Does the relationship between IgE and the CD14 gene depend on ethnicity?

The CD14 (-159 C/T) SNP is associated with sCD14 levels and allergic asthma, but not with CD14 expression on monocytes

LPS-ligation to CD14/TLR-4 on monocytes/macrophages triggers the production of IL-12-family cytokines. IL12/18 promote TH₁-differentiation, counteracting the TH₂-driven asthma. Therefore, CD14 modulation could alter the TH₂-differentiation and should be taken into account when studying asthma. To analyse the alteration in CD14 levels and its association with CD14 (−159 C/T) SNP (rs2569190) in Caucasian adults with stable allergic asthma, we performed a cross-sectional study (277 healthy subjects vs. 277 patients) where clinical parameters, CD14 values and the CD14 (−159 C/T) SNP were studied. Apart from typical biomarkers, we found an increment of neuron-specific enolase (NSE) in allergic asthma, probably linked to monocyte activity. Indeed, we evidenced increased monocyte numbers, but lower CD14 expression and normalised sCD14 values in patients. Moreover, we noticed an association of the T allele (P = 0.0162) and TT genotype (P = 0.0196) of the CD14 SNP with a decreased risk of allergic asthma and augmented sCD14 levels. In conclusion, monocyte CD14 expression and normalized sCD14 values were reduced in stable state asthmatics, and this could be related to the presence of an expanded CD14^low monocyte subset. This study also demonstrates that the CD14 (−159 C/T) polymorphism is a risk factor for moderate-severe allergic asthma in adult Caucasians.

No simple answers for the Finnish and Russian Karelia allergy contrast: Methylation of CD14 gene

BACKGROUND

Finnish and Russian Karelian children have a highly contrasting occurrence of asthma and allergy. In these two environments, we studied associations between total serum immunoglobulin E (IgE) with methylation levels in cluster of differentiation 14 (CD14).

METHODS

Five hundred Finnish and Russian Karelian children were included in four groups: Finnish children with high IgE (n = 126) and low IgE (n = 124) as well as Russian children with high IgE (n = 125) and low IgE (n = 125). DNA was extracted from whole blood cells and pyrosequenced. Three CpG sites were selected in the promoter region of CD14.

RESULTS

Methylation levels in two of the three CpG sites were higher in the Finnish compared to Russian Karelian children. In the promoter area of CD14, the Finnish compared to Russian children with low IgE had a significant (p < 0.0001) increase in methylation levels at the Amp5Site 2. Likewise, the Finnish compared to Russian children with high IgE had a significant (p = 0.003) increase in methylation levels at the Amp5Site 3. In Russian children with low vs. high IgE, there were significant differences in methylation levels, but this was not the case on the Finnish side. In the regression analysis, adding the methylation variation of CD14 to the model did not explain the higher asthma and allergy risk in the Finnish children.

CONCLUSIONS

The methylation levels in the promoter region of CD14 gene were higher in the Finnish compared to Russian Karelian children. However, the methylation variation of this candidate gene did not explain the asthma and allergy contrast between these two areas.

IL-4 receptor alpha single-nucleotide polymorphisms rs1805010 and rs1801275 are associated with increased risk of asthma in a Saudi Arabian population

BACKGROUND

The IL-4 receptor alpha subunit (IL-4Rα), when associated with the common gamma chain receptor, or the IL-13Rα1 subunit, transduces signals to STAT6 in response to IL-4 and IL-13 stimulations. This results in a number of cell-specific responses including Th2 differentiation, lymphocyte proliferation and IgE production. Given the prominent role of IL-4Rα in allergic disorders, several single-nucleotide polymorphisms (SNPs) have been found associated with asthma and other atopic disorders, including rs1805010 (I75V) and rs1801275 (Q576R) SNPs; however, lack of significant association have also been reported for some ethnic groups. The objective of this study was to determine whether IL-4Rα rs1805010 and rs1801275 polymorphisms are associated with asthma in patients from Saudi Arabia.

MATERIALS AND METHODS

One hundred and ninety severe asthmatic patients (11-70 years old) and 194 healthy subjects of equivalent age range were recruited for blood donation. DNA was purified and genotyping for rs1801275 and rs1805010 polymorphisms in the IL-4Rα gene was performed by PCR amplification, followed by cycle sequencing of the purified PCR fragments using BigDye chain terminator and capillary electrophoresis.

RESULTS

Pearson's Chi-square tests showed that the minor alleles, G, for both rs1805010 and rs1801275 SNPs, were significantly more frequent in asthmatics than in the healthy group (Yates' P < 0.05); conversely, the major alleles, A, were significantly more frequent in healthy than in asthmatics (P < 0.05). Concerning association analysis, odds for A/G-G/G genotypes were significantly higher to be associated with asthma predisposition (rs1801275: OR = 2.12; 95% CI = 1.39-3.22; P < 0.001*; rs1805010: OR = 1.6; 95% CI = 1.01-2.53; P < 0.05*; dominant model). Analysis of gender-genotype interactions, with genders nested within A/G-G/G, indicated higher odds for females than males of significant association with asthma (rs1801275: OR = 5.19, 95% CI = 2.09-12.94*; rs1805010: OR = 3.73, 95% CI = 2.06-6.74*). Rs1805010 and rs1801275 were in linkage disequilibrium (D' = 0.27; P < 0.0004*), with G-G haplotype being more frequent in asthmatics than in healthy subjects (OR = 2.43, 95% CI = 1.59-3.71*).

CONCLUSIONS

The risk alleles, G, of IL-4Rα rs1805010 and rs1801275 SNPs and corresponding A/G-G/G genotypes were significantly associated with asthma predisposition in asthmatics from Saudi Arabia.

Maternal Genetic Variants of IL4/IL13 Pathway Genes on IgE With "Western or Eastern Environments/Lifestyles"

Purpose

We investigated maternal genetic effects of four IL-4/IL-13 pathway genes as well as their interactions with the "Western or Eastern lifestyles/environments" on IgE in Karelian children.

Methods

This study included 609 children and their mothers. Total IgE levels in children and mothers were measured and 10 single nucleotide polymorphisms (SNPs) in IL-4, IL-4Ra, IL-13, and STAT6 were genotyped in mothers and their children.

Results

The maternal G allele of IL-13 130 (rs20541) was significantly (P=0.001) associated with decreased IgE in children in the Karelian population (Pooling Finnish and Russian children), as well as in Finnish (P=0.030) and Russian children (P=0.018). The IgE levels were significantly (P=0.001) higher in Russian children whose mothers were homozygous for the G allele of the IL-4Ra 50 (rs1805010) SNP than that in Russian children of mothers who were AG heterozygotes or AA homozygotes. After accounting for children's genotypes, we observed interactive effects on children's IgE for maternal IL-13 130 genotypes (P=0.014) and maternal IL-4Ra 50 genotypes (P=0.0003) with "Western or Eastern" lifestyles/environments. With the adjustment for multiple comparisons using a false discovery rate (FDR) of 0.05, the interactive effect of the maternal IL-4Ra50 SNP was significant.

Conclusion

Maternal genetic variants in IL-4/IL-13 pathway genes, such as IL-13 130 and IL-4Ra50, influenced IgE levels in school children that were independent of the children's genetic effects. These effects differ in "Western or Eastern" environments.

CD14 tobacco gene-environment interaction in atopic children

Studying gene-environment interactions may elucidate the complex origins of atopic diseases. The aim of this study was to evaluate the association of CD14 polymorphisms and atopy in Egyptian children and to study whether atopy is influenced by CD14 interaction with tobacco smoke exposure. CD14 -159 C/T and CD14 -550 C/T were genotyped in 500 asthmaic children, 150 allergic rhinitis children and 150 controls. We found that CD14 -159T allele, CD14 -550T allele and CD14 -159T/-550T haplotype were significantly associated with atopic asthma and allergic rhinitis groups. CD14 -159 TT and CD14 -550 TT genotypes associated with elevated IgE levels in children exposed to tobacco smoke. The TT genotype of CD14 -159 C/T and CD14 -550 C/T was associated with higher serum levels of sCD14. The present study indicated that CD14 gene polymorphisms may contribute to susceptibility to atopy in Egyptian children and influenced with tobacco smoke exposure.

A systematic review of CD14 and toll-like receptors in relation to asthma in Caucasian children

The aetiology of childhood asthma is complex. An early dysfunction in the immunological development of the innate immune system in combination with environmental factors possibly triggers asthma. CD14 and toll-like receptors are important components of the innate immune system. The aim of this systematic review was to obtain a better insight into the relation between CD14 and toll-like receptors and childhood asthma in Caucasians. We searched PubMed and EMBASE for relevant articles. In total, 44 articles were included. The quality of the selected studies was independently assessed by the first two authors using the Newcastle-Ottawa quality assessment scale. Toll-like receptor 2, toll-like receptor 6, toll-like receptor 9, and toll-like receptor 10 appear to have some association with childhood asthma in Caucasians. The evidence for a relation of CD14 with childhood asthma is limited. In conclusion, there is no convincing evidence yet for a role of CD14 and toll-like receptors in relation to childhood asthma. Future studies should include haplotype analysis and take environmental factors into account to further clarify the role of CD14 and toll-like receptors on childhood asthma.

Polymorphisms in the promoter of the CD14 gene and their associations with susceptibility to pulmonary tuberculosis

Although the role of CD14 in recognizing Mycobacterium tuberculosis is well-understood, the possible role of polymorphisms in susceptibility to develop tuberculosis remains unclear. This study evaluates whether there is an association of polymorphisms within the promoter of the CD14 gene with susceptibility to pulmonary tuberculosis. In a case-control study, we genotyped the eight known single nucleotide polymorphisms SNPs within the promoter of the CD14 gene of 698 Han Chinese subjects. Statistically significant differences between tuberculosis patients and healthy controls were found for G-1619A, T-1359G, A-1145G, and C-159T. The haplotype-GGGT, composed of these four SNPs, exhibited a significant association with the disease. Furthermore, expression levels of soluble CD14 were significantly higher in tuberculosis patients with the GGGT haplotype than with other haplotypes, while IgE expression levels were significantly reduced. Our results suggest that these four SNPs within the promoter of the CD14 gene are associated with susceptibility to pulmonary tuberculosis.

Interleukin-10 (IL-10) polymorphisms are associated with IL-10 production and clinical malaria in young children

The role of interleukin-10 (IL-10) in malaria remains poorly characterized. The aims of this study were to investigate (i) whether genetic variants of the IL-10 gene influence IL-10 production and (ii) whether IL-10 production as well as the genotypes and haplotypes of the IL-10 gene in young children and their mothers are associated with the incidence of clinical malaria in young children. We genotyped three IL-10 single nucleotide polymorphisms in 240 children and their mothers from a longitudinal prospective cohort and assessed the IL-10 production by maternal peripheral blood mononuclear cells (PBMCs) and cord blood mononuclear cells (CBMCs). Clinical episodes of Plasmodium falciparum malaria in the children were documented until the second year of life. The polymorphism IL-10 A-1082G (GCC haplotype of three SNPs in IL-10) in children was associated with IL-10 production levels by CBMC cultured with P. falciparum-infected erythrocytes (P = 0.043), with the G allele linked to low IL-10 production capacity. The G allele in children was also significantly associated with a decreased risk for clinical malaria infection in their second year of life (P = 0.016). Furthermore, IL-10 levels measured in maternal PBMCs cultured with infected erythrocytes were associated with increased risk of malaria infection in young children (P < 0.001). In conclusion, IL-10 polymorphisms and IL-10 production capacity were associated with clinical malaria infections in young children. High IL-10 production capacity inherited from parents may diminish immunological protection against P. falciparum infection, thereby being a risk for increased malaria morbidity.

Associations of allergic sensitization and clinical phenotypes with innate immune response genes polymorphisms are modified by house dust mite allergen exposure

INTRODUCTION

Polymorphisms within innate immunity genes are associated with allergic phenotypes but results are variable. These associations were not analyzed with respect to allergen exposure. We investigated associations of TLR and CD14 polymorphisms with allergy phenotypes in the context of house dust mite (HDM) exposure.

MATERIAL AND METHODS

Children, aged 12-16 years (n=326), were recruited from downtown and rural locations and assessed by allergist. Skin prick tests, total and HDM-specific sIgE measurements were done. HDM allergen concentrations in dust were measured. Genetic polymorphisms were identified using restriction fragment length polymorphism (RFLP).

RESULTS

Allergic rhinitis, asthma and atopy were more prevalent in urban area. Although HDM allergen concentrations were higher in rural households, sIgE were present more frequently in urban children. In the whole population no association was found between HDM exposure and sensitization. In children with CD14/-159CC, CD14/-159TT and TLR9/2848GA genotypes increased exposure to HDM was associated with reduced incidence of allergic rhinitis. Significant associations of increased HDM exposure with reduced incidence of atopy were found for the whole population and subjects with CD14/-159CC, CD14/-1359GT, TLR4/896AA and TLR9/2848GA genotypes. Among children with CD14/-159CC and CD14/-1359GG significant positive correlation between HDM allergen concentrations in household and sensitization to HDM was observed. In contrast, protective effect of high HDM allergen exposure against specific sensitization was seen in subjects with TLR4/896 AG.

CONCLUSIONS

Development of specific sensitization and allergy may be associated with innate immune response genes polymorphisms and is modified by allergen exposure.

Disparity of innate immunity-related gene effects on asthma and allergy on Karelia

BACKGROUND

We investigated the interactive effects of 11 innate immunity-related genes (IL10, IL12b, IL8, TLR2, TLR4, CD14, IFNGR, CC16, IFNg, CMA1, and TGFB) and four IgE response genes (IL4, IL13, IL4RA, and STAT6) with 'Western' or 'Eastern' environments/lifestyles on asthma and allergy in Karelian children.

METHODS

Karelian children (412 Finnish and 446 Russian) were recruited and assessed for a range of allergic conditions, with 24 single-nucleotide polymorphisms genotyped in 15 genes.

RESULTS

The genotype-phenotype relationships differed in Finnish and Russian Karelian children. The interaction between polymorphisms and the variable representing 'Western' and 'Eastern' environments/ lifestyles was significant for IL10-1082 (p = 0.0083) on current rhinitis, IL12b 6408 on current conjunctivitis (p = 0.016) and atopy (p = 0.034), IL8 781 on atopic eczema (p = 0.0096), CD14 -550 on current rhinitis (p = 0.022), IFNgR1 -56 on atopic eczema(p = 0.038), and STAT6 2964 on current itchy rash (p = 0.037) and total serum IgE (p = 0.042). In addition, the G allele of IL13 130 was associated with a lower level of total serum IgE in Finnish (p = 0.003) and Russian (p = 0.01) children and overall (pooling the two populations together, p = 0.00006). After adjusting for multiple tests, the association between IL13 130 and IgE and the interactive effects of IL10-1082 on current rhinitis and IL8 781 on atopic eczema were significant by controlling a false-positive rate of 0.05 and 0.10, respectively.

CONCLUSIONS

Living in an Eastern vs. Western environment was associated with a different genetic profile associated with asthma and allergy in the Karelian populations.

Genetic polymorphism of manganese superoxide dismutase is associated with childhood asthma

OBJECTIVE

Cellular defenses against allergens and reactive oxygen species (ROS) exposure are critical in the pathogenesis of asthma. CD14 is a receptor for various bacterial products, such as lipopolysaccharides (LPS), and is also a mediator of inflammatory processes. Manganese superoxide dismutase (MnSOD) is an ROS scavenger, and myeloperoxidase (MPO) can convert hydrogen peroxide into hypochlorous acid; thus, they are considered to be involved in inflammatory defense. The authors conducted a case-control study to evaluate the susceptibility to childhood asthma based on CD14, MnSOD, and MPO genes.

METHODS

The CD14 -260, MnSOD -9, and MPO -463 genotypes were identified by polymerase chain reactions for 116 asthmatic children and 232 healthy controls. Questionnaires were administered to obtain demographic characteristics. Allergen testing used common Taiwanese aeroallergens.

RESULTS

A higher level of parental education, family history of asthma, incense burning at home, allergen-test positive, and the MnSOD Val-Ala/Ala-Ala genotypes (matched relative risk = 2.0; 95% confidence interval = 1.0-4.2) were significantly associated with childhood asthma. Interactions between CD14, MnSOD, MPO genotypes and allergy status were significantly associated with asthma risk in these children (all p <.001). Furthermore, atopic cases with MnSOD Val-Ala/Ala-Ala (log eosinophil 2.66/mm(3), log total serum immunoglobulin E [IgE] 2.48 IU/ml) or Val-Val (log eosinophil 2.61/mm(3), log total serum IgE 2.63 IU/ml) genotypes had elevated eosinophil counts and total serum IgE levels as compared to nonatopic cases with MnSOD Val-Val genotype (log eosinophil 2.27/mm(3), log total serum IgE 1.83 IU/ml).

CONCLUSIONS

Susceptible MnSOD genotypes might modulate the development of asthma in Taiwanese children.

The importance of environment on respiratory genotype/phenotype relationships in the Inuit

BACKGROUND

Genetic and environmental influences and their interactions are central to asthma pathogenesis. This study aimed to investigate the effects of different macro-environments on asthma genotype-phenotype associations in two geographically separated populations with common ancestry.

METHODS

To accomplish this, two unselected populations of Inuit were recruited, one living in Greenland (n = 618) and the other in Denmark (n = 739). Subjects were genotyped for CD14 C-159T, SCGB1A1 A38G, ADRB2 Arg16Gly and Gln27Glu. The resulting genetic data were analysed for relationships with asthma-related parameters including lung function, ever asthma, atopy, rhinitis and dermatitis.

RESULTS

The results showed contrasting magnitude and direction of genetic associations between the two geographically separate Inuit populations. In Greenland, the ADRB2 16Arg allele was associated with male-specific lower lung function, but in Denmark the same allele was associated with male-specific higher lung function. This allele was also associated with higher incidence of ever asthma in Denmark but not in Greenland. The SCGB1A1 38A allele was associated with lower rhinitis prevalence in Greenland but not in Denmark.

CONCLUSIONS

These associations suggest that environment interacts with candidate asthma genes to modulate asthma pathogenesis in the Inuit.

Nuclear receptor coregulator SNP discovery and impact on breast cancer risk

Background

Coregulator proteins are "master regulators", directing transcriptional and posttranscriptional regulation of many target genes, and are critical in many normal physiological processes, but also in hormone driven diseases, such as breast cancer. Little is known on how genetic changes in these genes impact disease development and progression. Thus, we set out to identify novel single nucleotide polymorphisms (SNPs) within SRC-1 (NCoA1), SRC-3 (NCoA3, AIB1), NCoR (NCoR1), and SMRT (NCoR2), and test the most promising SNPs for associations with breast cancer risk.

Methods

The identification of novel SNPs was accomplished by sequencing the coding regions of these genes in 96 apparently normal individuals (48 Caucasian Americans, 48 African Americans). To assess their association with breast cancer risk, five SNPs were genotyped in 1218 familial BRCA1/2-mutation negative breast cancer cases and 1509 controls (rs1804645, rs6094752, rs2230782, rs2076546, rs2229840).

Results

Through our resequencing effort, we identified 74 novel SNPs (30 in NCoR, 32 in SMRT, 10 in SRC-3, and 2 in SRC-1). Of these, 8 were found with minor allele frequency (MAF) >5% illustrating the large amount of genetic diversity yet to be discovered. The previously shown protective effect of rs2230782 in SRC-3 was strengthened (OR = 0.45 [0.21-0.98], p = 0.04). No significant associations were found with the other SNPs genotyped.

Conclusions

This data illustrates the importance of coregulators, especially SRC-3, in breast cancer development and suggests that more focused studies, including functional analyses, should be conducted.

The era of genome-wide association studies: opportunities and challenges for asthma genetics

In the era of genome-wide association (GWA) studies, delineating pathogenic asthma genetic pathways has provided both challenges and opportunities. Initial GWA studies on asthma and asthma-like phenotypes provided some successes in terms of ascertaining new potential asthma candidate genes. However, due to asthma having a heterogeneous etiology, replications of these genotype-phenotype association studies are generally lacking. Furthermore, genes by environment interactions are generally not considered when GWA studies are conducted. Therefore, there is a need for extensive collaborations in multi-disciplinary research fields, including different environments and populations, to investigate the functional importance of variations in the human genome in relation to asthma pathogenesis.

Opposite gene by environment interactions in Karelia for CD14 and CC16 single nucleotide polymorphisms and allergy

BACKGROUND

Finnish Karelians have a higher prevalence of allergic disease than Russian Karelians. As both populations are generally from the same ethnic group, the Karelian population offers a unique opportunity to analyse genetic and allergic disease interactions between 'Western' and 'Eastern' environments.

OBJECTIVES

We investigated associations between allergic diseases and CD14 and CC16 polymorphisms in Finnish vs Russian Karelian women.

METHODS

Adult female Karelians (330 Finnish and 274 Russian) were recruited, examined for a range of symptoms and conditions including rhinitis, itchy rash, asthma and atopy and genotyped for CD14 C-159T and CC16 A38G.

RESULTS

For both CD14 C-159T and CC16 A38G, the risk allele for atopic phenotypes in Finnish Karelia was the protective allele in Russian Karelia. For CD14 C-159T, an interactive effect on ever itchy rash (P(interaction) = 0.004), itchy rash <12 mo (P(interaction) = 0.001) and dry cough at night in the past 12 months (<12 months) (P(interaction) = 0.011) was found; the risk allele was C in Russians and T in Finns. For CC16 A38G, an interaction was significant for ever rhinitis (P(interaction) = 0.006), rhinitis <12 mo (P(interaction) = 0.004), and marginally significant for ever hayfever (P(interaction) = 0.07), allergic eye symptoms <12 mo (P(interaction) = 0.09); their risk allele was G in Russians and A in Finns.

CONCLUSION

An Eastern vs Western environment appears to exert an effect via opposite alleles on risk of allergic diseases in adult women.

CD14 and toll-like receptor gene polymorphisms, country living, and asthma in adults

RATIONALE

It has been shown that country living protects against asthma, which may be explained by microbial exposures.

OBJECTIVES

To study whether single nucleotide polymorphisms (SNPs) in CD14 and Toll-like receptor (TLR) 2, TLR4 and TLR9 genes are associated with asthma in adults, and whether these SNPs modify associations between country living and asthma.

METHODS

Twenty-five SNPs in CD14, TLR2, TLR4, and TLR9 genes were genotyped in adult subjects from the French Epidemiological study on the Genetics and Environment of Asthma, Bronchial Hyperresponsiveness, and Atopy (EGEA). We conducted a case-control analysis on unrelated subjects (239 with asthma and 596 without asthma), and a family-based association test (FBAT) in 192 families ascertained through probands with asthma.

MEASUREMENTS AND MAIN RESULTS

The TLR2/+596 C allele was associated with an increased risk for asthma in both case-control and family-based analyses (under a dominant model, odds ratio [OR] 1.91 and 95% confidence interval [CI] 1.34-2.72, P = 0.0003; Z statistics from FBAT = 2.48, P = 0.01). In skin prick test (SPT) positive subjects, the CD14/-260 C allele was negatively associated with asthma (additive model, OR 0.66; CI 0.48-0.91). Significant gene-environment interactions between variation in CD14 and TLR genes and country living during childhood were found for ten SNPs. In SPT positive subjects carrying CD14/-260 CC, country living protected against asthma (OR, 0.32; 95% CI, 0.12-0.85), whereas country living was not associated with asthma in subjects who were atopic and carrying CD14/-260 T (OR, 1.11; 95% CI, 0.65-1.90) (gene-environment interaction, P < 0.05).

CONCLUSIONS

TLR2 and CD14 SNPs were associated with asthma and atopic asthma respectively. In addition, CD14, TLR2, TLR4, and TLR9 SNPs modified associations between country living and asthma.