various combinations with antibiotics and/or bismuth. The dramatic increase in resistance to key antibiotics used in H. pylori eradication demands antibiotic susceptibility testing, surveillance of resistance and antibiotic stewardship.

Disease trends after Helicobacter pylori eradication based on Japanese nationwide claims and the health check-up database

BACKGROUND

Helicobacter pylori (H. pylori) infection is a risk factor for many diseases, including peptic ulcer disease and gastric cancer. While H. pylori eradication therapy can prevent these diseases, potentially unfavorable effects of eradication therapy have also been reported in some diseases, such as gastroesophageal reflux disease (GERD), Barrett’s esophagus (BE), inflammatory bowel disease (IBD), allergic diseases, and metabolic diseases. Consequently, both positive and negative impacts should be considered when assessing the effects of H. pylori eradication therapy.

AIM

To compare the incidence of these diseases before and after H. pylori eradication and to comprehensively assess its effects.

METHODS

This retrospective cohort study used a Japanese nationwide health claims database (April 2009-March 2020), developed by the Japanese Ministry of Health, Labour and Welfare. The database contained almost all health insurance claims data issued in Japan, and specific health check-up data for individuals who took the check-ups. Descriptive statistics were used for the analyses. Patients who received primary eradication therapy were defined as those prescribed medi-cation for H. pylori eradication. New diagnoses, defined as incidence of upper gastrointestinal diseases and IBD, and prevalence of allergic diseases were compared before and after eradication. The incidence and prevalence of each disease were also compared between the 3-year period before eradication (from the 4^th to the 2^nd year prior to the year of eradication) and the 3-year period after eradication (from the 1^st to the 3^rd year after the year of eradication) based on the age category and calendar year and month. Changes in body mass index and proportion of patients with metabolic syndrome (MS) were examined before and after eradication.

RESULTS

We identified 5219731 patients who received primary eradication therapy. The 65-69 years age group had the greatest number of patients in both sexes. There was no significant increase in the incidence of GERD after eradication when considering the effects of aging and reporting period. However, the incidence of BE was higher in the 3-year period after eradication than in the 3-year period before eradication for all age categories (0.02%-0.10% vs < 0.01%-0.05%). The incidence of IBD and prevalence of allergic disease were also higher after eradication. In contrast, the incidence of gastric and duodenal ulcers and gastritis was reduced after eradication. In patients with at least one entry of health check-up data (1701111 patients), the percentage of patients with MS showed a slight increase following eradication (11.0% in the year of eradication and 12.2% after 5 years).

CONCLUSION

The results suggest that H. pylori eradication therapy reduces peptic ulcers and gastritis; however, it is associated with increased incidence of several other chronic diseases.

Crosstalk of Microorganisms and Immune Responses in Autoimmune Neuroinflammation: A Focus on Regulatory T Cells

Regulatory T cells (Tregs) are the major determinant of peripheral immune tolerance. Many Treg subsets have been described, however thymus-derived and peripherally induced Tregs remain the most important subpopulations. In multiple sclerosis, a prototypical autoimmune disorder of the central nervous system, Treg dysfunction is a pathogenic hallmark. In contrast, induction of Treg proliferation and enhancement of their function are central immune evasion mechanisms of infectious pathogens. In accordance, Treg expansion is compartmentalized to tissues with high viral replication and prolonged in chronic infections. In friend retrovirus infection, Treg expansion is mainly based on excessive interleukin-2 production by infected effector T cells. Moreover, pathogens seem also to enhance Treg functions as shown in human immunodeficiency virus infection, where Tregs express higher levels of effector molecules such as cytotoxic T-lymphocyte-associated protein 4, CD39 and cAMP and show increased suppressive capacity. Thus, insights into the molecular mechanisms by which intracellular pathogens alter Treg functions might aid to find new therapeutic approaches to target central nervous system autoimmunity. In this review, we summarize the current knowledge of the role of pathogens for Treg function in the context of autoimmune neuroinflammation. We discuss the mechanistic implications for future therapies and provide an outlook for new research directions.

Association between Helicobacter pylori and risk of childhood asthma: a meta-analysis of 18 observational studies

Objective: The association between Helicobacter pylori (H. pylori) and childhood asthma is unclear. Thus, the aim of this study was to explore the association between H. pylori and childhood asthma.Methods: A literature search, study selection, and data extraction were performed independently and in duplicate. Data were analyzed using STATA software.Results: Eighteen studies enrolling 17,196 children were analyzed. All studies were of moderate-to-high quality. Four studies subcategorized H. pylori infection according to CagA status. Overall, there was a significant negative association between H. pylori and risk for childhood asthma (OR = 0.68; 95% CI, 0.54-0.87; P = 0.002), with no/marginal publication bias identified by the Egger's test and the Begg's test (P = 0.162 and P = 0.198, respectively). The observed inverse association persisted for CagA(+) strains of H. pylori (OR = 0.58; 95% CI, 0.35-0.96; P = 0.034) but not for CagA(-) strains (OR = 0.52; 95% CI, 0.12-2.28; P = 0.387). There was no significant difference between studies with respect to study design, participant age, geographical region, and method of measuring H. pylori.Conclusion: The evidence suggests that H. pylori infection, particularly CagA(+) H. pylori infection, is inversely associated with the risk of childhood asthma. Supplemental data for this article can be accessed at publisher's website.

Th17 Cells in Helicobacter pylori Infection: a Dichotomy of Help and Harm

Helicobacter pylori is a Gram-negative bacterium that infects the gastric epithelia of its human host. Everyone who is colonized with these pathogenic bacteria can develop gastric inflammation, termed gastritis. Additionally, a small proportion of colonized people develop more adverse outcomes, including gastric ulcer disease, gastric adenocarcinoma, or gastric mucosa-associated lymphoid tissue lymphoma. The development of these adverse outcomes is dependent on the establishment of a chronic inflammatory response. The development and control of this chronic inflammatory response are significantly impacted by CD4⁺ T helper cell activity. Noteworthy, T helper 17 (Th17) cells, a proinflammatory subset of CD4⁺ T cells, produce several proinflammatory cytokines that activate innate immune cell antimicrobial activity, drive a pathogenic immune response, regulate B cell responses, and participate in wound healing. Therefore, this review was written to take an intricate look at the involvement of Th17 cells and their affiliated cytokines (interleukin-17A [IL-17A], IL-17F, IL-21, IL-22, and IL-26) in regulating the immune response to H. pylori colonization and carcinogenesis.

Association between infection with Helicobacter pylori and atopy in young Ethiopian children: A longitudinal study

BACKGROUND

Epidemiological evidence from developed countries indicates that Helicobacter pylori infection correlates with a reduced risk of atopy and allergic disorders; however, limited data are available from low-income countries.

OBJECTIVE

We examined associations between H. pylori infection in early childhood and atopy and reported allergic disorders at the age of 6.5 years in an Ethiopian birth cohort.

METHODS

A total of 856 children (85.1% of the 1006 original singletons in a population-based birth cohort) were followed up at age six and half years. An interviewer-led questionnaire administered to mothers provided information on demographic and lifestyle variables. Questions on allergic disease symptoms were based on the International Study of Asthma and Allergies in Children (ISAAC) core allergy and environmental questionnaire. Serum samples were analysed for total IgE levels and anti-H. pylori cytotoxin-associated gene A (CagA) IgG antibody using commercially available ELISA kits. Stool samples were analysed for H. pylori antigen using a rapid immunochromatographic test. The independent effects of H. pylori infection (measured at age of 3, 5 and 6.5 years) on prevalence and incidence of atopy and reported allergic disorders (measured at age of 6.5 years) were determined using multiple logistic regression.

RESULTS

In cross-sectional analysis, current H. pylori infection at age 6.5 years was inversely, though not significantly, related to prevalence of atopy and "any allergic condition" at age 6.5 years. However, detection of H. pylori infection at any point up to age 6.5 years was associated with a significantly reduced odds of both atopy and "any allergic condition" (adjusted OR AOR, 95% CI, 0.54; 0.32-0.92, P = .02, and .31; 0.10-0.94, P = .04, respectively). In longitudinal analyses, H. pylori infection at age 3 was inversely associated with incidence of atopy (AOR, 95% CI, 0.49; 0.27-0.89, P = .02). Furthermore, among H. pylori-infected children, those with a CagA+ strain had a more pronounced reduction in odds of atopy (AOR = 0.35 vs 0.63 for CagA+ vs CagA-), and this reduction reached borderline significance.

CONCLUSION

These data are consistent with the hypothesis that early exposure to H. pylori is inversely associated with atopy and allergic conditions. A possible modest protective association against atopy was observed in those infected with a more virulent CagA+ strain of H. pylori.

Accumulated evidence on Helicobacter pylori infection and the risk of asthma: A meta-analysis

BACKGROUND

Helicobacter pylori (H pylori) infection has been suggested to be related to a decreased risk of asthma, but findings in the literature are inconsistent.

OBJECTIVE

To quantitatively summarize the existing evidence on the association between H pylori infection and asthma risk.

METHODS

The PubMed database was searched for observational studies of H pylori infection in relation to the risk of asthma published in English through May 2017. Measurements of association were pooled using a meta-analytic approach and expressed as odds ratios (ORs) with 95% confidence intervals (95% CIs).

RESULTS

Twenty-four studies were identified in this meta-analysis, including 8 case-control studies composed of 1,247 cases and 2,410 controls, and 16 cross-sectional studies composed of 50,290 participants (4,185 cases and 46,105 noncases). The average H pylori infection rates were 40.01% and 48.74% in case-control and cross-sectional studies, respectively. Five studies subcategorized H pylori infection according to CagA status, in which 59.37% of H pylori-infected participants were identified as having CagA positivity. Helicobacter pylori infection was significantly inversely associated with the risk of asthma in case-control studies (OR 0.83, 95% CI 0.71-0.98) but was borderline significant in cross-sectional studies (OR 0.88, 95% CI 0.76-1.02). The observed inverse association persisted for CagA-positive H pylori infection (OR 0.77, 95% CI 0.63-0.93, P for interaction = .03) but not for CagA-negative strains (OR 1.08, 95% CI 0.66-1.78). No significant difference was observed across age or region subgroups.

CONCLUSION

The accumulated evidence supports that H pylori infection, especially CagA-positive H pylori infection, is inversely associated with the risk of asthma.

Helicobacter, Hygiene, Atopy, and Asthma

The hygiene hypothesis links environmental and microbial exposures in early life to the prevalence of atopy, allergy, and asthma. Helicobacter pylori infection is typically acquired in childhood and acquisition of the infection is associated with poor household hygiene. Some population surveys have shown an inverse association between H. pylori infection and atopy, allergy, and asthma leading to the suggestion that H. pylori infection may be protective against disease; others consider it simply a biomarker for poor household hygiene. We review the relevant surveys, cohort studies, meta-analyses, and studies testing the protective hypothesis. Overall, the results of surveys and cohort studies are inconsistent, whereas meta-analyses show a significant but weak inverse correlation. In contrast, studies directly testing the protection hypothesis in relation to asthma in populations with poor hygiene and low H. pylori prevalence failed to confirm a protective effect. H. pylori is a major cause of human disease including chronic gastritis, peptic ulcer, and gastric malignancies. H. pylori infections most likely serve as a biomarker for poor hygienic conditions in childhood. We conclude that while synergistic interactions between environmental factors in childhood are important determinants of the pathogenesis of atopy, allergy, and asthma; H. pylori is inversely related to good hygiene and thus it's presence serves as a biomarker rather than for a specific prevention role for H. pylori or H. pylori antigens.

ACG Clinical Guideline: Treatment of Helicobacter pylori Infection

Helicobacter pylori (H. pylori) infection is a common worldwide infection that is an important cause of peptic ulcer disease and gastric cancer. H. pylori may also have a role in uninvestigated and functional dyspepsia, ulcer risk in patients taking low-dose aspirin or starting therapy with a non-steroidal anti-inflammatory medication, unexplained iron deficiency anemia, and idiopathic thrombocytopenic purpura. While choosing a treatment regimen for H. pylori, patients should be asked about previous antibiotic exposure and this information should be incorporated into the decision-making process. For first-line treatment, clarithromycin triple therapy should be confined to patients with no previous history of macrolide exposure who reside in areas where clarithromycin resistance amongst H. pylori isolates is known to be low. Most patients will be better served by first-line treatment with bismuth quadruple therapy or concomitant therapy consisting of a PPI, clarithromycin, amoxicillin, and metronidazole. When first-line therapy fails, a salvage regimen should avoid antibiotics that were previously used. If a patient received a first-line treatment containing clarithromycin, bismuth quadruple therapy or levofloxacin salvage regimens are the preferred treatment options. If a patient received first-line bismuth quadruple therapy, clarithromycin or levofloxacin-containing salvage regimens are the preferred treatment options. Details regarding the drugs, doses and durations of the recommended and suggested first-line and salvage regimens can be found in the guideline.

Management of Helicobacter pylori infections

BACKGROUND

Infection with Helicobacter pylori is associated with severe digestive diseases including chronic gastritis, peptic ulcer disease, and gastric cancer. Successful eradication of this common gastric pathogen in individual patients is known to prevent the occurrence of peptic ulcer disease and gastric cancer.

DISCUSSION

With half of the world's population being infected with H, pylori and only few antibiotics result in an effective eradication, a successful antibiotic driven worldwide eradication program seems unlikely. In addition, H. pylori eradication is not always beneficial as it has been described that eradication can be associated with an increased frequency of other disorders such as pediatric asthma, inflammatory bowel diseases and Barrett's Esophagus. We have to accept that eradication of this infection is a two-edged sword that is both useful and harmful and we should therefore focus our H. pylori eradication policy toward selectively identify and destroy only the virulent strains.

CONCLUSION

In order to still be able to effectively treat H. pylori infections in the future we need an alternative diagnostic/treatment algorithm. This would involve a shift towards more precise and enhanced disease predicting diagnosis that tries to identify patients with chance of developing severe diseases such as gastric cancer, rather than the current regime that is geared towards find and destroy all H. pylori.

Outcomes in Patients with Helicobacter pylori Undergoing Laparoscopic Sleeve Gastrectomy

BACKGROUND

In vertical sleeve gastrectomy (VSG), the majority of the stomach is resected and much of the tissue colonized with Helicobacter pylori and the bulk of acid producing cells are removed. In addition, the effect of H. pylori colonization of the stomach of patients undergoing stapling procedures is unclear. As a result, the need for detection and treatment of H. pylori in patients undergoing VSG is unknown.

METHODS

Four hundred and eighty patients undergoing VSG are the subject of this study. Three surgeons at a single institution performed the procedures. The remnant stomach was sent to pathology and tested for the presence of H. pylori using immunohistochemistry. All patients were discharged on proton pump inhibitors.

RESULTS

Of the 480 patients who underwent VSG, 52 were found to be H. pylori positive based on pathology. There was no statistically significant difference in age (p = 0.77), sex (p = 0.48), or BMI (p = 0.39) between the groups. There were 17 readmissions post-op. Five of these were in the H. pylori positive cohort. Six of these complications were classified as severe (anastomotic leak, intra-abdominal collection, or abscess), with two in the H. pylori positive cohort (Table 1). There was no statistically significant difference in the severe complication rates between the two groups (p = 0.67). There were no readmissions for gastric or duodenal ulceration or perforation.

CONCLUSIONS

Our data suggests that there is no increase in early complications in patients with H. pylori undergoing VSG. If these findings are confirmed in a long-term follow-up, it would mean that preoperative H. pylori screening in patients scheduled for VSG is not necessary.

Systems-wide analyses of mucosal immune responses to Helicobacter pylori at the interface between pathogenicity and symbiosis

Helicobacter pylori is the dominant member of the gastric microbiota in over half of the human population of which 5-15% develop gastritis or gastric malignancies. Immune responses to H. pylori are characterized by mixed T helper cell, cytotoxic T cell and NK cell responses. The presence of Tregs is essential for the control of gastritis and together with regulatory CX3CR1+ mononuclear phagocytes and immune-evasion strategies they enable life-long persistence of H. pylori. This H. pylori-induced regulatory environment might contribute to its cross-protective effect in inflammatory bowel disease and obesity. Here we review host-microbe interactions, the development of pro- and anti-inflammatory immune responses and how the latter contribute to H. pylori's role as beneficial member of the gut microbiota. Furthermore, we present the integration of existing and new data into a computational/mathematical model and its use for the investigation of immunological mechanisms underlying initiation, progression and outcomes of H. pylori infection.

Modeling the Regulatory Mechanisms by Which NLRX1 Modulates Innate Immune Responses to Helicobacter pylori Infection

Helicobacter pylori colonizes half of the world’s population as the dominant member of the gastric microbiota resulting in a lifelong chronic infection. Host responses toward the bacterium can result in asymptomatic, pathogenic or even favorable health outcomes; however, mechanisms underlying the dual role of H. pylori as a commensal versus pathogenic organism are not well characterized. Recent evidence suggests mononuclear phagocytes are largely involved in shaping dominant immunity during infection mediating the balance between host tolerance and succumbing to overt disease. We combined computational modeling, bioinformatics and experimental validation in order to investigate interactions between macrophages and intracellular H. pylori. Global transcriptomic analysis on bone marrow-derived macrophages (BMDM) in a gentamycin protection assay at six time points unveiled the presence of three sequential host response waves: an early transient regulatory gene module followed by sustained and late effector responses. Kinetic behaviors of pattern recognition receptors (PRRs) are linked to differential expression of spatiotemporal response waves and function to induce effector immunity through extracellular and intracellular detection of H. pylori. We report that bacterial interaction with the host intracellular environment caused significant suppression of regulatory NLRC3 and NLRX1 in a pattern inverse to early regulatory responses. To further delineate complex immune responses and pathway crosstalk between effector and regulatory PRRs, we built a computational model calibrated using time-series RNAseq data. Our validated computational hypotheses are that: 1) NLRX1 expression regulates bacterial burden in macrophages; and 2) early host response cytokines down-regulate NLRX1 expression through a negative feedback circuit. This paper applies modeling approaches to characterize the regulatory role of NLRX1 in mechanisms of host tolerance employed by macrophages to respond to and/or to co-exist with intracellular H. pylori.

Evaluation of the Correlation Between Childhood Asthma and Helicobacter pylori in Kashan

Background:

Asthma is a chronic inflammatory air-way disease with increasing prevalence rate during the recent years. There are studies about the relationship between asthma and infectious diseases, including the association between asthma and Helicobacter pylori. According to the latest studies, there is an epidemiological correlation between asthma prevalence and prevalence of H. pylori.

Objectives:

The aim of this research was to study the correlation between H. pylori and asthma by biopsy in five to eighteen year-old children who had undergone endoscopy at Shahid Beheshti Hospital.

Patients and Methods:

Three hundred children (5 to 18 years old) undergoing endoscopy owing to gastro-intestinal problems at Shahid Beheshti Hospital were observed for childhood asthma using the Gina 2010 questionnaire which included 24 questions with “yes” and “no” answers to identify asthmatic patients with five positive answers. Next, the patients were referred to an allergy and asthma specialist for clinical examinations, spirometry and post bronchodilator test (Post BD).

Results:

Among 138 H. pylori positive patients, eight cases (5.8 %) were asthmatic while of the 162 H. pylori negative patients 28 (17.3%) were asthmatic. This difference was statistically significant (P Value = 0.002). The correlation between H. pylori and asthma was studied after controlling the confounding variables including, gender, age and family history. The results obtained for the above-mentioned variables were significant (P Values of 0.004, 0.005 and 0.002, and Odd-Ratio Mantel Haenszel (ORMH) of 3.38, 3.24 and 4.06, respectively).

Conclusions:

Our findings showed that there is an inverse correlation between H. pylori and asthma. Performing more studies with larger sample sizes is necessary to confirm these results.

Helicobacter pylori infection as a protective factor against multiple sclerosis risk in females

BACKGROUND

In recent years, a relationship between Helicobacter pylori and many disease conditions has been reported, however, studies in its relationship with multiple sclerosis (MS) have had contradictory results.

OBJECTIVE

To determine the association between the H. pylori infection and MS.

METHODS

550 patients with MS were included in the study and were matched by gender and year of birth to 299 controls. Patients were assessed for clinical and demographic parameters. An enzyme immunoassay was used to detect the presence of specific IgG antibodies against H. pylori in the serum sample of both groups.

RESULTS

H. pylori seropositivity was found to be lower in the patients with MS than in controls (16% vs 21%) with the decrease pertaining to females (14% vs 22%, p=0.027) but not males (19% vs 20%, p=1.0). When adjusted for age at onset, year of birth and disease duration, H. pylori seropositive females presented with a lower disability score than seronegative females (p=0.049), while among males the reverse was true (p=0.025). There was no significant association between H. pylori seropositivity and relapse rate.

CONCLUSIONS

Our results could reflect a protective role of H. pylori in the disease development. However, it may be that H. pylori infection is a surrogate marker for the 'hygiene hypothesis', a theory which postulates that early life infections are essential to prime the immune system and thus prevent allergic and autoimmune conditions later in life. The fact that the association between H. pylori seropositivity and MS risk was seen almost exclusively in females requires further investigation.

Helicobacter pylori-Mediated Protection against Extra-Gastric Immune and Inflammatory Disorders: The Evidence and Controversies

A large number of studies link H. pylori infection with a reduced risk of developing extra-gastric conditions such as allergy, asthma, inflammatory bowel disease, coeliac disease and multiple sclerosis. The strength of the evidence for these protective associations is quite variable, and published studies often do not agree. This review article discusses some of the reasons for these discrepancies, and the difficulties faced when designing studies. Examples of some protective disease associations are described in detail, where the evidence is most abundant and thought to be more reliable. The most convincing of these are supported by published mechanistic data, for example with animal models, or incidence of disease exacerbation in humans following H. pylori eradication. Although controversial, this field is very important as the prevalence of H. pylori is decreasing throughout the world whilst many chronic diseases are becoming more common. These trends are likely to continue in the future, therefore it is important that we fully understand if and how H. pylori confers protection.

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.

Helicobacter pylori infection and atopic diseases: Is there a relationship? A systematic review and meta-analysis

AIM: To review and conduct a meta-analysis of the existing literature on the relationship between Helicobacter pylori (H. pylori), atopy and allergic diseases.

METHODS: Studies published in English assessing the prevalence of atopy and/or allergic diseases in patients with H. pylori infection and the prevalence of H. pylori infection in patients with atopy and/or allergic diseases were identified through a MEDLINE search (1950-2014). Random-effect model was used for the meta-analysis.

RESULTS: Pooled results of case-control studies showed a significant inverse association of H. pylori infection with atopy/allergic disease or with exclusively atopy, but not with allergic disease, whereas pooled results of cross-sectional studies showed only a significant association between allergic disease and H. pylori infection.

CONCLUSION: There is some evidence of an inverse association between atopy/allergic diseases and H. pylori infection, although further studied are needed.

Extraintestinal manifestations of Helicobacter pylori: A concise review

Helicobacter pylori (H. pylori) infection has been clearly linked to peptic ulcer disease and some gastrointestinal malignancies. Increasing evidence demonstrates possible associations to disease states in other organ systems, known as the extraintestinal manifestations of H. pylori. Different conditions associated with H. pylori infection include those from hematologic, cardiopulmonary, metabolic, neurologic, and dermatologic systems. The aim of this article is to provide a concise review of the evidence that supports or refutes the associations of H. pylori and its proposed extraintestinal manifestations. Based on data from the literature, PUD, mucosal associated lymphoid tumors lymphoma, and gastric adenocarcinoma has well-established links. Current evidence most supports extraintestinal manifestations with H. pylori in immune thrombocytopenic purpura, iron deficiency anemia, urticaria, Parkinson’s, migraines and rosacea; however, there is still plausible link with other diseases that requires further research.

Systems modeling of the role of interleukin-21 in the maintenance of effector CD4+ T cell responses during chronic Helicobacter pylori infection

The development of gastritis during Helicobacter pylori infection is dependent on an activated adaptive immune response orchestrated by T helper (Th) cells. However, the relative contributions of the Th1 and Th17 subsets to gastritis and control of infection are still under investigation. To investigate the role of interleukin-21 (IL-21) in the gastric mucosa during H. pylori infection, we combined mathematical modeling of CD4(+) T cell differentiation with in vivo mechanistic studies. We infected IL-21-deficient and wild-type mice with H. pylori strain SS1 and assessed colonization, gastric inflammation, cellular infiltration, and cytokine profiles. Chronically H. pylori-infected IL-21-deficient mice had higher H. pylori colonization, significantly less gastritis, and reduced expression of proinflammatory cytokines and chemokines compared to these parameters in infected wild-type littermates. These in vivo data were used to calibrate an H. pylori infection-dependent, CD4(+) T cell-specific computational model, which then described the mechanism by which IL-21 activates the production of interferon gamma (IFN-γ) and IL-17 during chronic H. pylori infection. The model predicted activated expression of T-bet and RORγt and the phosphorylation of STAT3 and STAT1 and suggested a potential role of IL-21 in the modulation of IL-10. Driven by our modeling-derived predictions, we found reduced levels of CD4(+) splenocyte-specific tbx21 and rorc expression, reduced phosphorylation of STAT1 and STAT3, and an increase in CD4(+) T cell-specific IL-10 expression in H. pylori-infected IL-21-deficient mice. Our results indicate that IL-21 regulates Th1 and Th17 effector responses during chronic H. pylori infection in a STAT1- and STAT3-dependent manner, therefore playing a major role controlling H. pylori infection and gastritis. Importance: Helicobacter pylori is the dominant member of the gastric microbiota in more than 50% of the world's population. H. pylori colonization has been implicated in gastritis and gastric cancer, as infection with H. pylori is the single most common risk factor for gastric cancer. Current data suggest that, in addition to bacterial virulence factors, the magnitude and types of immune responses influence the outcome of colonization and chronic infection. This study uses a combined computational and experimental approach to investigate how IL-21, a proinflammatory T cell-derived cytokine, maintains the chronic proinflammatory T cell immune response driving chronic gastritis during H. pylori infection. This research will also provide insight into a myriad of other infectious and immune disorders in which IL-21 is increasingly recognized to play a central role. The use of IL-21-related therapies may provide treatment options for individuals chronically colonized with H. pylori as an alternative to aggressive antibiotics.

Helicobacter pylori infection and extragastric disorders in children: a critical update

Helicobacter pylori (H. pylori) is a highly prevalent, serious and chronic infection that has been associated causally with a diverse spectrum of extragastric disorders including iron deficiency anemia, chronic idiopathic thrombocytopenic purpura, growth retardation, and diabetes mellitus. The inverse relation of H. pylori prevalence and the increase in allergies, as reported from epidemiological studies, has stimulated research for elucidating potential underlying pathophysiological mechanisms. Although H. pylori is most frequently acquired during childhood in both developed and developing countries, clinicians are less familiar with the pediatric literature in the field. A better understanding of the H. pylori disease spectrum in childhood should lead to clearer recommendations about testing for and treating H. pylori infection in children who are more likely to develop clinical sequelae. A further clinical challenge is whether the progressive decrease of H. pylori in the last decades, abetted by modern clinical practices, may have other health consequences.

Predictive computational modeling of the mucosal immune responses during Helicobacter pylori infection

T helper (Th) cells play a major role in the immune response and pathology at the gastric mucosa during Helicobacter pylori infection. There is a limited mechanistic understanding regarding the contributions of CD4+ T cell subsets to gastritis development during H. pylori colonization. We used two computational approaches: ordinary differential equation (ODE)-based and agent-based modeling (ABM) to study the mechanisms underlying cellular immune responses to H. pylori and how CD4+ T cell subsets influenced initiation, progression and outcome of disease. To calibrate the model, in vivo experimentation was performed by infecting C57BL/6 mice intragastrically with H. pylori and assaying immune cell subsets in the stomach and gastric lymph nodes (GLN) on days 0, 7, 14, 30 and 60 post-infection. Our computational model reproduced the dynamics of effector and regulatory pathways in the gastric lamina propria (LP) in silico. Simulation results show the induction of a Th17 response and a dominant Th1 response, together with a regulatory response characterized by high levels of mucosal Treg) cells. We also investigated the potential role of peroxisome proliferator-activated receptor γ (PPARγ) activation on the modulation of host responses to H. pylori by using loss-of-function approaches. Specifically, in silico results showed a predominance of Th1 and Th17 cells in the stomach of the cell-specific PPARγ knockout system when compared to the wild-type simulation. Spatio-temporal, object-oriented ABM approaches suggested similar dynamics in induction of host responses showing analogous T cell distributions to ODE modeling and facilitated tracking lesion formation. In addition, sensitivity analysis predicted a crucial contribution of Th1 and Th17 effector responses as mediators of histopathological changes in the gastric mucosa during chronic stages of infection, which were experimentally validated in mice. These integrated immunoinformatics approaches characterized the induction of mucosal effector and regulatory pathways controlled by PPARγ during H. pylori infection affecting disease outcomes.

Helicobacter pylori infection in a pig model is dominated by Th1 and cytotoxic CD8+ T cell responses

Helicobacter pylori infection is the leading cause for peptic ulcer disease and gastric adenocarcinoma. Mucosal T cell responses play an important role in mediating H. pylori-related gastric immunopathology. While induced regulatory T (iTreg) cells are required for chronic colonization without disease, T helper 1 (Th1) effector responses are associated with lower bacterial loads at the expense of gastric pathology. Pigs were inoculated with either H. pylori strain SS1 or J99. Phenotypic and functional changes in peripheral blood mononuclear cell (PBMC) populations were monitored weekly, and mucosal immune responses and bacterial loads were assessed up to 2 months postinfection. Both H. pylori strains elicited a Th1 response characterized by increased percentages of CD4(+)Tbet(+) cells and elevated gamma interferon (IFN-γ) mRNA in PBMCs. A subset of CD8(+) T cells expressing Tbet and CD16 increased following infection. Moreover, a significant increase in perforin and granzyme mRNA expression was observed in PBMCs of infected pigs, indicating a predominant cytotoxic immune response. Infiltration of B cells, myeloid cells, T cells expressing Treg- and Th17-associated transcription factors, and cytotoxic T cells was found in the gastric lamina propria of both infected groups. Interestingly, based on bacterial reisolation data, strain SS1 showed greater capacity to colonize and/or persist in the gastric mucosa than did strain J99. This novel pig model of infection closely mimics human gastric pathology and presents a suitable avenue for studying effector and regulatory responses toward H. pylori described in humans.

Association between Helicobacter pylori and asthma: a meta-analysis

OBJECTIVE

Helicobacter pylori infection is recognized as a worldwide public health threat. Some studies have suggested that individuals with asthma have a lower rate of H. pylori infection, but the relation remains controversial. This meta-analysis was carried out to quantify the association between H. pylori infection and asthma.

METHODS

Published information on the prevalence of H. pylori in individuals with asthma was collected to assess the potential associations between H. pylori infection and the risk of asthma. Fourteen eligible studies were selected for analysis. Data on the study populations, detection method of H. pylori, and publication year were summarized. Meta-regression models and subgroup analyses were established to screen the factors resulting in heterogeneity.

RESULTS

Of the 106 articles retrieved, 14 fulfilled the inclusion criteria. The 14 studies involved 28 283 patients, with a total H. pylori infection rate of 40.53%. This meta-analysis found a significantly lower rate of H. pylori infection in the asthmatics than in the controls (odds ratio=0.84, 95% confidence interval: 0.73-0.96, P=0.013). Subgroup analysis indicated a similar infection rate of CagA-positive H. pylori infection in the asthmatic group and the control group (odds ratio=0.73, 95% confidence interval: 0.41-1.28, P=0.03).

CONCLUSION

The pooled data suggest that asthmatics have a significantly lower rate of H. pylori infection. Large-scale and multicenter studies should be carried out to further determine the relation between this bacterium and allergic disorders.

The role of Helicobacter pylori infection in the development of allergic asthma

Asthma is one of the most prevalent chronic diseases in developed countries, with steady increases in asthma prevalence evident, particularly in the last few decades. As genetic factors are unlikely to contribute to the rise in asthma prevalence, changes in lifestyle and exposure to environmental stimuli have been proposed to account for this trend. The 'disappearing microbiota' hypothesis postulates that major shifts in the human microbiome, resulting from dramatic lifestyle changes, account for the increase in asthma prevalence. In this context, persistent gastric colonization with the human-specific pathogen Helicobacter pylori has been negatively associated with the occurrence of asthma in epidemiological studies. In addition, experimental models of allergic airway disease revealed a direct link between infection with H. pylori and suppression of allergic airway disease through the induction of regulatory T cells. These and other new insights hold the promise of opening up new avenues toward the development of innovative, new strategies directed at asthma treatment and prevention.

The association between asthma and Helicobacter pylori: a meta-analysis

OBJECTIVE

The severity and incidence of asthma have increased drastically in the developed nations of the world over the last decades. Currently, some evidences indicate an inverse association between Helicobacter pylori and asthma, but some studies did not get the same conclusion. To make this question clear, we systematically reviewed the published evidence for an association between H. pylori infection and asthma.

METHODS

Medline and SCI databases up to April 2012 were searched to identify studies that evaluated the association between H. pylori and asthma. Relevant publications were searched using the following keywords or synonyms: asthma or Helicobacter pylori. Methodologic quality was scored by using a standardized list of criteria, and meta-analysis was conducted to calculate crude odds ratios (ORs) with 95% confidence intervals (CIs).

RESULTS

Nineteen studies met our inclusion criteria: nine cross-sectional studies, seven case-control studies, and three prospective cohort studies. The overall methodologic quality score was high. Pooled ORs for the association between asthma and H. pylori infection were 0.84 (95% CI: 0.74-0.96) in nine cross-sectional studies, 0.94 (95% CI: 0.79-1.12) in seven case-control studies, and 0.82 (95% CI: 0.53-1.27) in three cohort studies. The pooled OR for all included studies was 0.81 (95% CI: 0.72-0.91) in children and 0.88 (95% CI: 0.71-1.08) in adults.

CONCLUSIONS

We found a weak evidence for an inverse association between asthma and H. pylori infection both in children and in adults.

Helicobacter pylori colonization ameliorates glucose homeostasis in mice through a PPAR γ-dependent mechanism

Background

There is an inverse secular trend between the incidence of obesity and gastric colonization with Helicobacter pylori, a bacterium that can affect the secretion of gastric hormones that relate to energy homeostasis. H. pylori strains that carry the cag pathogenicity island (PAI) interact more intimately with gastric epithelial cells and trigger more extensive host responses than cag⁻ strains. We hypothesized that gastric colonization with H. pylori strains differing in cag PAI status exert distinct effects on metabolic and inflammatory phenotypes.

Methodology/Principal Findings

To test this hypothesis, we examined metabolic and inflammatory markers in db/db mice and mice with diet-induced obesity experimentally infected with isogenic forms of H. pylori strain 26695: the cag PAI wild-type and its cag PAI mutant strain 99–305. H. pylori colonization decreased fasting blood glucose levels, increased levels of leptin, improved glucose tolerance, and suppressed weight gain. A response found in both wild-type and mutant H. pylori strain-infected mice included decreased white adipose tissue macrophages (ATM) and increased adipose tissue regulatory T cells (Treg) cells. Gene expression analyses demonstrated upregulation of gastric PPAR γ-responsive genes (i.e., CD36 and FABP4) in H. pylori-infected mice. The loss of PPAR γ in immune and epithelial cells in mice impaired the ability of H. pylori to favorably modulate glucose homeostasis and ATM infiltration during high fat feeding.

Conclusions/Significance

Gastric infection with some commensal strains of H. pylori ameliorates glucose homeostasis in mice through a PPAR γ-dependent mechanism and modulates macrophage and Treg cell infiltration into the abdominal white adipose tissue.

The impact of Helicobacter pylori on atopic disorders in childhood

BACKGROUND

 The prevalence of Helicobacter pylori in Western populations has steadily decreased. This has been suggested as one of the factors involved in the recent increase of asthma and allergy. Some studies have reported a negative association between H. pylori and asthma and allergy, but data are inconsistent and there are a few studies in children.

AIM

 We investigated whether the prevalence of H. pylori was associated with asthma symptoms, allergic rhinitis, and atopic dermatitis in childhood.

METHODS

 We determined IgG anti-H. pylori and CagA antibodies in serum of Dutch children, who took part in the PIAMA birth cohort study. Serum was collected from 545 children, aged 7-9 years (Dutch ethnicity 91.5%). Symptoms of asthma and atopy were assessed by yearly questionnaires. Chi-square tests and logistic regression were used.

RESULTS

 We found 9%H. pylori and 0.9% CagA seropositivity. Twelve (5.9%) children with reported wheezing ever were H. pylori positive, compared to 37 (10.9%) of the non-wheezers (p = .05). No significant differences in H. pylori prevalence were found between children with or without allergic rhinitis (8.5% vs 9.5%), atopic dermatitis (8.7% vs 9.2%), and physician-diagnosed asthma (7.1% vs 9.4%). Multivariate analysis showed no significant associations between H. pylori seropositivity and wheezing (OR 0.52; 95% CI 0.25-1.06), allergic rhinitis (OR 0.96; 95% CI 0.51-1.81), atopic dermatitis (OR 1.05; 95% CI 0.56-1.98) or physician-diagnosed asthma (OR 0.87; 95% CI 0.37-2.08).

CONCLUSION

 We found a borderline significantly lower H. pylori seropositivity in children with wheezing compared to non-wheezers, but no association between H. pylori serum-antibody status and allergic rhinitis, atopic dermatitis, or asthma.

The immunomodulatory properties of Helicobacter pylori confer protection against allergic and chronic inflammatory disorders

Chronic infection with the gastric bacterial pathogen Helicobacter pylori causes gastritis and predisposes carriers to a high risk of developing gastric and duodenal ulcers, gastric cancer, and gastric lymphoma, but has also recently been shown to protect against certain allergic and chronic inflammatory disorders. The immunomodulatory properties that allow the bacteria to persist for decades in infected individuals in the face of a vigorous, yet ultimately non-protective, innate, and adaptive immune response may at the same time confer protection against allergies, asthma, and inflammatory bowel diseases. Experimental evidence from mouse models suggests that H. pylori has evolved to skew the adaptive immune response toward immune tolerance rather than immunity, which promotes persistent infection on the one hand, and inhibits auto-aggressive and allergic T-cell responses on the other. Regulatory T-cells mediating peripheral immune tolerance have emerged as key cellular players in facilitating persistent infection as well as protection from allergies, in both observational studies in humans and experimental work in mice. Recent data suggest that H. pylori actively targets dendritic cells to promote tolerance induction. The findings discussed in this review raise the possibility of harnessing the immunomodulatory properties of H. pylori for the prevention and treatment of allergic and auto-immune diseases, and also provide new insights relevant for H. pylori-specific vaccine development.

Inverse association between Helicobacter pylori and pediatric asthma in a high-prevalence population

BACKGROUND

Helicobacter pylori-associated disease has led to aggressive diagnostic and eradication protocols that are partially responsible for the decrease in prevalence of H. pylori carriage. Recent evidence indicates that in low-prevalence populations, H. pylori may have protective effects on allergic diseases. The aim of this study was to explore the relationship between pediatric asthma and H. pylori infection in a population with high prevalence of H. pylori infection.

MATERIALS AND METHODS

A national referral laboratory was screened for all (13) C urea breath tests performed in children aged 5-18 years between 2007 and 2008, for patient demographics and physician-diagnosed asthma. Data concerning asthma-associated medication usage were extracted from electronic medical records and databases. Data were analyzed using a stepwise logistic regression model.

RESULTS

During the study period, 6959 patients underwent urea breath testing (average age 12.4±3.5years). Of these, 3175/6959 (45.6%) were positive for H. pylori, and 578/6959 (8.3%) had asthma. Rates of asthma in H. pylori-positive and H. pylori-negative children were 7.3 and 9.1%, respectively (odds ratio 0.82; 95% confidence interval (CI) 0.69-0.98; p=.032). We also confirmed that male gender, urban residence, and age are associated with childhood asthma.

CONCLUSIONS

We demonstrate an inverse association between H. pylori and pediatric asthma in a population with a high prevalence of H. pylori.

Is Helicobacter pylori infection associated with asthma risk? A meta-analysis based on 770 cases and 785 controls

OBJECTIVE

Helicobacter pylori (H. pylori) infection has been thought to play a critical role in disorders such as gastric and lung cancer. A number of studies have been devoted to the relationship between H. pylori infection and asthma risk, which have generated inconclusive results. In this study we aimed to derive a more precise estimation of the relationship.

METHODS

Meta-analyses evaluating the association of H. pylori infection and asthma risk were conducted and subgroup analyses on ethnicity and source of controls as well as CagA status were further conducted. Eligible studies were identified for the period up to Jul 2012.

RESULTS

A total of five case-control studies comprising 770 cases and 785 controls were lastly selected for analysis. The overall data failed to indicate a significant association of H. pylori infection and asthma risk (OR=1.01; 95%CI=0.82-1.24). Likewise, in the subgroup analysis regarding ethnicity, source of controls and CagA status, no associations could be observed.

CONCLUSIONS

The pooled data failed to suggest a marked association between H. pylori infection and asthma risk. Future studies are needed to confirm this conclusion.

The effect of Helicobacter pylori on asthma and allergy

Current evidence indicates an inverse association between Helicobacter pylori and asthma and allergy. H. pylori is a Gram-negative bacterium which represents the major cause of peptic ulcer and gastric cancer, and preferentially elicits a T helper (Th)-1 response. Many H. pylori factors, such as the neutrophil-activating factor of H. pylori (HP-NAP), are able to drive Th-1 polarization and to display a powerful inhibition of allergic Th-2 response. This article proposes an overview of the actual knowledge about the effects of H. pylori on asthma and allergy. Special attention has been drawn to HP-NAP as a potential novel strategy for the prevention and treatment of asthma and atopy.

Inverse association between Helicobacter pylori infection and allergic rhinitis in young Japanese

BACKGROUND AND AIM

The prevalence of allergic disorders, including asthma, atopic dermatitis, and allergic rhinitis has been increasing, and the prevalence of Helicobacter pylori (H. pylori) infection has been decreasing. Chronic bacterial infection during childhood is reported to protect the development of allergic diseases. The aim of the present study was to identify whether H. pylori infection influences the prevalence of allergic rhinitis, which has become a serious social problem, especially in the developed countries.

METHODS

We initially investigated the association between the prevalence of H. pylori and pollinosis symptoms in 97 healthy volunteers. We had investigated the association between the serum H. pylori-immunoglobulin (Ig) G antibodies and specific IgE antibodies for pollen, mites, and house dust in 211 consecutive patients.

RESULTS

There were 52.2% (36/69) of H. pylori-negative volunteers with allergic symptoms, which was significantly higher than H. pylori-positive volunteers (14.3%, 4/28, P < 0.05). The risk of pollinosis symptoms by H. pylori infection was 0.148 (95% confidence interval): 0.046-0.475, P < 0.05). The prevalence of H. pylori infection increased according to age, whereas that of specific IgE-positive patients gradually decreased. Among the IgE-positive patients, the prevalence of H. pylori-negative patients was significantly higher than H. pylori-positive patients who were younger in age (P < 0.05).

CONCLUSION

H. pylori infection decreased the pollinosis effects, especially among the younger volunteers. However, the prevalence of pollinosis in patients who were 50 years or older were almost same between H. pylori-positive and H. pylori-negative patients; therefore, the recent increase of pollinosis might relate to not only H. pylori infection, but also change in social environment.

Clinical aspects of pediatric food allergy and failed oral immune tolerance

Food allergy seems to represent a new spectrum of disease that has elicited significant community concern and extended waiting lists for allergists and gastroenterologists alike. The apparent rise in prevalence of IgE-mediated food allergy (and associated risk of anaphylaxis) has been postulated to result from effects of a "modern lifestyle" but as yet clear environmental risk factors have not yet emerged. Family history seems to contribute to risk suggesting that gene-environment interactions will be important for identifying a subpopulation with increased susceptibility to any identified lifestyle effects. Non-IgE-mediated food allergy (including food-induced enteropathies and colitides, eosinophilic esophagitis, and Crohn's disease) with potentially similar environmental triggers resulting in diverse immune dysregulatory mechanisms. The evidence underpinning the putative rise in food allergy is discussed and potential mechanisms of disease explored. Clinical aspects of various food allergic conditions including non-IgE-mediated food allergy are outlined.

The interaction between Helicobacter pylori and atopy: does inverse association really exist?

AIM

To date, cross-sectional and case-control studies suggest an inverse association between Helicobacter pylori infection and atopic diseases, whereas the immunologic basis has not been studied yet. In this study we investigated T helper (Th) cell function in H. pylori-infected children and compared cytokine responses in atopic and non-atopic groups.

METHODS

The study groups was recruited from a cohort of 327 healthy children evaluated and followed-up for 6 years to assess the natural history of H. pylori infection. Seventy-four of 136 healthy children who underwent (13)C urea breath test were eligible and accepted to participate. All participants were evaluated by a questionnaire, and skin-prick testing. According to the results, children were divided into four groups with respect to the presence or absence of H. pylori and atopy. Peripheral blood mononuclear cells isolated from 34 of 74 children were cultured with H. pylori, Der p 1, and phytohemagglutinin (PHA). Interferon-gamma (IFN-gamma), interleukin (IL)-4 and IL-10, transforming growth factor-beta (TGF-beta) levels were measured in supernatants.

RESULTS

The frequency of atopy was lower in H. pylori-infected group (31.9% vs. 48.1, p = .22), while atopic symptoms were similar between infected and non-infected children. While PHA and H. pylori induced IFN-gamma levels were significantly higher in H. pylori-infected children, concomitant presence of both atopy and H. pylori decreased the level of PHA and H. pylori induced IFN-gamma production. PHA and Der p 1-induced IL-4 levels were higher in atopic children, and IL-4 production was suppressed when they were concomitantly infected with H. pylori. The production of TGF-beta was found to be suppressed in atopic children irrespective of the presence of H. pylori infection.

CONCLUSION

The results of the current study demonstrated a counteractive Th1 and Th2 cytokine interaction between H. pylori infection and atopy. However, this counteractive immunologic balance did not protect against atopy.

Helicobacter pylori infection in children

The review summarizes the articles published on Helicobacter pylori in children between April 2007 and March 2008. Evidence is emerging in different populations including developing countries that the prevalence of H. pylori is declining in all age groups. The reasons for this are unclear but it is unlikely that treatment of infection or improvement in socioeconomic conditions fully explains the decline. For the first time, differences in the inflammatory response between adults and children have been well characterized in a group of adults and children from Chile with similar levels of H. pylori infection. This study suggests that the reduced inflammatory response to H. pylori at a cellular level in children could be the consequence of an enhanced Treg cell response, which in turn down-regulates H. pylori-induced inflammation. The publication of the Paediatric European Register for Treatment of Helicobacter pylori study (PERTH) is important as it demonstrates the advantages of different centers working in collaboration for the benefit of children. It also highlights the fact that while bismuth-based treatment is more effective than proton pump inhibitor-based treatment in children, bismuth preparations are not widely available for use in children.

Role of Helicobacter pylori Infection in the treatment and outcome of chronic urticaria

INTRODUCTION

Chronic urticaria is thought to have numerous causative factors including a large variety of infectious conditions, food intake, and drugs. The impact of Helicobacter pylori infection has been studied with ambiguous results. The aim of this study was to investigate the course of chronic urticaria in H. pylori-positive patients undergoing eradication compared to H. pylori-negative urticaria patients.

PATIENTS AND METHODS

We included 74 urticaria patients with positive H. pylori breath test and 74 age- and sex-matched H. pylori-negative controls. All urticaria patients underwent an extensive diagnostic work-up to search for trigger foci. H. pylori-infected patients were submitted to eradication therapy. Mean follow-up time was 58 months.

RESULTS

Neither the prevalence of H. pylori nor the eradication therapy had an influence on the clinical course of chronic urticaria. In 81.1% of H. pylori-infected patients at least one additional infectious focus was found. Nevertheless, it could be shown that individuals that described any kind of symptom relief presented with higher serum IgE levels at diagnosis (198.1 vs 115.7 kU/L, p= .027) but this effect was independent of H. pylori infection.

CONCLUSIONS

In conclusion there is no evidence that eradication of H. pylori improves the outcome in patients with chronic urticaria. The high rate of spontaneous remission and the coexistence of multiple foci will always obscure the evaluation of any specific antimicrobial therapy.

Helicobacter pylori-infection status and childhood living conditions are associated with signs of allergic diseases in an occupational population

This study assessed the hypothesis that Helicobacter pylori infection and specific living conditions in childhood are associated with allergic outcomes. A cross-sectional survey containing retrospective questions concerning childhood was performed in an occupational population in 2001. This survey included self-administered questionnaire data and stool tests. An inverse association between positive H. pylori infection status and physician diagnosis of allergy/12 month period of anti-allergic medication was observed in a logistic regression model, adjusted for potential confounders (age, sex, nationality, smoking status and education of the participant) (OR 0.26, 95% CI: 0.08-0.84). In addition, childhood living conditions were associated with H. pylori infection status and signs of allergies. In line with the "hygiene hypothesis" our model supports an inverse association between early childhood infection with H. pylori and allergic disease in adulthood.

Helicobacter pylori infection and allergic diseases: epidemiological study in Japanese university students

BACKGROUND AND AIM

A negative association between Helicobacter pylori infection and allergic diseases has not been consistent. The aim of this study was to examine the association between allergic diseases and H. pylori infection in Japan.

METHODS

Newly enrolled university students completed health survey questionnaires regarding general health and the presence of allergic diseases. Helicobacter pylori status was determined by the presence of serum H. pylori IgG and the presence of allergic manifestations was confirmed by interview.

RESULTS

A total of 1953 students had a routine health survey; H. pylori status was determined in 777 including 369 with allergic diseases and 408 controls. The reported frequency of allergic rhinoconjunctivitis, atopic dermatitis, urticaria, bronchial asthma and mixed diseases was 29.0%, 11.1%, 2.0%, 0.9% and 5.0%, respectively. Helicobacter pylori infection was diagnosed less frequently in the allergic group compared with controls (11.4% vs 17.6%, P = 0.015). Helicobacter pylori infection was less frequent in men with allergic diseases (OR 0.49, 95% CI 0.27-0.89).

CONCLUSION

Allergic diseases are frequent in young Japanese adults and are negatively associated with H. pylori infection especially in men.

Helicobacter pylori in allergic inflammation--fact or fiction?

BACKGROUND

Although it has been hypothesized that infections may play a preventive role in allergic diseases, the role of Helicobacter pylori (H. pylori) is not clear. In this study we aimed to determine the association between H. pylori infection and allergic inflammation.

METHODS

H. pylori infection was assessed in gastric mucosa tissue by microscopy. Skin prick tests (SPT) were performed with a battery of common inhalant and certain food allergens. Serum samples were tested for total immunoglobulin E (T.IgE). Predictive factors for H. pylori infection and atopy were examined by a questionnaire.

RESULTS

A total of 90 subjects suffering dyspeptic symptoms were enrolled into the study. SPT positivity was similar between H. pylori (+) and H. pylori (-) subjects. Among the possible factors examined: age; gender; educational status; pet at home; BMI, family size; number of children and siblings; monthly income; drinking water source; smoking; and serum T.IgE levels were not related with H. pylori infection. However, perennial allergic symptoms were significantly higher in the H. pylori (-) group, seasonal allergic symptoms were related with an increased risk for H. pylori infection.

CONCLUSIONS

In this sample group from a developing country H. pylori infection was not shown to be associated with atopic diseases. Therefore, the eradication of H. pylori may not be assumed to have an effect on allergic inflammation.