Polymorphisms in genes controlling inflammation and tissue repair in rheumatoid arthritis: a case control study

Evaluation of genetic polymorphisms in TNF‑α‑308G/A rs1800629 associated with susceptibility and severity of rheumatoid arthritis: A systematic review and meta‑analysis

To investigate the association of gene polymorphisms of TNF-α-308G/A rs1800629 with the susceptibility and severity of rheumatoid arthritis (RA), literature from PubMed, EMBASE, Web of Science and CNKI databases was searched. Two authors screened the literature independently, extracted data and evaluated the risk of bias of the included studies. According to the inclusion and exclusion criteria, five genetic models were established: The allelic model (A vs. G), dominant model (GA + AA vs. GG), recessive model (AA vs. GG + GA), co-dominant model (AA vs. GG) and super-dominant model (GG + AA vs. GA). Stata 17.0 software was used for the meta-analysis. A total of 34 eligible studies with 12,611 subjects were included, including 6,030 cases in the RA group and 6,581 controls. Meta-analysis calculations revealed that the genetic polymorphisms of TNF-α-308G/A rs1800629 were not significantly associated with susceptibility to RA, with an odds ratio and 95% confidence interval (CI) for each genetic model [A vs. G: 0.937 (0.762-1.152); GA + AA vs. GG: 0.918 (0.733-1.148); AA vs. GG + GA: 1.131 (0.709-1.802); AA vs. GG: 1.097 (0.664-1.813); and GG + AA vs. GA: 1.108 (0.894-1.373)]. For the association between TNF-α-308G/A rs1800629 gene polymorphisms and the severity of RA, the results of subgroup analysis calculations showed that TNF-α-308G/A rs1800629 gene polymorphisms were associated with the severity of RA in European populations, with the gene model and 95% CI [GA + AA vs. GG: 0.503 (0.297-0.853); and GG + AA vs. GA: 2.268 (1.434-3.590)]. When assessing the confidence in the positive results of the present study through the false-positive report probability, the positive results were observed to be reliable. No significant association was observed between genetic polymorphisms in TNF-α-308G/A rs1800629 and susceptibility to RA. However, a significant association exists with the severity of RA in European populations.

An integrated pipeline for prediction of Clostridioides difficile infection

With the expansion of electronic health records(EHR)-linked genomic data comes the development of machine learning-enable models. There is a pressing need to develop robust pipelines to evaluate the performance of integrated models and minimize systemic bias. We developed a prediction model of symptomatic Clostridioides difficile infection(CDI) by integrating common EHR-based and genetic risk factors(rs2227306/IL8). Our pipeline includes (1) leveraging phenotyping algorithm to minimize temporal bias, (2) performing simulation studies to determine the predictive power in samples without genetic information, (3) propensity score matching to control for the confoundings, (4) selecting machine learning algorithms to capture complex feature interactions, (5) performing oversampling to address data imbalance, and (6) optimizing models and ensuring proper bias-variance trade-off. We evaluate the performance of prediction models of CDI when including common clinical risk factors and the benefit of incorporating genetic feature(s) into the models. We emphasize the importance of building a robust integrated pipeline to avoid systemic bias and thoroughly evaluating genetic features when integrated into the prediction models in the general population and subgroups.

Association of tumor necrosis factor-alpha promoter region gene polymorphism at positions -308G/A, -857C/T, and -863C/A with etanercept response in Iraqi rheumatoid arthritis patients

Objectives

This study aims to evaluate the association between polymorphisms in the promoter region of the tumor necrosis factor-alpha (TNF-α) gene at locations -308G/A, -857C/T, and -863C/A with the tendency of being non-responder to etanercept.

Patients and methods

Between October 2020 and August 2021, a total of 80 patients (10 males, 70 females; mean age: 50 years; range, 30 to 72 years) with rheumatoid arthritis (RA) receiving etanercept for at least six months were included. The patients were divided into two groups responders and non-responders, based on their response after six months of continuous treatment. Following polymerase chain reaction amplification of the extracted deoxyribonucleic acid, sequencing by Sanger method was performed to identify the polymorphism at the TNF-α promoter region.

Results

In the responder group, the GG genotype of (-308G/A) and the AA genotype of (-863C/A) were both significantly present. The CC genotype of (-863C/A) was significantly present in the non-responders group. The CC of (-863C/A) SNP was the only genotype that appeared to increase the likelihood of being resistant to etanercept. The GG genotype of (-308G/A) was negatively correlated with the likelihood of being a non-responder. The (-857CC) and (-863CC) genotypes were significantly more prevalent in the non-responders group.

Conclusion

The presence of the (-863CC) genotype, alone or in combination with (-857CC), is linked to an increased likelihood of becoming a non-responder to etanercept. The GG genotype of -308G/A and the AA genotype of -863C/A significantly increase the likelihood of becoming responder to etanercept.

The relationship between 896A/G (rs4986790) polymorphism of TLR4 and infectious diseases: A meta-analysis

Toll-like Receptors (TLRs), such as the TLR4, are genes encoding transmembrane receptors of the same name, which induce a pro- or anti-inflammatory response according to their expression as the host's first line of defense against pathogens, such as infectious ones. Single nucleotide polymorphisms (SNPs) are the most common type of mutation in the human genome and can generate functional modification in genes. The aim of this article is to review in which infectious diseases there is an association of susceptibility or protection by the TLR4 SNP rs4986790. A systematic review and meta-analysis of the literature was conducted in the Science Direct, PUBMED, MEDLINE, and SciELO databases between 2011 and 2021 based on the dominant genotypic model of this SNP for general and subgroup analysis of infectious agent type in random effect. Summary odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were calculated for genotypic comparison. I² statistics were calculated to assess the presence of heterogeneity between studies and funnel plots were inspected for indication of publication bias. A total of 27 articles were included, all in English. Among the results achieved, the categories of diseases that were most associated with the SNP studied were in decreasing order of number of articles: infections by bacteria (29.63%); caused by viruses (22.23%); urinary tract infection-UTI (7.4%), while 11 studies (40.74%) demonstrated a nonsignificant association. In this meta-analysis, a total of 5599 cases and 5871 controls were finalized. The present meta-analysis suggests that there is no significant association between TLR4-rs4986790 SNP and infections (OR = 1,11; 95% CI: 0,75-1,66; p = 0,59), but in the virus subgroup it was associated with a higher risk (OR = 2,16; 95% CI: 1,09-4,30; p = 0,03). The subgroups of bacteria and parasites did not show statistical significance (OR = 0,86; 95% CI: 0,56-1,30; p = 0,47, and no estimate of effects, respectively). Therefore, it has been shown that a diversity of infectious diseases is related to this polymorphism, either by susceptibility or even severity to them, and the receptor generated is also crucial for the generation of cell signaling pathways and immune response against pathogens.

Proinflammatory Cytokines (IL-1, -6, -8, -15, -17, -18, -23, TNF-α) Single Nucleotide Polymorphisms in Rheumatoid Arthritis-A Literature Review

Conducted studies highlight that a mixture of genetic and environmental factors is responsible for rheumatoid arthritis (RA) development. This study aimed to analyze the available literature for the relationship between, on the one hand, single-nucleotide polymorphisms (SNPs) in the proinflammatory cytokines genes interleukin-1 (IL-1), -6, -8, -15, -17, -18, and -23, and tumor necrosis factor-alpha (TNF-α), and on the other hand, RA susceptibility, severity, and patients' response to applied treatment. The PubMed database was searched for sources. Preference was given to articles which were published within the past 20 years. Data indicate that the relationship between selected SNPs in proinflammatory cytokines genes and susceptibility to developing RA is inconclusive, and it depends on the ethnicity of the population. Although the allelic and genotypic frequencies of many SNPs in proinflammatory cytokines genes analyzed did not differ between RA patients and healthy controls, deeper analysis showed that these polymorphisms have a relationship with clinicopathological features of RA. SNPs in proinflammatory cytokines genes also "modify patients' response" to applied treatment. Further studies, on larger cohorts of subjects and in different populations, should be conducted to elucidate the role of SNPs in IL-1, -6, -8, -15, -17, -18, and -23, and TNF-α genes in RA patients.

The association between interleukin-6 promoter polymorphisms and rheumatoid arthritis by ethnicity: A meta-analysis of 33 studies

OBJECTIVE

We performed a meta-analysis to determine the effect Interleukin-6 (IL-6) promoter polymorphism (-174 G>C, -572 G>C, and -597 G>A) have on the development rheumatoid arthritis (RA) by ethnicity.

MATERIAL AND METHODS

PubMed, EBSCO, LILACS, and Scopus databases were searched for studies exploring the association between any IL6 polymorphisms and RA until November 2018. Genotype distributions were extracted and, depending on the level heterogeneity, determined by the ψ²-based Q test and the Inconsistency Index (I²), fixed-effects or random-effects models were used to calculate pooled odds ratios (ORs) with 95% confidence intervals (95%CIs) for the heterozygous, homozygous, dominant, recessive, and allelic genetic models.

RESULTS

From 708 identified publications, 33 were used in this analysis. For the -174 polymorphism, Asians (OR_heterozygous=7.57, 95%CI: 2.28-25.14, OR_homozygous=5.84, 95%CI: 2.06-16.56, OR_dominant=7.21, 95%CI: 2.30-22.63, OR_recessive=5.04, 95%CI: 1.78-14.28, OR_allelic=6.60, 95%CI: 2.26-19.28, p<.05) and Middle East countries (OR_heterozygous=2.30, 95%CI: 1.10-4.81, OR_dominant=2.27, 95%CI: 1.22-4.22, OR_allelic=2.29, 95%CI: 1.24-4.23, p<.05) were associated with a significant risk of developing RA. Whereas, for Latinos, the C-allele was associated with a benefit (OR_homozygous=0.26, 95%CI: .08-.82, OR_recessive=.25, 95%CI: .08-.80, p<.05). For the -572 polymorphism, Asians demonstrated a significant association for the homozygous and recessive genetic models (8 studies, OR_homozygous=1.56, 95%CI: 1.16-2.09, OR_recessive=1.63, 95%CI: 1.08-2.45, p<.05). For the -597 polymorphism, no association was observed.

CONCLUSIONS

Here, the -174 G>C polymorphism increased the risk of developing RA in Asians and Middle East populations. Interestingly, for Latinos, the polymorphism was associated with a benefit. For the -572 polymorphism, only the Asian population showed an increased risk of developing RA for the CC genotype.

Association of interleukin-6 promoter polymorphism with rheumatoid arthritis: a meta-analysis with trial sequential analysis

OBJECTIVES

The association of interleukin-6 (IL-6) -174G/C (rs1800795) and IL-6 -572G/C (rs1800796) single-nucleotide polymorphism (SNP) with the risk of acquiring rheumatoid arthritis (RA) was inconsistent among previous studies. This paper aims to investigate the association between IL-6 promoter polymorphism with RA in different ethnics.

METHODS

Relevant studies were searched using Medline and Google Search engines; STATA software was used to perform the meta-analysis. Pooled odds ratios (OR) were calculated to estimate the potential genetic associations. Subgroup analysis and sensitivity analysis were applied to explore the sources of heterogeneity. Lastly, we used TSA (trial sequential analysis) software to verify the reliability of meta-analysis results.

RESULTS

A total of 18 studies were included, involving 8116 subjects (3820 RA patients and 4296 controls). We found a tendency to associate RA with the IL-6 -174G/C allele in Asians (C vs G: OR = 4.56, 95% CI = 1.85-11.23; P < 0.001); with IL-6 -572G/C genotype or allele frequencies, there was no statistical differences between RA patients and controls (P > 0.05). TSA results indicate that the current meta-analysis can draw conclusions.

CONCLUSIONS

IL-6-174G/C gene polymorphism were associated with increased risk of RA in Asians, but not in Caucasians. There was no association between IL-6 -572G/C gene polymorphism and the risk of RA. Key Points • Although the association between interleukin-6 (IL-6) promoter polymorphism and rheumatic arthritis (RA) has been discussed in the previous meta-analysis, their conclusions are inconsistent. • In this study, trial sequential analysis (TSA) was introduced into the meta-analysis, and the following two important conclusions were confirmed: (1) IL-6-174G/C gene polymorphism was associated with increased risk of RA in Asians, but not in Caucasians. (2) There was no association between IL-6 -572G/C gene polymorphism and the risk of RA.

TLR4 and TLR9 polymorphisms are not associated with either rheumatoid arthritis or systemic lupus erythematosus in Mexican patients

Toll-like receptor (TLR)-mediated signaling pathways induce a proinflammatory microenvironment to eradicate pathogens. However, in rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE), TLRs can promote chronic inflammation. It has been shown that some TLR4 and TLR9 single nucleotide polymorphisms (SNPs) are risk factors for RA and SLE, but these findings have not been replicated in all populations; thus, results are inconclusive. We evaluated the TLR4 Asp299Gly, Thr399Ile, - 1892G/A SNPs, and the TLR9 Pro545Pro SNP to assess potential associations with RA and SLE in Mexican patients. This study included 474 patients with RA, 283 patients with SLE, and 424 healthy controls. We used a 5' nuclease allelic discrimination assay to genotype individuals for the four TLR4 and TLR9 polymorphisms. We found that the genotype or allelic frequencies of the TLR4 Asp299Gly, Thr399Ile, - 1892G/A, and TLR9 Pro545Pro polymorphisms were similar between patients and controls. We found no association under different genetic models. A haplotype analysis of TLR4 showed no association with either RA or SLE. We found no significant differences in the allelic or genotypic frequencies of TLR4 Asp299Gly, Thr399IIe, - 1892G/A, or TLR9 Pro545Pro between patients and controls. These findings suggested that these variants are not risk factors for RA or SLE in Mexican patients.

Fatigue assessment by FACIT-F scale in Pakistani cohort with Rheumatoid Arthritis (FAF-RA) study

Objective:

To fine out fatigue frequency and severity by FACIT-F scale in Pakistani cohort with rheumatoid arthritis.

Methods:

This study was conducted at department of Medicine division of rheumatology CPMC Lahore. After the approval of IRB, 192 patients of RA were recruited. Written, informed consent was taken, demographic details were noted, patients filled the URDU version of FACIT-F (fatigue severity scale). 5-ml of blood was taken for fasting blood sugar, viral markers and ESR by a trained phlebotomist. Each individual’s disease activity was assessed by DAS-28 and FACIT-F score was calculated.

Results:

The Mean age (39.9±10.5) years, (71.9%) were females. Fatigue frequency was 62% (n=126), age, education, hypertension, DAS-28, exercise levels and HCV gives significant association with fatigue score. Linear regression analysis, results showed one unit increase in DAS-28 will gives 2.71 unit increases in fatigue scores(P <0.05).

Conclusions:

We have very high frequency of fatigue in RA, increases with disease activity & associated conditions.

Pro-inflammatory cytokine response pre-dominates immuno-genetic pathway in development of rheumatoid arthritis

Rheumatoid arthritis (RA) is a crucial inflammatory joint disease characterized by loss of self-tolerance and severe cartilage loss, autoimmune, and subchondral bone erosions. Cytokines are the key regulators of inflammatory responses. Homeostatic imbalances in pro- and anti-inflammatory cytokine activities can result in pathogenic inflammatory reactions. These imbalances could be initiated by environmental factors but the ability to define the threshold of environmental impact relies on the genetic background of the pro- and anti-inflammatory cytokines. To address this a case-control association study was carried out in 429 individuals from Malayalam speaking ethnic population from South India. Functionally relevant SNPs from IL-10, IL-6, IL-1β and IL-1RN were genotyped using PCR -RFLP and sequencing. Meta-analysis was performed for the associated variants of IL-10, IL-1β. Significant association with RA was observed with IL-1β rs1143634, rs1143627, IL-10 rs1800896, IL-6 rs1800796, rs1800797. The associated SNPs are likely to impact transcriptional activity of a gene. Meta-analysis with global populations also provide evidence that IL-10 and IL-1β could be a global marker for RA. The functional significance of associated risk variants of IL-1β and IL-6 indicate increased production of the pro-inflammatory cytokines while IL-10 risk allele suggest reduced production of anti- inflammatory cytokines. The study concludes that increased production of pro-inflammatory cytokines and reduced production of anti- inflammatory cytokines may influence the Th1/Th2 equilibrium resulting in a triggering of Th1 mediated inflammatory responses in development of RA.

The relationship between periodontal status and rheumatoid arthritis - systematic review

There have been numerous publications investigating the relationship between periodontitis (PD) and rheumatoid arthritis (RA) so far.

This publication presents the common risk factors for the development of PD and RA. The major impact of the pathological bacterial factor and cigarette smoking with chronic inflammation playing the key role in both diseases has been confirmed by numerous studies in various populations over the years. More research focuses nowadays also on the role of improper diet and obesity. Pathophysiological pathways, such as increased concentration of proinflammatory cytokines, indirectly affecting the cardiovascular complications and coagulation disorders, which has an impact on function disorders of tissue metalloproteinase inhibitors and the plasminogen activation system, were also researched.

This systematic review of current literature has shown numerous discrepancies in previous analyses and the need for further detailed research on the relationship between periodontal status and RA.

Association of two polymorphisms Asp299Gly and Thr399Ile in Toll-like receptor 4 with rheumatoid arthritis: A meta-analysis

Our meta-analysis aims to evaluate the association of Asp299Gly and Thr399Ile with rheumatoid arthritis (RA) susceptibility and severity. By manually searching 3 electronic databases (PubMed, Embase and Web of Science), relevant articles were collected. After checking eligibility for every study, this meta-analysis on eligible studies was performed under 5 genetic models: (1) allelic contrast; (2) heterozygous model; (3) homozygous model; (4) dominant model; (5) recessive model. In Spanish populations, a significantly decreased RA risk was identified in allelic comparison (odds ratio [OR] = 0.73, 95% CI 0.55 ~ 0.96) and dominant model (OR = 0.74, 95% CI 0.56 ~ 0.99) of Asp299Gly polymorphism. A trend of reduced risk was also observed under the heterozygous model (OR = 0.77, 95% CI 0.58 ~ 1.03). As for Thr399Ile, it might also have a protective effect on Spanish populations in allelic comparison (OR = 0.71, 95% CI 0.44 ~ 1.15). In contrast, for both Asp299Gly and Thr399Ile, a higher risk of RA was detected in Chinese Han populations. The frequency of both Asp299Gly and Thr399Ile increased in rheumatoid factor (RF)-positive subjects in Chinese patients (Asp299Gly, RF+:RF- = 0.165:0.145; Thr399Ile, RF+:RF- = 0.170:0.161) and decreased in Spanish patients (Asp299Gly, RF+:RF- = 0.060:0.073; Thr399Ile, RF+:RF- = 0.046:0.056), but not to a statistically significant extent. Our meta-analysis suggested that both Asp299Gly and Thr399Ile might have a protective effect on Spanish populations, but the 2 polymorphisms could act as a susceptible factor in Chinese Han populations. To confirm our results, further investigation concerning the functional impacts of Asp299Gly and Thr399Ile are still needed.

Investigation of The Relationship Between IL-18 (-607 C/A), IL-18 (-137 G/C) Gene Variations and Ischemic Stroke Disease Development in Thrace Region of Turkey

BACKGROUND

Ischemic stroke is a clinical condition characterized by focal or global cerebral dysfunction resulting from inhibition of brain blood flow. Genetic factors play an important role in the pathogenesis of ischemic stroke. As a result of IL-18 (-607 C/A, -137 G/C) gene variations, it is thought that binding of transcription factors may be affected and IL-18 mRNA expression can be modulated. Therefore, the purpose of our study is to investigate the roles of IL-18 (-607 C/A), IL-18 (-137 G/C) gene variations in the development of ischemic stroke in Trakya Region of Turkey.

METHODS

Our study was performed with 90 ischemic stroke patients and 89 healthy controls. Genotype distributions of IL-18 (-607 C/A, -137 G/C) gene variations were determined using polymerase chain reaction (PCR) method.

RESULTS

GC genotype and CA genotype of IL-18 (-137 G/C) and IL-18 (-607 C/A) gene variations were determined higher significantly in patent group as compared with other genotypes. However, the statistically significant difference was not determined between patients with ischemic stroke and healthy control groups in terms of IL-18 (-137 G/C) and IL-18 (-607 C/A) gene variations (p > 0,05). Allele frequencies of IL-18 (-137 G/C) and IL-18 (-607 C/A) in patient and control groups were significantly different from the Hardy-Weinberg distribution (p < .001 for all).

CONCLUSION

Although these gene variations' genotype distributions were not determined as a genetic risk factor for the development of ischemic stroke, allele frequencies of IL-18 (-137 G/C) and IL-18 (-607 C/A) in patient and control groups were significantly different from the Hardy-Weinberg distribution.

Impact of IL-17F 7488T/C Functional Polymorphism on Progressive Rheumatoid Arthritis: Novel Insight from the Molecular Dynamic Simulations

Resorption of bones and cartilage coupled with structural changes in the inflamed joints are the major hallmark of rheumatoid arthritis (RA). Genetic polymorphisms in pro-inflammatory interleukins (ILs) appear to play an important role in the susceptibility towards progressive RA. We therefore aimed to investigate the association of single nucleotide polymorphisms (SNP), present in the hotspot coding/promoter regions of IL-6, -17 and -18, with RA susceptibility or severity in a larger study cohort from Pakistan together with finding clues as to how a functional SNP impacts the predisposition towards RA. TaqMan SNP genotyping approach was first used to assess IL-6 (rs1800795), IL-17 F (rs763780), IL-17A (rs2275913), and IL-18 (rs1946518) polymorphisms in 310 subjects (150 RA and 160 control). Molecular dynamic simulations (MDS) of wild- and mutant-type IL-17A with corresponding receptor were thereafter performed using AMBER-16; Chimera 1.13 was used for analyses. Our results showed the association of two SNPs, namely IL-6 - 174 G/C [allelic (OR = 0.960, 95% CI = 0.929-0.992, p = .009)] and IL-17 F 7488 T/C [allelic (OR = 0.907, 95%CI = 0.861-0.954, p = .000)] with increased RA risk in Pakistani subjects. When mapped, IL-17 F 7488 T/C was found involved in His₁₆₁→Arg₁₆₁ change near the C-terminus of IL-17 F. Comparative MDS revealed enhanced stability of the mutant hence advocating a potential role of IL-17F functional SNP in RA susceptibility and/or severity. This study provides a novel structural insight for SNP-derived functional mutation and its overall impact on binding with heterotrimeric receptor complex of IL-17 receptor thereby opening new avenues for understanding the biochemical basis of the disease.

The Association Between Interleukin-6 Promoter Polymorphisms and Rheumatoid Arthritis by Ethnicity: A Meta-Analysis of 33 Studies

OBJECTIVE

We performed a meta-analysis to determine the effect Interleukin-6 (IL-6) promoter polymorphism (-174 G>C, -572 G>C, and -597 G>A) have on the development rheumatoid arthritis (RA) by ethnicity.

MATERIAL AND METHODS

PubMed, EBSCO, LILACS, and Scopus databases were searched for studies exploring the association between any IL6 polymorphisms and RA until November 2018. Genotype distributions were extracted and, depending on the level heterogeneity, determined by the ψ2-based Q test and the Inconsistency Index (I2), fixed-effects or random-effects models were used to calculate pooled odds ratios (ORs) with 95% confidence intervals (95%CIs) for the heterozygous, homozygous, dominant, recessive, and allelic genetic models.

RESULTS

From 708 identified publications, 33 were used in this analysis. For the -174 polymorphism, Asians (ORheterozygous=7.57, 95%CI: 2.28-25.14, ORhomozygous=5.84, 95%CI: 2.06-16.56, ORdominant=7.21, 95%CI: 2.30-22.63, ORrecessive=5.04, 95%CI: 1.78-14.28, ORallelic=6.60, 95%CI: 2.26-19.28, p<.05) and Middle East countries (ORheterozygous=2.30, 95%CI: 1.10-4.81, ORdominant=2.27, 95%CI: 1.22-4.22, ORallelic=2.29, 95%CI: 1.24-4.23, p<.05) were associated with a significant risk of developing RA. Whereas, for Latinos, the C-allele was associated with a benefit (ORhomozygous=0.26, 95%CI: .08-.82, ORrecessive=.25, 95%CI: .08-.80, p<.05). For the -572 polymorphism, Asians demonstrated a significant association for the homozygous and recessive genetic models (8 studies, ORhomozygous=1.56, 95%CI: 1.16-2.09, ORrecessive=1.63, 95%CI: 1.08-2.45, p<.05). For the -597 polymorphism, no association was observed.

CONCLUSIONS

Here, the -174 G>C polymorphism increased the risk of developing RA in Asians and Middle East populations. Interestingly, for Latinos, the polymorphism was associated with a benefit. For the -572 polymorphism, only the Asian population showed an increased risk of developing RA for the CC genotype.

Analysis of the Association of TNF -238G>A Gene Polymorphism with the Risk of Rheumatoid Arthritis Development in Russian Population in the Republic of Karelia

We studied association of the TNF gene -238G>A polymorphism (rs361525) with the risk of rheumatoid arthritis development in the Russian population living in the Republic of Karelia. The influence of rs361525 on the development of rheumatoid arthritis was revealed: genetic predisposition to this disease is associated with the presence of GG genotype. The effect of the genotype on the polymorphic locus of -238G>A on TNF mRNA content was revealed. Increased content of transcripts of this gene is associated with the presence of A allele.

Interleukin 6 gene polymorphism is associated with protein serum level and disease activity in Polish patients with rheumatoid arthritis

Interleukin 6 (IL-6) is a pro-inflammatory cytokine involved in the development of rheumatoid arthritis (RA). The present study aimed to determine the possible association of the IL6 (rs1800795, G > C) polymorphism with RA susceptibility, disease progression and protein serum levels. Distribution of IL6 alleles and genotypes was similar in RA patients and controls. As expected, patients before induction of anti-tumour necrosis factor agents had significantly higher IL-6 levels as compared with controls (P = 0.002). The CC homozygous patients were characterised with the highest average concentrations of this pro-inflammatory cytokine before treatment (P = 0.028), and they also more frequently presented with more active disease (P = 0.048). These results imply that the IL6 rs1800795 CC homozygosity may play a rather unfavourable role in RA.

IL-8 Gene Variants and Expression in Childhood Asthma

PURPOSE

To examine the IL-8 expression levels and association of genetic variants with the risk of childhood persistent asthma prognosis.

METHODS

Overall, 170 asthmatic children and 170 healthy controls were included in this case-control study. The human IL-8 serum levels were measured using ELISA. The IL-8 mRNA expression levels were assessed by a real-time quantitative reverse transcription-polymerase chain reaction (qRT-PCR). The genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) methods.

RESULTS

The IL-8 expression at both protein and mRNA levels was found to be significantly elevated in asthmatic children compared to healthy subjects (P < 0.0001, P = 0.004; respectively). Higher levels of IL-8 mRNA are detected in subjects with moderate to severe asthma. The presence of IL8-251 A/T (rs4073) and + 781C/T (rs2227306) polymorphisms was significantly associated with an increased risk of asthma (P = 0.002, P = 0.036, respectively). In addition, we noted a significant association between these polymorphisms and an elevated risk of atopic asthma (P < 0.05). For rs2227306 SNP, the highest median level of IgE was detected for the presence of TT genotype (865 ± 99.74 IU/mL). Although, the rs4073 polymorphism conferred a higher risk to develop asthma at an advanced stage of severity (P = 0.008). The rs4073 T and rs2227306 C alleles are considered as risk factors for asthma development. The rs4073 T allele is represented also as a risk factor for asthma severity in Tunisian children.

CONCLUSIONS

Both IL-8 gene and protein expression may play a key role in asthma pathogenesis.

Circulating interleukin-6 and rheumatoid arthritis: A Mendelian randomization meta-analysis

Interleukin-6 (IL-6), as a pleiotropic cytokine, has been demonstrated to be closely associated with the pathogenisis of rheumatoid arthritis (RA). However, whether this association is causal or not remains unclear, because of the multifactorial role of IL-6 and related confounding factors. We aimed to evaluate the causal relevance between circulating IL-6 levels and the risk of RA through meta-analytical Mendelian randomization approach. IL-6 gene -174G/C variant was selected as an instrument in this Mendelian randomization meta-analysis. Article identification and data collection were conducted in duplicate and independently by 2 authors. The STATA software was used for data analysis. In total, 15 and 5 articles on the association of the -174G/C variant with RA risk and circulating IL-6 level, respectively, were included. The overall analysis showed that C allelic and GC+CC genotype were significantly with 1.59-fold (95% CI: 1.19-2.14) and 1.63-fold (95% CI: 1.17-2.26) increased risk of developing RA, respectively. Asian populations showed stronger association with 4.55-fold (95% CI: 1.62-12.75), 1.84-fold (95% CI: 1.13-2.99), and 4.69-fold (95% CI: 1.68-13.14) increased RA risk in carriers of -174C allelic, CC, and GC+CC genotype, respectively. Carriers of GC+CC genotype showed significant reduction in the circulating IL-6 level compared with GG carriers (WMD = -0.77; 95% CI: -1.16 to -0.38; P = 0.000) in overall populations. Mendelian randomization presented 6% and 22% increased risk of RA with 0.1 pg/mL reduction of circulating IL-6 level in overall and Asian populations, respectively. This Mendelian randomization meta-analysis demonstrated that the long-term genetically reduced circulating IL-6 level might be causally related to a higher risk of RA, especially in Asian populations.

Lack of tumor necrosis factor alpha gene polymorphism -857c/t (rs1799724) association in Pakistani rheumatoid arthritis patients

BACKGROUND

Rheumatoid arthritis (RA) is a common systemic autoimmune disease, influenced greatly by the pro-inflammatory cytokine tumor necrosis factor- alpha (TNF-α). Single nucleotide polymorphisms (SNPs) in regulatory regions of the TNF-α gene play a significant role in disease development and pathogenesis. The aim of this study was to investigate the association of TNF-α -857C/T (rs1799724) SNP with RA activity or severity in our Pakistani study group.

METHODS

The study included 134 (116 women, 18 men) patients with RA and 134 ethnically matched healthy controls (108 women, 26 men). Each patient's disease activity was measured by Disease Activity Score of 28 joints. The genotypes were determined in all included individuals following allele-specific polymerase chain reaction along with the prerequisite internal amplification controls. Statistical analysis including chi-square/Fischer exact test and one-way analysis of variance; nonparametric Kruskal-Wallis test was employed using Graphpad Prism 6 software for association study.

RESULTS

The prevalence of TNF-α -857C/T (rs1799724) polymorphism was not differentially distributed between RA patients and controls in either allele frequency, with odds ratio (95% CI) of 0.9661 (0.6714-1.390) and P-value of 0.8527, or genotype frequency with χ² of 0.5015 and P-value of 0.7782. Moreover, no correlation was found when genotype frequency distribution was analyzed with disease severity (P = 0.6321 and Kruskal-Wallis statistics of 1.098).

CONCLUSION

The study demonstrated -857C/T (rs1799724) polymorphism may not have influenced RA susceptibility in our study group. However, investigations of genetic variability influence on disease outcome in large prospective cohorts are required, so the complicated interconnection of genetic and environmental elements can be emulated for better understanding.

Genetic variants within immune-modulating genes influence the risk of developing rheumatoid arthritis and anti-TNF drug response: a two-stage case-control study

BACKGROUND

Rheumatoid arthritis (RA) is a chronic autoimmune disease that arises as a result of the interaction between genetic and environmental factors. A growing body of research suggests that genetic variants within immune-related genes can influence the risk of developing the disease and affect drug response.

MATERIALS AND METHODS

To test this hypothesis, we carried out a comprehensive two-stage case-control study in a White population of 1239 White RA patients and 1229 healthy controls to investigate whether 49 single nucleotide polymorphisms within or near 17 immune-related genes modulate the risk of developing RA and antitumor necrosis factor (anti-TNF) drug response.

RESULTS

Logistic regression analyses showed that carriers of the IL4rs2070874T and IL4rs2243250T and IL8RBrs1126580A alleles or the IL8RBrs2230054C/C genotype had a significantly increased risk of developing RA [odds ratio (OR)=1.37, 95% confidence interval (CI) 1.13-1.67, P=0.0016; OR=1.24, 95% CI 1.03-1.49, P=0.020; OR=1.23, 95% CI 1.08-1.41, P=0.002 and OR=1.19, 95% CI 1.04-1.36, P=0.01, respectively]. The association of the IL4 variants was further supported by a meta-analysis including 7150 individuals (P =0.0010), whereas the involvement of the IL8RB locus in determining the susceptibility to RA was also supported by gene-gene interaction analyses that identified significant two-locus and three-locus interaction models including IL8RB variants that act synergistically to increase the risk of the disease (P=0.014 and 0.018). Interestingly, we also found that patients harbouring the IFNGrs2069705C allele showed a significantly better response to anti-TNF drugs than those patients carrying the wild-type allele (P=0.0075).

CONCLUSIONS

Our data suggest that IL4 and IL8RB loci may have a small-effect genetic impact on the risk of developing RA, whereas IFNG might be involved in modulating the response to anti-TNF drugs.

The IL-8 Gene Polymorphisms in Behçet's Disease Observed in Denizli Province of Turkey

Behçet's disease is a multisystemic inflammatory disorder as a triad of symptoms including recurrent oral and genital aphthous ulceration and uveitis with unknown pathogenesis. IL-8, a proinflammatory cytokine, has been found increased in the active stage of BD. DNA samples were obtained from 88 patients with BD and 112 healthy control subjects in Denizli province of Turkey. All genotyping experiments of SNPs in IL-8 gene were performed using polymerase chain reaction-restriction fragment polymorphism. We found that IL-8 -845 T > C and -738 T > A sites are non-polymorphic. There were no differences in the polymorphisms of IL-8 +396 G/T, +781 C/T, and +1633 C/T sites except IL-8 -251 T > A in between patients and healthy controls. Analysis of IL-8 polymorphisms indicates that the distribution of frequencies seems to be associated with -251 T > A and gender, -251 T > A and erythema nodosum, -251 T > A and ocular involvement, +781 C > T and erythema nodosum, +396 G > T and pathergy positivity, and +1633 C > T and papulopustular lesion. We demonstrated that the frequencies of IL-8 haplotypes were significantly different with BD patients than control group. We found that the distribution of IL-8 haplotypes was significantly different with genital ulcers, ocular involvement, positive pathergy test, erythema nodosum, papulopustular lesions, and arthritis with BD patients than healthy control individuals. Our study suggests that IL-8 gene polymorphisms may affect susceptibility to BD and increase the risk of developing disease. In order to confirm and assess the association of IL-8 and other cytokine gene polymorphisms in the pathophysiology of BD, large cohort studies are needed.

Promoter polymorphism (-590, T/C) of interleukin 4 (IL4) gene is associated with rheumatoid arthritis: An updated meta-analysis

Rheumatoid arthritis (RA) is a chronic disease. It causes chronic inflammation of the joint. Recent studies suggested that interleukin 4 (IL4) contributes to susceptibility and severity of rheumatoid arthritis (RA). Especially, it was reported that promoter polymorphism (-590, T/C) of IL4 gene has been associated with susceptibility of RA. The aim of present study was to investigate whether the promoter polymorphism (-590, T/C) of IL4 gene is associated with the susceptibility of RA using meta-analysis. And in order to perform meta-analysis, comprehensive meta analysis program was used. Genetic models (co-dominant, dominant, recessive, and allele) were used to determine odds ratios (ORs), 95% confidence intervals (CIs), and P values. Nine case-control studies with case and control design were included in this meta-analysis. Overall, meta-analysis revealed a strong association with susceptibility of RA [OR = 1.303, 95% CI = 1.093-1.554, P = 0.003 in allele model (C vs. T); OR = 1.247, 95% CI = 1.054-1.474, P = 0.010 in dominant model (CC vs. CT + TT); OR = 2.148, 95% CI = 1.263-3.651, P = 0.005 in recessive model (CC + CT vs. TT)]. Our data demonstrated that promoter polymorphism (-590, T/C) of IL4 gene may be contributed to susceptibility of RA. However, more studies with a larger sample size are needed to provide more precise evidence.

Genetic polymorphisms associated with the inflammatory response in bacterial meningitis

Background

Bacterial meningitis (BM) is an infectious disease that results in high mortality and morbidity. Despite efficacious antibiotic therapy, neurological sequelae are often observed in patients after disease. Currently, the main challenge in BM treatment is to develop adjuvant therapies that reduce the occurrence of sequelae. In recent papers published by our group, we described the associations between the single nucleotide polymorphisms (SNPs) AADAT +401C > T, APEX1 Asn148Glu, OGG1 Ser326Cys and PARP1 Val762Ala and BM. In this study, we analyzed the associations between the SNPs TNF -308G > A, TNF -857C > T, IL-8 -251A > T and BM and investigated gene-gene interactions, including the SNPs that we published previously.

Methods

The study was conducted with 54 BM patients and 110 healthy volunteers (as the control group). The genotypes were investigated via primer-introduced restriction analysis-polymerase chain reaction (PIRA-PCR) or polymerase chain reaction-based restriction fragment length polymorphism (PCR-RFLP) analysis. Allelic and genotypic frequencies were also associated with cytokine and chemokine levels, as measured with the x-MAP method, and cell counts. We analyzed gene-gene interactions among SNPs using the generalized multifactor dimensionality reduction (GMDR) method.

Results

We did not find significant association between the SNPs TNF -857C > T and IL-8 -251A > T and the disease. However, a higher frequency of the variant allele TNF -308A was observed in the control group, associated with changes in cytokine levels compared to individuals with wild type genotypes, suggesting a possible protective role. In addition, combined inter-gene interaction analysis indicated a significant association between certain genotypes and BM, mainly involving the alleles APEX1 148Glu, IL8 -251 T and AADAT +401 T. These genotypic combinations were shown to affect cyto/chemokine levels and cell counts in CSF samples from BM patients.

Conclusions

In conclusion, this study revealed a significant association between genetic variability and altered inflammatory responses, involving important pathways that are activated during BM. This knowledge may be useful for a better understanding of BM pathogenesis and the development of new therapeutic approaches.

Electronic supplementary material

The online version of this article (doi:10.1186/s12881-015-0218-6) contains supplementary material, which is available to authorized users.

TLR2 and TLR4 in autoimmune diseases: a comprehensive review

Autoimmune diseases are immune disorders characterized by T cell hyperactivity and B cell overstimulation leading to overproduction of autoantibodies. Although the pathogenesis of various autoimmune diseases remains to be elucidated, environmental factors have been thought to contribute to the initiation and maintenance of auto-respond inflammation. Toll-like receptors (TLRs) are pattern recognition receptors belonging to innate immunity that recognize and defend invading microorganisms. Besides these exogenous pathogen-associated molecular patterns, TLRs can also bind with damage-associated molecular patterns produced under strike or by tissue damage or cells apoptosis. It is believed that TLRs build a bridge between innate immunity and autoimmunity. There are five adaptors to TLRs including MyD88, TRIF, TIRAP/MAL, TRAM, and SARM. Upon activation, TLRs recruit specific adaptors to initiate the downstream signaling pathways leading to the production of inflammatory cytokines and chemokines. Under certain circumstances, ligation of TLRs drives to aberrant activation and unrestricted inflammatory responses, thereby contributing to the perpetuation of inflammation in autoimmune diseases. In the past, most studies focused on the intracellular TLRs, such as TLR3, TLR7, and TLR9, but recent studies reveal that cell surface TLRs, especially TLR2 and TLR4, also play an essential role in the development of autoimmune diseases and afford multiple therapeutic targets. In this review, we summarized the biological characteristics, signaling mechanisms of TLR2/4, the negative regulators of TLR2/4 pathway, and the pivotal function of TLR2/4 in the pathogenesis of autoimmune diseases including rheumatoid arthritis, systemic lupus erythematosus, systemic sclerosis, Sjogren's syndrome, psoriasis, multiple sclerosis, and autoimmune diabetes.

Association of Toll like receptor Asp299Gly with rheumatoid arthritis risk: a systematic review of case-control studies and meta-analysis

OBJECTIVE

Rheumatoid arthritis (RA) is thought to be triggered by various genetic and environmental factors. Few human epidemiologic studies demonstrated that single nucleotide polymorphisms (SNPs) in Toll-like receptor (TLR) genes are associated with RA. We aimed to evaluate the effects of TLR polymorphisms on the risk of RA pathogenesis by using a meta-analysis approach.

METHODS

Following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines, a systematic search and meta-analysis of the literature was conducted. We screened the medical literature based on keywords search in MEDLINE and EMBASE 'Toll-like receptor', 'polymorphism', and rheumatoid arthritis. Meta-analyses were performed under the random-effects model by using: (1) recessive, (2) homozygous, (3) dominant, (4) codominant and allele contrast models.

RESULTS

A total of 3086 cases and 3756 controls in nine studies were included in the meta-analysis. Association between TLR4 Asp299Gly and RA risk was marginally significant [OR = 0.856 (95% CI, 0.716-1.022); P = 0.086] in the homozygous model. AA and GG homozygote genotypes tended to be significant protective factors against RA risk.

CONCLUSION

Our overall analyses indicated that TLR4 Asp299Gly polymorphism might contribute to RA pathogenesis.

Polymorphisms in the TNF-α, TNFR1 gene and risk of rheumatoid arthritis in Chinese Han population

Recent advances have highlighted a major genetic contribution to the pathogenesis of rheumatoid arthritis (RA).The aim of this study was to investigate whether polymorphisms of TNF-α (rs1800630, rs1800629) and TNFR1 (rs767455) were associated with susceptibility to and clinical outcome of RA in Chinese Han population. The target gene polymorphisms were genotyped in 256 patients with RA and 331 healthy controls using a high resolution melting (HRM) method. ESR, CRP, RF anti-CCP and anti-GPI level were also assayed and compared in genotypes of each polymorphism. Significant difference was observed in the genotype distributions and allele frequencies of TNF-α rs1800629 (P = 0.001, P < 0.001, respectively) between patients with RA and controls. There is no evidence to suggest an association between genotypes of the 3 SNPs according to age, gender, disease duration, DAS28 and serum level of autoantibodies. This study identifies a potentially important role for TNF-α rs1800629 polymorphisms in the susceptibility to RA.However, further studies in larger cohorts are required.

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.

RADB: a database of rheumatoid arthritis-related polymorphisms

Rheumatoid arthritis (RA) is an autoimmune disease that has a complex genetic basis. Therefore, it is important to explore the genetic background of RA. The extensive recent application of polymorphic genetic markers, especially single nucleotide polymorphisms, has presented us with a large quantity of genetic data. In this study, we developed the Database of Rheumatoid Arthritis-related Polymorphisms (RADB), to integrate all the RA-related genetic polymorphisms and provide a useful resource for researchers. We manually extracted the RA-related polymorphisms from 686 published reports, including RA susceptibility loci, polymorphisms associated with particular clinical features of RA, polymorphisms associated with drug response in RA and polymorphisms associated with a higher risk of cardiovascular disease in RA. Currently, RADB V1.0 contains 3235 polymorphisms that are associated with 636 genes and refer to 68 countries. The detailed information extracted from the literature includes basic information about the articles (e.g. PubMed ID, title and abstract), population information (e.g. country, geographic area and sample size) and polymorphism information (e.g. polymorphism name, gene, genotype, odds ratio and 95% confidence interval, P-value and risk allele). Meanwhile, useful annotations, such as hyperlinks to dbSNP, GenBank, UCSC, Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway, are included. In addition, a tool for meta-analysis was developed to summarize the results of multiple studies. The database is freely available at http://www.bioapp.org/RADB.

Database URL:http://www.bioapp.org/RADB.

Polymorphism of the IL-8 gene and the risk of ovarian cancer

Ovarian cancer still represents a challenge in gynecological oncology. Most patients are diagnosed in an advanced tumor stage. No specific screening or prevention strategies for ovarian cancer exist as of yet. Interleukin 8 (IL-8) is a pro-inflammatory chemokine known for its angiogenetic activity, and is supposedly responsible for tumor-associated angiogenesis in several malignant tumors. The aim of the study was to investigate the susceptibility of patients with an IL-8 gene polymorphism to developing ovarian cancer. Four single nucleotide polymorphisms (SNPs) (IL-8 -251, IL-8 +781, IL-8 +1633 and IL-8 +2767) of the IL-8 gene were screened, using the PCR method in 268 patients with ovarian cancer and 426 healthy women as a control group. Significant associations were noted in patients with the IL-8 +781 (T/T) genotype (p=0.0048) with increased frequencies of ovarian cancer, while women with the IL-8 +781 (C/C) allele suffer from ovarian cancer significantly less frequently (p=0.0003). Furthermore, the IL-8 +2767 (T/T) genotype is also associated with a higher risk of ovarian cancer (p=0.0177). Our results indicate, for the first time, that IL-8 polymorphism is associated with ovarian cancer.

Association between interleukin-6 gene polymorphisms and rheumatoid arthritis in Chinese Han population: a case-control study and a meta-analysis

The aim of this study was to investigate the possible association in the interleukin-6 (IL-6) gene with Rheumatoid arthritis (RA) in Chinese Han population from Shandong Province. Target regions of IL-6 gene were amplified by polymerase chain reaction (PCR) and genotyped. A logistic regression analysis was performed to detect potential associations in our case-control sample, the odd ratio(OR) and 95% confidence intervals(CIs) were calculated. Furthermore, we systematically tracked all the published studies in the field and performed a meta-analysis for the single nucleotide polymorphisms (SNPs) under study. 256 RA patients and 331 healthy controls were recruited into the case-control study. We found allele frequencies of rs1800795, rs1800797 and rs1474347 in RA patients differ from control subjects (P = 0.016, 0.024, 0.020, respectively). Significant difference was observed in haplotype frequencies of GCCGCT between RA patients and controls (P = 0.0001, OR = 4.066, 95%CI = 1.891 ~ 8.746), while GGCGCT frequencies was found lower in RA than controls (P = 0.006, OR = 0.669, 95%CI = 0.501 ~ 0.894). The results of the meta-analysis showed association polymorphism within the IL-6 promoter with RA. These findings suggest that rare IL-6 gene polymorphisms may associate with RA susceptibility in Han Chinese populations; however further studies are needed to assess the validity of the association of IL-6 with RA.

Polymorphisms of Toll-like receptor-4 and CD14 in systemic lupus erythematosus and rheumatoid arthritis

Background

Toll-like receptor 4 (TLR4) and its co-receptor CD14 play a major role in innate immunity by recognizing PAMPs and signal the activation of adaptive responses. These receptors can recognize endogenous ligands mainly auto-antigens. In addition, TLR4 (Asp299Gly) and CD14 (C/T -159) polymorphisms (SNPs) may modify qualitatively and/or quantitatively their expression. Therefore, they could be implied in autoimmune diseases and can influence both susceptibility and severity of systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA).

Patients and methods

TLR4 (Asp299Gly) and CD14 (C/T -159) SNPs were genotyped using polymerase chain reaction (PCR)-RFLP in 127 SLE patients, 100 RA patients, and 114 healthy controls matched in age and gender.

Results

CD14*T allele was significantly more frequent in SLE patients (0.456) comparatively to controls (0.355), p = 0.02 OR (95% CI) = 1.53 [1.04-2.24]. In RA patients, the higher frequency of CD14*T allele (0.405) failed to reach significance, p = 0.28. Investigation of the TLR4 (Asp299Gly) SNP showed no significant association neither with SLE nor with RA.

Analysis of these SNPs according to clinical and biological features showed a significant higher frequency of arthritis in SLE patients carrying CD14*T/T genotype (92%) comparatively to those with C/C and C/T genotypes (72.5%), p = 0.04. Moreover, SLE patients carrying CD14*T/T/TLR4*A/A haplotype had significantly more arthritis (91.3%) than the rest of SLE group (73%), p = 0,044 and confirmed by multivariable analysis after adjustment according to age and gender, p = 0.01.

Conclusion

The CD14 (-159)*T allele seems to be associated with susceptibility to SLE and arthritis occurrence.

DNA methyltransferase 3B gene promoter and interleukin-1 receptor antagonist polymorphisms in childhood immune thrombocytopenia

Primary immune thrombocytopenia (ITP) is one of the most common blood diseases as well as the commonest acquired bleeding disorder in childhood. Although the etiology of ITP is unclear, in the pathogenesis of the disease, both environmental and genetic factors including polymorphisms of TNF-a, IL-10, and IL-4 genes have been suggested to be involved. In this study, we investigated the rs2424913 single-nucleotide polymorphism (SNP) (C46359T) in DNA methyltransferase 3B (DNMT3B) gene promoter and the VNTR polymorphism of IL-1 receptor antagonist (IL-1 Ra) intron-2 in 32 children (17 boys) with the diagnosis of ITP and 64 healthy individuals. No significant differences were found in the genotype distribution of DNMT3B polymorphism between the children with ITP and the control group, whereas the frequency of allele T appeared significantly increased in children with ITP (P = 0.03, OR = 2, 95% CI: 1.06-3.94). In case of IL-1 Ra polymorphism, children with ITP had a significantly higher frequency of genotype I/II, compared to control group (P = 0.043, OR = 2.60, 95% CI: 1.02-6.50). Moreover, genotype I/I as well as allele I was overrepresented in the control group, suggesting that allele I may have a decreased risk for development of ITP. Our findings suggest that rs2424913 DNMT3B SNP as well as IL-1 Ra VNTR polymorphism may contribute to the susceptibility to ITP.

Lack of association of TLR4 polymorphisms with susceptibility to rheumatoid arthritis and ankylosing spondylitis: a meta-analysis

OBJECTIVE

The aim of the study was to determine whether polymorphisms of toll-like receptor 4 (TLR4) confer susceptibility to rheumatoid arthritis (RA) and ankylosing spondylitis (AS).

METHODS

A meta-analysis was conducted on the association between the D299G/T399I polymorphisms and RA/AS (when available) using (1) the allelic contrast, (2) the recessive, (3) the dominant, and (4) the additive models.

RESULTS

A total of eleven relevant studies met the inclusion criteria were identified, including RA: D299G (six studies), T399I (three studies); AS: D299G (five studies), T399I (four studies). Meta-analysis was performed with fixed/random effect models. Overall, no significant RA/AS risk was found in all genetic models when all studies were pooled into the meta-analysis (P>0.05).

CONCLUSIONS

The present study might suggest that TLR4 D299G/T399I polymorphisms are not associated with RA/AS susceptibility.

Lack of association between TLR4 rs4986790 polymorphism and risk of cardiovascular disease in patients with rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory disease associated with increased cardiovascular (CV) mortality. Toll-like receptor-4 (TLR4) activates the innate immune response via NF-kB pathway and mitogen-activated protein kinase signaling, leading to expression of proinflammatory cytokines and chemokines. The G allele of TLR4 rs4986790 (+896A>G, Asp299Gly) gene polymorphism has been implicated in reduction of risk of atherosclerosis. In this study, 1481 RA patients fulfilling the 1987 American College of Rheumatology (ACR) criteria were genotyped for the rs4986790 TLR4 variant to determine the influence of this variant in the risk of CV events in these patients. Also, HLA-DRB1 status was determined using molecular based methods. Moreover, potential influence of rs4986790 variant in the development of subclinical atherosclerosis was assessed in a subgroup of RA patients with no history of CV events by the measurement of surrogate markers of subclinical atherosclerosis. No statistically significant differences in allele or genotype frequencies for the rs4986790 variant between RA patients who experienced CV events or not were found. Likewise, no significant association between this gene variant and any of the surrogate markers of subclinical atherosclerosis was found. In summary, results in our study do not support the hypothesis that the rs4986790 (+896A>G, Asp299Gly) TLR4 variant may influence predisposition for subclinical atherosclerosis and clinically evident CV disease in RA patients.