Polymorphisms in the interleukin-4 and IL-4 receptor genes modify risk for chronic inflammatory arthropathies in women

Cytokine gene polymorphisms and suicide risk in an Indian ancestral population: A case-control study

BACKGROUND

India currently accounts for a majority of global suicide deaths. Research in European ancestry has established that suicide mortality has a significant genetic component, and suggests that inflammation may play a crucial role in the pathophysiology of suicide. Inflammation is also highly relevant in regions of increased pollution exposure, such as the megacities of India. To address the existing gaps in genetic research on suicide and possible association with inflammatory biomarkers, we examined genetic polymorphism and clinical risk phenotypes in a population-based suicide-death cohort, India.

MATERIAL AND METHODS

Genotyping of IL-1β(rs16944) & (rs1143627), IL-4(rs2070874), IL-6(rs1800795) and IL-10(rs1800896) was done in 234 post-mortem suicide-death cases and 256 post-mortem controls (N = 490) using PCR RFLP method.

RESULTS

Our analyses identified three significant (p < 0.001) associations of cytokine variants with suicide death, including IL-1β(rs16944), OR = 0.627; IL-4(rs2070874), OR = 0.524; and IL-6(rs1800795), OR = 2.509. Cases were more likely female and were more likely to have a history of psychiatric illness, though rate of psychiatric illness was low in suicide cases(9%).

CONCLUSION

Our genetic results are generally consistent with previous research on risk for depression and suicidal behaviour, and both genetic and phenotypic results provide new insights into risk factors that may contribute to suicide in India.

Polymorphisms of genes encoding interleukin-4 and its receptor in Iranian patients with juvenile idiopathic arthritis

As cytokines, including interleukin-4 (IL-4), seem to have a pivotal role in the pathogenesis of juvenile idiopathic arthritis (JIA), this study is aimed at investigating of association of polymorphisms in IL-4 and IL-4 receptor α (IL-4RA) genes with susceptibility to JIA. A case-control study was conducted on 53 patients with JIA and 139 healthy unrelated controls. Single nucleotide polymorphisms of IL-4 gene at positions -1098, -590, and -33, as well as IL-4RA gene at position +1902 were genotyped using polymerase chain reaction with sequence-specific primers method and compared between patients and healthy individuals. At the allelic level, C allele at IL-4 -33 was found to be more frequent in patients compared to control (P value <0.01). At the genotypic level, CC genotype at IL-4 -590 (P value <0.01), together with CC and TT genotypes at IL-4 -33 (P value <0.01), were significantly higher in patients with JIA, while TC genotypes at IL-4 -590 and -33 positions were found to be lower in case group (P value <0.01). At the haplotypic level, IL-4 (positions -1098, -509, -33) TTC, GCC, and TTT haplotypes were significantly lower than controls (P value <0.01, P value = 0.03, and P value = 0.04, respectively). Although, TCC haplotype at the same positions was found to be higher in patients (P value <0.01). Polymorphic site of +1902 IL-4RA gene did not differ between cases and controls. Polymorphisms in promoter region of IL-4 but not IL-4RA genes confer susceptibility to JIA and may predispose individuals to adaptive immune responses.

Polymorphisms within the human leucocyte antigen-E gene and their associations with susceptibility to rheumatoid arthritis as well as clinical outcome of anti-tumour necrosis factor therapy

Involvement of the non-classical human leucocyte antigen-E (HLA-E) in both innate and acquired immune response suggests its possible role in development of autoimmune pathologies. This study was undertaken to investigate relationships between the HLA-E gene single nucleotide polymorphisms (SNPs) and a risk of rheumatoid arthritis (RA), as well as to evaluate a potential of these polymorphisms to modulate clinical outcome of anti-tumour necrosis factor (TNF) treatment in female patients. A total of 223 female patients with RA receiving anti-TNF biological therapy and 134 female healthy subjects were enrolled into the study. Genotypings for two SNPs within the HLA-E gene (rs1264457 HLA-E*01:01/01:03; rs1059510 HLA-E*01:03:01/01:03:02) were performed using a polymerase chain reaction (PCR) amplification employing LightSNiP assays. Clinical response was evaluated according to the European League Against Rheumatism (EULAR) criteria at 12 and 24 weeks after initiation of the therapy. The frequency of the HLA-E*01:01/01:01 genotype was decreased significantly in RA patients in comparison to controls (P = 0.031). The presence of the HLA-E*01:01/01:01 genotype in patients correlated with better EULAR response after 12 weeks of anti-TNF treatment, while 01:03 allele carriers were generally unresponsive to the treatment (P = 0.014). The HLA-E*01:03/01:03 genotype was also over-represented among non-responding patients in comparison to HLA-E*01:01/01:01 homozygotes (P = 0.021). With respect to the HLA-E rs1059510 variation, a better response after 12 weeks was observed more frequently in patients carrying the HLA-E*01:03:01/01:03:01 genotype than other genotypes (P = 0.009). The results derived from this study imply that HLA-E polymorphisms may influence RA susceptibility and affect clinical outcome of anti-TNF therapy in female RA patients.

The biologic basis of clinical heterogeneity in juvenile idiopathic arthritis

Objective

Childhood arthritis encompasses a heterogeneous family of diseases. Significant variation in clinical presentation remains despite consensus-driven diagnostic classifications. Developments in data analysis provide powerful tools for interrogating large heterogeneous data sets. We report a novel approach to integrating biologic and clinical data toward a new classification for childhood arthritis, using computational biology for data-driven pattern recognition.

Methods

Probabilistic principal components analysis was used to transform a large set of data into 4 interpretable indicators or composite variables on which patients were grouped by cluster analysis. Sensitivity analysis was conducted to determine key variables in determining indicators and cluster assignment. Results were validated against an independent validation cohort.

Results

Meaningful biologic and clinical characteristics, including levels of proinflammatory cytokines and measures of disease activity, defined axes/indicators that identified homogeneous patient subgroups by cluster analysis. The new patient classifications resolved major differences between patient subpopulations better than International League of Associations for Rheumatology subtypes. Fourteen variables were identified by sensitivity analysis to crucially determine indicators and clusters. This new schema was conserved in an independent validation cohort.

Conclusion

Data-driven unsupervised machine learning is a powerful approach for interrogating clinical and biologic data toward disease classification, providing insight into the biology underlying clinical heterogeneity in childhood arthritis. Our analytical framework enabled the recovery of unique patterns from small cohorts and addresses a major challenge, patient numbers, in studying rare diseases.

Interleukin-4, interleukin-4 receptor, and interleukin-18 polymorphisms and rheumatoid arthritis: a meta-analysis

OBJECTIVE

The aim of this study was to determine whether the functional interleukin-4 (IL-4) -590 C/T, IL-4 receptor (IL-4R) 1902 G/A, IL-18 -607 C/A, and -137 G/C polymorphisms polymorphisms confer susceptibility to rheumatoid arthritis (RA).

METHODS

Meta-analysis was conducted on the associations between these IL-4, IL-4R, and IL-18 polymorphisms and RA.

RESULTS

A total of 12 comparative studies were included in this meta-analysis. Meta-analysis of the IL-4 -590 C/T polymorphism showed an association in all study subjects and Europeans (OR for the TT genotype = 2.280, 95% CI = 1.315-3.952, p = 0.003; OR = 2.139, 95% CI = 1.089-4.199, p = 0.027). However, meta-analysis showed no association between RA and the IL-4R 1902 G allele in all study subjects and Europeans. Meta-analysis showed no association between RA and the IL-18 -607 C allele (OR = 1.159, 95% CI = 0.967-1.387, p = 0.110). Meta-analysis of the IL-18 -137 G/C polymorphism revealed no association between RA and the IL-18 -137 G/C polymorphism.

CONCLUSIONS

This meta-analysis demonstrates that the IL-4 -590 T/C polymorphism is associated with susceptibility to RA in Europeans, but the IL-4R + 1902 G/A, IL-18 -607 C/A and -137 G/C polymorphisms are not associated with RA.

Associations of interleukin-4 receptor gene polymorphisms (Q551R, I50V) with rheumatoid arthritis: evidence from a meta-analysis

BACKGROUND AND AIMS

Published data on the associations between interleukin-4 receptor (IL-4R) gene polymorphisms (Q551R, I50V) and rheumatoid arthritis (RA) risk are controversial. To quantitatively evaluate the relationships, a meta-analysis was performed.

METHODS

Studies were identified from the databases of PubMed, MEDLINE, Chinese Biomedical Literature Database, and Chinese National Knowledge Infrastructure, with the last report up to June 2012. The effect summary odds ratio (OR) and 95% confidence interval (CI) were obtained.

RESULTS

A total of six separate comparisons involving 2173 patients and 1892 controls were included to assess the association of IL-4R gene Q551R polymorphism and RA susceptibility. Overall, no significantly elevated RA risk was found in the meta-analysis. The pooled OR for the minor R allele was 0.942 (95% CI: 0.848-1.047, p=0.268) in patients with RA. After stratification by ethnicity, there was still no significant association detected in the European population (OR=0.979, 95% CI: 0.875-1.094). As for I50V polymorphism, there were four comparisons involving 1653 patients and 1584 controls in this meta-analysis. The pooled OR for the V allele was 1.104 (95% CI: 1.001-1.217) in RA, the V allele of the IL-4R gene I50V variant might be a risk factor for RA. However, the relationship between the V allele of IL-4R gene I50V polymorphism and rheumatoid factor positive in patients with RA was not identified through a minor meta-analysis, including four independent relevant comparisons.

CONCLUSIONS

This meta-analysis indicates that the I50V polymorphism of IL-4R gene may confer susceptibility to RA; up to now, there is still not enough evidence to reveal the association of the IL-4R gene Q551R polymorphism with RA risk.

IL7RA polymorphisms and chronic inflammatory arthropathies

The C allele of a single nucleotide polymorphism (SNP), rs6897932, located in the interleukin-7 receptor alpha chain (IL7RA) was recently found to be associated with multiple sclerosis and Type I diabetes. We analysed 13 SNPs in the IL7RA gene in a combined cohort of patients with chronic inflammatory arthropathies (rheumatoid arthritis and juvenile idiopathic arthritis; 368 patients and 532 unaffected subjects). No significant associations with disease were found with the exception of the non-synonymous SNP rs6897932. This SNP showed modest enrichment of the TT genotype in arthritic patients compared with controls [P = 0.02; OR 1.72 (95% CI 1.08-2.75)]. Our data are suggestive for a role of rs6897932 in predisposition to chronic inflammatory arthropathies.

The -589C>T polymorphism in the interleukin-4 gene (IL-4) is associated with a reduced risk of myocardial infarction in young individuals

BACKGROUND

Inflammatory reactions contribute to the development of arterial disease. We investigated the role of interleukin-4 (IL-4) in the development of myocardial infarction (MI) by genotyping patients with MI and control subjects for the -589C>T (rs2243250) single nucleotide polymorphism (SNP), which tags a functional haplotype of IL-4.

METHODS AND RESULTS

Study of Myocardial Infarctions Leiden (SMILE) included 560 men with a first MI and 646 control subjects. The Valencia study included 305 patients with MI at T genotype was found [odds ratio (OR) 0.84; 95% CI 0.37-1.95 for -589TT and 0.82; 95% CI 0.62-1.07 for -589CT compared with -589CC]. In patients younger than 50 years, carriership of one or two -589T alleles was associated with a reduced risk of MI (OR 0.57: 95% CI 0.34-0.95). This result was replicated in the Valencia study, where carriers of one or two -589T alleles had a reduced risk of MI (OR 0.67: 95% CI 0.47-0.95), with a strong protective effect of the -598T allele in homozygous -589T (OR 0.33: 95% CI 0.10-1.05). In the control subjects of the Valencia study, the -589T allele was associated with reduced levels of F1+2.

CONCLUSION

Our data indicate that the IL-4 haplotype tagged by the -589T allele reduces the risk of MI in young individuals.

A comprehensive review of the genetics of juvenile idiopathic arthritis

Juvenile idiopathic arthritis (JIA) is the most common chronic arthropathy of childhood which is believed to be influenced by both genetic and environmental factors. The progress in identifying genes underlying JIA susceptibility using candidate gene association studies has been slow. Several associations between JIA and variants in the genes encoding the human leukocyte antigens (HLA) have been confirmed and replicated in independent cohorts. However it is clear that genetic variants outside the HLA also influence susceptibility to JIA. While a large number of non-HLA candidate genes have been tested for associations, only a handful of reported associations such as PTPN22 have been validated. In this review we discuss the principles behind genetic studies of complex traits like JIA, and comprehensively catalogue non-HLA candidate-gene association studies performed in JIA to date and review several validated associations. Most candidate gene studies are underpowered and do not detect associations, and those that do are often not replicated. We also discuss the principles behind genome-wide association studies and discuss possible implications for identifying genes underlying JIA. Finally we discuss several genetic variants underlying multiple clinically distinct autoimmune phenotypes.