Genetic and environmental factors in the immunopathogenesis of atopy: interaction of Helicobacter pylori infection and IL4 genetics

Helicobacter pylori seropositivity protects against childhood asthma and inversely correlates to its clinical and functional severity

BACKGROUND

In recent years, the prevalence of asthma has risen in developed countries, and its extent related to a change in our indigenous microbiota. Helicobacter pylori disappearance across the population represents a fundamental change in our human microbiota and has preceded the rise in asthma prevalence.

OBJECTIVE

To assess the relationship between childhood asthma and Helicobacter pylori infection.

METHODS

Quantitative determination of Helicobacter pylori IgG among 90 asthmatic children and 90 - age and gender - matched non-atopic, non-asthmatic healthy children was performed using ELISA in serum of all participants.

RESULTS

Helicobacter pylori IgG seropositivity was found in 25.6% of asthmatics compared to 44.4% of controls. Asthmatics showed lower median Helicobacter pylori IgG titre compared to healthy controls. We also detected a significant inverse relationship between Helicobacter pylori IgG titre and asthma severity.

CONCLUSION

Helicobacter pylori seropositivity protects against childhood asthma and inversely correlates to its clinical and functional severity.

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.

Downregulated regulatory T cell function is associated with increased peptic ulcer in Helicobacter pylori-infection

BACKGROUND

Helicobacter pylori (H. pylori) chronically colonizes gastric/duodenal mucosa and induces gastroduodenal disease such as gastritis and peptic ulcer and induces vigorous innate and specific immune responses; however, the infection is not removed, a state of chronic active gastritis persists for life if untreated. The objective of this study was to determine the number of regulatory T cells (Tregs) in gastric mucosa of patients with gastritis and peptic ulcer and determined the relationship between main virulence factor of H. pylori and Tregs.

METHODS AND MATERIALS

A total of 89 patients with gastritis, 63 patients with peptic ulcer and 40 healthy, H. pylori-negative subjects were enrolled in this study. Expression of CD4 and Foxp3 was determined by immunohistochemistry. Antrum biopsy was obtained for detection of H. pylori, bacterial virulence factors and histopathological assessments. TGF-β1, IL-10 and FOXP3 expressions were determined by real-time polymerase chain reaction (qPCR).

RESULTS

The numbers of CD4⁺ and Foxp3⁺ T cells as well as the expression of IL-10, TGF-β1, FOXP3, INF-γ and IL-17A in infected patients were significantly higher than the ones in uninfected patients. Also, the number of CD4⁺ T cells was independent on the vacuolating cytotoxin A (vacA) and outer inflammatory protein A (oipA), but it was positively correlated with cytotoxin-associated gene A (cagA). Instead, the number of Foxp3⁺ T cells was dependent on the vacA and oipA, but it was independent on cagA. The number of Foxp3⁺ T cells and the expression of IL-10, TGF-β1 and FOXP3 in infected patients with gastritis were significantly higher than the ones in infected patients with peptic ulcer. Moreover, the number of CD4⁺ T cells and the expression of IL-17A and INF-γ was the lowest in the gastritis patients, however, increased progressively in the peptic ulcer patients. Additionally, the numbers of CD4⁺ and Foxp3⁺ T cells as well as the expression of IL-10, TGF-β1, FOXP3 and INF-γ were positively correlated with the degree of H. pylori density and chronic inflammation.

CONCLUSION

Tregs are positively associated with vacA alleles and oipA status of H. pylori and histological grade but negatively associated with peptic ulcer disease.

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 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-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.

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

Background

An inverse relation between Helicobacter pylori infection and allergic disease has been reported by a range of independent epidemiological studies, but evidence from longitudinal studies is scarce.

Objective

We have investigated the effects of H. pylori infection on the incidence and prevalence of allergic diseases and sensitization in a low-income birth cohort.

Methods

In 2005/2006, a population-based birth cohort was established in Butajira, Ethiopia, and the 1006 singleton babies born were followed up at ages 1, 3, and 5. Symptoms of allergic disease were collected using the ISAAC questionnaire, allergen skin tests performed, and stool samples analysed for H. pylori antigen and geohelminths. Multiple logistic regression was used to determine the independent effects of H. pylori measured at age 3 on the incidence of each outcome between ages 3 and 5 years (in those without the outcome at age 3), controlling for potential confounders, and to additionally assess cross-sectional associations.

Results

A total of 863 children were followed up to age 5. H. pylori infection was found in 25% of the children at both ages 3 and 5, in 21% at age 5 but not 3, and in 17% at age 3 but not at age 5. H. pylori infection at age 3 was significantly associated with a decreased risk of incident eczema between ages 3 and 5 (adjusted OR, 95% CI, 0.31; 0.10–0.94, P = 0.02). Cross-sectionally at age 5, H. pylori infection was inversely associated with skin sensitization (adjusted OR, 95% CI, 0.26; 0.07–0.92, P = 0.02).

Conclusion and clinical relevance

These findings provide further evidence to suggest that early-life exposure to H. pylori may play a protective role in the development of allergy.

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.

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.

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.

Enteric infections, diarrhea, and their impact on function and development

Enteric infections, with or without overt diarrhea, have profound effects on intestinal absorption, nutrition, and childhood development as well as on global mortality. Oral rehydration therapy has reduced the number of deaths from dehydration caused by infection with an enteric pathogen, but it has not changed the morbidity caused by such infections. This Review focuses on the interactions between enteric pathogens and human genetic determinants that alter intestinal function and inflammation and profoundly impair human health and development. We also discuss specific implications for novel approaches to interventions that are now opened by our rapidly growing molecular understanding.

Association between C-589T polymorphisms of interleukin-4 gene promoter and asthma: a meta-analysis

BACKGROUND

A number of studies of genetic epidemiology have assessed the association of C-589T (also referred to as C-590T; rs number, 2243250) polymorphisms in the promoter region of interleukin-4 (IL-4) gene with asthma in different populations. However, the results are inconsistent and inconclusive.

OBJECTIVES

We performed a meta-analysis of the association between C-589T polymorphisms of IL-4 and asthma with the following objectives: to estimate the magnitude of the gene effect and the possible mode of inheritance.

METHODS

A genetic model-free approach was used to perform a meta-analysis. Asthma (atopy status nondefined), nonatopic and atopic asthma subgroups were separately analyzed. Heterogeneity and publication bias were also explored.

RESULTS

Our meta-analysis summarized the evidence regarding the association between C-589T polymorphisms in the promoter region of IL-4 gene and asthma. When all asthma groups were pooled, a significant association of increased asthma risk and T allele was found. In subgroup analysis, our results indicated a significant association and a recessive genetic mode of C-589T polymorphisms of IL-4 with atopic asthma. The CC genotype was about 21 percent less likely to have atopic asthma than the genotype CT and TT. However, C-589T polymorphisms were not significantly associated with nonatopic asthma.

CONCLUSIONS

This meta-analysis suggests there may be an important effect of single nucleotide polymorphisms (SNPs) in the promoter region of IL-4 gene on the pathogenesis of atopic asthma. This warrants further investigation in larger studies and meta-analysis.

Environmental epigenetics and asthma: current concepts and call for studies

Recent studies suggest that epigenetic regulation (heritable changes in gene expression that occur in the absence of alterations in DNA sequences) may in part mediate the complex gene-by-environment interactions that can lead to asthma. The variable natural history of asthma (i.e., incidence and remission of symptoms) may be a result of epigenetic changes, such as DNA methylation, covalent histone modifications, microRNA changes, and chromatin alterations, after early or later environmental exposures. Findings from multiple epidemiologic and experimental studies indicate that asthma risk may be modified by epigenetic regulation. One study suggested that the transmission of asthma risk may occur across multiple generations. Experimental studies provide substantial in vitro data indicating that DNA methylation of genes critical to T-helper cell differentiation may induce polarization toward or away from an allergic phenotype. Despite this initial progress, fundamental questions remain that need to be addressed by well-designed research studies. Data generated from controlled experiments using in vivo models and/or clinical specimens collected after environmental exposure monitoring are limited. Importantly, cohort-driven epigenetic research has the potential to address key questions, such as those concerning the influence of timing of exposure, dose of exposure, diet, and ethnicity on susceptibility to asthma development. There is immense promise that the study of environmental epigenetics will help us understand a theoretically preventable environmental disease.

Helicobacter pylori colonisation and eczema

The hygiene hypothesis postulates that the increase in atopic diseases may in part be due to diminished exposure to microorganisms. But it is unknown which type of infection does render protection. An epidemiological study was conducted in Leipzig, Germany, and its rural county, involving 3347 school starters. Two types of infection were considered: (1) gastrointestinal colonisation (Helicobacter pylori detection using in vivo [(13)C] urea breath test) and (2) respiratory infections (physician-diagnosed lower (bronchitis) and upper (common cold) respiratory infections). H pylori colonisation was selected because it is very common and plays an important role in gastrointestinal disorders. Atopic eczema was selected as the (allergic) target variable because of its high frequency in the age of the study participants. The results, adjusted for relevant confounders, showed a significant inverse association between H pylori infection and eczema (adjusted odds ratio (aOR) = 0.31, p = 0.006) in children not predisposed to atopy. In contrast, bronchitis increased the risk of eczema (aOR = 1.98, p<0.001). Bacterial digestive tract colonisation (infection) seems to protect against eczema in comparison with the effect of respiratory tract infections. The hygiene hypothesis may be better explained when gastrointestinal and respiratory infections are subtly differentiated.

Helicobacter pylori colonisation and eczema

The hygiene hypothesis postulates that the increase in atopic diseases may in part be due to diminished exposure to microorganisms. But it is unknown which type of infection does render protection. An epidemiological study was conducted in Leipzig, Germany, and its rural county, involving 3347 school starters. Two types of infection were considered: (1) gastrointestinal colonisation (Helicobacter pylori detection using in vivo [(13)C] urea breath test) and (2) respiratory infections (physician-diagnosed lower (bronchitis) and upper (common cold) respiratory infections). H pylori colonisation was selected because it is very common and plays an important role in gastrointestinal disorders. Atopic eczema was selected as the (allergic) target variable because of its high frequency in the age of the study participants. The results, adjusted for relevant confounders, showed a significant inverse association between H pylori infection and eczema (adjusted odds ratio (aOR) = 0.31, p = 0.006) in children not predisposed to atopy. In contrast, bronchitis increased the risk of eczema (aOR = 1.98, p<0.001). Bacterial digestive tract colonisation (infection) seems to protect against eczema in comparison with the effect of respiratory tract infections. The hygiene hypothesis may be better explained when gastrointestinal and respiratory infections are subtly differentiated.

Genetic susceptibility to infectious diseases: big is beautiful, but will bigger be even better?

Genetic epidemiology, including twin studies, provides robust evidence that genetic variation in human populations contributes to susceptibility to infectious disease. One of the major limitations of studies that attempt to identify the genes and mechanisms that underlie this susceptibility has been lack of power caused by small sample size. With the development of novel technologies, burgeoning information on the human genome, the HapMap project, and human genetic diversity, we are at the beginning of a new era in the study of the genetics of complex diseases. This review looks afresh at the epidemiological evidence that supports a role for genetics in susceptibility to infectious disease, examines the somewhat limited achievements to date, and discusses current advances in methodology and technology that will potentially lead to translational data in the future.

Allelic polymorphisms in the interleukin-4 promoter regions and their association with bronchial asthma among the Russian population

BACKGROUND

Susceptibility to the development of bronchial asthma (BA) and other atopic diseases is known to be associated with genetic components.

OBJECTIVE

To evaluate the possible role of the polymorphisms in IL-4 gene promoters (C-33T, C-590T and G-1098T) in modulating allergic response and asthma in the Russian population.

METHODS

The polymorphism analysis was carried out by PCR-RFLP; IL-4 and total IgE concentrations were determined by ELISA.

RESULTS

In the case group, the T allele was found at frequencies of 74% (C-33T), 51% (C-590T) and 5% (G-1098T); in the control group the frequencies were 22, 42 and 8%, respectively. Only the C-33T polymorphism was associated with BA. The concentrations of total IgE and serum IL-4 were raised in the case group, while in the control group they were normal. Serum IL-4 level depended on C-33T polymorphism both in the case and control groups, the mutant T allele promoting its increase. The dependence on C-590T polymorphism was detected only in the case group. As for the total IgE level, in both cases it depended on the polymorphism in the case group rather than the control. G-1098T polymorphism did not demonstrate any correlations with total IgE or serum IL-4 levels. All 3 polymorphisms did not affect the severity of BA in the case group. On the basis of the computer analysis, we propose that the T-33C region is the CREB-binding site.

CONCLUSIONS

Our data suggest that IL-4 promoter polymorphism in the Russian population might play a role both conferring susceptibility to BA and modulating the levels of serum IL-4 and total IgE.