Involvement of IL-10 gene promoter polymorphisms in the susceptibility for childhood asthma

Interleukin 10 -1082 G/A Gene Polymorphism and Susceptibility to Bronchial Asthma in Children: A Single-Center Study

Interleukin-10 (IL-10) is the key regulator of immune responses preventing the undesirable exaggerated ones. Genetic variation in the promoter region of IL-10 may influence its serum level and contribute to susceptibility to bronchial asthma in children. This is a case-control study including 100 patients and 100 healthy control children who had undergone skin prick test, estimation of total IgE and serum level of IL-10 by enzyme-linked immunosorbent assay, and polymerase chain reaction-restriction fragment length polymorphism for IL-10 gene polymorphism. A significant association between IL-10 polymorphism and susceptibility to pediatric asthma was found. AA genotype represented (66%) of the patient group compared to (6%) only of the control group, while AG genotype was detected in 20% of patients and 4% of control. In contrast, wild genotype GG was found in 14% of patients and 90% of control with a highly statistically significant difference among both groups (P < 0.001). The serum level of IL-10 was significantly elevated in the GG genotype in comparison to other genotypes (P < 0.001), and it was negatively correlated with the severity of asthma among the studied pediatric asthmatic group (P < 0.001). In conclusion, IL-10 polymorphism may play an important role in the development of bronchial asthma in children.

Interleukin-10 Gene Promoter Polymorphisms and Susceptibility to Asthma: Systematic Review and Meta-analysis

Several studies have previously assessed the association between interleukin (IL)-10 gene polymorphisms and the risk of asthma, leading to conflicting results. To resolve the incongruent outcomes yielded from different single studies, we conducted the most up-to-date meta-analysis of the IL-10 gene rs1800896, rs1800871, and rs1800872 single-nucleotide polymorphisms (SNPs) and susceptibility to asthma. A systematic literature search performed until April 2020, and the pooled odds ratio (OR) and their corresponding 95% confidence interval (CI) were calculated to determine the association strength. Thirty articles comprising 5678 asthmatic patients and 6079 controls met the inclusion criteria. No significant association was found between rs1800872 SNP and susceptibility to asthma across all genetic models in the overall and subgroup analyses. The rs1800871 SNP had only significant association with a decreased risk of asthma in Europeans (OR 0.66, CI 0.53-0.82, P < 0.001). However, rs1800896 SNP was significantly associated with a decreased risk of asthma by dominant (OR 0.67, CI 0.50-0.90, P < 0.001) and heterozygote (OR 0.66, CI 0.49-0.88, P < 0.001) models in the overall analysis. Subgroup analyses indicated significant association of rs1800896 SNP by dominant (OR 0.45, CI 0.28-0.72, P < 0.001) and heterozygote (OR 0.43, CI 0.26-0.70, P < 0.001) models in the African population. The IL-10 rs1800896 SNP confers protection against the risk of asthma, especially in Africans. Additionally, rs1800871 SNP has a protective role against asthma in Europeans.

Interleukin-10 gene polymorphism rs1800896 is associated with post-bronchiolitis asthma at 11-13 years of age

AIM

Interleukin-10 (IL-10) is an anti-inflammatory cytokine that is involved with bronchiolitis and asthma. We evaluated associations between four IL-10 polymorphisms, namely rs1800871, rs1800872, rs1800890 and rs1800896, and post-bronchiolitis asthma in young adolescents.

METHODS

The cohort consisted of 125 children hospitalised for bronchiolitis at Tampere University Hospital, Finland, in 2000-2004, at less than six months of age. At 11-13 years, asthma diagnoses and asthma-presumptive symptoms, allergic rhinitis and use of inhaled corticosteroids (ICS) were registered. Data on the four polymorphisms and their genotypes, haplotypes and allele frequencies were analysed in relation to asthma, allergic rhinitis and asthma medication.

RESULTS

The variant IL-10 rs1800896 genotype was associated with less persistent asthma at five to seven and 11-13 years of age (4.3 versus 15.2%, p = 0.04) than the wild genotype and less ICS use during the previous 12 months (5.4 versus 18.2%, p = 0.03), as was the variant allele G. Allele A was associated with more persistent asthma and ICS use. The significant differences between the variant and wild genotypes were lost in adjusted logistic regression, but the direction of the association remained.

CONCLUSION

IL-10 rs1800896 gene polymorphism was associated with post-bronchiolitis asthma at 11-13 years of age in children hospitalised for bronchiolitis at less than six months of age.

Relationship of systemic IL-10 levels with proinflammatory cytokine responsiveness and lung function in agriculture workers

BACKGROUND

Agriculture workers are exposed to microbial component- and particulate matter-enriched organic dust aerosols. Whereas it is clear that exposure to these aerosols can lead to lung inflammation, it is not known how inflammatory responses are resolved in some individuals while others develop chronic lung disease. Interleukin (IL)-10 is an immunomodulatory cytokine that is recognized as a potent anti-inflammatory and pro-resolving factor. The objective of this study was to determine whether there is a relationship of systemic IL-10 and proinflammatory responses and/or respiratory health effects in humans with prior agriculture exposure.

METHODS

This is a cross sectional study of 625 veterans with > 2 years of farming experience. Whole blood was stimulated with or without organic dust and measured for IL-6, TNFα and IL-10. Participants underwent spirometry and respiratory symptoms were assessed by questionnaire.

RESULTS

We found that baseline IL-10 concentration from the whole blood assay was inversely associated with ΔTNF-α (r = - 0.63) and ΔIL-6 (r = - 0.37) levels. Results remained highly significant in the linear regression model after adjusting for age, sex, BMI, race, education, smoking status, and white blood cell count (ΔTNF-α, p < 0.0001; ΔIL-6, p < 0.0001). We found no association between chronic cough (p = 0.18), chronic phlegm (p = 0.31) and chronic bronchitis (p = 0.06) and baseline IL-10 levels using univariate logistic regression models. However, we did find that higher FEV1/FVC was significantly associated with increased baseline IL-10 concentration.

CONCLUSIONS

Collectively, these studies support a potential role for IL-10 in modulating an inflammatory response and lung function in agriculture-exposed persons.

IL-10 and IL-17F Promoter Single Nucleotide Polymorphism and Asthma: A Case-Control Study in South India

BACKGROUND

Several studies have assessed the association between IL-17F and IL-10 promoter polymorphisms and asthma, but the results were conflicting. Furthermore, few studies have evaluated the association of cytokine polymorphisms with asthma and its clinical phenotypes.

OBJECTIVE

This study was conducted to evaluate the association of IL-10 (interleukin 10) and IL-17F (interleukin 17F) promoter polymorphisms (rs1800871, rs1800896 and rs1889570) with asthma and its clinical phenotypes including severity, atopic status, spirometric parameters, and response to treatment in south Indian population. A sub-study was conducted to assess cytokine levels in subjects with different gene variants.

METHODS

IL-10 and IL-17F polymorphisms were genotyped in 419 asthmatic patients and 393 controls using Mass ARRAY.

RESULTS

Our results showed an association between IL-10 SNPs and mild asthma. No association was found with any of three SNPs in moderate to severe asthma. Comparison of genotype distribution of IL-17F rs1887570 AA variant among atopic and non-atopic patients showed significant difference (p = 0.024). Correlation analysis of IL-10 and IL-17F SNPs to clinical variables showed a positive correlation between IL-17F rs1887570 AA and number of allergen sensitized (rs = 0.142, p = 0.004). Significant improvement in lung function was observed after 2 months of ICS (Inhaled corticosteroids) and LABA (long acting β2 agonist) treatment in all subjects with no statistically significant difference among SNPs variants. Cytokines levels were similar in different SNP variants.

CONCLUSION

We observed an association between IL-10 rs1800871 and rs1800896 SNPs and mild asthma, as well as IL-17F rs1887570 AA variant and number of allergens sensitized.

Polymorphisms in IL-6, IL-10, TNF-α, IFN-γ and TGF-β1 genes and susceptibility to acute otitis media in early infancy

BACKGROUND

Genetic susceptibility has a major role in the pathogenesis of acute otitis media (AOM). In the present study, we investigated the variability of 5 cytokine genotypes as related to susceptibility and outcome of AOM in early infancy.

METHODS

Single nucleotide polymorphisms in IL-6 (-174 G→C), IL-10 (-592 C→A, -819 C→T and -1082 G→A), TNF-α (-308 G→A), IFN-γ (+874 A→T) and TGF-β1 (codon 10 C→T; codon 25 G→C) genes were investigated and related to clinical course and outcome in 96 infants younger than 9 months with AOM.

RESULTS

Compared with wild genotypes, IL-10 (-592, -819 and -1082) and TGF-β1 (codon 10) genotypes carrying the alternative allele were related to more AOM episodes (P < 0.0001, P < 0.0001, P < 0.0001 and P = 0.002, respectively) and the need for tympanostomy tubes. Furthermore, IL-10 (-1082) and TGF-β1 (codon 10) genotypes carrying the alternative allele were related to later onset of first AOM episode than wild-type genotypes (P = 0.007 and P = 0.039, respectively). No relationship was found about AOM complications.

CONCLUSIONS

Our findings suggest that IL-10 and TGF-β1 genotypes are related to the age of AOM onset, multiple AOM episodes and insertion of tympanostomy tubes, pointing to the involvement of anti-inflammatory cytokines in AOM during infancy.

Defective IL-10 expression and in vitro steroid-induced IL-17A in paediatric severe therapy-resistant asthma

BACKGROUND

Understanding of immune mechanisms underpinning asthma has emerged from studies in adults. It is increasingly recognised, both immunologically and in the development of novel therapies, that adult responses cannot be used accurately to predict those of children.

METHODS

Using a well-defined paediatric cohort of severe therapy-resistant asthma (STRA) patients, we investigated cytokine profiles in the airway by analysis of bronchoalveolar lavage fluid. The in vitro capacity of peripheral blood mononuclear cells (PBMCs) for cytokine production was also assessed following polyclonal T cell activation in culture, in the absence or presence of dexamethasone and 1α,25-dihydroxyvitamin D3.

RESULTS

Children with both moderate and STRA had significantly diminished levels of anti-inflammatory interleukin (IL)-10 in airway lavage samples when compared with non-asthmatic controls (p<0.001). Their PBMCs also demonstrated significantly impaired capacity to secrete IL-10 in culture (p<0.001). Dexamethasone regulated the balance between PBMC IL-10 and IL-13 production, increasing IL-10 secretion (p<0.001) and decreasing IL-13 (p<0.001) but unexpectedly enhanced IL-17A production in all groups-most strikingly in the STRA cohort (p<0.001). The inclusion of the active form of vitamin D, 1α,25-dihydroxyvitamin D3, in culture enhanced dexamethasone-induced IL-10 (p<0.05) without marked effects on IL-13 or IL-17A production. Furthermore, systemic vitamin D status directly correlated with airway IL-10 (r=0.6, p<0.01).

CONCLUSIONS

These findings demonstrate reduced peripheral and local IL-10 synthesis in paediatric asthma, and support therapeutic augmentation of low circulating vitamin D in severe, difficult-to-treat asthma, in order to correct impaired IL-10 levels. Conversely, steroids enhanced IL-17A levels, and therefore any steroid-sparing properties of vitamin D may have additional benefit in STRA.

Interleukin-10 promoter 1082/-819/-592 polymorphisms are associated with asthma susceptibility in Asians and atopic asthma: a meta-analysis

BACKGROUND

Although interleukin-10 (IL-10) is a potent inhibitor of allergic diseases, the association between promoter -1082/-819/-592 polymorphisms and asthma susceptibility remains inconclusive. We sought to determine if IL-10 promoter -1082/-819/-592 polymorphisms contribute to asthma susceptibility and are associated with phenotypes of atopic asthma.

METHODS

Systematic computerized searches were performed. Pooled odds ratios (ORs) and 95 % confidence intervals (CIs) were estimated by using random-effect and fixed-effect models, based on between-study heterogeneity. Subgroup analyses were performed according to age, ethnicity, and atopy. Publication bias was detected by funnel plot using Egger's test.

RESULTS

A total of 4,716 asthmatic patients and 5,093 controls were included. The asthma susceptibility correlated significantly with IL-10 promoter gene -1082 polymorphism [OR (95 % CI) 1.26 (1.02, 1.55) for AA vs. AG + GG] and -592 polymorphism [OR (95 % CI) 1.12 (1.07, 1.34) for AC + AA vs. CC] (both P < 0.05), but not with -819 polymorphism (P > 0.05). Subgroup analyzes suggested that the AA versus AG + GG genotype of -1082A/G polymorphism and AC + AA versus CC genotype of -592A/C polymorphism contributed significantly to increased asthma susceptibility in adults [OR (95 % CI) 1.39 (1.03, 1.87) for -1082A/G and 1.53 (1.25, 1.87) for -592A/C polymorphism]. The Asian population [OR (95 % CI) 1.35 (1.1, 1.7) for -1082A/G and 1.4 (1.12, 1.64) for -592A/C polymorphism] and subjects with atopic asthma [OR (95 % CI) 1.49 (1.18, 1.88) for -1082A/G and 1.23 (1.01, 1.48) for -592A/C polymorphism] also had an increased susceptibility of asthma. No publication bias was detected.

CONCLUSIONS

IL-10 promoter -1028A/G, -592A/C polymorphisms and their haplotypes, but not -819T/C polymorphism, correlate with asthma susceptibility.

TNF-alpha, IL-4R-alpha and IL-4 polymorphisms in mild to severe asthma from Italian Caucasians

Asthma is a chronic airway inflammatory disease associated with airway hyperresponsiveness which affects subjects with genetic predisposition. An association has been reported between some polymorphisms in various cytokine genes and asthma. Most of them are single nucleotide polymorphisms (SNPs). These polymorphisms are detected in the protein coding sequence or in the promoter region thus influencing cytokine production. We investigated the involvement of SNP mapping in 5 cytokine genes in mild to severe asthmatics of Italian Caucasians. The frequency of alleles and genotypes, relatively to 10 allelic specificities of the cytokine genes, was defined in 57 asthmatics and in 124 control subjects by a Polymerase Chain Reaction-Sequence Specific Primer method. TNF-alpha -308A and TNF-alpha -238A allele frequencies were higher in asthmatics than in controls (p less than 0.001). Significant differences in the frequency of IL-4 -590T allele and of IL-4Ralpha +1902A allele were also detected in asthmatics in comparison with controls (pless than 0.001 and p=0.005, respectively). Similarly, IL-1alpha -889C allele was present in 84.1 percent of asthmatics and in 70.2 percent of controls (p=0.013). Furthermore, the IL-4Ralpha +1902A/A and IL-1alpha -889C/C homozygous conditions and the TNF-alpha -308G/A, TNF-alpha -238G/A, IL-4 -590T/C and IL-10 -1082G/A heterozygous conditions were significantly associated with asthma (p less than 0.05). ACA haplotype of IL-10 was observed only in asthmatic patients. This study reports, for the first time, the frequency of 10 different single nucleotide polymorphisms in 5 cytokine genes in the Italian Caucasians. Furthermore, we also indicate that in our population some single nucleotide polymorphisms are associated with mild to severe bronchial asthma.

Immunological parameters and gene polymorphisms (C-590T IL4, C-597A IL10) in severe bronchial asthma in children from the Krasnoyarsk region, West Siberia

Background

Bronchial asthma is a common disease caused by interplay between multiple determinants, including genetic and immune variations.

Objective

To investigate the main indices of humoral and cellular branches of immunity, features of cytokine regulation and cytokine genes in children with atopic bronchial asthma (BA) with different levels of disease control.

Design

Fifty children with controlled BA (CBA) and 50 with uncontrolled BA (UBA) were analyzed. Mean age in the sample was 13.36±2.24 years. A control group of healthy children (n=50) was also studied. All individuals were Russians (Eastern Slavs) from the Krasnoyarsk Territory, West Siberia. Diagnoses, severity and level of disease control were defined according to the Global Initiative for Asthma (GINA) recommendations. The lymphocytes were counted in blood using fluorescent microscopy. Humoral branch indices and cytokine levels (IL-2, IL-4, IL-10 and TNF-α) in blood serum were measured by ELISA. Genotyping of single-nucleotide polymorphism (SNP) in −590 position of the IL4 and −597 position of the IL10 gene was performed by restriction fragment length analysis.

Results

No statistically significant differences in total IgE and cytokines blood levels were found in CBA and UBA. However, significant differences between the groups were found for CD³⁺, CD⁴⁺ and CD⁸⁺ cell counts. The T-590 allele of the IL4 gene, which is responsible for an increased serum level of IL-4, showed a tendency to an association with UBA. A decreased level of IL-10 enhances control over BA, which proves its association with the allelic variant A-597 IL10.

Conclusion

Our data show that children with UBA have higher counts of CD³⁺ cells and an increase of sub-population of CD⁴⁺-cells as well as higher levels of IgE, IL-4 and TNF-α in blood serum as compared to CBA. Polymorphisms of the IL4 and IL10 genes are associated with allergic inflammation in UBA.

Interleukin 10 (IL10) and transforming growth factor β1 (TGFβ1) gene polymorphisms in persistent IgE-mediated cow's milk allergy

OBJECTIVES

The aim of this cross-sectional study was to evaluate whether interleukin 10 (IL10) and transforming growth factor β1 (TGFβ1) gene polymorphisms were associated with persistent IgE-mediated cow's milk allergy in 50 Brazilian children. The diagnostic criteria were anaphylaxis triggered by cow's milk or a positive double-blind, placebo-controlled food challenge. Tolerance was defined as the absence of a clinical response to a double-blind, placebo-controlled food challenge or cow's milk exposure.

METHOD

The genomic DNA of the 50 patients and 224 healthy controls (HCs) was used to investigate five IL10 gene polymorphisms (-3575A/T, -2849A/G, -2763A/C, -1082G/A, -592C/A) and one TGFβ1 polymorphism (-509C/T).

RESULTS

Among the five IL10 polymorphisms analyzed, homozygosis for the G allele at the -1082 position was significantly higher in the patients compared with the healthy controls (p=0.027) and in the persistent cow's milk allergy group compared with the healthy controls (p=0.001).

CONCLUSIONS

Homozygosis for the G allele at the IL10 -1082G/A polymorphism is associated with the persistent form of cow's milk allergy.

Human leukocyte antigen-G expression in differentiated human airway epithelial cells: lack of modulation by Th2-associated cytokines

Background

Human leukocyte antigen (HLA)-G is a nonclassical class I antigen with immunomodulatory roles including up-regulation of suppressor T regulatory lymphocytes. HLA-G was recently identified as an asthma susceptibility gene, and expression of a soluble isoform, HLA-G5, has been demonstrated in human airway epithelium. Increased presence of HLA-G5 has been demonstrated in bronchoalveolar lavage fluid recovered from patients with mild asthma; this suggests a role for this isoform in modulating airway inflammation though the mechanisms by which this occurs is unclear. Airway inflammation associated with Th2 cytokines such as IL-4 and IL-13 is a principal feature of asthma, but whether these cytokines elicit expression of HLA-G is not known.

Methods

We examined gene and protein expression of both soluble (G5) and membrane-bound (G1) HLA-G isoforms in primary differentiated human airway epithelial cells collected from normal lungs and grown in air-liquid interface culture. Cells were treated with up to 10 ng/ml of either IL-4, IL-5, or IL-13, or 100 ng/ml of the immunomodulatory cytokine IL-10, or 10,000 U/ml of the Th1-associated cytokine interferon-beta, for 24 hr, after which RNA was isolated for evaluation by quantitative PCR and protein was collected for Western blot analysis.

Results

HLA-G5 but not G1 was present in dAEC as demonstrated by quantitative PCR, western blot and confocal microscopy. Neither G5 nor G1 expression was increased by the Th2-associated cytokines IL-4, IL-5 or IL-13 over 24 hr, nor after treatment with IL-10, but was increased 4.5 ± 1.4 fold after treatment with 10,000 U/ml interferon-beta.

Conclusions

These data demonstrate the constitutive expression of a T lymphocyte regulatory molecule in differentiated human airway epithelial cells that is not modulated by Th2-associated cytokines.

Interleukin-10 promoter gene polymorphisms and susceptibility to asthma: a meta-analysis

Objective

The aim of this study was to explore whether the interleukin (IL)-10 polymorphisms and their haplotypes contribute to asthma susceptibility.

Methods

MEDLINE, EMBASE and the COCHRANE library databases were utilized to identify available articles. A meta-analysis was conducted on IL-10 -1082 G/A, -819 C/T, -592 C/A polymorphisms, and their haplotypes and asthma.

Results

Eleven studies involving 2,215 asthma patients and 2,170 controls were considered in the meta-analysis. The meta-analysis revealed no association between asthma and the IL-10 -1082 G allele [Odds ratio (OR) = 0.87, 95% Confidence interval (CI) = 0.68–1.12, p = 0.28]. However, meta-analysis of the five studies in Hardy-Weinburg equilibrium produced the relationship between the IL-10 -1082 G allele and asthma (OR = 0.71, 95% CI = 0.60–0.83, p<0.0001). Stratification by ethnicity indicated an association between the IL-10 -1082 G allele and asthma in East Asians (OR = 0.74, 95% CI = 0.57–0.96, p = 0.02), but not in West Asians. Furthermore, stratification by age indicated an association between the IL-10 -1082 G allele and asthma in adults and mixed groups (OR = 0.77, 95% CI = 0.62–0.96, p = 0.02; OR = 0.67, 95% CI = 0.49–0.92, p = 0.01). No association was found between asthma and IL-10 -819 C/T and IL-10 -592 C/A polymorphisms and their haplotypes.

Conclusion

The IL-10 -1082 G/A polymorphism confers susceptibility to asthma in East Asians and in adults. However, the IL-10 -819 C/T, -592 C/A polymorphisms and their haplotypes are not associated with asthma.

Beneficial effects of sitostanol on the attenuated immune function in asthma patients: results of an in vitro approach

Background

In vitro and animal studies have suggested that plant sterols and stanols increase cytokine production by T-helper-1 cells. This may be beneficial for patient groups characterized by a T-helper-2 dominant immune response, e.g. asthma patients. (1) to evaluate whether sitostanol induces a T-helper-1 shift in peripheral blood mononuclear cells (PBMCs) from asthma patients, and (2) to unravel the role of regulatory T-cells in this respect.

Methodology/Principal Findings

PBMCs from 10 asthma patients and 10 healthy subjects were isolated and incubated with 1.2 µM sitostanol, while stimulated with 5 µg/ml PHA. Similar amounts of cholesterol were used to determine whether effects were specific for plant stanols or for sterols in general. Changes in cytokine production were measured using antibody arrays and ELISAs. Changes in regulatory T-cell population size were measured by flow cytometry, using intracellular Foxp3 staining. Sitostanol increased production of IFNγ by 6.5% and IL-2 by 6.0% compared to cholesterol (p<0.01). No changes in IL-4 and IL-13 were found. Interestingly, this effect was only present in PBMCs from asthma patients. The number of Foxp3+ cells tended to increase and their activity, measured by IL-10 production, increased after sitostanol treatment in PBMCs from asthma patients compared to controls by 32.3% (p = 0.077) and 13.3% (p<0.05), respectively.

Conclusions/Significance

Altogether, the sitostanol-induced Thelper-1 shift in PBMCs from asthma patients and the stimulating effects of sitostanol on Treg cell numbers and activity indicate a possible novel approach for plant stanol ester enriched functional foods in the amelioration of asthmatic symptoms. Functional effects, however, require further evaluation.

Interleukin-10 promoter polymorphisms and asthma risk: a meta-analysis

Several studies assessed the associations of interleukin-10 (IL-10) polymorphisms with asthma in different populations. However, the results were inconclusive. The aim of the present study was to further assess the associations by the method of meta-analysis. Pubmed, EMBASE, Wanfang Database, China National Knowledge Infrastructure (CNKI) and Weipu Database were searched. Data were extracted independently by two authors. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of associations. Seventeen potentially eligible articles were identified (4478 cases and 4803 controls). Significant associations between -1082A/G and -592A/C polymorphisms and asthma were observed. However, there was no significant association between -819T/C polymorphism and asthma risk. In addition, there were significant associations of the IL-10 haplotypes with asthma. In summary, this meta-analysis suggested that IL-10 promoter polymorphisms were associated with asthma risk.