Levels of Interleukin-21 in Patients With Untreated Chronic Periodontitis

Comparative evaluation of serum and gingival crevicular fluid levels of interleukin 21 in periodontally diseased and healthy patients

Background

Periodontitis is an inflammatory reaction to subgingival pathogenic microorganisms that causes gradual deterioration of the gingiva, periodontal ligament, and alveolar bone. Interleukin (IL)-21 is the most recently found member of type I cytokine family that is upregulated during inflammation. The current study aims to investigate the biological plausibility of IL-21 as a biomarker for chronic periodontitis.

Materials and methods

This cross-sectional clinico-biochemical investigation included 15 systemically healthy, 15 periodontally healthy, 15 chronic gingivitis, and 15 chronic periodontitis subjects aged 25 to 60 years. Following subject enrollment, gingival crevicular fluid (GCF) and blood samples were then taken from each subject. The concentration of IL-21 in all samples was determined using enzyme-linked immunosorbent assay (ELISA) kit. The data was examined using the Kruskal-Wallis test and the Spearman correlation test.

Results

Serum IL-21 levels in chronic periodontitis patients were substantially greater than in periodontally healthy individuals. GCF IL-21 levels were substantially greater in gingivitis and chronic periodontitis patients compared to periodontally healthy individuals. In terms of clinical indicators, serum IL-21 levels correlated significantly with bleeding index (BI) in the chronic periodontitis group. In chronic periodontitis group, disease severity as evaluated by probing pocket depth (PPD) and clinical attachment loss (CAL) did not correlate with serum or GCF IL-21 levels.

Conclusion

According to the current study's findings, periodontally involved patients had higher IL-21 levels than periodontally healthy patients, suggesting it can be used as biomarker. Further studies with larger sample size can shed more light on the clinical advantage of IL-21 as a possible marker for disease activity and progression.

Comparative Evaluation of Gingival Crevicular Fluid Interleukin-17, 18 and 21 in Different Stages of Periodontal Health and Disease

Background and Objectives: The elicitation of a host’s immune−inflammatory responses to overcome oral bacterial biofilm challenges is mediated by numerous cytokines. We explored the role of three such cytokines, viz. interleukin (IL)-17, 18 and 21, by measuring their levels in the gingival crevicular fluid (GCF) of Indian individuals with healthy gingiva, chronic gingivitis, or chronic periodontitis. Materials and Method: Ninety systemically healthy individuals were enrolled in the study on the basis of predefined criteria and were categorized into three groups of 30 participants each. Groups A, B and C were composed of a control group with healthy gingiva, subjects with chronic gingivitis and subjects with chronic periodontitis, respectively. The periodontal disease status was assessed on the basis of a subject’s gingival index, probing pocket depth, clinical attachment loss and radiographic evidence of bone loss. After the complete history-taking and identification of gingival sulcus/pocket depth areas for GCF collection, a sample was collected from each subject in all groups for an estimation of the cytokine levels using ELISA. Statistical analysis was performed using SPSS v 21.0. Intergroup comparisons were conducted using a post hoc Tukey’s test. A value of p < 0.05 was considered to be statistically significant. Results: The mean IL-17, 18 and 21 concentrations in pg/mL was the greatest for Group C (99.67 ± 18.85, 144.61 ± 20.83 and 69.67 ± 12.46, respectively), followed by Group B (19.27 ± 2.78, 22.27 ± 2.43 and 22.74 ± 1.43, respectively) and finally by Group A (healthy control; 11.56 ± 0.99, 17.94 ± 1.24 and 12.83 ± 1.21 respectively). A statistically significant difference in the mean concentrations of two interleukins (IL-17 and IL-18) was observed between Groups A and C and also between Groups B and C. A statistically significant difference in the mean concentrations of IL-21 was observed between Groups B and C. Conclusions: Within the limitations of the present study, the findings revealed that the GCF levels of IL-17, IL-18 and IL-21 rose and correlated well with the severity of the disease. Thus, these cytokines present in GCF have the potential to be considered as biomarkers for periodontal tissue destruction. IL-21 in particular appears to be a promising biomarker for differentiating between gingivitis and periodontitis.

A review of T helper 17 cell-related cytokines in serum and saliva in periodontitis

Periodontitis is a chronic inflammatory disease with a complex underlying immunopathology. Cytokines, as molecular mediators of inflammation, play a role in all stages of disease progression. T helper 17 (Th17) cells are thought to play a role in periodontitis. Th17 cell development and maintenance requires a pro-inflammatory cytokine milieu, with many of the cytokines implicated in the pathogenesis of periodontitis. Serum and saliva are easily accessible biofluids which can represent the systemic and local environment to promote the development of Th17 cells. Here we review human clinical studies that investigate IL-1β, IL-4, IL-6, IL-10, IL-17A, IL-17F, IL-21, IL-22, IL-23, IL-25, IL-31, IL-33, IFN-γ, sCD40L and TNF-α in serum and saliva in periodontitis. We highlight their putative role in the pathogenesis of periodontitis and place them within a wider context of animal and other clinical studies.

Interleukin-21 and its association with chronic periodontitis

Context:

Interleukin-21 (IL-21) is a pleiotropic cytokine, well documented to contribute to the development of Th17 cells which have been shown to play an important role in the pathogenesis of periodontitis. Periodontal disease is a chronic infection of tooth-supporting tissue.

Aim:

This study evaluates the saliva and serum levels of IL-21 in patients with chronic periodontitis and periodontally healthy individuals.

Settings and Design:

The present study was carried out in the Department of Microbiology in association with Department of Oral Medicine and Radiology, Maratha Mandal's N.G.H Institute of Dental Sciences and Research Centre, Belgavi, Karnataka.

Materials and Methods:

Fifty samples of each group were included in the present study. The levels of IL-21 were assessed using a commercially available enzyme-linked immunosorbent assay (ELISA) kit and the results were expressed as pg/mL.

Statistical Analysis Used:

Statistical analysis was performed using SPSS 17.0 software. Data were expressed as mean ± standard deviation and interquartile ranges and comparison of controls and cases by Mann–Whitney test.

Results:

Serum and salivary levels of IL-21 were significantly higher in chronic periodontitis group than in controls (P < 0.001). Clinical periodontal parameters correlated positively with serum IL-21 levels.

Conclusions:

IL-21 is highly expressed in patients with chronic periodontitis and correlated well with clinical parameters of periodontal destruction. Therefore, IL-21 appears to play a role in tissue destruction and can be used as diagnostic biomarker in chronic periodontitis. Saliva can be considered to be a useful alternative to serum as a diagnostic sample.

The effect of periodontal therapy on neopterin and vascular cell adhesion molecule-1 levels in chronic periodontitis patients with and without acute myocardial infarction: a case-control study

The presence of neopterin in gingival crevicular fluid (GCF) is a marker for local and acute immune activation, and the presence of vascular cell adhesion molecule (VCAM-1) in GCF is accepted as a marker for chronic vascular inflammation.

The Effect of Periodontitis on Expression of Interleukin-21: A Systematic Review

Purpose. Inflammation and tissue breakdown are led by an array of inflammatory destructive mediators associated with initiation and progression of inflammatory diseases like periodontitis. Current evidence shows that these inflammatory mediators have a definitive role in the pathogenesis of various systemic diseases with an inflammatory component. Interleukin-21 (IL-21) has been associated with systemic diseases like rheumatoid arthritis and Crohn's disease that follow a chronic inflammatory cascade. Similarly recent studies have associated Interleukin-21 levels with periodontitis. This systematic review was aimed to assess the levels of IL-21 in subjects with periodontitis. Methods. A complete literature search was done in PubMed, Medline, Science Direct, and Cochrane databases and Google Scholar based on the inclusion/exclusion criteria. Six relevant articles were procured. Full text was read individually by two reviewers and data extraction was done based on STROBE statement. Results. After data extraction five observational and one interventional study were obtained. All the studies showed an increased expression of IL-21 in periodontitis and the interventional study showed reduction in IL-21 levels after nonsurgical periodontal therapy (NSP). Conclusion. Interleukin-21 levels are higher in periodontitis than controls. With this limited evidence further longitudinal studies are required to consider this as a definitive inflammatory marker.

Inflammatory Mediators of Leprosy Reactional Episodes and Dental Infections: A Systematic Review

Reactional episodes in leprosy are a result of complex interactions between the immune system, Mycobacterium leprae, and predisposing factors, including dental infections. To determine the main inflammatory mediators in the immunopathological process of dental infections and leprosy reactions, we conducted a systematic review of primary literature published between 1996 and 2013. A three-stage literature search was performed (Stage I, "leprosy reactions" and "inflammatory mediators"; Stage II, "dental infections" and "inflammatory mediators"; and Stage III, "leprosy reactions," "dental infections," and "inflammatory mediators"). Of the 911 eligible publications, 10 were selected in Stage I, 68 in Stage II, and 1 in Stage III. Of the 27 studied inflammatory mediators, the main proinflammatory mediators were IL-6, IFN-γ, TNF-α, IL-1β, and IL-17; the main anti-inflammatory mediators were IL-10 and IL-4. Serum IL-6 and TNF-α concentrations were significant during periodontal and reactional lesion evolution; IFN-γ and IL-1β were associated with types 1 and 2 reactions and chronic periodontal disease. The proinflammatory mediators in dental infections and leprosy reactions, especially IL-6 and TNF-α, were similar across studies, regardless of the laboratory technique and sample type. IFN-γ and IL-1β were significant for leprosy reactions and periodontal diseases. This pattern was maintained in serum.

Association study between salivary levels of interferon (IFN)-gamma, interleukin (IL)-17, IL-21, and IL-22 with chronic periodontitis

OBJECTIVE

To investigate if the salivary levels of IL-17, IL-21, IL-22, and its ratio regarding salivary IFN-γ may be linked with the periodontal clinical status.

DESIGN

One hundred and five chronic periodontitis (CP) subjects and 44 healthy controls (HC) were recruited. Periodontal status was assessed based on full-mouth clinical periodontal measurements. Cytokine salivary levels were analyzed by ELISA. The association between the analytes with CP was analyzed using a binary logistic regression model.

RESULTS

A statistically significant increase in salivary levels of IFN-γ and IFN-γ/IL-22 ratio in CP group could be detected, but there was no significant domination of any Th17 cytokine that could be of predictive value for health/disease status. Univariate and binary logistic regression analyses revealed a strong and independent association of IFN-γ salivary levels and IFN-γ/IL-22 ratio with disease status. An interaction effect of ageing on IFN-γ levels also could be noted.

CONCLUSION

While salivary levels of IFN-γ and IFN-γ/IL-22 ratio may act as strong/independent indicators of the amount and extent of periodontal breakdown, the low detection frequency of Th17 cytokines in saliva samples make these determinations useless for the detection of disease presence and/or its severity.

Inflammatory mediators in the pathogenesis of periodontitis

Periodontitis is a chronic inflammatory condition of the periodontium involving interactions between bacterial products, numerous cell populations and inflammatory mediators. It is generally accepted that periodontitis is initiated by complex and diverse microbial biofilms which form on the teeth, i.e. dental plaque. Substances released from this biofilm such as lipopolysaccharides, antigens and other virulence factors, gain access to the gingival tissue and initiate an inflammatory and immune response, leading to the activation of host defence cells. As a result of cellular activation, inflammatory mediators, including cytokines, chemokines, arachidonic acid metabolites and proteolytic enzymes collectively contribute to tissue destruction and bone resorption. This review summarises recent studies on the pathogenesis of periodontitis, with the main focus on inflammatory mediators and their role in periodontal disease.

Possible involvement of IL-21 and IL-10 on salivary IgA levels in chronic periodontitis subjects

Specific cytokines and the costimulatory protein CD40 play role in inducing immunoglobulin (Ig)A production by B cells in the humoral immune response. However, to date, the role of these mediators was not investigated in chronic periodontitis. Therefore, the aim of this study was to assess the local levels of interleukin (IL)-21, IL-21 receptor (IL-21R), IL-4, IL-10 and CD40 ligand (CD40L) on chronic periodontitis subjects and their relationship with the salivary levels of IgA. Gingival biopsies and un-stimulated saliva were collected from chronic periodontitis (n = 15) and periodontally healthy (n = 15) subjects. The mRNA levels of IL-4, IL-10, IL-21, IL-21R, CD40L in the gingival biopsies were evaluated by quantitative real-time polymerase chain reaction. The salivary levels of IgA and the levels of IL-4 and IL-10 in the gingival biopsies were analyzed by ELISA. The mean levels of IgA were significantly higher in the chronic periodontitis compared to periodontally healthy group (P < 0.05). The mRNA levels for IL-21 was higher (P < 0.05) in the chronic periodontitis when compared to the healthy group. However, the expression of IL-21R and CD40L did not differ between groups. The IL-10 was significantly elevated at mRNA and protein levels in chronic periodontitis when compared to periodontally healthy group (P < 0.05). Conversely, the mRNA levels as well as the protein amount of IL-4 were significantly lower (P < 0.05) in chronic periodontitis than healthy ones. In conclusion, the upregulation of IL-21 and IL-10 and downregulation of IL-4 in periodontitis tissues may be collectively involved in the increased levels of salivary IgA in chronic periodontitis subjects.