Interleukin-18 gene polymorphism, but not interleukin-2 gene polymorphism, is associated with rheumatoid arthritis

Association of Interleukin-2, but not Interferon-Gamma, single nucleotide polymorphisms with juvenile idiopathic arthritis

BACKGROUND

Cytokines, including interleukin-2 (IL-2) and interferon-gamma (IFN-γ), seem to play a role in the pathogenesis of juvenile idiopathic arthritis (JIA). The aim of this study was to investigate the associations of IL-2 and IFN-γ single nucleotide polymorphisms (SNPs) with susceptibility to JIA in an Iranian population.

METHODS

Genomic DNA of 54 Iranian patients with JIA and 139 healthy unrelated controls were typed for IL-2 (G/T at -330 and +166) as well as IFN-γ gene (A/T at +874), using polymerase chain reaction with sequence-specific primers method, and compared between patients and controls.

RESULTS

A significantly higher frequency of the IL-2 -330 GG genotype (p<0.01) was found in the JIA patients compared to the controls. However, the GT genotype at the same position was notably lower than in controls (p<0.01). Moreover, IL-2 (-330, +166) GT haplotype was more frequent in patients with JIA in comparison with controls. No significant differences was observed between the two groups of case and control for IL-2 (G/T at +166) and IFN-γ (A/T at +874) SNPs.

CONCLUSION

The results of the current study suggest that certain SNPs of IL-2 gene have association with individuals' susceptibility to JIA. However, further investigations are required to confirm the results of this study.

Interleukin-18, interleukin-12B and interferon-γ gene polymorphisms in Brazilian patients with rheumatoid arthritis: a pilot study

Polymorphisms in interleukin (IL)-18, IL-12 and interferon (IFN)-γ genes are associated with different levels of cytokines expression and have been associated with rheumatoid arthritis (RA). IL-18 +105 A/C, IL-12B +1188 A/C and IFN-γ +874 T/A polymorphisms were analyzed by restriction fragment length polymorphism-polymerase chain reaction (PCR) and amplification refractory mutation system PCR from 90 RA patients and 186 healthy individuals. There were significant differences to IL-18 +105 A/C polymorphism between the RA and control groups (odds ratio = 3.77; P < 0.0001). Individual carriers of the variant allele C had a 3.77-fold increased risk of for RA (P = 0.0032). No association was observed for IL-12B and IFN-γ polymorphisms. Our finds suggest a possible role for IL-18 polymorphism in the RA susceptibility in studied population.

Interleukins and interleukin receptors in rheumatoid arthritis: Research, diagnostics and clinical implications

Rheumatoid arthritis (RA) is an autoimmune disease, resulting in a chronic, systemic inflammatory disorder. It may affect many tissues and organs, but it primarily affects the flexible joints. In clinical practice patient care generates many questions about diagnosis, prognosis, and treatment. It is challenging for health care specialists to keep up to date with the medical literature. This review summarizes the pathogenesis, the polymorphisms of interleukin and interleukin genes and the standard available and possible future immunologic targets for RA treatment. The identification of disease-associated interleukin and interleukin receptor genes can provide precious insight into the genetic variations prior to disease onset in order to identify the pathways important for RA pathogenesis. The knowledge of the complex genetic background may prove useful for developing novel therapies and making personalized medicine based on the individual’s genetics.

Relationship between single nucleotide polymorphism of interleukin-18 and susceptibility to pulmonary tuberculosis in the Chinese Han population

Interleukin-18 (IL-18) is a multi-functional cytokine capable of inducing either Th1 or Th2 polarization depending on the immunologic milieu. IL-18 may influence the host response to Mycobacterium tuberculosis (M.tb) infection. To investigate the relationship between single nucleotide polymorphisms of the IL-18 and susceptibility to pulmonary tuberculosis in the Chinese Han population, the IL-18 gene was sequenced to detect polymorphisms and to examine the genotype frequencies in 300 patients and 702 healthy controls. DNA sequencing revealed three IL-18 variants: rs1946518, rs5744247, and rs549908. It also revealed that allele A of rs1946518 confers a 1.47-fold increased risk of developing tuberculosis (TB) (P = 0.0001, OR [95%CI] = 1.47 [1.21-1.78]), and that the C allele of rs5744247 confers a 0.77-fold decreased risk of disease (P = 0.01, R [95%CI] = 0.77 [0.632-0.937]). The genotypes rs1946518, rs5744247 and rs549908 were found to be significantly associated with TB. Estimation of the frequencies of haplotypes revealed a potential risk haplotype AGA (P = 0.01, OR [95%CI] = 1.41 [1.15-1.72]) and a protective haplotype CCA (P = 0.01, OR [95%CI] = 0.70 [0.57-0.85]) for TB. The present findings suggest that polymorphisms in the IL-18 gene may affect susceptibility to TB and increase the risk of developing the disease in the Chinese Han population.

IL-18 105 A>C polymorphism contributes to renal manifestations in patients with SLE

Systemic lupus erythematosus (SLE) is a multisystem autoimmune connective tissue disorder characterized by various aberrations including increased production of IL-18. As IL-18 105 A>C polymorphic variants have been linked to increased production of this cytokine, we investigated the prevalence of IL-18 105 A>C (rs549908) polymorphic variants in SLE patients (n = 111) and controls (n = 152). There were no significant differences in the distribution of IL-18 105 A>C polymorphic variants in SLE patients and controls. However, there was a significant association between the IL-18 105 AA genotype (recessive model) and renal manifestations OR = 3.360 (1.523–7.415, P = 0.0039) and the P value remained statistically significant after Bonferroni correction (P corr = 0.0351).Our findings indicate that the IL-18 105 AA genotype variant can contribute to renal manifestations in patients with SLE.

Genetic variation in Th1/Th2 pathway genes and risk of non-Hodgkin lymphoma: a pooled analysis of three population-based case-control studies

The balance between T-helper 1 (Th1) and T-helper 2 (Th2) activity is critical in lymphoid cell development and differentiation. Immune dysfunction underlies lymphomagenesis, so an alteration in the regulation of key Th1/Th2 cytokines may lead to the development of non-Hodgkin lymphoma (NHL). To study the impact of polymorphisms in Th1/Th2 cytokines on NHL risk, we analyzed 145 tag single nucleotide polymorphisms (SNPs) in 17 Th1/Th2 cytokine and related genes in three population-based case-control studies (1946 cases and 1808 controls). Logistic regression was used to compute odds ratios (OR) for NHL and four major NHL subtypes in relation to tag SNP genotypes and haplotypes. A gene-based analysis adjusting for the number of tag SNPs genotyped in each gene showed significant associations with risk of NHL combined and one or more NHL subtypes for Th1 (IL12A and IL12RB1) and Th2 (IL4, IL10RB, and IL18) genes. The strongest association was for rs485497 in IL12A, which plays a central role in bridging the cellular and humoral pathways of innate resistance and antigen-specific adaptive immune responses (allele risk OR= 1·17; P(trend)= 0·00099). This SNP was also associated specifically with risk of follicular lymphoma (allele risk OR= 1·26; P(trend)= 0·0012). These findings suggest that genetic variation in Th1/Th2 cytokine genes may contribute to lymphomagenesis.

Genetic variation in Th1/Th2 pathway genes and risk of non-Hodgkin lymphoma: a pooled analysis of three population-based case-control studies

The balance between T-helper 1 (Th1) and T-helper 2 (Th2) activity is critical in lymphoid cell development and differentiation. Immune dysfunction underlies lymphomagenesis, so an alteration in the regulation of key Th1/Th2 cytokines may lead to the development of non-Hodgkin lymphoma (NHL). To study the impact of polymorphisms in Th1/Th2 cytokines on NHL risk, we analyzed 145 tag single nucleotide polymorphisms (SNPs) in 17 Th1/Th2 cytokine and related genes in three population-based case-control studies (1946 cases and 1808 controls). Logistic regression was used to compute odds ratios (OR) for NHL and four major NHL subtypes in relation to tag SNP genotypes and haplotypes. A gene-based analysis adjusting for the number of tag SNPs genotyped in each gene showed significant associations with risk of NHL combined and one or more NHL subtypes for Th1 (IL12A and IL12RB1) and Th2 (IL4, IL10RB, and IL18) genes. The strongest association was for rs485497 in IL12A, which plays a central role in bridging the cellular and humoral pathways of innate resistance and antigen-specific adaptive immune responses (allele risk OR= 1·17; P(trend)= 0·00099). This SNP was also associated specifically with risk of follicular lymphoma (allele risk OR= 1·26; P(trend)= 0·0012). These findings suggest that genetic variation in Th1/Th2 cytokine genes may contribute to lymphomagenesis.

Interleukin-18 gene 105A/C genetic polymorphism is associated with the susceptibility of Kawasaki disease

Interleukin-18 (IL-18)-656T/G, -607A/C, and -137C/G promoter polymorphisms had been reported associated with Kawasaki disease (KD). An IL-18 genetic A/C polymorphism at coding position 105 (rs549908) has been linked with asthma, rheumatoid, and systemic lupus erythematosus. We tested a hypothesis that the IL-18 105A/C genetic polymorphism confers KD susceptibility. Study participants were Taiwanese KD patients and a healthy control group. Our data indicated that the frequency of C allele was significantly higher in the patient group (13.9%) than in the control group (2.7%; P<0.0001, odds ratio [OR]=5.93; 95% confidence interval [CI]=2.57-13.73). Therefore, persons with the C allele may have higher risk of developing KD. In addition, compared with the haplotype frequencies between case and control groups, the KD patients with TACC haplotype appeared to be a significant "at-risk" haplotype compared with other haplotypes (OR: 4.62, 95% CI: 1.71-12.43; P=0.001). KD patient with the TAGA haplotype appeared to be a significant "protective" haplotype compared with other haplotypes (OR: 0.51, 95% CI:0.29-0.89; P=0.017). Our results suggest that 105A/C polymorphism and the haplotypes in IL-18 gene are associated with the risk of KD in Taiwanese population.

Detecting shared pathogenesis from the shared genetics of immune-related diseases

Recent genetic studies have revealed shared immunological mechanisms in several immune-related disorders that further our understanding of the development and concomitance of these diseases. Our Review focuses on these shared aspects, using the novel findings of recently performed genome-wide association studies and non-synonymous SNP scans as a starting point. We discuss how identifying new genes that are associated with more than one autoimmune or chronic inflammatory disorder could explain the genetic basis of the shared pathogenesis of immune-related diseases. This analysis helps to highlight the key molecular pathways that are involved in these disorders and the potential roles of novel genes in immune-related diseases.

Characterization of the immune response in the synovitis, acne, pustulosis, hyperostosis, osteitis (SAPHO) syndrome

OBJECTIVE

The aetiology of SAPHO (synovitis, acne, palmoplantar pustulosis, hyperostosis, osteitis) syndrome seems to involve genetic, infectious and immunological components. We examined innate and adaptive immune responses in SAPHO syndrome, as compared with PsA and RA. We also studied the effect of etanercept on immunological parameters.

METHODS

We studied 29 patients with SAPHO syndrome, as well as 22 patients with RA, 21 patients with PsA and 15 healthy controls. Adaptive immune responses were investigated by assaying total serum immunoglobulins and several autoantibodies. Innate immunity was studied by quantifying blood PMN functions and plasma cytokine levels. PMN responses to Propionibacterium acnes were tested ex vivo. Eight patients who received etanercept for refractory rheumatic disorders were tested before and after 28 days of treatment.

RESULTS

SAPHO syndrome was associated with elevated IL-8 and IL-18 plasma levels. IL-8 and TNF-alpha production by purified PMN was higher in the three patient groups than in the healthy controls, but the oxidative burst and IL-18 production were normal. No autoantibodies were detected in SAPHO patients. Induction of PMN IL-8 and TNF-alpha production by P. acnes was impaired in the SAPHO group as compared with the RA and PsA groups. After 28 days of etanercept therapy, PMN IL-8 and TNF-alpha production was down-regulated and TNF-alpha plasma levels were increased.

CONCLUSIONS

These results support the view that the SAPHO syndrome may be triggered by an infectious state involving P. acnes, contributing to the strong humoral and cellular pro-inflammatory responses. Etanercept modulation of PMN activation status emphasizes these new immunological findings.

A/C polymorphism in the interleukin-18 coding region among Taiwanese systemic lupus erythematosus patients

Interleukin-18 (IL-18) is associated with chronic inflammation, autoimmune diseases and various cancers and infectious diseases. An IL-18 genetic A/C polymorphism at coding position 105 (rs549908) has been linked with asthma and rheumatoid arthritis. We tested a hypothesis that the IL-18 genetic polymorphism confers systemic lupus erythematosus (SLE) susceptibility. Study participants were Taiwanese SLE patients and a healthy control group. Our results indicate (1) a significantly higher A allele frequency in SLE patients (P = 0.003; OR = 1.97; 95% CI = 1.26-3.08) and (2) a significantly higher A allele frequency in SLE patients with a central nervous system disorder (P = 0.027; OR = 7.18; 95% CI = 0.95-54.28). Our results suggest that the A/C polymorphism contributes to SLE pathogenesis.