Exposure to Helicobacter pylori infection in early childhood and the risk of allergic disease and atopic sensitization: a longitudinal birth cohort study

Helicobacter pylori infection in infant rhesus macaque monkeys is associated with an altered lung and oral microbiome

It is estimated that more than half of the world population has been infected with Helicobacter pylori. Most newly acquired H. pylori infections occur in children before 10 years of age. We hypothesized that early life H. pylori infection could influence the composition of the microbiome at mucosal sites distant to the stomach. To test this hypothesis, we utilized the infant rhesus macaque monkey as an animal model of natural H. pylori colonization to determine the impact of infection on the lung and oral microbiome during a window of postnatal development. From a cohort of 4-7 month-old monkeys, gastric biopsy cultures identified 44% of animals infected by H. pylori. 16S ribosomal RNA gene sequencing of lung washes and buccal swabs from animals showed distinct profiles for the lung and oral microbiome, independent of H. pylori infection. In order of relative abundance, the lung microbiome was dominated by the phyla Proteobacteria, Firmicutes, Bacteroidota, Fusobacteriota, Campilobacterota and Actinobacteriota while the oral microbiome was dominated by Proteobacteria, Firmicutes, Bacteroidota, and Fusobacteriota. In comparison to the oral cavity, the lung was composed of more genera and species that significantly differed by H. pylori status, with a total of 6 genera and species that were increased in H. pylori negative infant monkey lungs. Lung, but not plasma IL-8 concentration was also associated with gastric H. pylori load and lung microbial composition. We found the infant rhesus macaque monkey lung harbors a microbiome signature that is distinct from that of the oral cavity during postnatal development. Gastric H. pylori colonization and IL-8 protein were linked to the composition of microbial communities in the lung and oral cavity. Collectively, these findings provide insight into how H. pylori infection might contribute to the gut-lung axis during early childhood and modulate future respiratory health.

Prevalence and associated risk factors of Helicobacter pylori infection in East Africa: a systematic review and meta-analysis

BACKGROUND

Helicobacter pylori is the main cause of chronic gastritis, peptic ulcer, lymphoma, and gastric cancer in humans. The prevalence and factors associated with H. pylori infection are varied across countries. Thus, a comprehensive review has not been done on prevalence and associated factors in East Africa. Therefore, this systematic review and meta-analysis aimed to estimate the pooled prevalence and identify factors associated with H. pylori infection in East Africa.

METHODS

Articles written in English language were retrieved from PubMed, Scopus, and Science Direct. Relevant articles were selected and screened using Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines. Publication bias was assessed qualitatively and qualitatively using funnel plot symmetry and Egger's test, respectively. Heterogeneity was assessed using the I2 measure. Data were analyzed using Stata software, version 14, and the "metan" command.

RESULTS

A total of 231 articles were retrieved from nineteen countries in East Africa. Of these, 70 articles were eligible for the review. The pooled prevalence of H. pylori in East Africa was 50.98% (95% CI: 45.05-56.90). The prevalence of H. pylori infection ranged from 7.7 to 94.5% in East African countries. The highest pooled prevalence was from Sudan (61.3%, 95% CI: 52.6-69.9), and the lowest prevalence was reported from Uganda (40.7%, 95% CI: 33-48.3). Persons with no formal education (OR: 2.03; 95% CI: 1.22-2.83), lack of hand washing habit after toilet (OR: 2.24; 95% CI: 1.45-3.02), having a history of dyspepsia (OR: 2.25; 95% CI: 1.31-3.18), living in rural areas (OR = 1.80; 95% CI: 0.38-3.23), and having unclean water source (OR = 1.5; 95% CI:0.45-3.45) were all associated with higher risk for H. pylori infection.

CONCLUSION

More than half of the populations of East African countries were positive for H. pylori infection. Rural residence, source of water, and alcohol consumption were significantly associated with H. pylori infection. Therefore, healthcare workers could provide health education on the aforementioned risk factors, and the government and other stakeholders could improve the source of drinking water in East Africa.

Update on the association between Helicobacter pylori infection and asthma in terms of microbiota and immunity

H. pylori is a gram-negative bacterium that is usually acquired in childhood and can persistently colonize the gastric mucosa of humans, affecting approximately half of the world's population. In recent years, the prevalence of H. pylori infection has steadily reduced while the risk of allergic diseases has steadily climbed. As a result, epidemiological research indicates a strong negative association between the two. Moreover, numerous experimental studies have demonstrated that eradicating H. pylori increases the risk of allergic diseases. Hence, it is hypothesized that H. pylori infection may act as a safeguard against allergic diseases. The hygiene hypothesis, alterations in gut microbiota, the development of tolerogenic dendritic cells, and helper T cells could all be involved in H. pylori's ability to protect against asthma. Furthermore, Studies on mice models have indicated that H. pylori and its extracts are crucial in the management of asthma. We reviewed the in-depth studies on the most recent developments in the relationship between H. pylori infection and allergic diseases, and we discussed potential mechanisms of the infection's protective effect on asthma in terms of microbiota and immunity. We also investigated the prospect of the application of H. pylori and its related components in asthma, so as to provide a new perspective for the prevention or treatment of allergic diseases.

Helicobacter pylori Infection in Infant Rhesus Macaque Monkeys is Associated with an Altered Lung and Oral Microbiome

Background

It is estimated that more than half of the world population has been infected with Helicobacter pylori. Most newly acquired H. pylori infections occur in children before 10 years of age. We hypothesized that early life H. pylori infection could influence the composition of the microbiome at mucosal sites distant to the stomach. To test this hypothesis, we utilized the infant rhesus macaque monkey as an animal model of natural H. pylori colonization to determine the impact of infection on the lung and oral microbiome during a window of postnatal development.

Results

From a cohort of 4-7-month-old monkeys, gastric biopsy cultures identified 44% of animals infected by H. pylori. 16S ribosomal RNA gene sequencing of lung washes and buccal swabs from animals showed distinct profiles for the lung and oral microbiome, independent of H. pylori infection. In relative order of abundance, the lung microbiome was dominated by the phyla Proteobacteria, Firmicutes, Bacteroidota, Fusobacteriota, Campilobacterota and Actinobacteriota while the oral microbiome was dominated by Proteobacteria, Firmicutes, Bacteroidota, and Fusobacteriota. Relative to the oral cavity, the lung was composed of more genera and species that significantly differed by H. pylori status, with a total of 6 genera and species that were increased in H. pylori negative infant monkey lungs. Lung, but not plasma IL-8 concentration was also associated with gastric H. pylori load and lung microbial composition.

Conclusions

We found the infant rhesus macaque monkey lung harbors a microbiome signature that is distinct from that of the oral cavity during postnatal development. Gastric H. pylori colonization and IL-8 protein were linked to the composition of microbial communities in the lung and oral cavity. Collectively, these findings provide insight into how H. pylori infection might contribute to the gut-lung axis during early childhood and modulate future respiratory health.

Therapeutic properties of Helicobacter pylori-derived vacuolating cytotoxin A in an animal model of chronic allergic airway disease

BACKGROUND

It has previously been shown that the Helicobacter pylori (H. pylori)-derived molecule vacuolating cytotoxin A (VacA) could be suitable for the treatment of allergic airway disease. The therapeutic activity of the protein, which acts through modulation of dendritic cells (DC) and regulatory T cells (Tregs), was demonstrated in murine short-term acute models. The aim of this study is to further evaluate the therapeutic potential of VacA by determining the effectiveness of different application routes and the suitability of the protein for treating the chronic phase of allergic airway disease.

METHODS

VacA was administered by the intraperitoneal (i.p.), oral (p.o.) or intratracheal (i.t.) routes, and long-term therapeutic effectiveness, allergic airway disease hallmarks, and immune phenotype were analyzed in murine models of acute and chronic allergic airway disease.

RESULTS

Administration of VacA via the i.p., p.o or i.t. routes was associated with a reduction in airway inflammation. The i.p. route showed the most consistent effect in reducing airway inflammation and i.p. treatment with VacA was the only treatment that significantly reduced mucus cell hyperplasia. In a murine model of chronic allergic airway disease, both short- and long-term treatment with VacA showed a therapeutic effect, with a reduction in a variety of asthma hallmarks, including bronchoalveolar lavage eosinophilia, lung inflammation and goblet cell metaplasia. Short-term treatment was associated with induction of Tregs, while repetitive long-term administration of VacA influenced immunological memory in the lung.

CONCLUSIONS

In addition to showing therapeutic efficacy in short-term models, treatment with VacA also appeared to be effective in suppressing inflammation in a chronic airway disease model. The observation that treatment was effective after administration via several different routes highlights the potential of VacA as a therapeutic agent with different routes of administration in humans.

Helicobacter pylori in children: think before you kill the bug!

Since the discovery of Helicobacter pylori (H. pylori) as the causative organism for gastric and duodenal ulcers four decades ago and subsequent recognition as class 1 gastric carcinogen, countless numbers of studies have been conducted and papers published, on the efficacy of various management strategies to eradicate the infection. In adults, a global consensus by the experts in the field concluded that H. pylori gastritis is an infectious disease and requires treatment irrespective of the presence or absence of symptoms due to the potential for serious complication like peptic ulcer disease and gastric neoplasia. However, although more than half the world's population harbors H. pylori, these serious complications occur only in a small minority of the infected population, even less so in childhood. More importantly, there is accumulating evidence for beneficial role of H. pylori against many chronic health conditions, from several epidemiological and laboratory studies. No doubt, eradication therapy is indicated in children with H. pylori-related peptic ulcer disease. Even though the pediatric guidelines from various learned societies recommend against a "test and treat" strategy, this is not always adhered to. With the accumulating evidence of the possible beneficial role of H. pylori, it is time to pause and think, are we causing more harm than good by eradicating H. pylori in every child who has this bug?

Treatment with Helicobacter pylori-derived VacA attenuates allergic airway disease

Background

Asthma is an incurable heterogeneous disease with variations in clinical and underlying immunological phenotype. New approaches could help to support existing therapy concepts. Neonatal infection of mice with Helicobacter pylori or administration of H. pylori-derived extracts or molecules after birth have been shown to prevent the development of allergic airway disease later in life. This study evaluated the potential therapeutic efficacy of H. pylori vacuolating cytotoxin A (VacA) in allergic airway inflammation and investigated the underlying immunological mechanisms for its actions.

Methods

Murine models of allergic airway diseases, and murine and human in vitro models were used.

Results

In both an acute model and a therapeutic house dust mite model of allergic airway disease, treatment with H. pylori-derived VacA reduced several asthma hallmarks, including airway hyperresponsiveness, inflammation and goblet cell metaplasia. Flow cytometry and ELISA analyses revealed induction of tolerogenic dendritic cells (DC) and FoxP3 positive regulatory T cells (Tregs), and a shift in the composition of allergen-specific immunoglobulins. Depletion of Tregs during treatment with VacA reversed treatment-mediated suppression of allergic airway disease. Human monocyte derived DCs (moDC) that were exposed to VacA induced Tregs in co-cultured naïve autologous T cells, replicating key observations made in vivo.

Conclusion

H. pylori-derived VacA suppressed allergic airway inflammation via induction of Tregs in both allergic airway disease models. These data suggest that the immunomodulatory activity of VacA could potentially be exploited for the prevention and treatment of allergic airway disease.

Adverse pregnancy outcomes and Helicobacter pylori infection: A meta-analysis

INTRODUCTION

Helicobacter pylori infection during pregnancy has some adverse effects, but its effects are still conflicting. This meta-analysis study was performed to assess the relationship between H pylori infection and adverse effects during pregnancy.

METHODS

Through a systematic literature search up to August 2020, 31 studies included 16 887 pregnant females at baseline and reported a total of 5852 H pylori infection positive and 8196 H pylori infection negative pregnant females, were found recording relationships between H pylori infection and adverse effects during pregnancy. Odds ratio (OR) with 95% confidence intervals (CIs) was calculated between H pylori infection positive vs H pylori infection negative in adverse effects during pregnancy using the dichotomous methods with a random or fixed-effect model.

RESULTS

H pylori infection positive during pregnancy was significantly related to higher rate of preeclampsia (OR, 2.68; 95% CI, 2.02-3.56, P < .001), foetal growth restriction (OR, 1.45; 95% CI, 1.26-1.66, P < .001), gestational diabetes mellitus (OR, 2.63; 95% CI, 1.51-4.59, P < .001), and hyperemesis gravidarum (OR, 14.45; 95% CI, 10.24-20.38, P < .001) compared with H pylori infection negative. However, H pylori infection positive during pregnancy was not significantly correlated with spontaneous onset of labour (OR, 1.00; 95% CI, 0.83-1.21, P = .98) compared with H pylori infection negative.

CONCLUSIONS

H pylori infection may have an independent relationship with certain adverse effects during pregnancy. H pylori infection positive during pregnancy was significantly related to a higher rate of preeclampsia, foetal growth restriction, gestational diabetes mellitus, and hyperemesis gravidarum compared with H pylori infection negative. This relationship encouraged us to recommend screening and treating females for H pylori infection before and during pregnancy to avoid any possible complications.

Impact of early life geohelminths on wheeze, asthma and atopy in Ecuadorian children at 8 years

BACKGROUND

Early-life exposures to geohelminths may protect against development of wheeze/asthma and atopy.

OBJECTIVE

To study the effect of maternal geohelminths and infections in children during the first 5 years on atopy, wheeze/asthma and airways reactivity/inflammation at 8 years.

METHODS

Birth cohort of 2404 neonates followed to 8 years in rural Ecuador. Data on wheeze/asthma were collected by questionnaire and atopy by skin prick test (SPT) reactivity to 9 allergens. We measured airways reactivity to bronchodilator, fractional exhaled nitric oxide (FeNO) and nasal eosinophilia. Stool samples were examined for geohelminths by microscopy.

RESULTS

1933 (80.4%) children were evaluated at 8 years. Geohelminths were detected in 45.8% of mothers and 45.5% of children to 5 years. Frequencies of outcomes at 8 years were as follows: wheeze (6.6%), asthma between 5 and 8 years (7.9%), SPT (14.7%), airways reactivity (10%) and elevated FeNO (10.3%) and nasal eosinophilia (9.2%). Any maternal geohelminth was associated with reduced SPT prevalence (OR 0.72). Childhood Trichuris trichiura infections during the first 5 years were associated with reduced wheeze (OR 0.57) but greater parasite burdens with Ascaris lumbricoides at 5 years were associated with increased wheeze (OR 2.83) and asthma (OR 2.60). Associations between maternal geohelminths and wheeze/asthma were modified by atopy. Parasite-specific effects on wheeze/asthma and airways reactivity and inflammation were observed in non-atopic children.

CONCLUSIONS

Our data provide novel evidence for persistent effects of in utero geohelminth exposures on childhood atopy but highlight the complex nature of the relationship between geohelminths and the airways. Registered as an observational study (ISRCTN41239086).

Helicobacter pylori is associated with weakened pulmonary function and reduced incidence of allergic conditions in patients with chronic cough

The present study aimed to investigate the potential association between Helicobacter pylori (a H. pylori) positive state and chronic cough. A clinical observational study with systematic analysis was performed, including 278 patients with complaints of chronic cough and 148 healthy controls. a H. pylori positive state was present in 61.2% of the patients in the chronic cough group and 68.9% in the chronic refractory cough group, as opposed to 43.9% in the control group. There was a significant improvement in 65.5% of the patients with chronic refractory cough following successful a H. pylori eradication therapy. In addition, patients with chronic cough exposed to a H. pylori exhibited decreased pulmonary function with a decrease in forced expiratory volume in 1 sec by 84 ml, a decrease in the forced vital capacity by 53 ml and a decrease in maximal vital capacity by 46 ml. The difference was even more obvious in the chronic refractory cough group. The allergy status differed significantly according to age between a H. pylori-positive and -negative cases in the cough variant asthma and allergic cough groups. Among patients aged <40 years, a H. pylori-positive cases had a lower prevalence of atopy and lower total serum immunoglobin E levels compared with a H. pylori-negative cases. However, there was no significant association between a H. pylori status and C-reactive protein levels, erythrocyte sedimentation rate or eosinophil count in the peripheral blood. In conclusion, the present study demonstrated that a H. pylori infection may be a factor associated with chronic cough and it may be associated with a decline in pulmonary function and reduced incidence of allergic conditions. Thus, a H. pylori may represent a target for the treatment of chronic cough.

Prevalence and risk factors for wheeze, decreased forced expiratory volume in 1 s and bronchoconstriction in young children living in Havana, Cuba: a population-based cohort study

OBJECTIVES

Asthma has not been extensively studied in low-income and middle-income countries, where risk factors and access to treatment may differ from more affluent countries. We aimed to identify the prevalence of asthma and local risk factors in Havana, Cuba.

SETTING

Four municipalities in Havana, Cuba.

PARTICIPANTS

A population-based cohort study design of young children living in Havana, Cuba. Children were recruited from primary care centres at age 12-15 months.

PRIMARY AND SECONDARY OUTCOME MEASURES

Data on wheeze in the past 12 months, asthma treatment and environmental exposures collected regularly until the age of 6 years, when forced expiratory volume in 1 s (FEV₁) and reversibility to aerosolised salbutamol were also measured.

RESULTS

1106 children provided data at the age of 6 years old. The prevalence of wheeze in the previous 12 months was 422 (38%), and 294 (33%) of the study population had bronchodilatation of 12% or more in FEV₁ after administration of inhaled salbutamol. In the previous 12 months, 182 (16%) of the children had received inhaled corticosteroids, 416 (38%) salbutamol inhalers and 283 (26%) a course of systemic steroids.Wheeze in the first year and a family history of asthma were both positively associated with bronchodilatation to inhaled salbutamol (1.94%; 95% CI 0.81 to 3.08 and 1.85%; CI 0.14 to 3.57, respectively), while paracetamol use in the first year was associated with wheeze at 6 years (OR 1.64, 95% CI 1.14 to 2.35). There were large differences in FEV₁, bronchodilatation and risk of wheeze across different geographical areas.

CONCLUSIONS

Asthma is common in young children living in Havana, and the high prevalence of systemic steroids administrated is likely to reflect the underuse of regular inhaled corticosteroids. If replicated in other comparable low-income and middle-income countries, this represents an important global public health issue.

Helicobacter pylori in early childhood and asthma in adolescence

Objective

An inverse effect of Helicobacter pylori (H. pylori) on the occurrence of asthma is debated and early acquisition of H. pylori may be important. We analyzed sera from 197 children from Environment and Childhood Asthma (ECA) study in Oslo for Helicobacter pylori (H. pylori) at 2 and 10 years, and symptoms and signs of asthma at 16 years of age.

Results

While 16.4% of children who were H. pylori negative at 2 and 10 years had current asthma at 16 years, none of the 12 children who were H. pylori positive at 2 years of age had asthma at the age of 16 years, regardless of H. pylori status at 10 years. This trend for less current asthma in children who were H. pylori positive at 2 years compared to persistent or transient negative status at 10 years was not statistically significant, probably due to low number of H. pylori positive children at 2 years of age. Acquisition of H. pylori in school age did not appear to influence the risk of current asthma. Much larger prospective studies are probably required to document whether or not early H. pylori infection may be involved in the risk of asthma development in later childhood.

Mechanisms of persistence, innate immune activation and immunomodulation by the gastric pathogen Helicobacter pylori

The gastric bacterium Helicobacter pylori efficiently evades innate immune detection and persistently colonizes its human host. Understanding the genetic determinants that H. pylori uses to establish and maintain persistence, along with their cellular targets, is key to our understanding of the pathogenesis of this extraordinarily successful bacterial colonizer of the human stomach. This review highlights recent advances in elucidating innate immune recognition of H. pylori, its interactions with myeloid cells and the consequences that this very local infection has for immune responses at extragastric sites in models of allergy, autoimmunity and parasitic infection. The human-specific, gram-negative gastric colonizer and carcinogen H. pylori represents the prototype of a persistent bacterial pathogen. It is transmitted during early childhood, typically from mother to infant, and is believed to persist in its human host from the cradle to the grave. The tremendous success of H. pylori in infecting and colonizing half of the world's population, and in continuously accompanying humans since they migrated out of Africa over 60000 years ago, can largely be attributed to its ability to manipulate the host immune system to its own advantage, and to thereby ensure its own persistence and chronicity. In his final years as an active PI, Stanley Falkow increasingly recognized the need to understand bacterial persistence strategies as a prerequisite of understanding the pathogenesis of chronic bacterial infections, and, inspired in large part by Denise Monack's work on Salmonella persistence, many of our discussions at the time revolved around this topic. Multiple labs have since made important contributions to our understanding of innate immune detection of H. pylori, the types and polarization of adaptive immune responses that ensue, the ability of H. pylori to skew such immune responses to its advantage, and its ability to manipulate the host immune system with far-reaching, even systemic consequences. This review attempts to cover some of these topics, with a particular focus on the most recent contributions by researchers in the field.

Helicobacter pylori Reactivates Human Immunodeficiency Virus-1 in Latently Infected Monocytes with Increased Expression of IL-1β and CXCL8

Background

Helicobacter pylori are gram-negative bacteria, which colonize the human stomach. More than 50% of the world's population is infected by H. pylori. Based on the high prevalence of H. pylori, it is very likely that HIV and H. pylori infection may coexist. However, the molecular events that occur during HIV-H. pylori co-infection remain unclear. Latent HIV reservoirs are the major obstacle in HIV cure despite effective therapy. Here, we explored the effect of H. pylori stimulation on latently HIV-infected monocytic cell line U1.

Methods

High throughput RNA-Seq using Illumina platform was performed to analyse the change in transcriptome between unstimulated and H. pylori-stimulated latently HIV-infected U1 cells. Transcriptome analysis identified potential genes and pathways involved in the reversal of HIV latency using bioinformatic tools that were validated by real-time PCR.

Results

H. pylori stimulation increased the expression of HIV-1 Gag, both at transcription (p<0.001) and protein level. H. pylori stimulation also increased the expression of proinflammatory cytokines IL-1β, CXCL8 and CXCL10 (p<0.0001). Heat-killed H. pylori retained their ability to induce HIV transcription. RNA-Seq analysis revealed 197 significantly upregulated and 101 significantly downregulated genes in H. pylori-stimulated U1 cells. IL-1β and CXCL8 were found to be significantly upregulated using transcriptome analysis, which was consistent with real-time PCR data.

Conclusion

H. pylori reactivate HIV-1 in latently infected monocytes with the upregulation of IL-1β and CXCL8, which are prominent cytokines involved in the majority of inflammatory pathways. Our results warrant future in vivo studies elucidating the effect of H. pylori in HIV latency and pathogenesis.

Seroprevalence and determinants of Helicobacter pylori infection among asymptomatic under-five children at a Tertiary Hospital in the South-Western region of Nigeria

Background

The epidemiology of Helicobacter pylori (H. pylori) infection among under-five children in the South West Nigeria remains largely understudied. There is no data on the subject from the study area.

Objectives

This study was conducted to assess the seroprevalence of H. pylori infection among under-five children at a tertiary hospital in the South Western, Nigeria and to determine its associated socio-demographic factors.

Methods

Sera of 360 children were analyzed for anti H. pylori Ig G using enzyme linked immunosorbent assay test kit (BQ ELISA Ig G KIT) and H. pylori infection risk factors were determined. Determinants of H. pylori infection was determined using binary logistic regression analysis and p-values < 0.05 were taken as statistically significant.

Results

H. pylori infection seroprevalence rate was 32.8% and increased with age. Living in one room accommodation, large families, playing with soil, family history of dyspepsia, practice of premastication, sharing of plates and cutlery, and water closet toilet were associated with H. pylori Ig G seropositivity (p<0.05) on binary regression analysis.

Conclusion

The seroprevalence of H. pylori infection in under -five children is high, increasing as the age of the children increased. This may suggest that instituting preventive measures at young age, targeting identified factors may be effective in reducing the burden of H. pylori infection.

Transmaternal Helicobacter pylori exposure reduces allergic airway inflammation in offspring through regulatory T cells

BACKGROUND

Transmaternal exposure to tobacco, microbes, nutrients, and other environmental factors shapes the fetal immune system through epigenetic processes. The gastric microbe Helicobacter pylori represents an ancestral constituent of the human microbiota that causes gastric disorders on the one hand and is inversely associated with allergies and chronic inflammatory conditions on the other.

OBJECTIVE

Here we investigate the consequences of transmaternal exposure to H pylori in utero and/or during lactation for susceptibility to viral and bacterial infection, predisposition to allergic airway inflammation, and development of immune cell populations in the lungs and lymphoid organs.

METHODS

We use experimental models of house dust mite- or ovalbumin-induced airway inflammation and influenza A virus or Citrobacter rodentium infection along with metagenomics analyses, multicolor flow cytometry, and bisulfite pyrosequencing, to study the effects of H pylori on allergy severity and immunologic and microbiome correlates thereof.

RESULTS

Perinatal exposure to H pylori extract or its immunomodulator vacuolating cytotoxin confers robust protective effects against allergic airway inflammation not only in first- but also second-generation offspring but does not increase susceptibility to viral or bacterial infection. Immune correlates of allergy protection include skewing of regulatory over effector T cells, expansion of regulatory T-cell subsets expressing CXCR3 or retinoic acid-related orphan receptor γt, and demethylation of the forkhead box P3 (FOXP3) locus. The composition and diversity of the gastrointestinal microbiota is measurably affected by perinatal H pylori exposure.

CONCLUSION

We conclude that exposure to H pylori has consequences not only for the carrier but also for subsequent generations that can be exploited for interventional purposes.

The risk of Helicobacter pylori infection for adverse pregnancy outcomes: A systematic review and meta-analysis

OBJECTIVE

To estimate the current evidence regarding the association between Helicobacter pylori infection during pregnancy and adverse pregnancy outcomes.

MATERIALS AND METHODS

A systematic literature search for relevant publications was conducted using PubMed, EMBASE, Cochrane Library, and Web of science databases through November 17th, 2018. The pooled odds ratios (ORs) with their corresponding 95% confidence intervals (CIs) were selected as the effect size. Subgroup analysis and sensitivity analysis were performed.

RESULTS

Thirty-one studies with a total of 22 845 participants were identified. There was significant association of H pylori infection with preeclampsia (OR: 2.51; 95% CI: 1.88-3.34; P < 0.001), fetal growth restriction (OR: 2.28; 95% CI: 1.21-4.32; P = 0.01), gestational diabetes mellitus (OR: 2.03; 95% CI: 1.56-2.64; P < 0.001), spontaneous abortion (OR: 1.50; 95% CI: 1.05-2.14; P = 0.024), and birth defect (OR: 1.63; 95% CI: 1.05-2.54; P = 0.03). Sensitivity analysis showed the significant association between H pylori infection and low birthweight (OR: 1.59; 95% CI: 1.05-2.40; P = 0.03).

CONCLUSION

The present meta-analysis offers proof to support that H pylori infection during pregnancy can increase the risk on adverse pregnancy outcomes. Screening and treating for H pylori infection before pregnancy should be taken into account.

Helicobacter pylori infections in Ethiopia; prevalence and associated factors: a systematic review and meta-analysis

BACKGROUND

Helicobacter pylori (H.pylori) infections are prevalent and recognized as major cause of gastrointestinal diseases in Ethiopia. However, Studies conducted on the prevalence, risk factors and other clinical forms of H.pylori on different population and geographical areas are reporting conflicting results. Therefore, this review was conducted to estimate the pooled prevalence of H.pylori infections and associated factors in Ethiopia.

METHODS

PubMed, Embase, Google scholar, and Ethiopian Universities' repositories were searched following the Preferred Items for Systematic review and Meta-analysis (PRISMA) guideline. The quality of included studies was assessed using the Newcastle-Ottawa Scale in meta-analysis. Heterogeneity between studies was assessed using Cochrane Q test and I2 test statistics based on the random effects model. Comprehensive meta-analysis (CMA 2.0) and Review Manager (RevMan 5.3) were employed to compute the pooled prevalence and summary odds ratios of factors associated with of H.pylori infection.

RESULTS

Thirty seven studies with a total of 18,890 participants were eligible and included in the analysis. The overall pooled prevalence of H.pylori infection was 52.2% (95% CI: 45.8-58.6). In the subgroup analysis by region, the highest prevalence was found in Somalia (71%; 95% CI: 32.5-92.6) and the lowest prevalence was reported in Oromia (39.9%; 95% CI: 17.3-67.7). Absence of hand washing after toilet (OR = 1.8, 95% CI; 1.19-2.72), alcohol consumption (OR = 1.34, 95% CI; 1.03-1.74) and gastrointestinal (GI) symptoms (OR = 2.23, 95% CI; 1.59-3.14) were associated with H.pylori infection. The trend of H.pylori infection showed a decreasing pattern overtime from 1990 to 2017 in the meta-regression analysis.

CONCLUSION

The prevalence of H.pylori infection remains high; more than half of Ethiopians were infected. Although the trend of infection showed a decreasing pattern; appropriate use of eradication therapy, health education primarily to improve knowledge and awareness on the transmission dynamics of the bacteria, behavioral changes, adequate sanitation, population screening and diagnosis using multiple tests are required to reduce H.pylori infections. Recognizing the bacteria as a priority issue and designing gastric cancer screening policies are also recommended.

Allergy-related disorders (ARDs) among Ethiopian primary school-aged children: Prevalence and associated risk factors

Background

There has been a noticeable increase in the prevalence of allergy-related disorders (ARDs) in the modern era. Urbanization is believed to be a major environmental risk factor for the onset of ARDs but data from low- to middle-income countries is limited.

Objective

Our purpose was to assess the prevalence of ARDs and atopy among a population of rural Ethiopian school children and identify environmental and lifestyle factors associated with such disorders.

Methods

We performed a cross-sectional study on 541 school-children. An interviewer-led questionnaire administered to the mothers of each participant 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. Skin prick test for common allergens German cockroach (Blattella germanica) and dust mite (Dermatophagoides) was performed to define atopy. Multiple logistic regression analyses were performed to determine the odds ratio between ARDs and atopy with specific environmental and lifestyle habits.

Results

541 children responded to the survey questions: the majority of participants were female (60.3%) and aged 10–15 years-old. The prevalence of any ARD was 27%, while the rates of ever-having eczema, rhinitis, and wheeze was found to be 16.8%, 9.6%, and 8.6% respectively. Only 3.6% (19 school-children) tested positive for any skin sensitization. Analysis of associated factors for ARDs found that a family history of allergic disorders (AOR: 2.80; p-value<0.01), use of insecticides (AOR: 2.05; p-value<0.01), and wearing open-toed shoes (AOR: 2.19; p-value = 0.02) were all significantly associated factors. Insecticide use, river-bathing, and infection with intestinal parasites were found to be significantly associated factors for atopy. Other potential risk factors such as frequent use of soap, bacterial infection, and household crowding had no statistical significance.

Conclusion

Our study suggests that the prevalence of skin sensitization and ARDs in rural populations of developing countries is still relatively low. We identified several possible risk factors for further investigation. Overall, the significance of identified risk factors appears to indicate that genetic predisposition and exposure to environmental pollution are more important to the etiology of ARDs and atopy than specific lifestyle behaviors.

Environmental factors and eosinophilic esophagitis

The incidence and prevalence of eosinophilic esophagitis (EoE) have markedly increased over the past 2 decades, outpacing increased detection of the disease. Although genetic susceptibility markers for EoE have begun to be elucidated, the rate at which EoE has increased in incidence suggests environmental factors predominate. Despite many advances in understanding of the pathogenesis of EoE, the cause of EoE is unknown. This article reviews the emerging data related to environmental risk factors for EoE. Many of these environmental factors are rooted in the theoretical framework of the hygiene hypothesis, specifically mediation of disease development through dysbiosis. Other hypotheses are based on associations that have been observed in studies of non-EoE allergic disease. We describe the evidence that early-life exposures, including antibiotic use, acid suppression, and cesarean delivery, can increase the risk of disease. We also describe the evidence that infectious agents, such as Helicobacter pylori, are inversely associated with disease. Current evidence on geographic risk factors, such as population density, climate zone, and seasonality, is reviewed. We also describe behavioral factors that have been evaluated. Limitations of the existing research are discussed, and recommendations for future areas of research, including assessment of gene-environment interaction, are presented.

Review: Prevalence and dynamics of Helicobacter pylori infection during childhood

INTRODUCTION

Long-term persistent Helicobacter pylori infection has been associated with ulceropeptic disease and gastric cancer. Although H. pylori is predominantly acquired early in life, a clear understanding of infection dynamics during childhood has been obfuscated by the diversity of populations evaluated, study designs, and methods used.

AIM

Update understanding of true prevalence of H. pylori infection during childhood, based on a critical analysis of the literature published in the past 5 years.

METHODS

Comprehensive review and meta-analysis of original studies published from 2011 to 2016.

RESULTS

A MEDLINE^® /PubMed^® search on May 1, 2016, using the terms pylori and children, and subsequent exclusion, based on abstract review using predefined criteria, resulted in 261 citations. An Embase^® search with the same criteria added an additional 8 citations. In healthy children, meta-analysis estimated an overall seroprevalence rate of 33% (95% CI: 27%-38%). Seven healthy cohort studies using noninvasive direct detection methods showed infection prevalence estimates ranging from 20% to 50% in children ≤5 and 38% to 79% in children >5 years. The probability of infection persistence after a first positive sample ranged from 49% to 95%. Model estimates of cross-sectional direct detection studies in asymptomatic children indicated a prevalence of 37% (95% CI: 30%-44%). Seroprevalence, but not direct detection rates increased with age; both decreased with increasing income. The model estimate based on cross-sectional studies in symptomatic children was 39% (95% CI: 35%-43%).

CONCLUSIONS

The prevalence of H. pylori infection varied widely in the studies included here; nevertheless, model estimates by detection type were similar, suggesting that overall, one-third of children worldwide are or have been infected. The few cohort and longitudinal studies available show variability, but most studies, show infection rates over 30%. Rather surprisingly, overall infection prevalence in symptomatic children was only slightly higher, around 40%. Studies including only one positive stool sample should be interpreted with caution as spontaneous clearance can occur.

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.

Early life socioeconomic position and immune response to persistent infections among elderly Latinos

Persistent infections, such as cytomegalovirus (CMV), herpes simplex virus-1 (HSV-1), Helicobacter pylori (H. pylori), and Toxoplasma gondii (T. gondii), are common in the U.S. but their prevalence varies by socioeconomic status. It is unclear if early or later life socioeconomic position (SEP) is a more salient driver of disparities in immune control of these infections. Using data from the Sacramento Area Latino Study on Aging, we examined whether early or later life SEP was the strongest predictor of immune control later in life by contrasting two life course models, the critical period model and the chain of risk model. Early life SEP was measured as a latent variable, derived from parental education and occupation, and food availability. Indicators for SEP in later life included education level and occupation. Individuals were categorized by immune response to each pathogen (seronegative, low, medium and high) with increasing immune response representing poorer immune control. Cumulative immune response was estimated using a latent profile analysis with higher total immune response representing poorer immune control. Structural equation models were used to examine direct, indirect and total effects of early life SEP on each infection and cumulative immune response, controlling for age and gender. The direct effect of early life SEP on immune response was not statistically significant for the infections or cumulative immune response. Higher early life SEP was associated with lower immune response for T. gondii, H. pylori and cumulative immune response through pathways mediated by later life SEP. For CMV, higher early life SEP was both directly associated and partially mediated by later life SEP. No association was found between SEP and HSV-1. Findings from this study support a chain of risk model, whereby early life SEP acts through later life SEP to affect immune response to persistent infections in older age.

Developments in the field of allergy in 2014 through the eyes of Clinical and Experimental Allergy

The pathogenesis of asthma continues to be a major topic of interest to our authors with reviews and original papers on the role of viruses, mechanisms of inflammation, biomarkers, and phenotypes of asthma being major topics. A number of papers described new treatments for asthma focusing on blocking the Th2 response reflecting the fact that two decades of work in this area is finally bearing fruit. The pathogenesis of chronic rhinosinusitis is a growing area of interest, but there has been less on the genetics of airways disease than in previous years possibly reflecting the degree of rigour (and therefore a smaller body of work), with which these sorts of studies are now being undertaken. There continues to be a wide range of papers dealing with mechanisms of allergic disease ranging from clinical-based studies to basic research and the use of in vivo animal models especially mice. As before, mechanisms and new approaches to immunotherapy are common themes. Several were published in the allergens section investigating modification of allergens to increase their effectiveness and reduce the risk of adverse events. Risk factors for allergic disease was a common theme in the epidemiology section and food allergy a common theme in clinical allergy with papers on the development of protocols to induce tolerance and attempts to find biomarkers to distinguish sensitization from allergic disease. This was another exciting year for the editors, and we hope the readers of the journal.

Effect of Helicobacter pylori infection on growth trajectories in young Ethiopian children: a longitudinal study

BACKGROUND

Helicobacter pylori infection has been associated with early childhood growth impairment in high- and middle-income countries; however, few studies have examined this relationship within low-income countries or have used a longitudinal design. The possible effects of H. pylori infection on growth trajectories were examined in a cohort of young Ethiopian children.

METHODS

In 2011/12, 856 children (85.1% of the 1006 original singletons in a population-based birth cohort) were followed up at age 6.5 years. An interviewer-led questionnaire administered to mothers provided information on demographic and lifestyle variables. Height and weight were measured twice, and the average of the two measurements was used. Exposure to H. pylori infection was assessed using a rapid H. pylori stool antigen test. The independent associations of positive H. pylori infection status (measured at ages 3 and 6.5 years) with baseline height and weight (age 3 years) and height and weight growth trajectory (from age 3 to 6.5 years) were modelled using hierarchical linear models.

RESULTS

At baseline (age 3 years), the children's mean height was 85.7cm and their mean weight was 11.9kg. They gained height at a mean rate of 8.7cm/year, and weight at a mean rate of 1.76kg/year. H. pylori infection was associated with lower baseline measurements and linear height trajectory (β=-0.74cm and -0.79cm/year, respectively), after controlling for demographics and markers of socio-economic status. However, the positive coefficient was associated with quadratic growth in height among H. pylori-infected children (β=0.28, 95% confidence interval 0.07 to 0.49, p<0.01), and indicated an increase in height trajectory as the child increased in age. A non-significant difference in baseline and trajectory of weight was observed between H. pylori-infected and non-infected children.

CONCLUSIONS

These findings add to the growing body of evidence supporting that H. pylori infection is inversely associated with childhood growth trajectory, after controlling for a range of factors associated with reduced growth and H. pylori status. Further follow-up will be important to confirm possible catch-up in height trajectory among H. pylori-infected children as they grow older.

Particularities of allergy in the Tropics

Allergic diseases are distributed worldwide and their risk factors and triggers vary according to geographical and socioeconomic conditions. Allergies are frequent in the Tropics but aspects of their prevalence, natural history, risk factors, sensitizers and triggers are not well defined and some are expected to be different from those in temperate zone countries. The aim of this review is to investigate if allergic diseases in the Tropics have particularities that deserve special attention for research and clinical practice. Such information will help to form a better understanding of the pathogenesis, diagnosis and management of allergic diseases in the Tropics. As expected, we found particularities in the Tropics that merit further study because they strongly affect the natural history of common allergic diseases; most of them related to climate conditions that favor permanent exposure to mite allergens, helminth infections and stinging insects. In addition, we detected several unmet needs in important areas which should be investigated and solved by collaborative efforts led by the emergent research groups on allergy from tropical countries.

Helicobacter pylori: Does Gastritis Prevent Colitis?

Background

Since its discovery in the early 1980s, Helicobacter pylori has been linked to a variety of gastric and extragastric diseases. Chronic infection with H. pylori causes histologically evident gastritis in all colonized individuals and is the predominant risk factor for gastric and duodenal ulcers as well as gastric adenocarcinoma. However, increasingly robust experimental and epidemiological evidence suggests that H. pylori may at the same time be beneficial to its carriers, as it efficiently prevents allergic disorders and chronic inflammatory conditions. The purpose of this review is to summarize and document the latest evidence for a possible inverse association of H. pylori infection status and the risk of inflammatory bowel disease (IBD), as provided in both experimental and human observational studies. The pathogenesis of IBDs, the available mouse models for these diseases and the dual role of H. pylori in health and disease are presented in dedicated chapters.

Summary and Key Messages

Almost all available epidemiological data suggest that H. pylori infection is inversely associated with both Crohn's disease (CD) and ulcerative colitis in European, Asian as well as American populations; large meta-analyses reviewing 30 original articles or more document that this inverse association is especially strong in CD patients and in children and young adults. Experimental data available from various mouse models of IBD confirm that live H. pylori infection as well as treatment with immunomodulatory molecules of H. pylori reduce clinical and histopathological IBD symptoms. Various proposed mechanisms involving the tolerization of dendritic cells, the production of protective cytokines and the preferential induction and differentiation of regulatory T-cells are presented. The implications of the beneficial aspects of the Helicobacter-host interaction for H. pylori eradication decisions, as well as potential new therapeutic options in the treatment of IBD are discussed in this review.

Helicobacter pylori in children with asthmatic conditions at school age, and their mothers

BACKGROUND

Helicobacter pylori prevalence in Western countries has been declining simultaneously with increases in childhood asthma and allergic diseases; prior studies have linked these phenomena.

AIMS

To examine the association between H. pylori colonisation in children and risk of asthma and related conditions at school age. We secondly examined additional effects of maternal H. pylori status by pairing with children's status.

METHODS

This study was embedded in a multi-ethnic population-based cohort in Rotterdam, The Netherlands. We measured anti-H. pylori and anti-CagA antibodies in serum of children obtained at age 6 years, and of their mothers obtained during midpregnancy. Asthma or related conditions were reported for children at age 6 years. We used multivariate logistic regression analyses among 3797 subjects.

RESULTS

In children, the H. pylori positivity rate was 8.7%, and 29.2% of these were CagA-positive. A child's colonisation with a CagA-negative-H. pylori strain was associated with an increased risk of asthma (Odds ratio 2.11; 95% CI 1.23-3.60), but this differed for European (3.64; 1.97-6.73) and non-European (0.52; 0.14-1.89) children. When taking into account maternal H. pylori status, only H. pylori-positive children with an H. pylori-negative mother had increased risk of asthma (2.42; 1.11-5.27), accounting for 3.4% of the asthma risk.

CONCLUSIONS

Colonisation of a European child with a CagA-negative-H. pylori strain at age 6 was associated with an increased prevalence of asthma, but there was no association for non-European children. The underlying mechanisms for the observed risk differences require further research.

The Gastrointestinal Tract Microbiota and Allergic Diseases

The gastrointestinal (GI) tract microbiota is required for optimal digestion of foods, for the development of resistance against pathogens (termed colonization resistance), for the development of mucosa-associated lymphoid tissue, and for local as well as systemic immune homeostasis. Certain constituents of the GI tract microbiota are widely recognized as critical regulators and modulators of their host's immune response. These include bacterial members of the microbiota as well as parasitic nematodes. Immune regulation by immunomodulatory members of the GI microbiota primarily serves to subvert host antimicrobial immune defenses and promote persistent colonization, but as a side effect may prevent or suppress immunological disorders resulting from inappropriate responses to harmless antigens, such as allergy, colitis or autoimmunity. Many of the best understood GI-resident immunomodulatory species have co-evolved with their mammalian hosts for tens of thousands of years and masterfully manipulate host immune responses. In this review, we discuss the epidemiological evidence for the role of the GI tract microbiota as a whole, and of specific members, in protection against allergic and other immunological disorders. We then focus on the mechanistic basis of microbial immunomodulation, which is presented using several well-understood paradigmatic examples, that is, helminths, Helicobacter pylori, Bifidobacteria and Lactobacilli. In a final chapter, we highlight past and ongoing attempts at harnessing the immunomodulatory properties of GI microbiota species and their secreted products for intervention studies and describe the promises and limitations of these experimental approaches. The effects of pro- and prebiotics, bacterial lysates, as well as of fecal microbiota transplantation are presented and compared.

Helicobacter pylori-Mediated Protection from Allergy Is Associated with IL-10-Secreting Peripheral Blood Regulatory T Cells

Helicobacter pylori infections are usually established in early childhood and continuously stimulate immunity, including T-helper 1 (Th1), Th17, and regulatory T-cell (Treg) responses, throughout life. Although known to be the major cause of peptic ulcer disease and gastric cancer, disease occurs in a minority of those who are infected. Recently, there has been much interest in beneficial effects arising from infection with this pathogen. Published data robustly show that the infection is protective against asthma in mouse models. Epidemiological studies show that H. pylori is inversely associated with human allergy and asthma, but there is a paucity of mechanistic data to explain this. Since Th1 and Treg responses are reported to protect against allergic responses, we investigated if there were links between the human systemic Th1 and Treg response to H. pylori and allergen-specific IgE levels. The human cytokine and T-cell responses were examined using peripheral blood mononuclear cells (PBMCs) from 49 infected and 58 uninfected adult patients. Concentrations of total and allergen-specific plasma IgE were determined by ELISA and ImmunoCAP assays. These responses were analyzed according to major virulence factor genotypes of the patients' colonizing H. pylori strains. An in vitro assay was employed, using PBMCs from infected and uninfected donors, to determine the role of Treg cytokines in the suppression of IgE. Significantly higher frequencies of IL-10-secreting CD4(+)CD25(hi) Tregs, but not H. pylori-specific Th1 cells, were present in the peripheral blood of infected patients. Total and allergen-specific IgE concentrations were lower when there was a strong Treg response, and blocking IL-10 in vitro dramatically restored IgE responses. IgE concentrations were also significantly lower when patients were infected with CagA(+) strains or those expressing the more active i1 form of VacA. The systemic IL-10(+) Treg response is therefore likely to play a role in H. pylori-mediated protection against allergy in humans.

Helicobacter pylori and allergy: Update of research

Recently a lot of literature has been published about the possible preventive action of Helicobacter pylori (H. pylori) against allergy. The present review summarizes research data about the association between H. pylori and allergic diseases, as well as discusses possible hypotheses about the preventive action of H. pylori against atopy. There is evidence from observational studies to support a weak inverse association between prevalence of H. pylori infection and allergy. However, confounders like some unidentified socioeconomic factors, antibiotic use and others could bias the association. Although data from cohort studies point to a possible association of H. pylori with some of the allergic diseases, no definite proof for causal relationship has been clearly demonstrated yet. A biological mechanism proposed to explain the preventive action of H. pylori to allergy is reduced exposure to a major stimulus for the generation of Treg cells in individuals without H. pylori infection. In addition, H. pylori could be an indicator for changes in gut microbiome, reflecting the complex interaction between microbes and immune system.

Helicobacter pylori Infection in Pediatrics

This review includes the main pediatric studies published from April 2014 to March 2015. The host response of Treg cells with increases in FOXP3 and TGF-β1 combined with a reduction in IFN-γ by Teff cells may contribute to Helicobacter pylori susceptibility in children. Genotypic variability in H. pylori strains influences the clinical manifestation of the infection. Helicobacter pylori infection is associated with variables indicative of a crowded environment and poor living conditions, while breast-feeding has a protective effect. Intrafamilial infection, especially from mother to children and from sibling to sibling, is the dominant transmission route. Studies showed conflicting results regarding the association between H. pylori infection and iron deficiency anemia. One study suggests that H. pylori eradication plays a role in the management of chronic immune thrombocytopenic purpura in H. pylori-infected children and adolescents. The prevalence of H. pylori was higher in chronic urticaria patients than in controls and, following H. pylori eradication, urticarial symptoms disappeared. An inverse relationship between H. pylori infection and allergic disease was reported. Antibiotic resistance and insufficient compliance to treatment limit the efficacy of eradication therapy. Sequential therapy had no advantage over standard triple therapy. In countries where H. pylori infection is prevalent, studies focusing on virulence factors and antibiotic susceptibility may provide anticipation of the prognosis and may be helpful to reduce morbidity and mortality.

Effect of early and current Helicobacter pylori infection on the risk of anaemia in 6.5-year-old Ethiopian children

BACKGROUND

Epidemiological and clinical studies in high income countries have suggested that Helicobacter pylori (H. pylori) may cause anaemia, but evidence is lacking from low income countries.We examined associations between H. pylori infection in early childhood and anaemia at the age of 6.5 years in an Ethiopian birth cohort.

METHODS

In 2011/12, 856 children (85.1 % of the 1006 original singletons in a population-based birth cohort) were followed up at age six and half. An interviewer-led questionnaire administered to mothers provided information on demographic and lifestyle variables. Haemoglobin level and red cell indices were examined using an automated haematological analyzer (Cell Dyn 1800, Abbott, USA), and stool samples analyzed for H. pylori antigen. The independent effects of H. pylori infection (measured at age 3.5 and 6.5 years) on anaemia, haemoglobin level, and red cell indices (measured at age 6.5 years) were determined using multiple logistic and linear regression.

RESULTS

The prevalence of anemia was 34.8 % (257/739), and the mean (SD) haemoglobin concentration was 11.8 (1.1) gm/dl. Current H. pylori infection at age 6.5 years was positively, though not significantly related to prevalence of anaemia (adjusted OR, 95 % CI, 1.15; 0.69, 1.93, p = 0.59). Any H. pylori infection up to age 6.5 years was significantly associated with an increased risk of anaemia at age 6.5 (adjusted OR, 95 % CI, 1.68; 1.22, 2.32, p = 0.01). A significant reduction in haemoglobin concentration and red cell indices was also observed among children who had any H. pylori infection up to age 6.5 (Hb adjusted β = -0.19, 95 % CI, -0.35 to -0.03, p = 0.01; MCV adjusted β = -2.22, 95 % CI, -3.43 to -1.01, p = 0.01; MCH adjusted β = -0.63, 95 % CI, -1.15 to - 0.12, p = 0.01; and MCHC adjusted β = -0.67, 95 % CI, -1.21 to -0.14, p = 0.01), respectively.

CONCLUSION

This study provides further evidence from a low income country that any H. pylori infection up to age 6.5 is associated with higher prevalence of anaemia, and reduction of haemoglobin level and red cell indices at age 6.5.

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.

Helicobacter pylori infection reduces disease severity in an experimental model of multiple sclerosis

Recent research has demonstrated that infection with the bacterial pathogen Helicobacter pylori is less common amongst patients with multiple sclerosis (MS), an inflammatory demyelinating disease of the central nervous system (CNS). We aimed to compare the prevalence of H. pylori amongst MS patients and healthy controls, and also investigated the impact of this infection on an animal model for MS, experimental autoimmune encephalomyelitis (EAE). The H. pylori status of 71 MS patients and 42 healthy controls was determined by serology. Groups of C57BL/6 mice were infected with H. pylori, or given diluent alone as a placebo, prior to inducing EAE. Clinical scores were assessed for all mice, and spleens and spinal cord tissue were harvested. CD4⁺ T cell subsets were quantified by flow cytometry, and T cell proliferation assays were performed. In MS patients the seroprevalence of H. pylori was half that of healthy controls (p = 0.018). Over three independent experiments, prior H. pylori infection had a moderate effect in reducing the severity of EAE (p = 0.012). In line with this, the antigen-specific T cell proliferative responses of infected animals were significantly reduced (p = 0.001), and there was a fourfold reduction in the number of CD4⁺ cells in the CNS. CD4⁺ populations in both the CNS and the spleens of infected mice also contained greatly reduced proportions of IFNγ⁺, IL-17⁺, T-bet⁺, and RORγt⁺ cells, but the proportions of Foxp3⁺ cells were equivalent. There were no differences in the frequency of splenic CD4⁺cells expressing markers of apoptosis between infected and uninfected animals. H. pylori was less prevalent amongst MS patients. In mice, the infection exerted some protection against EAE, inhibiting both Th1 and Th17 responses. This could not be explained by the presence of increased numbers of Foxp3⁺ regulatory T cells, or T cell apoptosis. This is the first direct experimental evidence showing that H. pylori may provide protection against inflammatory demyelination in the CNS.

New Diagnostic Strategies for Detection of Helicobacter pylori Infection in Pediatric Patients

Helicobacter pylori (H pylori) is a common chronic bacterial infection that is an important cause of peptic ulcer disease and gastroduodenal disease in children. H pylori is also associated with extragastric manifestations, including growth reduction, iron-deficiency anemia, and idiopathic thrombocytopenic purpura. Current guidelines recommend endoscopy with biopsy for the definitive demonstration of H pylori infection. In contrast to serology, the fecal antigen test and the urea breath test provide reliable, sensitive, and specific results for detecting active H pylori infection in children before and after treatment. The first-line treatment option for pediatric patients is triple therapy with a proton pump inhibitor and 2 antibiotics, which include amoxicillin and clarithromycin or metronidazole. Decreasing eradication rates and the emergence of antibiotic-resistant strains of H pylori have led to the use of other treatments, such as sequential therapy or triple therapy with newer antibiotics, particularly in geographic areas with high rates of antibiotic resistance. Patients should be tested after treatment to confirm eradication, as the absence of symptoms does not necessarily mean that H pylori is no longer present. This clinical roundtable monograph provides an overview of H pylori infection, as well as expert insight into the diagnosis and management of H pylori infection in children.