Interleukin-2, -16, and -17 gene polymorphisms in Iranian patients with chronic periodontitis

Polymorphism of salivary proteins and risk of periodontal diseases: A systematic review and meta-analysis of clinical studies

OBJECTIVES

The present systematic review and meta-analysis aimed to assess the association between salivary protein polymorphisms and the risk of periodontal diseases (PD).

DATA

The review incorporated cross-sectional, case-control, retrospective/prospective cohort, and randomized controlled trials assessing the influence of salivary protein polymorphisms on the risk of PD development were included in this review.

SOURCES

A thorough literature search was conducted across electronic databases, namely PubMed, Scopus, Embase, and Web of Science, without any restrictions on publication language and year.

STUDY SELECTION

A total of 168 studies were identified, of which 19 were eligible for inclusion. The risk of bias (RoB) assessment of the included studies was conducted at the methodological level.

RESULTS

A total of 16 studies were included. Polymorphism in the gene encoding TNF-α was found to be protective against gingivitis, while those encoding IL-1α and IL-1β were associated with developing gingivitis. Of the 42 proteins investigated, various gene polymorphisms were identified as protective or risk factors for periodontitis. Protective genes include CFH, DNMT1, OPRM1, and TLR9. Conversely, certain salivary protein genes (e.g., CRP, ERN1, FAM5C, IDH2, LTA, TET2, MPA, NLRP3, TLR4) were associated with periodontitis risk. Notably, IL6, MMP9, and MUC7 genes showed no association with PD, while MMP13 was linked to early implant loss. Overall, the meta-analysis found a statistically significant association between salivary proteins' polymorphisms and risk of PD.

CONCLUSIONS

Salivary protein polymorphisms significantly influence PD, revealing protective and risk-associated genotypes. Despite limitations, findings suggest therapeutic targets, emphasizing the complex genetics-periodontal health interplay.

CLINICAL SIGNIFICANCE

This study unveils salivary protein polymorphisms as pivotal factors in PD. Protective genes including CFH and TLR9, and risk-associated genes including CRP and TLR4, indicate a genetic basis for PD susceptibility.

Interleukin-16 genetic polymorphisms in Guangxi Chinese with hepatitis B virus-related liver cirrhosis

BACKGROUND

Our previous study has reported that interleukin-16 (IL-16) genetic polymorphisms are significantly related to chronic hepatitis B (CHB) and hepatitis B virus-related (HBV-related) hepatocellular carcinoma (HCC). As CHB, liver cirrhosis (LC), and HCC are development processes, this study aimed to determine genetic correlation of IL-16 polymorphisms with HBV-related LC in a Chinese population.

METHODS

IL-16 gene rs11556218, rs4072111, and rs4778889 polymorphism in 129 patients with HBV-related LC and 168 healthy individuals were genotyped via polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). PCR-RFLP results were verified by DNA sequencing.

RESULTS

The allelic and genotypic distributions of IL-16 rs11556218, rs4072111, and rs4778889 polymorphisms in HBV-related LC patients showed no significant difference from those in healthy controls. Furthermore, no relationship was observed between the haplotype distribution and susceptibility to HBV-related LC.

CONCLUSIONS

This work provided the first evidence that the IL-16 genetic polymorphisms may not be associated with HBV-related LC risk.

Expression of inflammatory mediators in periodontitis and T2D patients: a systematic review and meta-analysis

The high concentration of glucose in the blood in Type 2 diabetes (T2D) may be related to either insulin resistance or insulin deficiency. Moreover, the literature points to periodontitis as the main oral disease caused by glycemia imbalance. The quantification of inflammatory markers in blood or saliva samples of T2D patients may represent a valuable tool in revealing how well an individual's immune system can respond to injuries and periodontal treatment. In addition, an evaluation of the cytokine expression is extremely relevant to help understand the connection between periodontitis and T2D. This systematic review and meta-analysis aimed to evaluate the expression of inflammatory markers in T2D patients with periodontitis, compared with non-diabetic patients with periodontitis. A total of 3,894 studies were retrieved after a systematic literature search, 15 of which were included in the systematic review, and 4 of these 15, in the meta-analysis. The results did not indicate any statistical difference between the groups regarding TNF-α and IL-6 markers. T2D patients with periodontitis had increased levels of IL-10, compared with non-diabetic individuals with periodontitis (p = 0.003). On the other hand, the IL-4 concentration in non-diabetic individuals with periodontitis was high, compared with the T2D group (p< 0.001). Several studies did not include quantitative results and were excluded from the meta-analysis. The high IL-10 expression and low IL-4 expression in the T2D group suggest an association between the level of these markers and the impairment of the immune response in T2D patients with periodontitis.

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 IL2 Genotypes and Risk and Severity of Chronic Periodontitis in a Chinese Han Population: A Case-control Study

Chronic periodontitis (CP) is a kind of multifactorial common oral diseases. Multiple immune molecules including interleukin-2 (IL-2) are involved in the occurrence and development of CP. To investigate the association between the IL2 rs2069762 polymorphism and the risk of CP in Chinese individuals, we recruited 375 CP patients and 443 controls in this case-control study. The PCR-RFLP method was used for genotyping. Data revealed that the GG genotype was related with a decreased risk of CP (GG vs TT: OR, 0.58, 95%CI, 0.37-0.92, P-value = 0.020; GG vs TG+TT: OR, 0.61, 95%CI, 0.39-0.94, P-value = 0.027). Besides, G allele was shown to decrease the risk of CP. In addition, the IL2 rs2069762 polymorphism was related with the severity of CP. To sum up, the IL2 rs2069762 polymorphism is related with a decreased risk and severity of CP in Chinese individuals.

Cytokines and Their Genetic Polymorphisms Related to Periodontal Disease

Periodontal disease (PD) is a chronic inflammatory disease caused by the accumulation of bacterial plaque biofilm on the teeth and the host immune responses. PD pathogenesis is complex and includes genetic, environmental, and autoimmune factors. Numerous studies have suggested that the connection of genetic and environmental factors induces the disease process leading to a response by both T cells and B cells and the increased synthesis of pro-inflammatory mediators such as cytokines. Many studies have shown that pro-inflammatory cytokines play a significant role in the pathogenesis of PD. The studies have also indicated that single nucleotide polymorphisms (SNPs) in cytokine genes may be associated with risk and severity of PD. In this narrative review, we discuss the role of selected cytokines and their gene polymorphisms in the pathogenesis of periodontal disease.

Association of IL16 polymorphisms with periodontitis in Brazilians: A case- control study

Periodontitis (PD) is a chronic inflammatory process resulting from the relationship of the immune response with the components in dental plaque. Cytokines and their genetic polymorphisms seem to be involved in the immunopathogenesis of this disease. This study aimed to evaluate the correlation of IL16 polymorphism with PD. A case-control study was conducted in a sample of individuals from southern Brazil. The genotyping of IL16, rs11556218 T>G, rs4072111 C>T e rs4778889 T>C, was performed using the PCR-RFLP methodology. The serum level of IL-16 was determined using an IL-16 ELISA kit for humans. SNPStats and OpenEpi software and Wilcoxon's U test were used to perform statistical analysis. IL16 rs11556218 polymorphism was significantly associated to PD in nonsmoking patients: individuals with G/G genotype were less likely to develop PD compared to the T/T genotype (OR = 0.10; Pc = 0.019, codominant model). In addition, the TTT haplotype was associated with a high risk for PD (OR = 2.45; P = 0.01). A low IL-16 serum level was observed among individuals with PD when compared to controls (P = 0.027). Thus, the IL16 rs16556218 polymorphism and the serum levels of IL-16 were associated with periodontitis in a Brazilian sample, and this was influenced by environmental factors such as smoking.

Non-significant association between - 330 T/G polymorphism in interleukin-2 gene and chronic periodontitis: findings from a meta-analysis

BACKGROUND

Chronic periodontitis (CP) is an immune-inflammatory disease that promotes tissue damage around the teeth. Among the several inflammatory mediators that orchestrate the periodontitis, there is the interleukin (IL)-2. Genetic variations in IL2 gene may be associated with the risk and severity of the disease. Contrary results are available in the literature with inconclusive findings and none meta-analysis to gather these data.

METHODS

A literature search was performed for studies published before June 11, 2019 in diverse scientific and educational databases. The data was extracted by two investigators and the statistical evaluation was performed by Review Manager statistical program with heterogeneity (I²) and Odds Ratio (OR) with 95% of Confidence Intervals (CI) calculations and a sensitive analysis to assess the accuracy of the obtained results. The publication bias was evaluated by Begg' and Egger's test with Comprehensive meta-analysis software. The value of P < 0.05 was considered as significant.

RESULTS

Five studies were identified in diverse ethnical groups with 1425 participants. The - 330 T/G polymorphism in IL2 gene was not significantly associated with CP in allelic evaluation (P > 0.05) as well as in the genotypic comparisons (P = 0.15). The Begg's test and the linear regression Egger's test did not show any evidence of publication bias risk (P > 0.05) which was corroborated by the absence of obvious asymmetry in Funnel plot graphic.

CONCLUSIONS

This meta-analysis showed a non-significant association between - 330 T/G polymorphism in IL2 gene and CP in any allelic evaluation.

Influence of inflammasome NLRP3, and IL1B and IL2 gene polymorphisms in periodontitis susceptibility

The pathogenesis of periodontitis (PD) involves several molecules of the immune system that interact in a network to eliminate the periodontopathogens, yet, they contribute to periodontal tissue destruction. The different mechanisms that lead to periodontal tissue damage are not clear. Despite this, immune response genes have been related to the development of PD previously, such as those involved in inflammasomes which are multiprotein complexes and cytokines including Interleukin-1. The aim of the study was to evaluate the polymorphisms in NLRP3 inflammasome, cytokine and receptor of cytokines genes in the development of periodontitis. This case-control study was conducted in 186 patients with PD (stage II and III and grade B) and 208 controls (localized gingivitis and periodontally healthy individuals). Genotyping was performed using PCR-RFLP for the SNP rs4612666 in NLRP3 and using PCR-SSP for IL1A, IL1B, IL1R, IL1RN, IL4RA, INFG, TGFB1, TNF, IL2, IL4, IL6, and IL10. Cytokine serum levels were measured using Luminex technology. SNPStats and OpenEpi software were used to perform statistical analysis. The higher frequencies of NLRP3 T/C and IL1B -511 T/T genotypes and IL2 (+166, -330) GT haplotype were observed in patients with PD compared to controls. The SNPs in NLRP3, IL1R +1970, IL6–174, TNF -308, IL2 +166 and -330, TGFB1 +869 and +915, IL4RA +1902, IL4–1098 and -590 were associated to PD in men. In conclusion, polymorphisms in NLRP3, IL1B and IL2 genes were associated to PD susceptibility. Men carrying the NLRP3, IL1R, IL6, TNF, IL2, TGFB1, IL4RA and IL4 polymorphisms had greater susceptibility than women for developing PD.

Meta-Analysis of Risk Association between Interleukin-17A Gene Polymorphism and Chronic Periodontitis

The association of genetic polymorphisms with periodontitis has been studied extensively. The interleukin-7 (IL-17) is a group of cytokines, which comprises six different molecules (IL-17A, B, C, D, E, and F). Among this, IL-17A is the most commonly understood cytokine, and its polymorphism plays a critical role in inflammatory diseases and periodontal inflammation. The present study was aimed at pooling the data available for meta-analysis and to evaluate whether IL-17A (rs2275913) polymorphism is associated with the susceptibility of chronic periodontitis.