Influence of interleukin-4 gene polymorphisms and interleukin-4 serum level on susceptibility and severity of rheumatoid arthritis in Egyptian population

BackgroundRheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease in which interleukin-4 (IL-4) plays an important role. This study aimed to investigate the influence of IL-4 variable number of tandem repeats (VNTRs) and IL-4-590 promoter polymorphisms on RA susceptibility, activity and severity in Egyptian population.Materials and methodsOne hundred and seventy-two RA patients and 172 controls were enrolled in this study. IL-4 VNTR and IL-4-590 promoter polymorphisms were genotyped using polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP). Serum IL-4 and anti-cyclic citrullinated peptides (anti-CCPs) antibody concentrations were measured by enzyme linked immunosorbent assay (ELISA).ResultsSubjects with IL-4-590 TT genotype were significantly more likely to develop RA. IL-4 VNTR 1/1 genotype, IL-4-590 TT and CT genotypes were significantly more associated with erosive RA and positive anti-CCP antibody. RA severity parameters were significantly increased, while, IL-4 level was significantly decreased in RA patients with IL-4 VNTR 1/1 and IL-4-590 TT genotypes. Only patients with IL-4-590 TT genotype showed a significant increase of all RA activity parameters.ConclusionIL-4 VNTR and IL-4-590 promoter polymorphisms may be helpful for assessing RA severity in Egyptian population. Moreover, IL-4-590 promoter polymorphism may be associated with increased risk and activity of RA.     

Association study of TRAF1/C5 polymorphism (rs10818488) with susceptibility to rheumatoid arthritis and systemic lupus erythematosus: A meta-analysis

To determine whether the tumor necrosis factor (TNF)-receptor associated factor 1/complement component 5 (TRAF1/C5) polymorphism (rs10818488) confers susceptibility to rheumatoid arthritis (RA) and systemic lupus erythematous (SLE), a meta-analysis was performed. A total of 11 studies with 17 comparisons (11 for RA, 6 for SLE) were available for this meta-analysis, which consisted of 13,456 patients, 12,259 controls for RA and 1,894 patients, 6,729 controls for SLE. A significant association of the A allele of TRAF1/C5 polymorphism (rs10818488) with RA susceptibility was detected in the North Africa population (OR = 1.557, 95% CI: 1.225–1.977). Furthermore, the association between this allelic variant and SLE risk was additionally found in population of European (OR = 1.247, 95% CI: 1.060–1.466). Analysis also showed the A/G allelic frequency of TRAF1/C5 variant (rs10818488), in different healthy populations, had a different distribution (χ² = 269.41, P < 0.001). Taken together, our study demonstrates that the TRAF1/C5 polymorphism (rs10818488) may confer susceptibility to RA in North Africa population, and in European population, it might be a contributory factor towards SLE.     

Association of STAT4 with rheumatoid arthritis in the Korean population

A recent study in the North American White population has documented the association of a common STAT4 haplotype (tagged by rs7574865) with risk for rheumatoid arthritis (RA) and systemic lupus erythematosus. To replicate this finding in the Korean population, we performed a case-control association study. We genotyped 67 single nucleotide polymorphisms (SNPs) within the STAT1 and STAT4 regions in 1123 Korean patients with RA and 1008 ethnicity-matched controls. The most significant four risk SNPs (rs11889341, rs7574865, rs8179673, and rs10181656 located within the third intron of STAT4) among 67 SNPs are identical with those in the North American study. All four SNPs have modest risk for RA susceptibility (odds ratio 1.21-1.27). A common haplotype defined by these markers (TTCG) carries significant risk for RA in Koreans [34 percent versus 28 percent, P=0.0027, OR (95 percent CI)=1.33 (1.10-1.60)]. By logistic regression analysis, this haplotype is an independent risk factor in addition to the classical shared epitope alleles at the HLA-DRB1 locus. There were no significant associations with age of disease onset, radiographic progression, or serologic status using either allelic or haplotypic analysis. Unlike several other risk genes for RA such as PTPN22, PADI4, and FCRL3, a haplotype of the STAT4 gene shows consistent association with RA susceptibility across Whites and Asians, suggesting that this risk haplotype predates the divergence of the major racial groups.     

Association between polymorphism in TRAF1/C5 gene and risk of rheumatoid arthritis: a meta-analysis

Rheumatoid arthritis (RA) is a common chronic inflammatory autoimmune disease. Single nucleotide polymorphisms of tumor necrosis factor-receptor associated factor 1/complement component 5 (TRAF1/C5) gene are suspected to be associated with the risk of RA. This meta-analysis was performed to study the relationship between the polymorphism rs10818488 in TRAF1/C5 gene with RA. We retrieved the relevant articles from PubMed, EMBASE and the China National Knowledge Infrastructure databases. Odd ratios were calculated to assess the association between TRAF1/C5 rs10818488 polymorphism and RA risk. Meta-analyses were performed on the total data set and separately for the major ethnic groups and RF and ACAP status. All analyses were performed using the Stata software. Eight articles were included in the present analysis. Meta-analysis showed a weak association between TRAF1/C5 rs10818488 polymorphism and RA in all subjects (OR = 1.13, 95 % CI = 1.01–1.27, P _{heterogeneity} < 0.001). Stratified analyses indicated that the TRAF1/C5 rs10818488 A allele was significantly associated with RA in Caucasians (OR = 1.29, 95 %CI = 1.14–1.47, P _{heterogeneity} = 0.026), Asians (OR = 0.92, 95 %CI = 0.86–0.99, P _{heterogeneity} = 0.378) and Africans (OR = 1.56, 95 %CI = 1.23–1.98, P _{heterogeneity} = 0.876), also significantly in positive ACPA and positive RF patients versus controls (ORs were 1.20 and 1.25, 95 %CIs were 1.08–1.33 and 1.14–1.37, P values for heterogeneity were 0.215 and 0.133, respectively). Genetic polymorphism rs10818488 in TRAF1/C5 gene might be associated with RA susceptibility.     

Association of common polymorphisms in known susceptibility genes with rheumatoid arthritis in a Slovak population using osteoarthritis patients as controls

Introduction  

Both genetic and environmental factors contribute to rheumatoid arthritis (RA), a common and complex autoimmune disease. As well as the major susceptibility gene HLA-DRB1, recent genome-wide and candidate-gene studies reported additional evidence for association of single nucleotide polymorphism (SNP) markers in the PTPN22, STAT4, OLIG3/TNFAIP3 and TRAF1/C5 loci with RA. This study was initiated to investigate the association between defined genetic markers and RA in a Slovak population. In contrast to recent studies, we included intensively-characterized osteoarthritis (OA) patients as controls.     

Macrophage migration inhibitory factor (MIF): Genetic evidence for participation in early onset and early stage rheumatoid arthritis

Macrophage migration inhibitory factor (MIF) is an upstream pro-inflammatory cytokine that is associated with the pathogenesis of autoimmune inflammatory diseases including rheumatoid arthritis (RA). Two polymorphisms in the upstream region exist in the MIF gene and are associated with RA susceptibility or severity in different populations. In this case-control study, we investigated whether MIF polymorphisms are associated with RA susceptibility or activity in a western Mexican population .The relationship of MIF levels with clinical features of disease also was assessed. Genotyping of the ?794 CATT_5–8 (rs5844572) and the ?173 G > C (rs755622) polymorphisms was performed by PCR and PCR-RFLP respectively on 226 RA patients and 210 healthy subjects. Serum MIF levels were determined by ELISA. We found a significant association between the ?794 CATT_5–8 6,7 MIF genotype with RA. Moreover, we detected an association between the ?794 CATT₇ allele with early onset RA. The ?794 CATT₇ and ?173^*C alleles, which are in linkage disequilibrium, were associated with high disease activity on RA patients. A positive correlation between circulating MIF levels and C-reactive protein, erythrocyte sedimentation rate, rheumatoid factor, anti-citrullinated protein/peptides antibodies and TNFα was detected. MIF levels appear to be associated with disease progression rather than disease activity, which is distinct from the established relationship between disease activity and TNFα levels. In conclusion, the MIF gene and protein are associated with RA in a western Mexican population, with a main contribution onto early onset and early stages of disease.     

Association between genes encoding components of the IL-4/IL-4 receptor pathway and dermatitis in children

Objective

To determine whether IL-4, IL-4Rα and STAT6 polymorphisms are associated with susceptibility to dermatitis in Egyptian children.

Methods

We genotyped three groups of children, consisting of 106 atopic dermatitis (AD) children, 95 non-AD children, and 100 of healthy controls, for IL-4 (− 590 C/T), (− 33 C/T), IL-4Rα (I50V), (Q576R) and STAT6 (2964 G/A), (2892 C/T) gene polymorphisms using PCR-RFLP assay. Total serum IgE and serum IL-4 levels were detected by ELISA.

Results

There was a non-significant association of IL-4 − 590 C/T, − 33 C/T polymorphisms in the children with non-AD or those with AD when compared with the controls. We identified a significant association between IL-4Rα I50V, Q576R polymorphisms and dermatitis susceptibility in AD (p = 0.002, < 0.001 respectively), whereas no such association was observed in non-AD group (p = 0.52, 0.99 respectively). A significant association between STAT6 polymorphisms and both types of dermatitis was found. Patients who were carriers of IL4 − 590C, IL-4Rα I50V G, STAT6 2964 A and STAT6 2892 T had an increased risk of AD [OR and 95% CI: 3.2 (2.5–4.2), p = 0.005]. Furthermore, there was no relation between each polymorphism and serum IL-4 level (p > 0.05 for each) while homozygosity for the risk alleles of IL-4, IL-4Rα and STAT6 SNPs were significantly associated with increased total IgE levels in all subjects.

Conclusion

In Egyptian children, the IL-4Rα and the STAT6 polymorphism may play a role in susceptibility to AD. In addition, gene–gene interaction between the IL-4, the IL-4Rα and the STAT6 significantly increases an individual's susceptibility to AD.     

Gene polymorphisms and serum levels of TL1A in patients with rheumatoid arthritis

Recent findings showed elevated expression of tumor necrosis factor (TNF)-like ligand 1A (TL1A) in rheumatoid arthritis (RA) patients and arthritis mice. However, whether TL1A gene polymorphisms may correlate with RA susceptibility needs to be discussed. This case-control study was performed on 350 RA patients and 556 healthy subjects to identify TL1A genetic variants (rs3810936, rs6478109, and rs7848647) and their possible association with TL1A levels, susceptibility to and severity of RA. Odds ratio and 95% confidence interval were calculated to represent the correlation between TL1A polymorphisms and RA. The TL1A serum levels were evaluated. Results showed that frequencies of TC, TT + TC genotypes of rs3810936, rs7848647 in RA patients were significantly lower in RA patients compared with controls. Patients with C allele showed more severe disease course (disease activity index: erythrocyte sedimentation rate, rheumatoid factor) than in carriers of T allele. However, the allele or genotype frequencies of rs6478109 were not associated with RA. In addition, TL1A genetic variants conferred higher TL1A levels in RA patients compared with controls. In conclusion, these findings indicated an association between TL1A rs3810936, rs7848647 variation and the susceptibility of RA in a sample of Chinese individuals, and TL1A may correlate with severity of RA.     

Peptidyl arginine deiminase type IV (<Emphasis Type="Italic">PADI4</Emphasis>) haplotypes interact with shared epitope regardless of anti-cyclic citrullinated peptide antibody or erosive joint status in rheumatoid arthritis: a case control study

Introduction  

Anti-cyclic citrullinated peptide autoantibodies (anti-CCP) are the most specific serologic marker for rheumatoid arthritis (RA). Genetic polymorphisms in a citrullinating (or deiminating) enzyme, peptidyl arginine deiminase type IV (PADI4) have been reproducibly associated with RA susceptibility in several populations. We investigated whether PADI4 polymorphisms contribute to anti-CCP-negative as well as -positive RA, whether they influence disease severity (erosive joint status), and whether they interact with two major risk factors for RA, Human Leukocyte Antigen-DRB1 (HLA-DRB1) shared epitope (SE) alleles and smoking, depending on anti-CCP and erosive joint status.     

Association of specific amino acid sequence (QRRAA) of HLA-DRB1*0405 with rheumatoid arthritis in a Tunisian population

This study aimed to investigate HLA-DRB1 alleles in rheumatoid arthritis (RA) patients from Tunisia and to examine the effect of these alleles on disease severity. HLA-DRBI alleles and sub-typing of DRBI*04 and *01 were determined in 90 patients and 100 healthy controls, by PCR-SSP. HLA-DRB1*04 was significantly higher in patients (51.1%) than in controls (27%) [OR=2.83, p=0.00066]. DRBJ*0405 was found to be the unique DR4 allele associated with RA (28.88% vs 6%) [OR=6.36, p=0.000059]. A significant decrease in the frequency of HLA-DRB1*0701 was observed in RA patients (16.66%) compared to controls (36%) [p=0.0026]. However, the frequency of patients carrying the shared epitope (SE) QRRAA, was slightly increased compared with controls (37.8% vs 23%) [OR=2.03, p=0.039]. We found that the presence of rheumatoid factor, HLA-DR4 and HLA-DRBI*0405 were not significantly associated with bone erosions or the presence of extra-joint involvement. In our population, the SE (QRRAA) expressed in DRBI*04 alleles is related to the susceptibility to RA but it is not involved in RA severity in Tunisia, while DRBI*0701 might protect against this disease.     

Bf and C3 polymorphisms in rheumatoid arthritis

Properdin factor B (Bf) and complement C3 polymorphisms were studied in 225 unrelated rheumatoid arthritis (RA) patients from North-East England. Patients were subdivided on the presence or absence of significant titres of rheumatoid factor and antinuclear factor. No association with the C3 system was detected. For the Bf system, a significant excess of Bf SS and deficiency of Bf FS phenotypes was observed in seropositive RA patients lacking antinuclear antibodies. This finding suggests that auto-antibody-defined subgroups of RA may be genetically heterogeneous with respect to Bf and confirms the status of Bf SS phenotype as a marker for RA susceptibility and/or severity.     

A new classification of HLA-DRB1 alleles differentiates predisposing and protective alleles for autoantibody production in rheumatoid arthritis

The HLA-DRB1 gene was reported to be associated with anticitrullinated protein/peptide autoantibody (ACPA) production in rheumatoid arthritis (RA) patients. A new classification of HLA-DRB1 alleles, reshaping the shared epitope (SE) hypothesis, was recently found relevant in terms of RA susceptibility and structural severity.     

A Combination of CD28 (rs1980422) and IRF5 (rs10488631) Polymorphisms Is Associated with Seropositivity in Rheumatoid Arthritis: A Case Control Study

IntroductionThe aim of the study was to analyse genetic architecture of RA by utilizing multiparametric statistical methods such as linear discriminant analysis (LDA) and redundancy analysis (RDA).MethodsA total of 1393 volunteers, 499 patients with RA and 894 healthy controls were included in the study. The presence of shared epitope (SE) in HLA-DRB1 and 11 SNPs (PTPN22 C/T (rs2476601), STAT4 G/T (rs7574865), CTLA4 A/G (rs3087243), TRAF1/C5 A/G (rs3761847), IRF5 T/C (rs10488631), TNFAIP3 C/T (rs5029937), AFF3 A/T (rs11676922), PADI4 C/T (rs2240340), CD28 T/C (rs1980422), CSK G/A (rs34933034) and FCGR3A A/C (rs396991), rheumatoid factor (RF), anti–citrullinated protein antibodies (ACPA) and clinical status was analysed using the LDA and RDA.ResultsHLA-DRB1, PTPN22, STAT4, IRF5 and PADI4 significantly discriminated between RA patients and healthy controls in LDA. The correlation between RA diagnosis and the explanatory variables in the model was 0.328 (Trace = 0.107; F = 13.715; P = 0.0002). The risk variants of IRF5 and CD28 genes were found to be common determinants for seropositivity in RDA, while positivity of RF alone was associated with the CTLA4 risk variant in heterozygous form. The correlation between serologic status and genetic determinants on the 1st ordinal axis was 0.468, and 0.145 on the 2nd one (Trace = 0.179; F = 6.135; P = 0.001). The risk alleles in AFF3 gene together with the presence of ACPA were associated with higher clinical severity of RA.ConclusionsThe association among multiple risk variants related to T cell receptor signalling with seropositivity may play an important role in distinct clinical phenotypes of RA. Our study demonstrates that multiparametric analyses represent a powerful tool for investigation of mutual relationships of potential risk factors in complex diseases such as RA.     

Polymorphisms of the TIM-1 gene are associated with rheumatoid arthritis in the Chinese Hui minority ethnic population

The T-cell immunoglobulin and mucin domain 1 (TIM-1) is known to be associated with susceptibility to rheumatoid arthritis (RA). We investigated the association of four single-nucleotide polymorphisms (SNPs) in the promoter region of the TIM-1 gene with susceptibility to RA in a Chinese Hui ethnic minority group. Using RFLP or sequence specific primer-PCR, 118 RA patients and 118 non-arthritis control individuals were analyzed for the -1637A>G, -1454G>A, -416G>C, and -232A>G SNPs in the TIM-1 gene. The polymorphisms -232A>G and -1637A>G in the promoter region of TIM-1 were found to be associated with susceptibility to the RA gene in the Hui population, while -416G>C and -1454G>A SNPs were not. Of these, the polymorphism of -232A>G is inconsistent with that found in a Korean population, suggesting that genetic variations of the TIM-1 gene contribute to RA susceptibility in different ways among different populations. Based on haplotype analysis, individuals with haplotypes AGCA (Χ(2) = 22.0, P < 0.01, OR (95%CI) >1), AGCG (Χ(2) = 18.16, P < 0.01, OR (95%CI) >1) and AGGA (Χ(2) = 5.58, P < 0.05, OR (95%CI) >1) are at risk to develop RA in the Chinese Hui population; those with the GAGA (Χ(2) = 7.44, P < 0.01, OR (95%CI) <1) haplotype may have a decreased likelihood of RA. GGCA and GGCG are more common in both RA and non-RA subjects. We conclude that -1637A>G and -232A>G polymorphisms of TIM-1 are associated with susceptibility to RA in the Chinese Hui population.     

The association of HLA-DRB1 alleles with rheumatoid arthritis in the Chinese Shantou population: a follow-up study.

We investigated the distribution of HLA-DRB1 alleles in a sample of the Chinese Shantou population, and explored the relationship between HLA-DRB1 alleles and the susceptibility and clinical features of rheumatoid arthritis (RA). We studied 117 consecutive patients with RA and control groups, including 38 cases of systemic lupus erythematosus and 100 healthy individuals. HLA-DRB1 genotyping was performed using PCR with sequence-specific primers. HLA-DRB1*04 subtypes were detected using spot hybridization of PCR products with sequence-specific oligonucleotide probes. We compared the frequency of HLA-DRB1 alleles in healthy control patients with that in patients with RA. Patients with RA were evaluated for sex, age at disease onset, disease duration, extra-articular involvement, presence of autoantibodies, global functional status, and radiographic damage. The frequency of HLA-DRB1*04 was found to be significantly higher in RA patients than in healthy individuals (49.6% vs 18.0%, odds ratio = 4.478, P < 0.001). HLA-DRB1*0405 was the most prominently associated subtype in RA patients (62.1% vs 27.8%, odds ratio = 4.255, P = 0.011). Compared with the HLA-DRB1*04-negative RA group, the mean duration of RA in the HLA-DRB1*04-positive RA group was longer, and the mean age at disease onset was lower. A 2-9 year follow-up study was performed, and the risk factors associated with the radiographic progression of RA were determined. Logistic regression analysis revealed that only HLA-DRB1*04 alleles were significantly associated with the radiographic progression of RA (B = 2.652, P = 0.018, Exp(B) = 14.182). Our observations indicated that the HLA-DRB1*04 alleles, especially the subtype HLA-DRB1*0405, were significantly associated with RA susceptibility in the Chinese Shantou population. The HLA-DRB1*04 alleles may be associated with the severity of RA.     

Molecular screening and association study of IL15 gene polymorphisms in rheumatoid arthritis

Interleukin 15 (IL-15) is a pleiotropic pro-inflammatory cytokine known to play a relevant role in rheumatoid arthritis (RA) pathogenesis. In this study we aimed to investigate for the first time the contribution of IL15 gene to RA susceptibility. We screened 13 single nucleotide polymorphisms (SNPs) localised within IL15 regulatory regions (promoter, 5' UTR region and 3' UTR region) in a total of 420 individuals, who were genotyped by direct sequencing of PCR products. In addition, an association study of these IL15 SNPs was conducted in three independent case-control cohorts of Spanish Caucasian origin, including a total of 645 RA patients and 656 healthy controls. The presence of the 13 selected IL15 SNPs in our population was confirmed and no new genetic variants were found. The distribution of the IL15 selected SNPs in RA patients and controls showed no statistically significant deviation in any of the populations studied. Additionally, we performed a haplotype analysis that revealed three IL15 haplotype blocks. None of the haplotype blocks was associated with RA susceptibility or severity in the three cohorts analysed. Our results suggest that the IL15 gene polymorphisms do not appear to play a major role in RA genetic predisposition in our population.     

Identification of low-frequency TRAF3IP2 coding variants in psoriatic arthritis patients and functional characterization

Introduction

In recent genome-wide association studies for psoriatic arthritis (PsA) and psoriasis vulgaris, common coding variants in the TRAF3IP2 gene were identified to contribute to susceptibility to both disease entities. The risk allele of p.Asp10Asn (rs33980500) proved to be most significantly associated and to encode a mutant protein with an almost completely disrupted binding property to TRAF6, supporting its impact as a main disease-causing variant and modulator of IL-17 signaling.

Methods

To identify further variants, exons 2-4 encoding both known TNF-receptor-associated factor (TRAF) binding domains were sequenced in 871 PsA patients. Seven missense variants and one three-base-pair insertion were identified in 0.06% to 1.02% of alleles. Five of these variants were also present in 931 control individuals at comparable frequency. Constructs containing full-length wild-type or mutant TRAF3IP2 were generated and used to analyze functionally all variants for TRAF6-binding in a mammalian two-hybrid assay.

Results

None of the newly found alleles, though, encoded proteins with different binding properties to TRAF6, or to the cytoplasmic tail of the IL-17-receptor α-chain, suggesting that they do not contribute to susceptibility.

Conclusions

Thus, the TRAF3IP2-variant p.Asp10Asn is the only susceptibility allele with functional impact on TRAF6 binding, at least in the German population.     

Influence of MIF,CD40, and CD226 polymorphisms on risk of rheumatoid arthritis

Macrophage migration inhibitory factor (MIF) is a key pro-inflammatory mediator. It plays an important role part in the pathogenesis of several inflammatory and immune diseases. A functional single nucleotide polymorphism (SNP) of MIF −173 G/C is known to influence MIF promoter activity in T lymphoblast cell lines and is associated with a higher serum MIF level. The CD40 is also crucial for some relevant functions of the immune system and may be related to rheumatoid arthritis (RA). And CD226 is an important cell-surface receptor molecule involved in the adhesion and activation of T-cell. We hypothesized that these polymorphisms may contribute to RA susceptibility. We studied MIF −173 G/C, CD40, and CD226 gene polymorphisms in 214 patients with RA and 478 controls in a Chinese population. Genotyping was done by using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). When the MIF −173 GG homozygote genotype was used as the reference group, the CC genotype was associated with a significantly increased risk for RA. In the recessive model, when the MIF −173 GG/GC genotypes were used as the reference group, the CC homozygote genotype was associated with a significant 1.56-fold increased susceptibility to RA. None of the CD40 rs1883832 C/T and CD226 rs763361 C/T polymorphisms achieved a significant difference in genotype distributions between cases and controls. In the stratification analyzes, a significantly increased risk for RA associated with the MIF −173 CC genotype was evident among CRP-negative patients compared with the MIF −173 GG/GC genotype. For the CD40 rs1883832 C/T variant, the risk effects of CD40 rs1883832 TT versus CD40 rs1883832 CC/CT were significant in men. These findings suggested that the functional SNP MIF −173 G/C variant allele was associated with the development of RA. However, CD40 and CD226 gene polymorphisms may not be associated with RA susceptibility. Due to the limitation of sample size, this study should be considered preliminary.