Polymorphisms in the IL4, IL4RA, and FCERIB genes and asthma severity

Associations between specific serum IgE response and 6 variants within the genes IL4, IL13, and IL4RA in German children: the German Multicenter Atopy Study

BACKGROUND

Among many published studies of specific IgE response or atopy, only a few showed positive marginal effects for 6 potentially functional single nucleotide polymorphisms (SNPs; C-590T in the IL4 gene, C-1055T and Arg130Gln in the IL13 gene, and Ile50Val, Ser478Pro, and Gln551Arg in the IL4RA gene). SNPs were commonly considered individually, and therefore the true effect could be masked by other genes or environmental factors.

OBJECTIVE

We tested the relationship between these 6 SNPs and sensitization to food, mite, cat, and outdoor allergens in unrelated German children drawn from the Multicenter Atopy Study. Gene-gene and gene-environment interactions were also evaluated.

METHODS

Multiple logistic regression models were used for the analyses of 4 sensitization outcomes.

RESULTS

The variant C-1055T was significantly associated with increased risk of sensitization to food and outdoor allergens, with odds ratios of 3.49 (95% CI, 1.52-8.02) and 2.27 (95% CI, 1.04-4.94), respectively. The effects of the TT genotype on food sensitization appear to depend on variants in the IL4RA gene, in which marginally significant interaction terms were observed. Significant evidence supported an interaction between exposure to maternal smoking and variant Gln551Arg on risk of cat sensitization. In addition, we found that the effect of variant C-590T on sensitization to mite depended on Der p 1 allergen levels in carpet dust samples.

CONCLUSIONS

These findings not only suggested that variants in the IL4, IL13, and IL4RA genes play an important role in controlling specific IgE response but also strengthened our understanding of gene-gene and gene-environment interaction on the development of specific sensitization in this study population.

MCP-1 gene regulatory region polymorphism in Chinese children with mild, moderate and near-fatal asthma

BACKGROUND

A polymorphism in the monocyte chemoattractant protein 1 (MCP-1) gene regulatory region has been associated with asthma in Caucasians. This polymorphism is possibly endemic to the Asian region, but its impact on Asian populations is unclear. In addition, the relationship of this marker with life-threatening asthma has not been clarified. The aim of this study was to test the genetic association between the MCP-1 -2518A/G polymorphism and asthma/atopy in a cohort of Chinese children, with particular emphasis on those patients who had experienced life-threatening asthma attacks.

METHODS

Forty-eight children with near-fatal asthma, 134 mild-to-moderate asthmatics, 69 allergic-disorder cases without asthma, and 107 nonasthmatic, nonatopic control children were genotyped by a polymerase chain reaction-based assay.

RESULTS

Comparison of the four groups of children (n = 358) revealed no detectable differences in genotype or allele frequencies of the MCP-1 -2518A/G polymorphism. There was no evidence of association between the polymorphism and any of the outcomes of interest including clinical severity, blood eosinophil count, atopy, total serum IgE levels, and degree of bronchial hyper-responsiveness.

CONCLUSION

These results suggest that the MCP-1 -2518A/G polymorphism is not a risk factor for near-fatal asthma. Furthermore, this polymorphism seems to play no role in the development of asthma or atopy in Chinese subjects, possibly as a result of the genetic heterogeneity between Asian and Caucasian populations with respect to regulation of MCP-1 expression. Our results underscore the necessity of accounting for ethnic background in the investigation of asthma-predisposition genes.

Severe asthma

Severe asthma is a term that is commonly used to describe patients with refractory, brittle, near fatal, and difficult-to-control asthma. Patients with severe asthma typically experience persistent symptoms despite medical therapy, report decreased quality of life and suffer an accelerated loss of lung function. The role of genetics, environmental exposure, and infection in the development of more severe asthma is the focus of ongoing research. While pathologic changes in these patients are now believed to involve lung parenchyma, in addition to large and small airways, the independent contribution of each of these compartments to the severe asthma phenotype is not well defined. The clinical evaluation of severe asthma patients should include investigating conditions commonly associated with severe asthma, such as gastroesophageal reflux disease, vocal cord dysfunction, and rhinosinusitis. In addition, advanced imaging techniques, measurement of exhaled gas or sputum indices, and airway biopsy are tools that may aid in evaluating severe asthma patients in the near future. Management of patients with severe asthma requires a comprehensive approach that includes non-pharmacological and pharmacological measures. Combination antiinflammatory and long-acting bronchodilator therapy remains the mainstay of management.

Interleukin-4 and -10 gene polymorphisms and spontaneous preterm birth in multifetal gestations

OBJECTIVE

The purpose of this study was to determine the relationship between maternal and fetal carriage of different alleles of interleukin-4 and -10 genes and pregnancy outcome in multifetal gestations.

STUDY DESIGN

Buccal swabs from mother-infant pairs of 73 multifetal gestations were assayed for polymorphisms at position -590 of the interleukin-4 gene and position -1082 of the interleukin-10 gene. Pregnancy outcome data were obtained subsequently.

RESULTS

Spontaneous preterm birth occurred in 29 of the pregnancies (39.7%). A higher frequency of the interleukin-4 T allele was found among mothers with spontaneous preterm birth compared with mothers without spontaneous preterm birth (36.2% vs 18.2%; P=.02; odds ratio, 2.6; 95% CI, 1.1-5.9). Moreover, 20.7% of mothers who had spontaneous preterm birth were homozygous for the interleukin-4 T allele, as opposed to only 2.3% of mothers who did not have a spontaneous preterm birth (P=.01; odds ratio, 11.2; 95% CI, 1.2-69.5). Similarly, in 55.2% of the pregnancies that were complicated by spontaneous preterm birth, 2 fetuses carried the interleukin-4 T allele, compared with only 29.5% of the pregnancies that were not complicated by spontaneous preterm birth (p<.05; odds ratio, 2.9; 95% CI, 1.0-8.8). There was no relationship between mother and infant IL-10 genotype and spontaneous preterm birth.

CONCLUSION

Maternal and fetal carriage of the interleukin-4 T allele is associated with an increased risk of spontaneous preterm birth in multifetal gestations.

Mechanisms of severe asthma

The mechanisms behind the development of severe asthma are poorly understood. However, these patients disproportionately consume healthcare resources related to asthma. Severe asthma may develop over time, or may develop shortly after onset of the disease. The genetic and environmental elements that may be most important in the development of severe disease are poorly understood. Physiologically, these patients often have air trapping and airway collapsibility. The pathology demonstrates a heterogeneity of findings, including continued eosinophilic inflammation, an apparently different pathology, structural changes likely to be remodelling related, and predominant distal disease. Treatment remains problematic and likely will remain so until a better understanding of this disease develops.

Molecular analysis of sequence variants in the Fcepsilon receptor I beta gene and IL-4 gene promoter in Italian atopic families

BACKGROUND

The genetic variants in the Fcepsilon receptor I beta gene (Glu237Gly) and the T allele of the (C590T) polymorphism of interleukin (IL)-4 gene promoter were reported to be associated with atopy. But the data of the studies in different populations are contrasting with one another.

METHODS

A group of 25 Italian nuclear families were studied. In each family at least two allergic subjects were present. The allergic children were 65 and the allergic relatives were 35. One hundred and three nonallergic unrelated controls included outpatiens with no history of atopy. The (C590T) promoter polymorphism of the IL-4 and the genetic variant Glu237Gly of Fcepsilon RI beta genes were analysed by the polymerase chain reaction-restriction fragment length polymorphism method.

RESULTS

A significant difference was observed in the genotype frequency at codon 237 of the Fcepsilon RI beta gene between allergic children and nonatopic control (P < 0.01) and in the allergic relatives (P < 0.001). In the children, the Glu237Gly polymorphism was also associated with elevated circulating levels of immunoglobulin E. The -590C/T allele of IL-4 promoter gene showed no association with atopy.

CONCLUSIONS

In our study, the Glu237Gly polymorphism of the Fcepsilon RI beta gene was associated with atopy. Our results have not pointed out an association between the (C590T) promoter polymorphism of the IL-4 gene and atopy. These data suggest the potential role of the Fc RI beta gene in the development of the allergy.

Genetic variants of TNF-[FC12]a, IL-1beta, IL-4 receptor [FC12]a-chain, IL-6 and IL-10 genes are not risk factors for sepsis in low-birth-weight infants

The amount of inflammatory cytokines is a major determinant for the development of sepsis in very-low-birth-weight (VLBW) neonates. We investigated whether variants of tumor necrosis factor-alpha, interleukin (IL)-1 beta, IL-4 receptor alpha-chain, IL-6 and IL-10 genes, associated with altered cytokine production, might influence the risk and complications of sepsis in VLBW infants. We determined the presence of these genetic variants in dried blood samples of 33 septic, 35 infected and 35 healthy VLBW neonates by PCR and RFLP methods and analyzed their association with the risk and complications of sepsis. The frequencies of genetic variants did not differ in uninfected and in infected infants with or without sepsis. Moreover, none of the studied complications was associated with carrier state of any of genetic variants. Four of the 5 septic neonates with disseminated intravascular coagulation, however, carried simultaneously the variants of IL-1 beta and IL-10 genes. We concluded that these genetic polymorphisms do not influence the risk and course of sepsis in VLBW neonates.

A complete screening of the IL4 gene: novel polymorphisms and their association with asthma and IgE in childhood

BACKGROUND

IL-4, a cytokine with immunomodulatory functions, is involved in the upregulation of IgE production characteristic of asthma and allergy. Thus far, 2 single nucleotide polymorphisms (SNPs) in the promoter (C-589T) and 5' untranslated region (C-33T) of the IL4 gene have been identified. Polymorphism C-589T was reported to influence total serum IgE levels and bronchial hyperresponsiveness. However, no study has investigated the putative existence of further SNPs in exons, introns, and flanking regions of the IL4 gene.

OBJECTIVE

A complete screening of the IL4 gene and its flanking regions for new polymorphisms was performed. Large-scale association studies in 1120 German schoolchildren were conducted to determine the effect of all polymorphisms present in the IL4 gene on the phenotypic expression of atopic diseases.

METHODS

Denaturing HPLC and standard sequencing techniques were performed to detect novel polymorphisms in 33 unrelated subjects unselected for atopic diseases. Linkage disequilibrium was assessed for all polymorphisms in the IL4 gene, and association studies were performed.

RESULTS

A total of 16 polymorphisms were identified in the IL4 gene, 14 of which were not reported previously. The pattern of linkage disequilibrium observed in IL4 could not be explained by physical distance. A significant association between a cluster of polymorphisms in strong linkage disequilibrium with each other and a physician's diagnosis of asthma and total serum IgE levels was found.

CONCLUSION

These results indicate a possible involvement of SNPs in the IL4 gene in the development of asthma and the regulation of total serum IgE.

Association studies for asthma and atopic diseases: a comprehensive review of the literature

Hundreds of genetic association studies on asthma-related phenotypes have been conducted in different populations. To date, variants in 64 genes have been reported to be associated with asthma or related traits in at least one study. Of these, 33 associations were replicated in a second study, 9 associations were not replicated either in a second study or a second sample in the same study, and 22 associations were reported in just a single published study. These results suggest the potential for a great amount of heterogeneity underlying asthma. However, many of these studies are methodologically limited and their interpretation hampered by small sample sizes.

Positive Selection on a Human-Specific Transcription Factor Binding Site Regulating IL4 Expression

A single nucleotide polymorphism in the promoter of the multifunctional cytokine Interleukin 4 (IL4) affects the binding of NFAT, a key transcriptional activator of IL4 in T cells. This regulatory polymorphism influences the balance of cytokine signaling in the immune system, with important consequences-positive and negative-for human health. We determined that the NFAT binding site is unique to humans; it arose by point mutation along the lineage separating humans from other great apes. We show that its frequency distribution among human subpopulations has been shaped by the balance of selective forces on IL4's diverse roles. New statistical approaches, based on parametric and nonparametric comparisons to neutral variants typed in the same individuals, indicate that differentiation among subpopulations at the IL4 promoter polymorphism is too great to be attributed to neutral drift. The allele frequencies of this binding site represent local adaptation to diverse pathogenic challenges; disease states associated with the common derived allele are side-effects of positive selection on other IL4 functions.

No linkage or association of five polymorphisms in the interleukin-4 receptor α gene with atopic asthma in Italian families

The literature contains conflicting reports on the association of common variants of the interleukin (IL)-4 receptor alpha (IL4RA) gene with atopic asthma. The purpose of the present study was to investigate the linkage and association of several gene polymorphisms with atopic asthma in a large series of well-characterized individuals. Analysis of five polymorphisms (I50V, E375A, C406R, S478P and Q551R) of the IL4RA gene was performed in 823 individuals from 182 families with atopic asthmatic children from north-east Italy. The subjects were tested for clinical asthma, total serum IgE level, skin prick test positivity to common aeroallergens, and bronchial hyperresponsiveness to methacholine. The frequency of the polymorphisms was similar to that reported for other populations. The 375, 406, 478 and 551 polymorphisms were in linkage disequilibrium, as previously reported. No linkage or transmission disequilibrium was observed in the families between any mutation and any of the phenotypes investigated. No multipoint haplotype was associated with any phenotype. In conclusion, the IL4RA gene does not seem to play an important role in genetic predisposition to atopic asthma in the population tested.

Lower prevalence of IL-4 receptor alpha-chain gene G variant in very-low-birth-weight infants with necrotizing enterocolitis

BACKGROUND/PURPOSE

Altered production of immunoregulatory cytokines is associated with the development of necrotizing enterocolitis (NEC) in preterm very low-birth-weight (VLBW) infants. According to data obtained in adults, functional genetic polymorphisms influence cytokine production capacity. The aim of this study was to evaluate whether functional polymorphisms of interleukin (IL)-1beta, IL-4 receptor alpha-chain (IL-4ra), IL-6, and IL-10 genes might be associated with the risk of NEC in VLBW infants.

METHODS

Dried blood spot samples of 46 VLBW infants with NEC were analyzed using polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) methods. Samples from 90 VLBW infants without NEC were used as controls.

RESULTS

Infants with NEC carried the mutant variant of IL-4ra less frequently than controls (0.125 v 0.224; P <.05) even after adjustment for risk factors of NEC. No significant differences were found in the allelic frequencies of IL-1beta, IL-6, and IL-10 genes between NEC and control infants.

CONCLUSIONS

Carrier state of IL-4ra mutant allele might be associated with lower risk of NEC in VLBW infants. This genetic variant is associated with enhanced IL-4 effect. IL-4 is a major regulator of Th1-Th2 shift. The authors hypothesize that infants carrying the IL-4ra mutant allele might have Th2 skewness that might defend against the development of NEC.

Associations between total serum IgE levels and the 6 potentially functional variants within the genes IL4, IL13, and IL4RA in German children: the German Multicenter Atopy Study

BACKGROUND

Increased total serum IgE levels are a common characteristic of atopic disorders. Six potentially functional variants, including C-590T in the IL4 gene, C-1055T and Arg130Gln in the IL13 gene, and Ile50Val, Ser478Pro, and Gln551Arg in the IL4RA gene, have been evaluated for their involvement in the control of total serum IgE levels and related atopic disorders, but the results of these studies have been inconsistent.

OBJECTIVE

We examined whether these 6 variants had genotypic effects on total serum IgE levels in 823 unrelated German children from a large infant cohort, the German Multicenter Atopy Study.

METHODS

Marginal effect models were used for the analyses of the repeated IgE measurements. Weighted linear regression and family-based tests of association were performed to minimize the possibility of spurious effects caused by selection bias or confounding on the basis of ethnic background.

RESULTS

There are significant associations between increased total serum IgE levels and 2 variants in the IL13 gene (P <.005 and.0002 for Arg130Gln and C-1055T, respectively). These genetic effects are unlikely to be due to solely linkage disequilibrium between 2 polymorphisms, population stratification, or nonrepresentative samples. In addition, exposure to maternal smoking appears to modify the above effects on total serum IgE levels. However, no statistical association was observed between this quantitative phenotype and the other 4 variants examined.

CONCLUSION

These findings suggest that variants C-1055T and Arg130Gln of the IL13 gene might play an important role on total serum IgE production in this study population.

Polymorphisms in the interleukin-4 and interleukin-4 receptor alpha chain genes confer susceptibility to asthma and atopy in a Caucasian population

BACKGROUND

IL-4 by binding to its receptor (IL-4R) is essential for the development of airway inflammation present in asthma, through the induction of IgE synthesis in B cells and differentiation of T cells to a Th2 phenotype.

OBJECTIVE

To investigate the role of four common polymorphisms in the IL-4 (IL4-34CT and IL4-589CT) and IL-4Ralpha chain (IL4RAI50V and IL4RAQ576R) genes in conferring susceptibility to the development of atopy and/or asthma.

METHODS

Two polymorphisms in the IL-4 gene promoter, IL4-34CT and IL4-589CT, and two polymorphisms in the IL-4Ralpha chain gene, IL4RAI50V and IL4RAQ576R, have been genotyped using PCR-based methods in 341 asthmatic families and in 184 non-asthmatic adults recruited from the south of England.

RESULTS

Case-control analysis did not reveal differences in the distribution of the four polymorphisms between asthmatics and controls. However, the transmission disequilibrium test showed that the IL4-589 T allele was preferentially transmitted to asthmatic children (P=0.036) and that the IL4RAQ576 was preferentially transmitted to children with atopic asthma (P=0.018). Haplotype analysis showed a strong association between the IL4-34T/-589T haplotype and asthma per se (P=0.041), and a strong association between the IL4RA I50/Q576 haplotype and atopic asthma (P=0.006).

CONCLUSION

Our data suggest that polymorphisms in the IL-4 and IL-4Ralpha chain genes might play a role both conferring susceptibility to and modulating severity of atopy and asthma.

Genetic variants of the IL13 and IL4 genes and atopic diseases in at-risk children

We studied a cohort containing 368 children at high risk of developing atopy and atopic disorders and 540 parents of those children to investigate whether the IL13 Arg130Gln and C-1112 T polymorphisms were associated with these outcomes. We also investigated whether haplotypes consisting of any two polymorphisms of IL13 Arg130Gln, IL13 C-1112 T and IL4 C-589 T were associated with these phenotypes. In 288 white children, the IL13 130Gln allele was associated with atopy (RR=1.9, P=0.047), and with atopic dermatitis (RR=2.5, P=0.014). The associations were confirmed using a family-based test of association (P=0.027 and 0.030, respectively) in all subjects. In white subjects there were associations of haplotypes consisting of IL13 Arg130Gln and IL4 C-589 T with atopic dermatitis (P=0.006) and with atopy (P=0.009). Our data suggest that the IL13 Arg130Gln polymorphism and haplotypes consisting of IL13 Arg130Gln and IL4 C-589 T were associated with the development of atopy and atopic dermatitis at 24 months of age.

Association and interaction of the IL4R, IL4, and IL13 loci with type 1 diabetes among Filipinos

In the search for genes involved in type 1 diabetes (T1D), other than the well-established risk alleles at the human leukocyte antigen loci, we have investigated the association and interaction of polymorphisms in genes involved in the IL4/IL13 pathway in a sample of 90 Filipino patients with T1D and 94 controls. Ten single-nucleotide polymorphisms (SNPs), including two promoter SNPs in the IL4R locus on chromosome 16p11, one promoter SNP in the IL4 locus on chromosome 5q31, and four SNPs--including two promoter SNPs--in the IL13 locus on chromosome 5q31 were examined for association, linkage disequilibrium, and interaction. We found that both individual SNPs (IL4R L389L; odds ratio [OR] 0.34; 95% confidence interval [CI] 0.17-0.67; P=.001) and specific haplotypes both in IL4R (OR 0.10; 95% CI 0-0.5; P=.001) and for the five linked IL4 and IL13 SNPs (OR 3.47; P=.004) were strongly associated with susceptibility to T1D. Since IL4 and IL13 both serve as ligands for a receptor composed, in part, of the IL4R alpha chain, we looked for potential epistasis between polymorphisms in the IL4R locus on chromosome 16p11 and the five SNPs in the IL4 and IL13 loci on chromosome 5q31 and found, through use of a logistic-regression model, significant gene-gene interactions (P=.045, corrected for multiple comparisons by permutation analysis). Our data suggest that the risk for T1D is determined, in part, by polymorphisms within the IL4R locus, including promoter and coding-sequence variants, and by specific combinations of genotypes at the IL4R and the IL4 and IL13 loci.

Polymorphisms of interleukin-4 promoter and receptor gene for schizophrenia in the Korean population

The purpose of the present paper was to investigate the interleukin (IL)-4 promoter gene -590 and receptor alpha (Ralpha) gene 1902 polymorphism in Korean schizophrenic patients. A total of 222 Korean patients diagnosed with schizophrenia according to Diagnostic and Statistical Manual of Mental Disorders (4th edn; DSM-IV) and 165 normal healthy controls participated in the present study. The DNA was extracted from whole blood using proteinase K, and the IL-4 promoter and receptor gene were amplified by polymerase chain reaction. The genotype was determined using single-strand conformation polymorphism (SSCP) analysis. The distribution of the alleles and genotypes in patients with schizophrenia was not significantly different from those of controls. In conclusion, these results suggest that the polymorphisms in IL-4 promoter gene -590 and IL-4 Ralpha gene 1902 are not involved in the pathophysiology of schizophrenia in the Korean population.

Cytokine gene polymorphisms in multifactorial diseases: gateways to novel targets for immunotherapy?

Recent advances in cytokine biology have led to novel approaches to the treatment of inflammatory diseases. In this article, we review recent data regarding the role of functional polymorphisms in the genes encoding the prototypic Th1 cytokine interferon gamma and Th2 cytokine interleukin 4 in multifactorial disorders. We have compared genetic data across a heterogeneous assortment of such conditions using a 'haplotype tagging' approach, and demonstrate that cytokine gene association studies are instrumental in the identification of specific disease states or clinical manifestations that are probably caused by genetically determined aberrant cytokine expression. Some of these new findings suggest cytokine effects that go beyond a classical Th1-Th2 dichotomy. Thus, we propose that this information could provide novel targets for immunotherapy and, in particular, might facilitate the identification of clinical subgroups of patients who, by virtue of their genetic constitution at these cytokine gene loci, are more likely to benefit from cytokine agonist or antagonist therapy.

The RANTES promoter polymorphism: a genetic risk factor for near-fatal asthma in Chinese children

BACKGROUND

RANTES promoter polymorphisms were found associated with asthma/atopy in some studies but not others, possibly reflecting the genetic heterogeneity among different ethnicities and different asthma severity.

OBJECTIVE

The purpose of this investigation was to test the genetic association between the RANTES -28C/G and -403G/A polymorphisms and asthma/atopy in a cohort of Chinese children, with particular emphasis on those patients who had experienced life-threatening asthma attacks.

METHODS

Forty-eight children with near-fatal asthma, 134 children with mild-to-moderate asthma, 69 children with allergic disorders but no asthma, and 107 nonasthmatic nonatopic control children were genotyped through use of a PCR-based assay.

RESULTS

No significant difference was demonstrated for frequency of the RANTES -28C/G polymorphism when the mild-to-moderate asthma, atopic/nonasthmatic, and normal control groups were compared. The RANTES -28G allele was present in a significantly higher proportion of the children with near-fatal asthma compared with the nonasthmatic nonatopic controls (odds ratio, 2.93 [1.41-6.06]; P =.006) and the children with mild-to-moderate asthma (odds ratio, 3.52 [1.73-7.16]; P =.001). The frequency of -28G allele carriage correlated with asthma severity. The RANTES -28G allele was also associated with an increased blood eosinophil count and a higher degree of bronchial hyperresponsiveness. The RANTES -403G/A polymorphism did not influence asthma/atopy susceptibility, blood eosinophil count, or bronchial hyperresponsiveness. Interestingly, a higher frequency of -403A allele carriage was observed in the moderate asthma subgroup compared with the mild asthma analog.

CONCLUSIONS

We conclude that the RANTES -28C/G polymorphism exacerbates asthma severity, representing a genetic risk factor for life-threatening asthma attacks in Chinese children. In addition, the linkage disequilibrium between these 2 polymorphisms is a potential confounder that must be considered in the design and interpretation of RANTES gene association studies.

Association between an interleukin-4 promoter polymorphism and the acquisition of CXCR4 using HIV-1 variants

BACKGROUND

A polymorphism at position -589 in the interleukin 4 (IL-4) promoter region was recently described as being associated with the presence of syncytium-inducing CXCR4 using (X4) HIV-1 variants.

OBJECTIVE

To study the IL-4 promoter polymorphism -589T in relation to HIV-1 disease progression and acquisition of X4 HIV-1 variants.

DESIGN AND METHODS

Retrospective longitudinal study among 342 HIV-1-infected homosexual men who participated in the Amsterdam Cohort study. Polymerase chain reaction was used in combination with restriction analysis to identify IL-4 promoter genotypes.

RESULTS

Carriers of the -589T allele (either -589 C/T heterozygotes or -589 T/T homozygotes), showed comparable progression to AIDS [relative hazard (RH), 0.94; P = 0.71], and survival (RH IL-4 -589 C/T or T/T, 0.94; P = 0.69) as carriers of the -589 C/C genotype (the reference group). In contrast to a previous study, we found that the -589T polymorphism was associated with a delayed acquisition of X4 HIV-1 variants (RH, 0.56; P = 0.02 for IL-4 -589 C/T or T/T) and a reduced number of CCR5 expressing memory CD4 T cells.

CONCLUSION

In the Amsterdam Cohort of homosexual men with HIV infection, the IL-4 -589T promoter polymorphism was associated with a delayed acquisition of X4 variants but did not affect overall disease progression.

Interleukin-10 genotypes associate with the risk of gastric carcinoma in Taiwanese Chinese

The association of cytokine genotypes with gastric carcinoma (GC) may be influenced by environmental factors and varies among different populations. Few studies have addressed the impact of different cytokine genotypes on the development and progression of GC. We analyzed 11 functional polymorphisms in tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-1, IL-4 and IL-10 genes in 220 Taiwanese Chinese with GC and in 230 healthy controls. The risk of genotypes was adjusted with confounding environmental risks. Our results revealed that the frequency of Helicobacter pylori infection [odds ratio (OR) 1.7, 95% confidence interval (CI) 1.19-2.56], cigarette smoking (OR 2.02, 95% CI 1.38-2.95) and high IL-10 producer genotype (OR 2.67, 95% CI 1.29-5.50) was significantly increased in the entire GC patients. Among different subtypes of GC, a higher risk of developing diffuse type (OR 1.64, 95% CI 1.01-2.67) or cardia cancer (OR 2.44, 95% CI 1.13-2.67) was observed for the CT/CC genotype of IL-4 at the position -590, whereas the high IL-10 producer genotype was significantly linked with the risk of cardia cancer (OR 3.21, 95% CI 1.06-9.73) or advanced stage (OR 2.29, 95% CI 1.12-4.64). No association was noted between GC and controls in the distribution of IL-1 and TNF-alpha genotypes. Logistic regression analyses revealed that H. pylori infection (OR 1.7, 95% CI 1.14-2.52), cigarette smoking (OR 1.87, 95% CI 1.27--2.96) and IL-10 genotype (OR 2.54, 95% CI 1.24-5.61) are independent risks for GC. Independent effects of IL-10 genotype, H. pylori infection and cigarette smoking indicate that carcinogenesis of GC is influenced by a variety of host and environmental factors.

Severe/fatal asthma

Severe asthma is poorly understood clinically, physiologically, and pathologically. While milder forms of asthma are generally easily treated, more severe forms often remain refractory to the best current medical care. Although some patients with severe asthma have had severe disease for most of their lives, there appears to be a second group that develops severe disease in adulthood. Additionally, it is not clear which genetic and environmental elements may be the most important in the development of severe disease. Physiologically, these patients often have airtrapping and may have loss of elastic recoil, as well. The pathology demonstrates a heterogeneity of findings, including continued eosinophilic inflammation, structural changes, distal disease, and, in at least one third of patients, a different pathology. Treatment remains problematic and likely will remain so until a better understanding of this disease develops.

Polymorphisms in the IL13, IL13RA1, and IL4RA genes and rate of decline in lung function in smokers

Targeted expression of interleukin (IL)-13 in the adult murine lung has been shown to cause emphysema. We hypothesized that variants in the IL13, IL13RA1, and IL4RA genes would be associated with an accelerated rate of decline of lung function among smokers. We determined the allele frequencies of five polymorphisms in the IL13, IL13RA1, and IL4RA genes in 588 continuing smokers chosen from the NHLBI Lung Health Study for having the fastest (n = 282) and slowest (n = 306) 5-yr rate of decline of lung function (mean change in FEV(1) %predicted/yr = -4.1 and +1.1, respectively). The IL4RA 551RR genotype was associated with rapid decline of lung function (odds ratio, 2.24; P = 0.043). However, none of the other four polymorphisms was associated with rate of decline in lung function. The association of 551RR with rapid decline of lung function became more significant in subjects who also had either the IL13 130RR or -1112TT genotypes. However, because multiple comparisons were made and only a few individuals had the 551RR genotype, these associations may represent type 1 error. Haplotypes consisting of alleles from the IL13 polymorphisms or from the IL4RA polymorphisms were not associated with rate of decline in lung function in smokers.

Polymorphisms of IL-4, IL-4R alpha, and AICDA genes in adult allergic asthma

The relationship between 3 polymorphisms sites [interleulin-4 (IL-4), IL-4 receptor (IL-4R) alpha chain and activation-induced cytidine deaminase (AICDA)] and adult allergic asthma in China was studied. By using case-control method, DNA and clinical data were obtained from allergic asthmatic patients and compared with those in the control subjects. The subjects were genotyped for the IL-4 C-589T promoter polymorphism, the IL-4R alpha chain Q576R and the AICDA C8408T by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. The results showed that the IL-4 C-589T was not associated with adult allergic asthma in China. However, the IL-4R alpha chain 576R/R and AICDA 8408T/T frequency was significantly increased in allergic asthma group as compared with that in the control group [odd ratio (OR) = 3.797 and 9.127, respectively; P < 0.01)] and was correlated with the increased plasma total IgE. These data suggested that the IL-4R alpha chain 576R/R and AICDA 8408T/T genotypes confer genetic susceptibility to adult allergic asthma in China.

Present status on the genetic studies of asthma

Asthma, one of the most common chronic diseases, is a complex and heterogeneous disorder. The results of genome screens for asthma-related traits in 11 different populations identified at least 18 regions of the genome that probably house asthma/atopy genes. The most consistently replicated regions are on chromosomes 2q, 5q, 6p, 12q and 13q. Positional cloning projects are ongoing in laboratories around the world to identify the asthma susceptibility loci in these regions. In addition, many candidate genes have been associated with asthma phenotypes, such as the genes in the IL-4/IL-13 pathway.

Interleukin-4 intron 3 polymorphism is not related to susceptibility to febrile seizures

Interleukin-4 (IL-4) is a cytokine with anti-inflammatory properties. This study was undertaken to investigate whether IL-4 intron 3 gene polymorphism could be used as markers of susceptibility to febrile seizures and epilepsy of children. Children were divided into three groups: group 1, febrile seizures (n = 51); group 2, epilepsy (n = 43); and group 3, normal control group (n = 83). Polymorphisms for IL-4 intron 3 were detected by polymerase chain reaction. Genotypes and allelic frequencies for IL-4 intron 3 gene polymorphism in three groups were compared. We found that proportions of different IL-4 intron 3 polymorphisms in three groups were nonsignificantly different. Proportions of RP1 homozygote/heterozygote/RP2 homozygote for IL-4 intron 3 in three groups were as follows: group 1, 56.9/41.2/1.9%; group 2, 62.8/32.6/4.6%; and group 3, 62.7/33.7/3.6%. The proportion of RP1/RP2 for IL-4 intron 3 in three groups were as follows: group 1, 77.5/22.5%, group 2, 79.1/20.9%, and group 3, 79.5/20.5%. We concluded that the association of IL-4 polymorphisms with febrile seizures and epilepsy of children does not exist. IL-4 intron 3 polymorphism is not a useful marker for prediction of the susceptibility of febrile seizure and epilepsy of children.

Association analysis of polymorphisms in the interleukin-4 receptor (alpha) gene with atopic asthma in patients from western Mexico

We undertook an association analysis between the ile50val, glu375ala, cys406arg, and ser761pro polymorphisms of the IL-4Ralpha gene and atopic asthma, total IgE levels and IL-4 serum levels in a population from western Mexico. We found that the ser761pro polymorphism was monomorphic for ser761, while there was no association between any of the other polymorphisms and the three phenotypes analysed.

Familial resemblance of asthma severity in the EGEA* study

Familial resemblance of asthma is well known but epidemiological research focused on familial resemblance of asthma severity is scanty. We studied whether asthma and asthma severity in first-degree relatives of cases with asthma were related to asthma severity of the index case. The analysis was based upon the examination of 944 subjects (348 cases, 239 relatives with asthma, and 357 subjects without asthma) and upon the information on 3467 first- degree relatives of probands. The risks of asthma in relatives of adult and pediatric cases were significantly higher than in relatives of subjects without asthma (OR 3.4 [95% CI 2.5-4.7] and 4.5 [2.6- 8.1], respectively). Proportions of asthma in relatives were not related to the asthma severity of cases for the three severity criteria studied (clinical score, FEV(1) % predicted, and inhaled corticosteroid use). Using both regression models and intraclass correlation coefficients, there was a significant familial resemblance for the clinical severity score (ICC = 0.23 and 0.23) and for FEV(1) (ICC = 0.19 and 0.25) among families of pediatric and adult probands, respectively. In conclusion, asthma occurrence in relatives may be independent of the severity of the cases with asthma, but results suggest familial resemblance in the severity of asthma when it occurs.

Allelic frequencies and patterns of single-nucleotide polymorphisms in candidate genes for asthma and atopy in Iceland

Numerous asthma and atopy loci have been reported in studies demonstrating associations of the asthma-related phenotypes atopy, elevated IgE levels, and bronchial hyperresponsiveness with alleles of microsatellite markers and single-nucleotide polymorphisms (SNPs) within specific cytokine/chemokine and IgE-regulating genes. Although the studies reporting these observations are compelling, most of them lack statistical power. We assessed the nature, pattern, and frequency of SNPs in 24 candidate genes in Iceland and looked for associations with asthma and atopy. We identified 42 SNPs with an average minor allele frequency of 20.3% (asthma) and 20.7% (control). Twenty SNPs (48%) were within coding sequences and 90% of those led to a predicted change in protein sequence. No differences were detected in the allelic frequencies of SNPs in any of these candidate genes between control subjects and the patients with atopic asthma. Moreover, linkage analysis that included 269 patients with atopic asthma uncovered no evidence of linkage to markers associated with these genes. We conclude that this study has failed to produce evidence in support of the notion that variations within these 24 candidate atopy and asthma genes significantly influence the expression of the atopic asthmatic phenotype or contribute to the susceptibility of atopic asthma.

Current concepts on the genetics of asthma

Asthma is a complex genetic disorder with variable phenotype, largely attributed to the interactions of the environment and multiple genes, each potentially having small effects. Numerous asthma and atopy loci have been reported in studies demonstrating associations and/or linkage of the asthma-associated phenotypes, atopy, elevated IgE levels, and bronchial hyperresponsiveness to alleles of microsatellite markers and single nucleotide polymorphisms within specific cytokine/chemokine and IgE regulating genes. Although the studies reporting these observations are compelling, most of them lack statistical power. This review compiles the evidence that supports linkage and associations to the various genetic loci and candidate genes. Whereas significant progress has been made in the field of asthma genetics in the past decade, the roles of the genes and genetic variations within the numerous candidate asthma genes that have been found to associate with the expression of the asthmatic phenotype remain to be determined.

Association of IFN-gamma and IFN regulatory factor 1 polymorphisms with childhood atopic asthma

BACKGROUND

IFN-gamma and related molecules play important roles in the differentiation and function of TH2 cells.

OBJECTIVE

We sought to determine whether IFNG and related genes contribute to any susceptibility to atopic asthma, a representative TH2-dominant disorder.

METHODS

We investigated the association of IFNG (CA repeat polymorphism within the first intron), IRF1 (GT repeat polymorphism within the intron 7), IFNGR1 (Val 14 Met), and IFNGR2 (Gln 64 Arg) gene polymorphisms with atopic asthma in the Japanese child population.

RESULTS

A significant association (P =.0018) was observed between IFNG gene polymorphism and atopic asthma. The tendency was more prominent in patients with age of onset of 3 years or younger (P =.0004) or patients with a family history of allergic diseases (P =.0038). Furthermore, there was a significant association between IRF1 gene whole-allele distribution and atopic asthma (P =.044). The tendency was more prominent in patients with onset at 3 years of age or less (P =.0058). On the other hand, IFNGR1 and IFNGR2 gene polymorphisms showed no association with atopic asthma.

CONCLUSION

These results suggested that among IFNG and related genes, IFNG and IRF1 genes confer genetic susceptibility to atopic asthma in Japanese children.

Regulation of allergic airways inflammation by cytokines and glucocorticoids

Cytokines mediate the allergic inflammatory response of the airways, and glucocorticosteroids ameliorate allergy symptoms by regulating cytokine expression. Recent studies provide insight into the manner by which cytokines work together to mediate allergic airway disease. Real progress has also been gained in our understanding of subcellular mechanisms of allergic inflammation, particularly the role of transcription factors in regulating the expression of specific cytokine profiles and the differentiation of the TH2 subset. This article provides an update of recently reported findings in this field and highlights emerging concepts of allergic inflammation.