A common IL-1 complex haplotype is associated with an increased risk of atopy

Cytokine production associated with smallpox vaccine responses

Smallpox was eradicated 34 years ago due to the success of the smallpox vaccine; yet, the vaccine continues to be studied because of its importance in responding to potential biological warfare and the adverse events associated with current smallpox vaccines. Interindividual variations in vaccine response are observed and are, in part, due to genetic variation. In some cases, these varying responses lead to adverse events, which occur at a relatively high rate for the smallpox vaccine compared with other vaccines. Here, we aim to summarize the cytokine responses associated with smallpox vaccine response to date. Along with a description of each of these cytokines, we describe the genetic and adverse event data associated with cytokine responses to smallpox vaccination.

High risk association of IL-1 receptor antagonist (IL-1RN) VNTR polymorphism with asthma in a North Indian population: a pilot study

BACKGROUND

A pilot case-control study was conducted to evaluate the role of IL-1 receptor antagonist (IL-1RN) VNTR penta-allelic polymorphism in asthma that has been associated with various inflammatory diseases worldwide. This is the first case-control study conducted in India, investigating the role of IL-1RN VNTR polymorphism in asthma pathogenesis.

METHODS

A case-control study was performed with a total of 824 adult subjects, inducting 410 asthma patients and 414 healthy controls from North India. The genotypes were identified by polymerase chain reaction.

RESULTS

Statistical analysis for the IL-1RN VNTR polymorphism revealed that the IL-1RN(*)2 allele was significantly associated with asthma with OR=1.45, 95% CI (1.15-1.85) and p=0.001. The IL-1RN(*)2/2 genotype posed a risk towards asthma with OR=1.66, 95% CI (0.97-2.86) and p=0.048. Most of the phenotypic traits were significantly associated with the disease.

CONCLUSIONS

IL-1RN(*)2 allele is a high risk factor for asthma in the studied North Indian population.

Gene polymorphisms of IL-6(-174) G/C and IL-1Ra VNTR in asthmatic children

OBJECTIVE

To check for the association of genetic polymorphisms of IL-6-(-174)G/C and IL-1RaVNTR with the susceptibility and severity of asthma in Egyptian children.

METHODS

Subjects included 69 asthmatic children and 98 healthy unrelated controls from the Nile Delta of Egypt. Cases consisted of 20 males and 49 females with an age mean +/- SD is 7.5 +/- 2.1 ranging between 2-13 years. DNA amplification using PCR with sequence-specific primers was done for detection of promotor single nucleotide polymorphism of IL-6 gene as well as intron 2 VNTR of IL-1Ra gene. Frequency of case-genotypes or alleles were compared to controls using Fisher exact test and Odds ratio.

RESULTS

Cases showed significant higher frequency of the genotypes: IL-6-174 GG (P<0.05, OR=3.2, 95% CI=1.09-10) that was evident mainly in the uncontrolled asthma subgroup indicative of the possibility of being a severity genotype. All cases as well as case-subgroups showed high significant frequency of IL-1Ra A1A1 (p<0.0001, OR=1.5, 95% CI=1.3-1.8). This may be considered a susceptibility genotype. Cases have also shown significant lower frequency of IL-6(-174) GC and IL-1Ra A1A2 genotypes (P<0.001 and P<0.0001 respectively).

CONCLUSION

IL-6 and IL-1Ra polymorphisms can be considered genetic markers for bronchial asthma susceptibility and/or severity among Egyptian children. This may have a potential impact on family counseling and management.

Interleukin-1R antagonist gene and pre-natal smoke exposure are associated with childhood asthma

The interleukin-1 receptor antagonist (IL1RN) is a potent anti-inflammatory cytokine. In the present study, association of the human IL1RN gene polymorphisms with asthma, bronchial hyperresponsiveness and forced expiratory volume in one second/forced vital capacity ratio was tested and the data was stratified by environmental tobacco smoke exposure in order to investigate a gene-smoking interaction. In an unselected subset (n = 921) of the Isle of Wight birth (UK) cohort, which has previously been evaluated for asthma and related manifestations at ages 1, 2, 4 and 10 yrs, three IL1RN single nucleotide polymorphisms (SNP) were genotyped. Logistic regression and repeated measurement models for tests of association using a representative SNP rs2234678 were used, as all SNPs tested were in strong linkage disequilibrium. In the overall analysis, the SNP rs2234678 was not associated with asthma. However, in the stratum with maternal smoking during pregnancy the rs2234678 GG genotype significantly increased the relative risk of asthma in children, both in analyses of repeated asthma occurrences and persistent asthma. In conclusion, the present results show that in the first decade of life, the gene-environment interaction of the interleukin-1 receptor antagonist gene polymorphism rs2234678 and maternal smoking during pregnancy increased the risk for childhood asthma.

The role of genetics in the development of asthma and atopy

PURPOSE OF REVIEW

The mapping of complex traits such as asthma and atopy is one of the most important and central areas of human genetics. This article will present an overview of the current status of genetic studies of asthma and atopy using genome screens and association studies that have occurred in the literature since January 2003.

RECENT FINDINGS

Many regions of the genome have been found to have linkage with the phenotypes of asthma and atopy. Over 70 variants in candidate genes have been reported to be associated with these phenotypes. The main regions these variants have been found are on chromosomes 2q, 5q, 6p, 11q, 12q, 16q and 17q. Five potential asthma susceptibility genes or complexes have been identified using a positional approach. These are ADAM33, DPP10, PHF11 and SETDB2, GPRA and SPINK5. It is evident that environmental factors will influence the expression of genes and the ultimate clinical phenotype of asthma and atopy.

SUMMARY

The development of asthma and atopy involves many genes and environmental factors. An understanding of their genetic basis has great implications for their management.

Association between allelic variants in cytokine genes and preeclampsia

OBJECTIVE

The purpose of this study was to examine the relationship between cytokine genotypes and preeclampsia.

STUDY DESIGN

We conducted a case-control study that examined cytokine genotypes among 150 primiparous preeclamptic women and 661 primiparous, normotensive women. Analyses were adjusted for age, prepregnancy cigarette smoking, and education.

RESULTS

Preeclamptic white women were more likely than normotensive white women to carry the up-regulating tumor necrosis factor-alpha-308 A/A (odds ratio, 4.1; 95% CI, 1.1-15.3) genotype. Both black and white women with preeclampsia were more likely than normotensive control subjects to carry the interleukin-1alpha-producing-4845 G/G genotype (black odds ratio, 11.6; 95% CI, 1.5-89.3; white odds ratio, 1.7; 95% CI, 0.7-3.9), -889 C/C genotype (black odds ratio, 5.1; 95% CI, 0.6-41.6; white odds ratio, 1.9; 95% CI, 0.8-4.7), and the interleukin-1alpha-4845/interleukin-1alpha-889/interleukin-1beta-3957 GCC/GCC haplotype (black odds ratio, 3.4; 95% CI, 1.3-8.7; white odds ratio, 2.1; 95% CI, 1.4-3.2).

CONCLUSION

Cytokine genotypes were associated with preeclampsia and may identify women who are at high risk for preeclampsia.

Interleukin-1 gene cluster polymorphisms predict risk of ESRD

BACKGROUND

Patients with chronic kidney disease manifest an inflammatory state relative to healthy individuals. Inflammation is regulated in part by genes of the interleukin-1 (IL-1) gene cluster. We hypothesized that polymorphisms in this gene cluster may be associated with risk of end-stage renal disease (ESRD).

METHODS

Polymorphisms in the IL-1 gene cluster were examined in a cohort of 239 racially diverse hemodialysis (HD) patients and 252 controls. These individuals were genotyped for 3 single nucleotide polymorphisms (SNPs) in the IL-1alpha and beta genes, and a variable-number-of-tandem-repeats polymorphism in the IL-1 receptor antagonist gene (IL-1RN). Polymorphisms were analyzed by logistic regression for their independent associations with ESRD, and the effect of allele dose of IL-1RN on risk for ESRD was examined. The interaction between race and genotype was also investigated.

RESULTS

A logistic regression model demonstrated that homozygosity for allele 2 of the IL-1RN variable-number-of-tandem-repeats (VNTR) polymorphism was associated with ESRD independent of race (P < 0.0005). The IL-1alpha-889 promoter SNP was associated with ESRD independent of race and of the IL-1RN polymorphism (P= 0.04). The IL-1beta-511 promoter SNP is associated with ESRD, but this is accounted for by race (P= 0.04).

CONCLUSION

Two polymorphisms within the IL-1 gene cluster are associated with ESRD independent of race. This finding is one of the strongest associations between genotype and ESRD reported, and suggests that polymorphisms in the IL-1 gene cluster affect the risk of development of ESRD.

Epistatic effect of IL1A and IL4RA genes on the risk of atopy

BACKGROUND

Several studies have demonstrated a linkage or association of the atopic phenotype with T-cell cytokine genes involved in the regulation of the TH1/TH2 balance (eg, IL4, IL13, and their common receptor, IL4RA). We have recently shown that polymorphism of the pro-inflammatory cytokine IL1A gene is strongly associated with atopy.

OBJECTIVE

We now examined whether the polymorphisms of IL1A (G/T at +4845) and IL4RA (T/C at +22446) would show an epistatic effect on the risk of atopy.

METHODS

Skin prick tests and gene polymorphism analyses were performed in a population-based sample of asthmatic and nonasthmatic subjects.

RESULTS

Our results showed that in the nonasthmatic group the previously described elevated risk of atopy in noncarriers of allele T of IL1A (ie, having the genotype GG) was restricted to individuals who were also noncarriers of allele C of IL4RA (genotype TT). This finding applies to the general population of Finland, where 3.3% of adults are asthmatic.

CONCLUSION

These data suggest that the IL1A and IL4RA genes show an epistatic effect on the risk of atopy.

Association of the interleukin-1 receptor antagonist gene with asthma

The interleukin-1 cluster on human chromosome 2q12-2q14 harbors various promising candidate genes for asthma and other inflammatory diseases. We conducted a systematic association study with single-nucleotide polymorphisms (SNPs) located in candidate genes situated in this cluster. Single-marker, two-locus and three-locus haplotype analysis of SNPs yielded several significant results (p < 0.05-0.0021) for the human IL1RN gene encoding the IL-1 receptor antagonist protein, an antiinflammatory cytokine that plays an important role in maintaining the balance between inflammatory and antiinflammatory cytokines. These findings were replicated and confirmed in an independent Italian family sample in which significant, although weaker, association with asthma was detected. A sequencing approach to the coding region of the human IL1RN gene revealed additional DNA variants, from which a selection was also associated with the disease in German and Italian samples. Calculation of the linkage disequilibrium for the human IL1RN gene showed strong linkage disequilibrium for nearly all analyzed SNPs. Further haplotype analysis indicated that six SNPs are sufficient for tagging all haplotypes with a prevalence of more than 1%. The most frequent haplotype constructed from these SNPs was 1.4-fold overtransmitted in the German family sample.