Cytokine gene polymorphisms associated with rheumatoid arthritis and periodontitis in Japanese adults

A Systematic Review and Meta-Analysis on Multiple Cytokine Gene Polymorphisms in the Pathogenesis of Periodontitis

Aim

Periodontitis is an inflammatory disease that destroys both soft and hard periodontal tissues. However, a complex periodontal cytokine network remains unclear. This systematic review explored multiple cytokine gene polymorphisms in the pathogenesis of periodontitis.

Material and Methods

A systematic search was performed using the databases from previous publications, which indicated the association between cytokine polymorphisms and periodontitis pathogenesis. Meta-analysis was conducted using fixed or randomized models to calculate the significance of multiple cytokine polymorphisms. A total of 147 articles were analyzed with polymorphisms in 12 interleukins [Th1 (IL-2, IFN-γ, and TNF-α), Th2 (IL-4 and IL-13), Th17 (IL-1α, IL-1β, IL-6, and IL-17), and Treg cytokines (IL-10 and TGF-β)]. Doi plot was used to probe the occurrence of publication bias.

Results

The polymorphisms of IL-2 and TNF-α of Th1 cytokine family may be associated with the pathogenesis or the prevention of periodontitis risk, while the polymorphism of IFN-γ is not related to periodontitis risk. The polymorphisms for IL-4 and IL-13 of Th2 cytokine family are not found to be associated with the pathogenesis of periodontitis. For the polymorphisms of the members of Th17 cytokine family, different IL-1α polymorphisms may have inverse actions in the pathogenesis of periodontitis. IL-1β is a noteworthy cytokine biomarker in periodontitis development and progression. IL-6 may have a protective function in the inflammatory responses of periodontitis, and IL-17 has a weak relationship the inflammatory responses. The polymorphisms for the members of Treg cell cytokines may have a protective function against periodontitis risk. LFK indexes show the major asymmetry due to publication bias.

Conclusion

IL-1β is a notable cytokine biomarker in periodontitis risk. Treg cytokines favor an anti-inflammatory and protective environment. Further data are needed to confirm the present conclusion due to publication bias.

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.

Ultra-Low Dose Cytokines in Rheumatoid Arthritis, Three Birds with One Stone as the Rationale of the 2LARTH® Micro-Immunotherapy Treatment

Tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) are two cytokines involved in the perpetuation of the chronic inflammation state characterizing rheumatoid arthritis (RA). Significant advances in the treatment of this pathology have been made over the past ten years, partially through the development of anti-TNF and anti-IL-1 therapies. However, major side effects still persist and new alternative therapies should be considered. The formulation of the micro-immunotherapy medicine (MIM) 2LARTH^® uses ultra-low doses (ULD) of TNF-α, IL-1β, and IL-2, in association with other immune factors, to gently restore the body’s homeostasis. The first part of this review aims at delineating the pivotal roles played by IL-1β and TNF-α in RA physiopathology, leading to the development of anti-TNF and anti-IL-1 therapeutic agents. In a second part, an emphasis will be made on explaining the rationale of using multiple therapeutic targets, including both IL-1β and TNF-α in 2LARTH^® medicine. Particular attention will be paid to the ULD of those two main pro-inflammatory factors in order to counteract their overexpression through the lens of their molecular implication in RA pathogenesis.

TGFB1 (rs1800470 and rs1800469) variants are independently associated with disease activity and autoantibodies in rheumatoid arthritis patients

To evaluate the association between TGFB1 + 869 T > C (rs1800470) and TGFB1-509 C > T (rs1800469) variants with susceptibility for rheumatoid arthritis (RA), disease activity, presence of rheumatoid factor (RF), anti-cyclic citrullinated peptide (anti-CCP) and TGF-β1 plasma levels. A total of 262 patients with RA and 168 control individuals were tested for the TGFB1 variants using a TaqMan genotyping assay. Disease activity score in 28 joints (DAS28) classified RA patients into two groups of disease activity: remission/mild (DAS28 < 3.2) and moderate/severe (DAS28 ≥ 3.2). TGFB1 + 869 T > C and -509 C > T variants, independently or in haplotype combination, were not associated with RA's susceptibility. Patients with the TGFB1-509 TT genotype had a higher frequency of DAS28 ≥ 3.2 (OR 2.58, 95% CI 1.04-6.42, p = 0.041). The TGFB1 + 869 CC genotype in seropositive patients for RF or anti-CCP was associated with decreased TGF-β1 levels (p = 0.032 and p = 0.039, respectively). Patients with the TGFB1 + 869 C allele and elevated RF titles demonstrated a higher frequency of DAS28 ≥ 3.2 (p = 0.037). The TGFB1 + 869 T > C variant was associated with diminished TGF-β1 plasma levels and moderate/severe activity disease only in seropositive RF patients. This is the first study showing that TGF-β1 plasma levels can be modulated by the interaction between the TGFB1 + 869 T > C variant and autoantibodies. However, the TGFB1-509 C > T variant was associated with moderate/severe activity disease, independently of autoantibodies positivity. Thus, our findings suggest that TGFB1 + 869 T > C and -509 C > T variants can predict activity disease in different RA patient subgroups.

TGF-β1 +869T/C (rs1982073) gene polymorphism and susceptibility to rheumatoid arthritis: Updated systematic review and meta-analysis

Rheumatoid arthritis (RA) is a complex autoimmune disease that affects about 1% of the world's population. The conclusions about the relationship between TGF gene polymorphism and the risk of RA are still inconsistent. Therefore, we performed a meta-analysis to re-evaluate the relationship between TGF-β1 T869C gene polymorphism and the risk of rheumatoid arthritis.

METHOD

We performed a systematic electronic search in PubMed, Embase, Elsevier, Web of Science, Cochrane Library, Medline and China National Knowledge Infrastructure database (up to August 2020). In the subgroup analysis, we divide the research into three groups: Asian, European and Mediterranean, The combined OR and 95%CI of the five models (allele model, homozygous model, heterozygous model, dominant model, recessive model) were calculated, respectively.

RESULTS

15 case-control studies (14 articles) were involved in this meta-analysis, including 2103 cases and 2143 healthy controls. In the overall analysis, it showed that there may be an significant association between TGF-β1+869T/C polymorphism and RA sensitivity (allele model, T vs. C: OR=1.444, 95% CI=1.171-1.782, P=0.001; homozygous model, TT vs. CC: OR=1.910, 95% CI=1.322-2.761, P=0.001; heterozygous model, CT vs. CC: OR=1.558, 95% CI=1.179-2.059,P=0.002; dominant model, TT+CT vs. CC: OR= 1.742, 95% CI=1.303-2.329, P=0.001; recessive model, TT vs. CT+CC: OR=1.400, 95% CI= 1.058-1.852, P=0.018).However, the results of ethnic subgroup analysis indicated that rs1982073 was not associated with RA risk in Europeans(allele model, T vs. C: OR=0.993, 95% CI=0.849-1.162, P=0.931, I² <0.1%, P>0.1).

CONCLUSION

In summary, our meta-analysis showed that the rs1982073 T allele does not increase RA susceptibility in Europeans.

Association of IL-10 -1082A>G, -819C>T, and -592C>A polymorphisms with susceptibility to chronic and aggressive periodontitis: a systematic review and meta-analysis

OBJECTIVES

Several epidemiological studies have evaluated association of interleukin 10 (IL-10) polymorphisms with risk of periodontitis. However, the results remain conflicting and inconclusive. Here, we carried out a comprehensive systematic review and meta-analysis to evaluate the association of IL-10 -1082A>G, -819C>T, and -592C>A polymorphisms with risk of chronic (CP) and aggressive (CP) periodontitis.

METHODS

Electronic databases including PubMed, Science Direct, SciELO, and CNKI were systematically searched to identify all relevant studies published up to 01 June 2020.

RESULTS

A total of 60 case-control studies with 5313 cases and 6528 controls met our inclusion criteria. Overall, the pooled data showed that the IL-10 -592C>A polymorphism was statistically associated with increased risk of periodontitis in the overall population, while no significant association was identified for IL-10 -1082A>G and IL-10 -819C>T polymorphisms. The subgroup analysis by ethnicity revealed that the IL-10 -1082A>G polymorphism was significantly associated with periodontitis risk in Caucasians, IL-10 -819C>T polymorphism in mixed population, and IL-10 -592C>A polymorphism in both Asians and mixed populations. When further analyzed by periodontitis type, only the IL-10 -592C>A polymorphism was associated with CP risk, but not AgP; and the IL-10 -1082A>G and -819C>T polymorphisms have not positive association neither in the CP and AgP.

CONCLUSIONS

The current meta-analysis showed that the IL-10 -592C>A polymorphism was statistically associated with periodontitis risk in the overall population. Moreover, the IL-10 -1082A>G, IL-10 -819C>T, and IL-10 -592C>A polymorphisms were associated with periodontitis risk by ethnicity. Therefore, the IL-10 polymorphisms are of high clinical relevance by ethnicity and would be a useful marker to identify patients who are at higher risk for periodontitis.

Usefulness of Cytokine Gene Polymorphisms for the Therapeutic Choice in Japanese Patients with Rheumatoid Arthritis

Background

Rheumatoid arthritis (RA) is characterized by systemic synovitis with bone erosion and joint cartilage degradation. Although the analysis of polymorphisms in cytokine-encoding genes is important or understanding the pathophysiology of RA and selecting appropriate treatment for it, few studies have examined such single-nucleotide polymorphisms (SNPs) specifically in Japanese patients. This study was established to investigate the associations between polymorphisms in cytokine-encoding genes, autoantibodies and therapeutic responses in Japanese RA patients.

Methods

The subjects in this study consisted of 100 RA patients and 50 healthy controls. We extracted data on sex, age, disease duration, rheumatoid factor (RF), anti-cyclic citrullinated peptide (anti-CCP) antibody, and therapeutic responses, including to methotrexate (MTX) and biological disease-modifying antirheumatic drugs (DMARDs). Genomic DNA was isolated from peripheral blood, which was genotyped for IL-10, TNF-α, TGF-β₁, and IFN-γ polymorphisms.

Results

Regarding IL-10 (−592 C/A and −819 C/T), significant decreases in the frequencies of the IL-10 (−592) CC genotype and (−819) CC genotype were found in RA patients compared with the levels in controls. For IFN-γ (+874 T/A), a significant decrease in the frequency of the TT genotype was found in RA patients compared with that in controls. Regarding TGF-β₁ (+869 T/C), patients with positivity for anti-CCP antibody had a significantly lower frequency of the CC genotype than those with negativity for it. Furthermore, the IL-10 (−592) CC genotype and (−819) CC genotype might be related to the biological DMARD-response.

Conclusion

Our results suggest that the analysis of polymorphisms in cytokine-encoding genes may be useful when selecting treatment for Japanese RA patients.

Associations between Polymorphisms in the IL-1 Gene and the Risk of Rheumatoid Arthritis and Systemic Lupus Erythematosus: Evidence from a Meta-Analysis

BACKGROUND

Previous studies on polymorphisms in interleukin-1 (IL-1) and the risk of rheumatoid arthritis (RA)/systemic lupus erythematosus (SLE) yielded inconsistent results.

OBJECTIVES

The authors performed this meta-analysis to more robustly evaluate associations between polymorphisms in the IL-1 gene and the risk of RA/SLE.

METHODS

MEDLINE, Embase, Web of Science, Wanfang, VIP, and CNKI were systematically searched for eligible studies, and 34 relevant studies were finally selected to be eligible for inclusion.

RESULTS

We found that IL-1A +4845G/T polymorphism was significantly associated with the risk of RA in the overall population (dominant comparison: p = 0.02; overdominant comparison: p = 0.05; allele comparison: p = 0.04), whereas IL-1B +3954C/T polymorphism was significantly associated with the risk of RA in the overall population (overdominant comparison: p = 0.03; allele comparison: p = 0.01) and Asians (recessive comparison: p = 0.007; allele comparison: p = 0.002). In addition, we found that IL-1A -889C/T polymorphism was significantly associated with the risk of SLE in Caucasians (allele comparison: p = 0.04), IL-1B -31T/C polymorphism was significantly associated with the risk of SLE in the overall population (recessive comparison: p = 0.04), and IL-1B -511C/T polymorphism was significantly associated with the risk of SLE in Asians (recessive comparison: p = 0.01; allele comparison: p = 0.03).

CONCLUSIONS

This meta-analysis suggests that IL-1A +4845G/T and IL-1B +3954C/T polymorphisms may influence the risk of RA, whereas IL-1A -889C/T, IL-1B -31T/C, and IL-1B -511C/T polymorphisms may influence the risk of SLE.

Association between gene polymorphisms of TGF-β and Smad3 and susceptibility to arthritis: a meta-analysis

OBJECTIVES

This meta-analysis was performed to investigate the associations between single-nucleotide polymorphisms (SNPs) in the TGF- β and Smad3 genes and arthritis.

METHODS

A meta-analysis was performed in STATA 14.0, with publication bias and meta-regression analysis. All types of arthritis were included, and subgroup analyses were performed to interpret variations among different types of arthritis.

RESULTS

Twenty-two qualified studieswere selected to analyze the pooled accuracy, and 4 SNP sites were involved. The analysis of the TGFB1 SNP rs1800470 showed an association with arthritis in allelic (P = 0.011), homozygous (P = 0.034) and recessive (P = 0.021) genetic models. The analysis of the TGFB1 SNP rs1800471 demonstrated a close association with rheumatoid arthritis (RA) in homozygous (P = 0.000, 95%) and recessive (P = 0.008) models. The analysis of the SMAD3 SNP rs12901499 revealed a close association with osteoarthritis (OA) in the allelic (P = 0.001) model.

CONCLUSION

This research showed that genetic variants of the TGF-β pathway impact arthritis. The polymorphisms rs1800470, rs1800471 and rs12901499 were correlated with a higher prevalence of arthritis.

Association of TNF-α-308G/A, -238G/A, -863C/A, -1031T/C, -857C/T polymorphisms with periodontitis susceptibility: Evidence from a meta-analysis of 52 studies

The association between tumor necrosis factor-alpha (TNF-α-308G/A, -238G/A, -863C/A, -1031T/C, and -857C/T) polymorphism and either chronic (CP) or aggressive (AgP) periodontitis susceptibility was conflicting. This meta-analysis aimed to quantitatively estimate the association.A total of 52 studies involving 5519 patients and 7260 controls were identified through a search of multiple electronic databases. Odds ratios (ORs) and their 95% confidence intervals using allele, homozygous, heterozygous, dominant, and recessive genetic models were computed to assess the strength of the association.The TNF-α-308G/A polymorphism was significantly associated with decreased risks of CP (GG vs AA: OR = 0.353, P < .001; GG+GA vs AA: OR = 0.480, P < .001) and AgP (G vs A: OR = 0.651, P < .001; GG vs AA: OR = 0.306, P < .001; GG+GA vs AA: OR = 0.384, P < .001) in Asians. There were no associations between TNF-α-238G/A, -863C/A, -1031T/C, -857C/T polymorphism and susceptibility to AgP. No associations were also found between CP susceptibility and TNF-α-238G/A, -857C/T polymorphism.These findings supported that TNF-α-308G/A polymorphism might be the protective factors of CP and AgP in Asians, and TNF-α-238G/A, -863C/A, -1031T/C, -857C/T polymorphism is not linked to AgP susceptibility.

Th2 cell regulatory and effector molecules single nucleotide polymorphisms and periodontitis

To investigate the association between T helper 2 (Th2) cell regulatory and effector molecules' genetic polymorphisms and periodontitis. Single nucleotide polymorphisms (SNPs) of 11 Th2 cell regulatory or effector molecules genes (CD28, CTLA4, IL4, IL5, IL6, IL9, IL10, IL13, IL4R, GATA3, STAT6, and rs1537415; total 130 SNPs) were studied in Chinese nonsmokers (163 periodontitis-free controls, 141 periodontitis patients) using Sequenom iPlex assays. SNPs potentially associated with periodontitis (adjusted allelic P < 0.1) in this cross-sectional study were further investigated via meta-analysis. Allele G of rs4553808 in promoter of CTLA4 was more frequently detected in periodontitis than controls (P < 0.005), but did not remain significant after age and gender adjustment. Haplotype (GTT) in a block of three CTLA4 SNPs (rs4553808, rs16840252, rs5742909) was significantly associated with periodontitis. Meta-analysis of SNPs identified indicated allele T of CTLA4 rs5742909 (3 studies; 461 control, 369 periodontitis) and allele G of IL6 rs1800796 (18 studies; 2760 control, 2442 periodontitis) were significantly associated with periodontitis (OR = 1.44 and OR = 1.30, respectively). Within limitations of this study, a haplotype of CTLA4 concerning Th2 cell regulation, may be associated with periodontitis in Chinese nonsmokers followed. Meta-analysis indicated rs5742909 of CTLA4 and rs1800796 of IL6 appeared significantly associated with periodontitis.

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.

Association between interleukin-10 gene polymorphisms and severe chronic periodontitis

OBJECTIVE

Periodontitis is an inflammatory disease that is a result of the interaction between pathogenic bacteria and host immune response. Genetic alterations in interleukin-10 (IL-10) gene may be associated with the increased risk of periodontitis. We investigated the association between genotype and haplotype frequencies of IL-10 gene polymorphisms and susceptibility to periodontitis in an Iranian population.

METHODS

In this case-control study, a total of 64 patients with periodontitis and 128 healthy subjects were recruited. The PCR-RFLP technique was used to detect IL-10 promoter genotypes at the positions of -1082 (G/A), -819 (C/T), and -592 (C/A) in association with the susceptibility to severe chronic periodontitis.

RESULTS

Regarding IL-10 -592 (C/A) and IL-10 -819 (C/T) alleles and genotypes, no significant association was observed between the risk of periodontitis and genotype frequencies. However, the frequency of GG genotype in IL-10 -1082 (G/A) polymorphic region was higher in normal subjects and was associated with the decreased risk of periodontitis under recessive model [OR = 2.89, 95% CI (0.99-8.43), p = 0.039]. Haplotype analysis revealed a significantly higher presence of H7 (AGC; -592/-1082/-819) [OR = 97.74, 95% CI (95.52-99.96), p < 0.0001].

CONCLUSION

IL-10 -1082(G/A) polymorphism and AGC (-592/-1082/-819) haplotype could be associated with the susceptibility to chronic periodontitis.

Association of interleukin-10-1082 (-1087) A > G polymorphisms and periodontitis risk: An updated meta-analysis based on 26 case-control studies

BACKGROUND

The association between interleukin-10 (IL-10)-1082 (-1087) A > G polymorphism and either chronic (CP) or aggressive periodontitis (AgP) susceptibility was conflicting. This meta-analysis aimed to quantitatively estimate the association.

METHODS

Pubmed, Embase, Web of Science, and WANFAN databases were searched for relevant studies that were submitted prior to January 31, 2018, and meta-analyses were performed using STATA 14.0.

RESULTS

Database mining yielded 26 studies of interest. For the IL-10-1082 (-1087) A > G (rs1800896) polymorphism and its relation to CP susceptibility, the overall analysis showed no significant estimates, but subgroup analysis revealed significant associations in the AA versus GG + GA model in the Caucasian population (odds ratio [OR] = 1.274, 95% confidence interval [CI] = 1.069-1.518, P = 0.007; I²  = 0.0%, P = 0.483) and in the GG versus AA + AG model in the Han population (OR = 6.66, 95% CI = 7.72-9.41, P = 0.000; I²  = 0.0%, P = 0.82), which all showed no obvious publication bias by Egger's linear regression test. For the association between an IL-10-1082 (-1087) A > G polymorphism and AgP susceptibility, the overall analysis and Caucasian subgroup analysis yielded nonsignificant estimates.

CONCLUSIONS

Our meta-analysis indicated that the IL-10-1082 (-1087) AA genotype in the Caucasian population, and the GG genotype in the Han population might be putative risk factors for CP.

PRACTICAL IMPLICATIONS

The IL-10-1082 (-1087) AA genotype and the GG genotype might be potential biomarkers for Caucasian CP and for Han CP, respectively. However, additional research will be required to validate the findings of this meta-analysis.

Immunomodulatory factors gene polymorphisms in chronic periodontitis: an overview

BACKGROUND

Chronic periodontitis (CP), defines as destruction of the supporting tissues of the teeth and resorption of the alveolar bone. It is widespread in human populations and represent an important problem for public health. CP results from inflammatory mechanisms created by the interaction between environmental and host genetic factors that confer the individual susceptibility to the disease.

AIM

The aim of the current study was to explore and summarize some functional biomarkers that are associated with CP susceptibility.

METHODS

CP is considered to be a multifactorial disease. The pathogenesis of multifactorial diseases is characterized by various biological pathways. The studies revealed that polymorphisms were associated with susceptibility to periodontal diseases. In other word, genetic variations can change the development of CP. However, there are some conflicting results, because there are different variations in frequency of some alleles in any populations. Therefore, we conducted the current review to completely understanding the special biomarkers for CP.

RESULTS

There is some evidence that SNPs in the IL-1α, IL-1β, IL1RN, IL-6, IL-10, TNF-α, TGF-β1, IFN-γ and VDR may be associated with CP susceptibility.

CONCLUSION

In conclusion, numerous studies have reported the host genetic factors associated with CP susceptibility and related traits. Therefore, it is prevail to study the multiple SNPs and their effects to find the useful diagnosis methods. The current study will investigate the relationship between polymorphisms in cytokine genes and the susceptibility to the chronic periodontitis.

Interleukin-10 polymorphisms (rs1800871, rs1800872 and rs1800896) and periodontitis risk: A meta-analysis

OBJECTIVE

The objective of this meta-analysis was to assess the association between three interleukin-10 (IL-10) promoter single nucleotide polymorphisms (rs1800871, rs1800872, and rs1800896) and periodontitis risk.

METHODS

A systematic search was conducted in PubMed, Embase, and China National Knowledge Infrastructure databases and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed.

RESULTS

Twenty-six studies met the inclusion criteria. The pooled analysis showed that rs1800871 was associated with an increased periodontitis risk under dominant model (CT + TT vs. CC: p = 0.004, OR = 1.79, 95% CI: 1.21-2.65) in Latin American populations but not in Asian (CT + TT vs. CC: p = 0.229, OR = 0.81, 95% CI: 0.58-1.14) and Caucasian (CT + TT vs. CC: p = 0.910, OR = 1.02, 95% CI: 0.75-1.39) populations. Similarly, rs1800872 conferred an increased risk of periodontitis only in Latin American populations (CA + AA vs. CC: p = 0.012, OR = 2.32, 95% CI: 1.20-4.47; A allele vs. C allele: p = 0.001, OR = 1.61, 95% CI: 1.22-2.14). No significant association was observed between rs1800896 and periodontitis risk. Subgrouping data according to periodontitis type revealed that rs1800872 was associated with both chronic periodontitis (A allele vs. C allele: p = 0.011, OR = 1.72, 95% CI: 1.13-2.62) and aggressive periodontitis (A allele vs. C allele: p = 0.038, OR = 1.32, 95% CI: 1.02-1.72).

CONCLUSION

The studies reviewed support that the IL-10 rs1800871 and rs1800872 polymorphisms may represent a potential genetic biomarker for periodontitis risk in Latin American populations.

The role of three interleukin 10 gene polymorphisms (- 1082 A > G, - 819 C > T, - 592 A > C) in the risk of chronic and aggressive periodontitis: a meta-analysis and trial sequential analysis

Background

Periodontitis is a major oral health problem and it is considered as one of the reasons for tooth loss in developing and developed nations. The objective of the current review was to investigate the association between IL10 polymorphisms − 1082 A > G (rs1800896), -819C > T (rs1800871), − 592 A > C (rs1800872) and the risk of either chronic periodontitis or aggressive periodontitis.

Methods

This is a meta- analysis study, following the preferred reporting items for systematic reviews and meta- analyses (PRISMA). Relevant studies were searched in the health related electronic databases. Methodological quality of the included studies were assessed using the Newcastle-Ottawa Scale. For individual studies, odds ratio (OR) and its 95%confidence interval (CI) were calculated to assess the strength of association between IL10 polymorphisms (− 1082 A > G, -819C > T, − 592 A > C) and the risk of periodontitis. For pooling of the estimates across studies included, the summary OR and its 95% CIs were calculated with random-effects model. The pooled estimates were done under four genetic models such as the allelic contrast model, the recessive model, the dominant model and the additive model. Trial sequential analysis (TSA) was done for estimation of the required information size for this meta-analysis study.

Results

Sixteen studies were identified for this review. The included studies were assessed to be of moderate to good methodological quality. A significant association between polymorphism of IL10–1082 A > G polymorphism and the risk of chronic periodontitis in the non-Asian populations was observed only in the recessive model (OR,1.42; 95% CI:1.11, 1.8,I²: 43%). The significant associations between − 592 A > C polymorphism and the risk of aggressive periodontitis in the non-Asian populations were observed in particular genetic models such as allele contrast (OR, 4.34; 95%CI:1.87,10.07,I²: 65%) and recessive models (OR, 2.1; 95% CI:1.16, 3.82,I²: 0%). The TSA plot revealed that the required information size for evidence of effect was sufficient to draw a conclusion.

Conclusions

This meta-analysis suggested that the IL10–1082 A > G polymorphism was associated with chronic periodontitis CP risk in non-Asians. Thus, in order to further establish the associations between IL10 (− 819 C > T, − 592 A > C) in Asian populations, future studies should include larger sample sizes with multi-ethnic groups.

Electronic supplementary material

The online version of this article (10.1186/s12903-018-0637-9) contains supplementary material, which is available to authorized users.

Genetic Relationship Between IL-6 rs1800796 Polymorphism and Susceptibility to Periodontitis

BACKGROUND

There are accumulating reports for the potential role of Interleukin-6 (IL-6) rs1800796 polymorphism in the risk of periodontitis. However, distinct conclusions are observed. In this study, we have an interest in comprehensively analyzing the genetic relationship between IL-6 rs1800796 and the susceptibility to periodontitis.

METHODS

We retrieved the eligible case-control studies from on-line database and conducted a meta-analysis. P-value of association test, OR (odd ratios) and 95% CI (confidence interval) were calculated for the assessment of potential genetic association.

RESULTS

We enrolled a total of 20 case-control studies for pooling analysis. A positive association between periodontitis cases and controls was observed in the overall meta-analysis under all genetic models (all P < 0.05, OR > 1). Similar results were detected in the "population-based, PB" and "China" subgroups (all P < 0.05, OR > 1). In the "Asian" subgroup, there is an increased periodontitis risk under the allele, homozygote, heterozygote, dominant and carrier models (all P < 0.05, OR > 1). Nevertheless, negative results were found in the "Caucasian" subgroup under all models [all P > 0.05]. In addition, a positive association between IL-6 rs1800796 and the risk of chronic periodontitis was detected under the models of allele [G vs. C], GG vs. CC, GG vs. CC+ CG and carrier [G vs. C] (all P < 0.05, OR > 1).

CONCLUSION

IL-6 rs1800796 may serve as one genetic risk factor for periodontitis patients in the Asian population, especially the Chinese population. G/G genotype of IL-6 rs1800796 appears to be associated with an increased risk of chronic periodontitis.

Interleukin-10 polymorphisms affect the key periodontal pathogens in Chinese periodontitis patients

Interleukin-10 (IL-10) polymorphisms have been shown to affect IL-10 production. This study investigated the influences of IL-10 polymorphisms on the susceptibility to chronic periodontitis (CP) and aggressive periodontitis (AP), and their possible role in the quantity of subgingival bacteria Aggregatibacter Actinomycetemcomitans and Porphyromonas gingivalis. 92 CP patients, 83 AP patients and 91 periodontal healthy controls were recruited. Serum IL-10 concentration was analyzed by enzyme-linked immunosorbent assay (ELISA). Gene polymorphisms were determined by multiplex SNaPshot technique. Bacteria were quantified by real-time polymerase chain reaction with TaqMan MGB probes. Taking into account age, gender and periodontal status, IL-10-592 AA, -819 TT and ATA/ATA genotype occurred more frequently in patients with CP than in healthy controls. In CP cases, higher quantity of subgingival A. actinomycetemcomitans and lower serum IL-10 levels could be detected in homozygous ATA/ATA carriers. These findings indicate that variants in IL-10 promoter gene were not only associated with predisposition to chronic periodontitis but also affected the subgingival number of A. Actinomycetemcomitans in a Chinese Han population.

Meta-analyses of IL1A polymorphisms and the risk of several autoimmune diseases published in databases

Background

Based on published data, we aimed to quantitatively elucidate the possible genetic influence of rs17561 G/T and rs1800587 C/T polymorphisms of the IL1A (interleukin 1 alpha) gene in the susceptibility to several autoimmune diseases.

Methods

A series of meta-analyses were carried out. After database searching, we utilized our inclusion/exclusion criteria to screen and include the eligible studies. P_association (P value of association test), Bonferroni-corrected P_association value; false discovery rate (FDR)-corrected P_association, ORs (odd ratios), and 95% CI (confidence interval) were generated to assess the magnitudes of genetic relationships.

Results

A total of 35 eligible articles were included. Pooled analysis data of both rs17561 G/T and rs1800587 C/T in the overall population indicated a negative association between cases of autoimmune diseases and negative controls (all P_association>0.05, Bonferroni-corrected P_association>0.05, FDR-corrected P_association>0.05). Similar results were found in most subgroup analyses (all P_association>0.05, Bonferroni-corrected P_association>0.05, FDR-corrected P_association>0.05), apart from the rs1800587 in the Graves’ disease subgroup, which showed an increased risk in some cases, compared with controls, under the models of allele T vs. C, carrier T vs. C, CT+TT vs. CC, and CT vs. CC (all P_association<0.05, Bonferroni-corrected P_association<0.05, FDR-corrected P_association>0.05, OR>1).

Conclusion

Based on the available data, C/T genotype of the rs1800587 polymorphism within IL1A gene may be associated with an increased Graves’ disease risk. We did not see evidence regarding a positive role for rs1800587 or rs17561 in the risk of other autoimmune diseases, such as systemic sclerosis or rheumatoid arthritis. These conclusions still merit further data support and molecular exploration.

Interleukin-1β rs1143627 polymorphism with susceptibility to periodontal disease

Association between interleukin-1 beta (IL-1β) rs1143627 polymorphism and periodontal disease susceptibility was inconsistent; hence we performed this meta-analysis to explore the precise correlation between them. The degree of association was appraised through calculating pooled odds ratio (OR) and its 95% confidence interval (CI). The databases known as PubMed, Embase, and Chinese National Knowledge Infrastructure were searched up to October 26, 2016. A total of 8 eligible case-control studies were finally included, which involved 229 aggressive periodontitis patients, 382 chronic periodontitis patients, and 555 healthy controls. All the five genetic models revealed a non-significant association between IL-1β rs1143627 polymorphism and periodontal disease susceptibility (TT vs. CC: OR = 1.22, 95% CI = 0.80-1.87; CT+TT vs. CC: OR = 0.66, 95% CI = 0.44-1.01; TT vs. CT + CC: OR = 1.19, 95% CI = 0.81-1.74; T vs. C: OR = 0.92, 95% CI = 0.81-1.12; CT vs. CC: OR = 0.92, 95% CI = 0.69-1.23). Sensitivity analyses indicated that the results were robust and the subgroup analyses reached similar conclusions. IL-1β rs1143627 polymorphism is not related to periodontal disease susceptibility in the overall population based on the current evidence, but further studies are required in more large scale sample size with risk factor adjusted.

The KCNQ1 gene polymorphism as a shared genetic risk for rheumatoid arthritis and chronic periodontitis in Japanese adults: A pilot case-control study

BACKGROUND

A number of studies have suggested a bidirectional relationship of periodontitis with rheumatoid arthritis (RA) and type 2 diabetes mellitus (T2DM). However, the genetic factors that underlie these relationships have not been elucidated.

METHODS

We conducted a multicenter case-control study that included 185 patients with RA and chronic periodontitis (CP), 149 patients with T2DM and CP, 251 patients with CP, and 130 systemically and periodontally healthy controls from a cohort of Japanese adults to assess the shared genetic risk factors for RA and CP as well as for T2DM and CP. A total of 17 candidate single nucleotide polymorphisms (SNPs) associated with RA, T2DM, and CP were genotyped.

RESULTS

Multiple logistic regression analyses revealed that the KCNQ1 rs2237892 was significantly associated with comorbidity of RA and CP (P = 0.005) after adjustment for age, sex, and smoking status. The carriers of the T allele among patients with RA and CP showed significantly higher disease activity scores including 28 joints using C-reactive protein values than the non-carriers (P = 0.02), although the age, female percentage, and smoking status were comparable. Other SNPs were not associated with comorbidity of RA and CP, T2DM and CP, or susceptibility to CP.

CONCLUSION

The results of the present pilot study suggest for the first time that the KCNQ1 rs2237892 may constitute a shared genetic risk factor for RA and CP, but not for T2DM and CP in Japanese adults.

IL-13 -1112 polymorphism and periodontitis susceptibility: a meta-analysis

Background

Several studies have examined the association between the IL-13 -1112C/T polymorphism and the risk of periodontitis. However, these studies have reached different conclusions. The aim of the current study was to investigate the link between this IL-13 -1112 polymorphism and susceptibility to periodontitis.

Methods

We utilized electronic databases, including the CNKI (China National Knowledge Infrastructure), Wanfang, PubMed, Embase, and Cochrane Library databases, to manually search for relevant research published through November 30, 2016. The Chinese and English terms used to search the literature included “periodontitis”, “periodontal disease”, “IL 13”, “IL-13”, and “interleukin-13”. In accordance with our inclusion criteria, we selected studies that involved case-control trials. All of these case-control trials described their objectives, design and specific statistical methods. For all included studies, odds ratios (ORs) and 95% confidence intervals (95% CIs) were provided or could be calculated from the study data. The quality of the included literature was evaluated using the Newcastle-Ottawa scale (NOS). STATA 12.0 was used to calculate the sizes of the combined effects and conduct a sensitivity analysis of the results.

Results

Our meta-analysis included 4 articles representing 5 case-control studies with a total of 710 cases and 671 control subjects. The meta-analysis results indicated that the CC vs TT model, CT vs TT model and TT vs CT + CC model (CC VS TT: OR = 0.615, 95% CI = 0.395–0.957; CT vs TT: OR = 0.518, 95% CI = 0.323–0.830; and TT vs CT + CC: OR = 1.739, 95% CI = 1.130–2.676) were significant in five IL-13 -1112 gene polymorphism and periodontitis susceptibility models. Subgroup analysis indicated that the CC vs TT, CT vs TT and TT vs CT + CC models were significant in the chronic periodontitis (CP) group, whereas no significant differences were found in the five aggressive periodontitis (AgP) group models. The sensitivity analysis showed that dropping any single study did not affect the pooled analysis results.

Conclusion

The IL-13 -1112 polymorphism may be associated with susceptibility to periodontitis. The IL-13 -1112 gene polymorphism may be associated with susceptibility to CP but not to AgP. Thus, large-scale, multi-ethnic case-control trials are still warranted.

Analysis of interleukin-10 gene polymorphisms in patients with chronic periodontitis and healthy controls

BACKGROUND

Interleukin-10 (IL-10) is an anti-inflammatory cytokine that has important roles in the periodontal diseases. The IL10-1082, -819, and -592 polymorphisms in the promoter region of IL-10 gene have been associated with various IL-10 expressions. The aim of this study was to investigate the association between these gene polymorphisms with chronic periodontitis in a sample of Iranian populations from Southeast of Iran.

MATERIALS AND METHODS

IL-10 single nucleotide polymorphisms were analyzed in 210 patients with chronic periodontitis (CP) and 100 individuals without CP by polymerase chain reaction-restriction fragment length polymorphism method. Statistical analysis of data was performed using the Chi-square test. The risk associated with single alleles, genotypes, and haplotypes were calculated by performing a multiple logistic regression analysis to estimate the odds ratio (OR) and 95% confidence interval (CI). P < 0.05 for statistical significance.

RESULTS

The prevalences of AG and GG genotypes of IL10-1082 were significantly different between CP and control groups in comparison to AA genotype (OR = 2.671; CI = 1.482-4.815; P = 0.001 for AG vs. AA, OR = 4.151; CI = 2.128-8.097; P < 0.001 for GG vs. AA). In addition, subjects with at least one IL10-1082-G allele were significantly had an increased risk for CP (OR = 2.157; CI = 1.531-3.038; P < 0.001). The distribution of the IL10-819 and IL10-592 genotypes was not different between CP and control subjects (P = 0.109 and P = 0.139, respectively). The combination of different genotypes showed that GCC haplotype was significantly different between groups (OR = 4.379; CI = 1.077-17.807; P = 0.039).

CONCLUSION

The results demonstrated that IL10-1082 polymorphism was a putative risk factor for chronic periodontitis and associated with increased susceptibility to CP.

Association of cytokines polymorphisms with chronic peridontitis and rheumatoid arthritis in a Mexican population

OBJECTIVE

Historically, it has been shown that rheumatoid arthritis (RA) and periodontitis (PE) share pathophysiological similarities and possibly a genetic background. In order to elucidate the genetic background between both diseases, we evaluated the distributions of five SNPs genotypes and all the possible haplotypes composed in subjects with isolated RA, PE, combined diseases and healthy controls.

MATERIALS AND METHODS

The study population consisted of 280 Mexican subjects. Genomic DNA was isolated from buccal epithelial cells collected by cheek scrapings and analyzed for the determination of the following SNPs: IL-1α + 4845 (rs17561), IL-1α -889 (rs1800587), IL-1β + 3954 (rs1143634), IL-1β -511(rs16944) and TNF-α -308 (rs1800629).

RESULTS

After adjustment for age, sex and smoking status, multiple logistic regression analysis revealed a no significant association in the genotype frequencies of TNF-α -308 and IL-1α + 4845 SNPs. Otherwise a significant association was observed in IL-1β + 3954 and IL-1β -511 (p < 0.05) while IL-1α -889 was of borderline statistical significance (p = 0.054). Also, we found three negative associated haplotypes with PE: IL-1α + 4845 G/IL-1β -511 A, IL-1β + 3954 C/IL-1β -511 A and interestingly IL-1α -889 C/IL-1β -511 A also with a positive association with RA.

CONCLUSIONS

Some genotypes and haplotypes are associated with the diseases. But it seems that the genetic background of the association between RA and PE needs to be explored deeper.

The Novel ASIC2 Locus is Associated with Severe Gingival Inflammation

An increasing body of evidence suggests a significant genetic regulation of inflammatory response mechanisms; however, little is known regarding the genetic determinants of severe gingival inflammation (GI). We conducted a genome-wide association study of severe GI among 4077 European American adults, participants in the Dental Atherosclerosis Risk In Communities cohort. The severe GI trait was defined dichotomously using the 90^th percentile of gingival index ≥2 extent score. Genotyping was performed with the Affymetrix 6.0 array platform and an imputed set of 2.5 million markers, based on HapMap Phase II CEU build 36, was interrogated. Genetic models were based on logistic regression and controlled for ancestry (10 principal components), sex, age, and examination center. One locus on chromosome 17 met genome-wide statistical significance criteria-lead single nucleotide polymorphism (SNP): rs11652874 [minor allele frequency=0.06, intronic to ASIC2 (acid sensing ionic channel-2, formerly named ACCN1); odds ratio=2.1, 95% confidence interval=1.6-2.7, p=3.9×10^-8]. This association persisted among subjects with severe periodontitis and was robust to adjustment for microbial plaque index. Moreover, the minor [G] allele was associated with higher levels of severe GI in stratified analyses among subsets of participants with high load of either "red" or "orange" complex pathogens, although this association was not statistically significant. While these results will require replication in independent samples and confirmation by mechanistic studies, this locus appears as a promising candidate for severe gingival inflammation. Our findings suggest that genetic variation in ASIC2 is significantly associated with severe gingival inflammation and the association is plaque-independent.

Periodontal pathogens participate in synovitis in patients with rheumatoid arthritis in clinical remission: a retrospective case-control study

OBJECTIVE

The objective of this study was to investigate the role of periodontal pathogens in RA in remission.

METHODS

Twenty-one patients with active RA and 70 patients in clinical remission, including 48 patients with synovitis [US power Doppler (USPD)(+) group] and 22 patients without synovitis [USPD(-) group] were clinically assessed by US. CRP, ESR, haemoglobin, MMP-3, RF and ACPA were measured. Antibody titres against four types of periodontal pathogen [Aggregatibacter actinomycetemcomitans, Eikenella corrodens (Ec), Porphyromonas gingivalis and Prevotella intermedia (Pi)] were analysed using ELISA.

RESULTS

Musculoskeletal US examination showed that 68.6% of patients with RA in clinical remission exhibited synovitis. CRP, ESR, haemoglobin, MMP-3 and RF levels in both the USPD(+) and USPD(-) groups were clearly lower compared with the RA group in non-remission. The IgG serum antibody titre against Ec in the non-remission RA(+) group was significantly greater than that in the USPD(+) group, and the IgG antibody titre against Pi in the non-remission RA and USPD(+) groups was greater than in the USPD(-) group.

CONCLUSION

More than half of RA patients in remission showed persistent synovitis. This synovitis may be associated with periodontal disease-causing Pi. Thus, treating periodontal disease should also be considered in order to achieve more profound remission of RA.

HLA Haplotypes and Genotypes Frequencies in Brazilian Chronic Periodontitis Patients

Human leukocyte antigens (HLA) have a pivotal role in immune response and may be involved in antigen recognition of periodontal pathogens. However, the associations of HLA with chronic periodontitis (CP) have not been previously studied in the Brazilian population. In an attempt to clarify the issue of genetic predisposition to CP, we examined the distribution of HLA alleles, genotypes, and haplotypes in patients from Southern Brazil. One hundred and eight CP patients and 151 healthy and unrelated controls with age-, gender-, and ethnicity-matched were HLA investigated by polymerase chain reaction with sequence specific oligonucleotides. To exclude smoking as a predisposing factor, statistical analyses were performed in the total sample and in nonsmoking individuals. The significant results showed a positive association of the A∗ 02/HLA-B∗ 40 haplotype with CP (total samples: 4.2% versus 0%, Pc = 0.03; nonsmokers: 4.3% versus 0%, Pc = 0.23) and a lower frequency of HLA-B∗ 15/HLA-DRB1∗ 11 haplotype in CP compared to controls (total samples: 0.0% versus 4.3%, Pc = 0.04; nonsmokers: 0 versus 5.1%, P = 1.0). In conclusion, the HLA-A∗ 02/B∗ 40 haplotype may contribute to the development of CP, while HLA-B∗ 15/DRB1∗ 11 haplotype might indicate resistance to disease among Brazilians.

Genetic Case-Control Study for Eight Polymorphisms Associated with Rheumatoid Arthritis

Rheumatoid arthritis (RA) is an autoimmune disease which has a significant socio-economic impact. The aim of the current study was to investigate eight candidate RA susceptibility loci to identify the associated variants in Egyptian population. Eight single nucleotide polymorphisms (SNPs) (MTHFR—C677T and A1298C, TGFβ1 T869C, TNFB A252G, and VDR—ApaI, BsmI, FokI, and TaqI) were tested by genotyping patients with RA (n = 105) and unrelated controls (n = 80). Associations were tested using multiplicative, dominant, recessive, and co-dominant models. Also, the linkage disequilibrium (LD) between the VDR SNPs was measured to detect any indirect association. By comparing RA patients with controls (TNFB, BsmI, and TaqI), SNPs were associated with RA using all models. MTHFR C677T was associated with RA using all models except the recessive model. TGFβ1 and MTHFR A1298C were associated with RA using the dominant and the co-dominant models. The recessive model represented the association for ApaI variant. There were no significant differences for FokI and the presence of RA disease by the used models examination. For LD results, There was a high D′ value between BsmI and FokI (D′ = 0.91), but the r² value between them was poor. All the studied SNPs may contribute to the susceptibility of RA disease in Egyptian population except for FokI SNP.

Study of the association between the interleukin-1 β c.3954C>T polymorphism and periodontitis in a population sample from Bahia, Brazil

BACKGROUND

Periodontitis is an inflammatory disease characterized by the loss of connective tissue and alveolar bone. Different factors are associated with the onset and prognosis of this disease, both environmental and genetic. The latter particularly relate to molecules secreted as a function of the host immune response, such as pro-inflammatory cytokines. Studies indicate that the polymorphism c. 3954C > T in the interleukin-1 β encoding gene (IL1B) can be considered as an aggravating factor in the periodontitis condition.

AIMS

This study aimed to evaluate whether there is an association between the IL1B c. 3954C > T gene polymorphism and the prevalence of periodontitis in the population from Vitória da Conquista-Bahia, Brazil.

MATERIALS AND METHODS

A total of 347 subjects (134 cases and 213 controls) who provided epithelial tissue of the oral cavity and saliva samples for DNA extraction and quantification of IL1B, respectively, were selected. Genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism followed by electrophoresis in agarose gel. The evaluation of the cytokine concentration was performed by enzyme-linked immunosorbent assay.

STATISTICAL ANALYSIS

Statistical calculations involved in this work include Chi-square test, Fisher Exact test, Mann-Whitney and Kruskal-Wallis tests.

RESULTS

Our findings revealed that: (i) No statistically significant relationship between periodontitis and the polymorphism studied was observed; (ii) no significant difference between the concentrations of IL1B in saliva between the case and control subjects and between the genotypes of these individuals and the concentrations of this cytokine.

CONCLUSIONS

We conclude that, in the sample evaluated, the IL1B c. 3954C > T polymorphism did not present as an etiological factor for periodontitis.

Interleukin-1β (3953/4) C→T polymorphism increases the risk of chronic periodontitis in Asians: evidence from a meta-analysis of 20 case-control studies

INTRODUCTION

To investigate the association of the interleukin-1β (IL-1β) (3953/4) C→T polymorphism with chronic periodontitis (CP) in Asians.

MATERIAL AND METHODS

Systematic searches of electronic databases and hand searching of references were performed, including PubMed, Embase, the Cochrane Library, and the Chinese National Knowledge Infrastructure (CNKI). Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of the associations. Publication bias was tested by Egger's test. Sensitivity analysis was conducted by limiting the meta-analysis studies conforming to Hardy-Weinberg equilibrium (HWE). Data analyses were carried out using RevMan 6.0.

RESULTS

A meta-analysis was performed on 20 published case-control studies, including 1,656 CP cases and 1,498 healthy controls. The pooled OR was 1.60 (95% CI = 1.02-2.52, p = 0.04) for the T allele carriers (TT + CT) compared with CC and 1.60 (95% CI = 1.06-2.42, p = 0.02) for T vs. C. Subgroup analysis by country revealed significant risks of CP among Indians carrying the T allele (TT vs. CC: OR = 3.88, 95% CI = 1.77-8.50, p = 0.0007).

CONCLUSIONS

The analysis showed that IL-1β (3953/4) C→T polymorphism probably increases the risk of CP in Asians, and the IL-1β+3954 TT genotype may be associated with a strongly increased risk of CP in Indians, but not in Chinese.

Host Responses in the Link Between Periodontitis and Rheumatoid Arthritis

Periodontitis and rheumatoid arthritis (RA) are common chronic inflammatory conditions and share many clinical and pathologic features. There is evidence to suggest that similar profiles of cytokine genotypes and their coding proteins are involved in the pathogenesis of periodontitis and RA. In particular, constitutive overproduction of pro-inflammatory cytokines, including tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6), has been implicated to play a pathologic role in the two inflammatory diseases. Results from studies with animal and human subjects have suggested an improvement of periodontal inflammatory condition after treatment with TNF-α inhibitors. Likewise, IL-6 receptor inhibition therapy has been suggested to have an effect on control of periodontal inflammation in patients with RA. In the present review, we provide an overview of studies showing the pathological role of cytokines in the linkage between periodontitis and RA, and further summarize the current studies assessing the effect of cytokine targeted therapy on periodontal condition.

Does a biological link exist between periodontitis and rheumatoid arthritis?

Periodontitis or Periodontal disease (PD) and Rheumatoid arthritis (RA) are two the most common chronic inflammatory diseases. Periodontitis is a biofilm associated destructive inflammatory disease of the periodontium caused by specific microorganisms. Rheumatoid arthritis is an autoimmune condition and is identified by elevated serum autoantibody titre directed against citrullinated peptides or rheumatoid factor. Periodontitis may involve some elements of autoimmunity. Recent studies have established that PD and RA show a common pathway and could be closely associated through a common dysregulation and dysfunction in inflammatory mechanism. The enzyme peptidyl arginine deiminase (PAD), expressed by Porphyromonas gingivalis (P. gingivalis) is responsible for the enzymatic deimination of arginine residuals to citrulline resulting in protein citrullination and its increased accumulation in RA. Citrullination by PAD may act as a putative biologic link between PD and RA. Association of Human leukocytic antigen-DR4 antigen has been established both with RA and PD. Several interleukins and inflammatory mediators (ILs) and Nuclear factor kappa beta ligand are linked to these common chronic inflammatory diseases. Antibodies directed against heat shock protein (hsp 70 ab) of P. gingivalis, P. melanogenicus and P. intermedia are raised in PD as well as RA. Both the conditions share many pathological and immunological similarities. Bacterial infection, genetic susceptibility, altered immune reaction and inflammatory mediators considered responsible for RA are also associated with PD. So it is plausible that a biological link may exist between PD and RA. Therapies aimed at modifying the expression and effect of inflammatory mediators and effector molecules such as matrix metalloproteinases, proinflammatory cytokines and autoantibodies of structural proteins may probably reduce the severity of both RA and PD.

TNF-α gene promoter polymorphisms contribute to periodontitis susceptibility: evidence from 46 studies

AIM

Tumour necrosis factor-alpha (TNF-α) plays a critical role in the pathogenesis of periodontal disease. TNF-α gene polymorphisms can influence the TNF-α production. Many studies have focused the association between TNF-α gene promoter polymorphisms and periodontitis risk, but these results are still controversial.

MATERIALS AND METHODS

A meta-analysis was performed to assess the effect of TNF-α -308G/A (rs1800629), -238G/A (rs361525) and -863C/A (rs1800630) polymorphisms on either chronic (CP) or aggressive periodontitis (AgP) risk. Odds ratios (ORs) along with their 95% confidence intervals (CIs) were calculated to assess the strength of the association. Forty-six studies involving 5186 cases and 6683 controls were retrieved and analyzed.

RESULTS

The TNF-α -308G/A AA genotype was associated with increased CP risk in Asians, non-smoking Asians and Caucasians, and this polymorphism was significantly associated with elevated risk of AgP in Asians and Caucasians. Asian individuals carrying AA genotype had a significantly increased risk for -863C/A. No significant association was identified between TNF -238G/A polymorphism and CP.

CONCLUSIONS

These findings supported that TNF-α -308G/A and -863C/A polymorphisms may contribute to the susceptibility of periodontitis.

Association of transforming growth factor-β1 T869C, G915C, and C509T gene polymorphisms with rheumatoid arthritis risk

The association of transforming growth factor-β1 (TGFβ1) is an important signaling pathway factor involving extracellular matrix regulation, and its gene polymorphisms with the risk of rheumatoid arthritis (RA) is currently still fiercely debated. Therefore, this meta-analysis was performed to determine if TGFβ1 T869C, G915C, and C509T gene polymorphisms correlate with the risk of developing RA. Association reports were identified from PubMed, Cochrane Library and CBM-disc (China Biological Medicine Database) on 1 May 2013, and eligible studies were recruited and synthesized to identifying patterns among study results. T869C TT genotype in the overall population was associated with increased RA risk (OR = 1.28, 95% CI: 1.02-1.60, p = 0.03). In the sub-group analysis, T869C TT genotype was shown to be a risk factor for RA, and T869C C allele or CC genotype a protective factor against RA disease in Asians, but these associations were not found in Caucasians. Furthermore, TGFβ1 C509T TT genotype was distinctly associated with RA susceptibility, but the T allele and CC genotype were not. TGFβ1 G915C gene polymorphism was not associated with RA susceptibility. In conclusion, the TT genotype of TGFβ1 T869C was associated with RA risk in the overall population and Asians. Furthermore, CC genotype or C allele was determined to be protective factors with respect to the RA risk in the overall population and Asians. Nonetheless, additional studies are required to firmly establish a correlation between the aforementioned polymorphisms and RA risk.

Association of interleukin-1 gene variations with moderate to severe chronic periodontitis in multiple ethnicities

Background and Objective

Genetic markers associated with disease are often non-functional and generally tag one or more functional “causative” variants in linkage disequilibrium. Markers may not show tight linkage to the causative variants across multiple ethnicities due to evolutionary divergence, and therefore may not be informative across different population groups. Validated markers of disease suggest causative variants exist in the gene and, if the causative variants can be identified, it is reasonable to hypothesize that such variants will be informative across diverse populations. The aim of this study was to test that hypothesis using functional Interleukin-1 (IL-1) gene variations across multiple ethnic populations to replace the non-functional markers originally associated with chronic adult periodontitis in Caucasians.

Material and Methods

Adult chronic periodontitis cases and controls from four ethnic groups (Caucasians, African Americans, Hispanics and Asians) were recruited in the USA, Chile and China. Genotypes of IL1B gene single nucleotide polymorphisms (SNPs), including three functional SNPs (rs16944, rs1143623, rs4848306) in the promoter and one intronic SNP (rs1143633), were determined using a single base extension method or TaqMan 5′ nuclease assay. Logistic regression and other statistical analyses were used to examine the association between moderate to severe periodontitis and IL1B gene variations, including SNPs, haplotypes and composite genotypes. Genotype patterns associated with disease in the discovery study were then evaluated in independent validation studies.

Results

Significant associations were identified in the discovery study, consisting of Caucasians and African Americans, between moderate to severe adult chronic periodontitis and functional variations in the IL1B gene, including a pattern of four IL1B SNPs (OR = 1.87, p < 0.0001). The association between the disease and this IL1B composite genotype pattern was validated in two additional studies consisting of Hispanics (OR = 1.95, p = 0.04) or Asians (OR = 3.27, p = 0.01). A meta-analysis of the three populations supported the association between the IL-1 genotype pattern and moderate to severe periodontitis (OR 1.95; p < 0.001). Our analysis also demonstrated that IL1B gene variations had added value to conventional risk factors in predicting chronic periodontitis.

Conclusion

This study validated the influence of IL-1 genetic factors on the severity of chronic periodontitis in four different ethnicities.

Association between interleukin-1β C (3953/4)T polymorphism and chronic periodontitis: evidence from a meta-analysis

The aim of this study was to perform a meta-analysis to evaluated the association between interleukin-1β (IL-1β) C(3953/4)T polymorphism and chronic periodontitis (CP). Systematic searches of electronic databases and hand searching of references were performed, including PubMed, Embase and Web of Science. The pooled odds ratios (ORs) with 95% confidence intervals (95%CIs) were calculated. Publication bias was tested by Begg's funnel plot and Egger's regression test. Sensitivity analysis was conducted by limiting the meta-analysis studies conforming to Hardy-Weinberg equilibrium (HWE) or high quality (score ≥ 7). Data analyses were carried out by Stata 11.0. There were significant associations between IL-1β C(3953/4)T polymorphism and CP (for T allele vs. C allele: OR = 1.30, 95%CI = 1.05-1.60, p = 0.02; for T/T vs. C/C: OR = 1.66, 95%CI = 1.12-2.45, p = 0.01; for C/T+T/T vs. C/C: OR = 1.28, 95%CI = 0.99-1.65; and for T/T vs. C/T+C/C: OR = 1.62, 95%CI = 1.15-2.29, p = 0.006). When stratified by ethnicity, statistically significantly elevated risk was found for Caucasians, but not for Asians. When stratified by study design, evidences of significant association was observed between IL-1β C(3953/4)T polymorphism and CP in both population-based studies and hospital-based studies. This meta-analysis indicates that there is strong evidence for association between IL-1β C(3953/4)T polymorphism and CP.