Association analysis of the interleukin 17 genes IL17A and IL17F as potential osteoarthritis susceptibility loci

The role of heterodimer IL-17-A/F in atopic dermatitis

Introduction

The importance of multifactorial dysregulation in immune response is well recognised in atopic dermatitis (AD). Th17 family cytokine IL-17 (IL-17A-F) is of significance in both acute and chronic phase of AD.

Aim

We analysed the differences between serum levels of IL-17A/F and IL-17A, IL-17-F, IL-13, IL-4, association of rs2275913 IL-17A and rs763780 IL-17F gene polymorphisms in paediatric AD patients and control subjects.

Material and methods

We assessed 30 children with AD and 30 healthy patients aged 2-12 years. Eczema Area and Severity Index, Investigator Global Assessment and Scoring Atopic Dermatitis scales were used to analyse the severity of skin lesions in AD patients. Genotyping was performed using PCR and the serum concentrations of IL-17A/F, IL-17A, IL-17F, while IL-13 and IL-4 interleukins were determined by enzyme-linked immuno-sorbent assays (ELISA).

Results

The revised median assessment scoring in disease severity showed that the studied AD population had a moderate course of the disease. The obtained results indicated elevated plasma levels of IL-17A/F and IL-17-13 in AD patients with no statistically significance of IL-17A, IL-17F and IL-4 compared to controls. AD duration was positively correlated with IL-13 levels and negatively with IL-17A/F (p < 0.05). Moreover, there was no significant difference between case and control groups in the frequency of genotypes and alleles at rs2275913 IL-17A and rs763780 IL-17F polymorphisms (p > 0.05).

Conclusions

This study demonstrates increased levels of IL-17A/F in atopic patients, which is positively correlated with severity of the disease and the early phase of the disease. These results highlight a functional role of this cytokine in the pathogenesis of AD in paediatric patients.

Serum and Synovial Fluid Levels of Interleukin-17A in Primary Knee Osteoarthritis Patients: Correlations With Functional Status, Pain, and Disease Severity

Objectives

This study aims to assess the serum and synovial fluid (SF) levels of interleukin (IL)-17A in primary knee osteoarthritis (KOA) patients and to study their correlations with functional status, pain, and disease severity.

Patients and methods

This cross-sectional study was conducted between December 2017 and March 2018 and it included 70 patients (46 males, 24 females; mean age 57.3±10.0 years; range 34 to 76 years) with primary KOA and 30 age-, sex-, and body mass index-matched healthy individuals (20 males, 10 females; mean age 53.3±10.3 years; range, 35 to 70 years). Western Ontario and McMaster Universities osteoarthritis index (WOMAC), visual analog scale (VAS), Lequesne index, and Kellgren and Lawrence (KL) grading scale were used for assessment of the disease. IL-17A levels were measured in the serum for patients and healthy controls, and in SF for patients only using an enzyme-linked immunosorbent assay.

Results

Serum levels of IL-17A were significantly higher in KOA patients than controls (p=0.04). A positive correlation was found between serum and SF IL-17A levels. Serum and SF IL-17A levels had positive correlations with VAS, WOMAC pain score, Lequesne pain score, WOMAC function score, and Lequesne index. SF IL-17A levels had strong positive correlations with radiographic severity (KL grade) and duration of OA.

Conclusion

Higher IL-17A levels in primary KOA patients were significantly associated with longer disease duration, higher pain scores, worse quality of life, extreme disability, and advanced structural damage. Therapeutics that target IL-17A warrant further investigation.

Common variants in IL17F gene contributed to the risk of hip osteoarthritis susceptibility in Han Chinese population

AIM

The prevalence of hip and knee osteoarthritis (OA) varies by ethnicity, suggesting genetic heterogeneity in populations and predilection sites. Given the unknown mechanism of IL17F gene in the etiology of OA, it is necessary to examine the potential shared susceptibility of IL17F gene between knee OA and hip OA (HOA). This study aimed to evaluate the association of the IL17F gene and susceptibility to HOA in a Han Chinese population.

METHODS

A total of 2650 study subjects, comprising 796 HOA patients and 1854 controls, were recruited into the present study. Seven tag single nucleotide polymorphisms (SNPs) were selected for genotyping. Single marker-based genetic association analyses were conducted at both the genotypic and allelic levels. χ² statistics were calculated for statistical testing, and odds ratios were obtained to estimate the effects of genotypes and alleles for each SNP.

RESULTS

The SNP rs763780 was identified to be significantly associated with the risk of HOA at both genotypic (χ²  = 12.45, P = .002) and allelic levels (χ²  = 11.83, P = .0006). A linkage disequilibrium (LD) block comprised of 3 SNPs (rs12201582-rs12203736-rs722323) was also significantly associated with the risk of HOA. In addition, rs2294835 was identified to be associated with HOA severity (χ²  = 12.10, P = .02).

CONCLUSION

Our results showed that IL17F gene contributed to the risk of HOA in a Han Chinese population, which would help to elucidate the pathogenesis of OA and facilitate the development of novel medicines and treatments for OA.

Association between the polymorphism of IL-17A and IL-17F gene with knee osteoarthritis risk: a meta-analysis based on case-control studies

Background

Knee osteoarthritis is a joint disease which is characterized by degeneration of articular cartilage and subsequent subchondral bone changes. Polymorphisms of IL-17A/F gene were the recognized candidate genes associated with knee osteoarthritis risk although the results were conflicting. The aim of this study was to determine whether IL-17A(rs2275913) and IL-17F(rs763780) polymorphisms confer susceptibility to knee osteoarthritis.

Method

Literature search was performed in PubMed, Medline, Cochrane Library, Web of science, Embase, and Google Scholar (last search was updated on June 20, 2019), and assessing this association was performed by calculating odds ratios with 95% confidence intervals. Statistical heterogeneity was quantitatively evaluated by using the Q statistic with its p value and I² statistic.

Result

Six case-control based studies were included involving IL-17A(rs2275913) (2134 cases and 2306 controls) and IL-17F(rs763780) (2134 cases and 2426 controls). The overall analysis suggested that the A allele of the rs2275913 polymorphism, and the C allele of the rs763780 polymorphism in the IL-17 gene may increase the risk of OA. However, subgroup analysis revealed that no association between IL-17A(rs2275913) gene and knee OA risk was found in Caucasian population.

Conclusions

This meta-analysis revealed that the IL-17A(rs2275913) gene polymorphisms may increase the risk of knee OA in Asians, and the IL-17F(rs763780) gene polymorphisms may increase the risk of knee OA both in Asians and Caucasians. However, because of the limitations of the present study, additional larger studies are needed to confirm our findings in the future.

Association of IL-17A-197G/A and IL-17F-7488T/C polymorphisms and osteoarthritis susceptibility: A meta-analysis

AIM

This meta-analysis was conducted with the aim of collecting and synthesizing the existing evidence on the association of interleukin-17A (IL-17A)-197G/A and IL-17F-7488T/C gene polymorphisms and osteoarthritis (OA) susceptibility.

METHODS

Six electronic databases including PubMed, EMBASE, Web of Science, Cochrane Library, CNKI, and Wanfang were systematically searched for potentially relevant studies previous to June 2019. The strengths of association were estimated by summary odds ratios (ORs) and 95% confidence intervals (95%CIs) in a model-free approach. Heterogeneity test and sensitivity analysis were also conducted to guarantee the reliability of this study.

RESULTS

Six eligible case-control studies comprising 1989 OA patients and 2116 healthy controls were obtained for the meta-analysis. Dominant model was confirmed to be the optimal genetic model (MM + Mm vs mm). The pooled estimate supported that IL-17A-197G/A and IL-17F-7488T/C polymorphisms were significantly associated with OA susceptibility in the overall population (IL-17A-197G/A: GG + GA vs AA, OR = 0.69, 95%CI 0.57-0.80; P < .001; IL-17F-7488T/C, TT + TC vs CC, OR = 0.46, 95%CI 0.29-0.71, P < .001). However, subgroup analyses suggested the association only existed in Asians and knee OA.

CONCLUSION

The findings of the present study indicate that IL-17A-197G/A and IL-17F-7488T/C polymorphisms are positively associated to reduced risk of knee OA, especially in Asian populations.

Alternative Interleukin 17A/F Locus Haplotypes are Associated With Increased Risk to Hip and Knee Osteoarthritis

We studied the genetic epidemiology of primary large-joint (hip and knee) osteoarthritis (OA), in order to find disease risk factors by a candidate-gene approach. We used case-control study in the Croatian Caucasian population. We genotyped 500 OA patients (260 hip, 240 knee; both with total joint replacements) and 597 healthy individuals for single-nucleotide polymorphisms (SNPs) in interleukin 17A (IL17A) (rs2275913) and IL17F (rs763780 and rs1889570) genes. On the basis of our population and allelic and genotypic frequencies haplotypes were predicted by PHASE software and compared between patients and controls. The three-SNP haplotype (rs2275913-rs763780-rs1889570) G-C-A confers predisposition to hip (p < 0.005) but not knee OA. The three-SNP haplotype having opposed nucleotides A-T-G was found significantly associated with 2.6 times higher risk for developing knee (p < 0.02) but not hip OA. The haplotype G-T (IL17A-IL17F; rs2275913-rs763780) is associated with protection to the disease in hip OA (p < 0.01). Our analyses show that two disparate haplotypes within the IL17A-F gene locus are associated with higher risk to developing hip and knee OA in the Croatian population. The data might suggest a difference in the etiology of hip OA from that of the knee OA, perhaps due to an unknown dissimilarity in vulnerability of these joints to the actions of IL17. Alternatively, other differences in genetic factors like the long non-protein coding region LINCMD1 and/or microRNA species like miR133b and miR206 found in the vicinity of the IL17 locus might be involved in the observed risk. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:1972-1978, 2019.

Plasma miR-136 can be used to screen patients with knee osteoarthritis from healthy controls by targeting IL-17

The current study mainly evaluated the plasma level of microRNA (miR)-136 in knee osteoarthritis (KOA) patients and determined if miR-136 could be used as a potential biomarker to screen KOA patients from healthy controls. It was demonstrated that plasma miR-136 was significantly decreased in the plasma of KOA patients. Moreover, the reduction in plasma miR-136 negatively correlated with the severity of KOA. Additionally, the increase in the serum interleukin (IL)-17 level positively correlated with the severity of KOA. More importantly, dual luciferase assays and western blot assays indicated that IL-17 was a target gene of miR-136. Further analysis showed that plasma miR-136 could be used as a biomarker to screen KOA patients from healthy controls. In summary, for the first time, the present study revealed that through targeting IL-17, decreased plasma miR-136 levels could be used as a potential biomarker to screen KOA patients from healthy controls.

Association of IL17 and IL23R gene polymorphisms with rheumatic heart disease in South Indian population

BACKGROUND

IL-23/Th17 signaling pathway plays a crucial role in the cell-mediated immune response against bacterial infections and also in the pathogenesis of inflammatory and autoimmune diseases. Recent studies indicate that Th17 cell-associated cytokines are involved in the progression and maintenance of valvular lesions in rheumatic heart disease (RHD). Variants in the genes of cytokines that are potentially involved in Th17 response may influence interindividual differences in their expression levels, thereby contributing to the pathogenesis of immune-mediated diseases such as RHD.

OBJECTIVE

The aim of the study is to investigate the association of IL17A, IL17F, and IL23R gene variants with the risk perception of RHD.

METHODS

A total of 225 individuals (99 RHD patients and 126 healthy siblings) were recruited for the study. The IL17A (rs2275913), IL17F (rs763780), and IL23R (rs10889677) polymorphisms were determined by polymerase chain reaction restriction fragment length polymorphisms and amplification-refractory mutation system-polymerase chain reaction methods, respectively.

RESULTS

The frequency of IL17A (rs2275913) A/A genotype was significantly high in pooled RHD patients (odds ratio [OR] = 2.76; p_c = 0.021), rheumatic fever (RF) patients (OR = 14.5; p_c = 0.0001), and mitral valvular lesions patients (OR = 2.74; p_c = 0.039) when compared to healthy siblings. However, the IL17F (rs763780) and IL23R (rs10889677) polymorphisms did not show any association with RHD.

CONCLUSIONS

The results suggest that IL17A (rs2275913) polymorphism is associated with the development of RF/RHD in South Indian population. Further studies are required to substantiate the association of these genes with the disease risk.

Interleukin-17 and Toll-like Receptor 10 genetic polymorphisms and susceptibility to large joint osteoarthritis

Primary osteoarthritis (OA) is the most common type of a joint disease. It has a polygenic risk inheritance pattern and affects older people. The etiology of this disease is not fully understood. The aim of this study was to investigate the associations between polymorphisms in pro-inflammatory interleukin-17 (IL17A and IL17F) and anti-inflammatory Toll-like Receptor 10 (TLR10) genes with the risk for development of advanced stage hip and knee primary OA in the Croatian population. A total of 500 OA patients and 597 controls were genotyped for IL17A SNP (rs2275913), IL17F SNPs (rs763780 and rs1889570), and TLR10 (rs11096957) genes. The allelic and genotypic frequencies of IL17F SNP (rs763780) showed statistically significant differences in comparisons of controls with hip-but not knee-OA patients. The major allele (T) of rs763780 was associated with the lower risk for developing hip OA (p = 7.9 × 10^-4 , OR = 0.45, 95%CI = 0.27-0.74), whereas the minor allele (C) was associated with susceptibility to hip OA (p = 7.9 × 10^-4 , OR = 2.24, 95%CI = 1.35-3.72). The genotype T/T was associated with the protection to hip OA (p = 3.9 × 10^-4 , OR = 0.41, 95%CI = 0.24-0.70), and, lastly, the genotype T/C was associated with the higher risk to acquiring hip OA (p = 2.6 × 10^-4 , OR = 2.50, 95%CI = 1.47-4.25). TLR10 SNP rs11096957 was found significantly associated with predisposition to hip OA (p = 0.04, OR = 1.41, 95%CI = 1.02-1.94) but not knee OA. Our findings suggest that hip OA in Croatian population might have a different genetic risk regarding the IL17 and TLR10 gene locus than knee OA. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1684-1693, 2018.

Lack of Association of the Polymorphisms IL-17A (-197G/A) and IL-17F (+7488A/G) with Multibacillary Leprosy in Mexican Patients

Background. Leprosy is a chronic infectious disease caused by the intracellular acid-fast bacilli Mycobacterium leprae; it has been determined that genetic factors of the host play an important role in the disease susceptibility. Thus, in this case-control study, we evaluated the possible association between the IL-17A G-197A (rs227593) and IL-17F A7488G (His161Arg, rs763780) gene SNPs and susceptibility to leprosy disease in Mexican population. Methods. Seventy-five leprosy patients and sixty-nine control subjects were included. Both SNPs were genotyped with the polymerase chain reaction-restriction fragment length polymorphism technique. Results. We found nonsignificant differences in genotype and allele frequencies related to IL-17A G-197A (rs227593) and IL-17F A7488G (His161Arg, rs763780) gene SNPs in MB as well as subclinical forms of leprosy disease versus healthy individuals. Conclusions. Since the sample size is not large enough, it is difficult to sustain an association of susceptibility to leprosy with genotypes or allele frequencies of IL-17A G-197A (rs227593) and IL-17F A7488G (His161Arg, rs763780), suggesting that IL-17 polymorphisms have no significant role in the genetic susceptibility to development of this disease in the Mexican Mestizo population.

IL-17F but not IL-17A gene polymorphism confers risk to multiple sclerosis in a Chinese Han population

Interleukin-17 has been shown to be associated with autoimmune disease. The aim of the current study is to investigate the potential association of IL-17 polymorphisms with multiple sclerosis (MS) in Chinese Han patients. Two SNPs, rs763780 of IL-17F gene and rs2275913 of IL-17A gene were genotyped in 622 MS patients and 743 healthy controls by using a polymerase chain reaction-restriction fragment length polymorphism method (PCR-RFLP). Allele and genotype frequencies distribution of the two SNPs were examined between patients and controls using the Chi-Square test. All genotypic and allelic frequencies of the tested IL-17 polymorphisms in control cohort were in Hardy-Weinberg equilibrium. A significantly increased frequency of rs763780 TT genotype (corrected p value (Pc)=0.024, odds ratio=1.472, 95% CI=1.133-1.913) and T allele (corrected P (Pc)=0.018, odds ratio=1.446, 95% CI=1.134-1.844) was detected in MS patients compared with controls. The genotypic and allelic frequencies of rs2275913 in IL-17A gene were not different between patients with MS and controls. These results suggest that rs763780 is associated with multiple sclerosis in a Chinese Han population.

Association of IL-17A and IL-17F single nucleotide polymorphisms with susceptibility to osteoarthritis in a Korean population

The damage incurred in osteoarthritis (OA) is mediated by a variety of cytokines, growth factors and inflammatory mediators. The importance of the interleukin-17 (IL-17) family in inflammatory and autoimmune disease is becoming increasingly apparent. Microsatellite association mapping reveals a primary osteoarthritis susceptibility locus on chromosome 6p12.3-q13. IL-17A and IL-17F genes that resided on chromosome 6p12.3-q13 are believed to play an important role in the primary OA susceptibility. We investigated the allele and genotype of IL-17A G-197A and IL-17F T7488C in 302 OA patients and 300 healthy subjects as controls. We employed a PCR-SSCP assay to identify the genotypes IL-17A G-197A and IL-17F T7488C. For IL-17A G-197A, there were significant differences in frequencies of genotype and allele of IL-17A G-197A between OA patients and controls (both p<0.0001). For IL-17F T7488C, there were no significant differences in the allele frequency and genotype distribution for IL-17F T7488C between OA patients and controls (p=0.938 and p=0.1735, respectively). In conclusion, current study showed that polymorphism of IL-17A G-197A may be closely associated with susceptibility to the development of OA in the Korean population. However, there was no relationship between IL-17F T7488C polymorphism and OA susceptibility.

Association between IL-17F gene polymorphisms and susceptibility to and severity of rheumatoid arthritis (RA)

Interleukin-17F (IL-17F) is a novel proinflammatory cytokine. IL-17F gene is an excellent candidate for chronic inflammatory disease. We investigated the association between rheumatoid arthritis (RA) and His161Arg (7488A/G; rs763780) and Glu126Gly (7383A/G; rs2397084) polymorphism of IL-17F gene. The gene polymorphisms in 220 Polish patients with RA and 106 healthy subjects were amplified by polymerase chain reaction with restriction endonuclease mapping. Overall, the polymorphisms of the IL-17F gene were not correlated with susceptibility to RA in Polish population. However, the IL-17F His161Arg variant was associated with parameters of disease activity, such as number of tender joints, HAQ score or DAS-28-CRP. Moreover, our findings have shown that Glu126Gly IL-17F gene polymorphism may be correlated with longer disease duration in patients with RA. Our results for the first time showed the relationship between IL-17F gene polymorphisms and severity of RA.

Genetics in osteoarthritis

Osteoarthritis is a degenerative articular disease with complex pathogeny because diverse factors interact causing a process of deterioration of the cartilage. Despite the multifactorial nature of this pathology, from the 50's it s known that certain forms of osteoarthritis are related to a strong genetic component. The genetic bases of this disease do not follow the typical patterns of mendelian inheritance and probably they are related to alterations in multiple genes. The identification of a high number of candidate genes to confer susceptibility to the development of the osteoarthritis shows the complex nature of this disease. At the moment, the genetic mechanisms of this disease are not known, however, which seems clear is that expression levels of several genes are altered, and that the inheritance will become a substantial factor in future considerations of diagnosis and treatment of the osteoarthritis.

[Genetics in osteoarthritis]

Osteoarthritis is a degenerative articular pathology with complex pathogeny because diverse factors interact causing a process of deterioration of the cartilage. In spite of the multifactorial nature of this pathology, from years 50 one knows that certain forms of osteoarthritis are related to a strong genetic component. The genetic bases of this disease do not follow the typical patterns of mendelian inheritance and probably they are related to alterations in multiple genes. The identification of a high number of candidates genes to confer susceptibility to the development of the osteoarthritis shows the complex nature of this disease. At the moment, the genetic mechanisms of this pathology are not known, however, which seems clear is that levels of expression of several genes are altered, and that the inheritance will become a substantial factor in future considerations of diagnosis and treatment of the osteoarthitis.

Interleukin-17F gene polymorphisms in Korean patients with Behçet's disease

IL-17 is a novel cytokine that is characterized by an ability to induce several types of cells to secrete proinflammatory cytokines in various inflammatory diseases. This study analyzed the influence of IL-17F gene polymorphisms on disease susceptibility and clinical features. Ninety-nine Behçet's disease (BD) patients and 114 controls were genotyped to analyze three single nucleotide polymorphisms (SNPs) including A126G, G155A, and A161G of the IL-17F gene using automated sequencing. We compared the frequencies of IL-17F alleles, genotypes, and haplotypes in patients with BD and controls using the chi-square or Fisher's exact test. Significant differences in the frequencies of allele and genotype in A126G SNP of IL-17 gene were found between BD patients and controls (P<0.001 and P<0.001, respectively). None of three IL-17F SNPs were associated with diverse clinical features in BD. The frequency of haplotype AA did not differ between patients with BD and controls (P=0.985). The haplotypes, AG, and GG, have positive and inverse association with BD susceptibility (P<0.001 and P<0.001, respectively). These findings suggest that IL-17 gene SNPs may influence the susceptibility of BD.