Interaction Between Oral Lichen Planus and Chronic Periodontitis with Th17-Associated Cytokines in Serum

Risk factors for the development of oral precancerous lesions in a cohort of 293 oral lichen planus patients with or without chronic periodontitis in southern Taiwan

Background/purpose

Oral lichen planus (OLP) may contribute to the risk of chronic periodontitis, and no reports have shown whether OLP patients with periodontitis have a greater risk of oral precancerous lesions, Candida infection or other clinicopathological diseases. This study aimed to assess the risk factors for the development of oral precancerous lesions in a cohort of 293 OLP patients with or without chronic periodontitis in southern Taiwan.

Materials and methods

The current study recruited 293 OLP patients without preexisting periodontitis at a tertiary institution from 1995 to 2018. The patients were divided into two groups based on the presence or absence of periodontitis. The study compared various clinical and pathological characteristics between the two groups, and also estimated the odds ratio (OR) and the 10-year cumulative risk of chronic periodontitis in OLP patients using logistic regression models and Kaplan‒Meier analysis methods, respectively.

Results

After adjusting for age and gender, the significant contributors to oral precancerous lesions in OLP patients (P < 0.05) were periodontal disease (OR = 2.24) and the male gender (OR = 7.52). Betel nut consumption (OR = 2.61), smoking (OR = 2.46), and candidiasis infection (OR = 3.02) also showed significant associations. Older OLP patients had a lower lesion risk, while a longer OLP duration heightened the periodontal disease likelihood.

Conclusion

The present study demonstrated that coexisting periodontal disease increases the likelihood of developing precancerous lesions in patients with OLP. Periodontal management with oral hygiene care and quitting betel nut consumption and smoking can reduce the risk.

Biomarkers for diagnosis of stage III, grade C with molar incisor pattern periodontitis in children and young adults: a systematic review and meta-analysis

AIM

To explore the existing salivary, gingival crevicular fluid (GCF), blood, and serum biomarkers associated with grade C molar-incisor pattern (C/MIP) periodontitis in systemically healthy children and young adults.

MATERIALS AND METHODS

Cross-sectional, case-control, and cohort studies on stage III grade C periodontitis or former equivalent diagnosis with analysis of molecular biomarkers in saliva, GCF, blood, or serum were retrieved from six databases and screened based on the eligibility criteria. The risk of bias in included studies was evaluated. Meta-analysis was planned for biomarkers assessed using the same detection methods and sample type in at least two papers.

RESULTS

Out of 5621 studies identified at initial screening, 28 papers were included in the qualitative analysis of which 2 were eligible for meta-analysis for IgG in serum samples. Eighty-seven biomarkers were assessed with the majority being higher in cases than in controls. Only the meta-analysis of total serum IgG with low heterogeneity value revealed a significant increase in its levels in C/MIPs compared to controls (standardised mean difference: 1.08; 95% CI: 0.76, 1.40).

CONCLUSION

There is a paucity of data on biomarkers associated with molar-incisor pattern periodontitis. Although serum IgG levels are raised, other more specific biomarkers in saliva, GCF, and blood/serum may be promising but require further investigation.

The potential roles of Th17 cells in the pathogenesis of oral lichen planus

BACKGROUND

Oral lichen planus (OLP) is a T cell-mediated chronic autoimmune disease, whose pathogenesis and etiology are not entirely understood. OLP is characterized by subepithelial lymphocyte infiltration and elevated intra-epithelial lymphocytes. The majority of lamina propria lymphocytes are CD4⁺ T cells. CD4⁺ helper T (Th) cells play a crucial role in activating CD8⁺ cytotoxic T cells (CTLs) through interactions and cytokine production. Th1 and Th2 cells are well-accepted to be associated with OLP pathogenesis. However, OLP treatment is challenging yet, the more information we have about the pathology of OLP, the easier it will be treated. With the discovery of Th17 cells in recent years and the demonstration of their role in autoimmune disease, many researchers started to investigate the role of Th17 in the pathogenesis of OLP.

METHODS

To make up this review, studies covering the role of TH17 in different types of lichen planus were selected from major databases.

RESULTS

As we review in this article, Th17 cells and their signature cytokines play an important role in OLP pathogenesis. As well, utilizing some anti-IL-17 antibodies showed promising results in improving the disease; however, more studies are still needed to better understand and treat OLP.

Regulatory T cell therapy suppresses inflammation of oral mucosa

Oral inflammatory diseases, including oral lichen planus (OLP) and recurrent aphthous ulcer (RAU), seriously affect the patient’s quality of life. Due to the lack of ideal disease models, it is difficult to determine whether novel immunotherapy strategies are effective in treating oral inflammatory diseases. Here, we show that the deficiency of Foxp3 or IL-2 caused oral mucosa inflammation in mice, proving that Treg cells are important in maintaining the immune homeostasis in the oral mucosa. Then we determined that adoptive transfer of CD4⁺CD25^-CD45Rb^high T cells could induce oral inflammation in Rag1^-/- mice, and co-transfer of Treg cells together with CD4⁺CD25^-CD45Rb^high T cells could suppress the development of oral inflammation in this mouse model. Our study showed that adoptive transfer of CD4⁺CD25^-CD45Rb^high T cells into Rag1^-/- mice could be a novel disease model of oral inflammation. Our data provides direct evidence that Treg cell therapy is effective in suppressing oral mucosa inflammation in mice. Therefore, Treg cell therapy may be a promising novel strategy to treat oral inflammatory diseases.

Oral Health, Antimicrobials and Care for Patients With Chronic Oral Diseases – A Review of Knowledge and Treatment Strategies

Periodontal and chronic oral mucosal diseases are significant life impacting conditions which may co-exist and synergistically act to cause more severe and widespread oral pathology with enhanced challenges in effective management. Clinicians regularly observe these effects and struggle to effectively manage both problems in many patients. There is limited understanding of many basic and applied scientific elements underpinning potentially shared aetiopathological features and management. Recent developments in translational science provide an opportunity to greater improve knowledge and subsequently care for patients with these problems.

Probiotics as Potential Biological Immunomodulators in the Management of Oral Lichen Planus: What's New?

Oral lichen planus (OLP) is a T cell-mediated chronic inflammatory disorder with multifactorial aetiology and malignant transformation potential. Despite the treatments so far identified, new tailored and safe specific measures are needed. Recently, human microbiota imbalance has been linked to several immune-mediated diseases, opening new therapeutic perspectives for probiotics; besides their ability to directly interact with the host microbiota, they also display a strain-specific immune-modulatory effect. Thus, this non-systematic review aims to elucidate the molecular pathways underlying probiotic activity, mainly those of Lactobacilli and Bifidobacteria and their metabolites in OLP pathogenesis and malignant transformation, focusing on the most recent in vitro and in vivo research evidence. Findings related to their activity in other immune-mediated diseases are here included, suggesting a probiotic translational use in OLP. Probiotics show immune-modulatory and microbiota-balancing activities; they protect the host from pathogens, hamper an excessive effector T cell response, reduce nuclear factor-kappa B (NF-kB) signalling and basal keratinocytes abnormal apoptosis, shifting the mucosal response towards the production of anti-inflammatory cytokines, thus preventing uncontrolled damage. Therefore, probiotics could be a highly encouraging prevention and immunotherapeutic approach for a safer and more sustainable OLP management.

Does oral lichen planus aggravate the state of periodontal disease? A systematic review and meta-analysis

BACKGROUND

The objective of this systematic review and meta-analysis (SRM) was to assess the evidence between the association of oral lichen planus and periodontal disease, evaluating the periodontal clinical parameters and biomarkers levels.

METHODS

This systematic review and meta-analysis followed PRISMA and was registered in PROSPERO (CRD42020181513). Searches were accomplished in databases for articles published until June 2021. The meta-analysis was performed with the variables: plaque index (PI), gingival index (GI), probing depth (PD), and clinical attachment loss (CAL). The mean difference was applied with a 95% confidence interval.

RESULTS

Six articles were included. Qualitative analysis showed the levels of biomarkers (matrix metalloproteinases, interleukins, and periodontal microbiological profile) are increased in subjects with periodontal disease and oral lichen planus. In the meta-analysis, these subjects also presented increases in all periodontal clinical parameters evaluated: GI-gingivitis 0.22 [0.14, 0.31] p < 0.0001 and periodontitis 0.12 [0.06, 0.19] p = 0.0003; PI-gingivitis 0.22 [0.12, 0.31] p < 0.0001 and periodontitis 0.15 [0.08, 0.23] p < 0.0001; PD-gingivitis 0.27 [0.06; 0.48] p = 0.0107 and periodontitis 0.11 [0.01; 0.21] p = 0.0299; and CA-periodontitis 0.06 [0.01, 0.12] p = 0.0176.

CONCLUSIONS

Evidence suggests a significant relationship between the severity of periodontal disease and the presence of oral lichen planus. Although the association is biologically plausible, further studies are needed using populations and well-defined biochemical and clinical outcomes with consideration of potential confounding factors.

CLINICAL RELEVANCE

This SRM provides information on the interaction between OLP and periodontal disease and guides clinicians to make evidence-based decisions and suggests recommendations for further high-quality studies.

Interest of periodontal maintenance in improving autoimmune diseases: about an oral lichen planus case report

Introduction: Oral lichen planus is an autoimmune inflammatory disease. These clinical manifestations can sometimes be confused and cumulated with clinical signs of periodontal disorders. The aim of this work is to illustrate the interest of a periodontal follow-up in the management of oral lichen planus by a clinical case report. Observation: A patient came for a consultation in dermatology for a persistent gingival erythema. The diagnosis of oral lichen planus was made and treatments were successively implemented. After six months of follow-up, an inflammatory gum was still present without showing improvement. A stage 3, grade B periodontitis associated with oral lichen planus was diagnosed and a periodontal treatment was initiated, combined with corticosteroids treatment as mouthwash. Four months after the beginning of this treatment, a marked decrease in gingival erythema was observed. Comments: There is often a close relationship between oral lichen planus and periodontal disease therefore a multidisciplinary approach can be very useful for optimal management.

Porphyromonas gingivalis exacerbates ulcerative colitis via Porphyromonas gingivalis peptidylarginine deiminase

Ulcerative Colitis (UC) has been reported to be related to Porphyromonas gingivalis (P. gingivalis). Porphyromonas gingivalis peptidylarginine deiminase (PPAD), a virulence factor released by P. gingivalis, is known to induce inflammatory responses. To explore the pathological relationships between PPAD and UC, we used homologous recombination technology to construct a P. gingivalis strain in which the PPAD gene was deleted (Δppad) and a Δppad strain in which the PPAD gene was restored (comΔppad). C57BL/6 mice were orally gavaged with saline, P. gingivalis, Δppad, or comΔppad twice a week for the entire 40 days (days 0-40), and then, UC was induced by dextran sodium sulfate (DSS) solution for 10 days (days 31-40). P. gingivalis and comΔppad exacerbated DDS-induced colitis, which was determined by assessing the parameters of colon length, disease activity index, and histological activity index, but Δppad failed to exacerbate DDS-induced colitis. Flow cytometry and ELISA revealed that compared with Δppad, P. gingivalis, and comΔppad increased T helper 17 (Th17) cell numbers and interleukin (IL)-17 production but decreased regulatory T cells (Tregs) numbers and IL-10 production in the spleens of mice with UC. We also cocultured P. gingivalis, Δppad, or comΔppad with T lymphocytes in vitro and found that P. gingivalis and comΔppad significantly increased Th17 cell numbers and decreased Treg cell numbers. Immunofluorescence staining of colon tissue paraffin sections also confirmed these results. The results suggested that P. gingivalis exacerbated the severity of UC in part via PPAD.

Elevated Serum Interleukin-23 Levels in Patients with Oral and Cutaneous Lichen Planus

Lichen planus is considered a chronic inflammatory disease which affects different sites, such as the skin, mucous membranes, hair, and nails. Based on the evidence, a complex cytokine network plays a crucial role in lichen planus pathogenesis. The study was aimed at assessing the serum IL-23 levels in the patients with cutaneous and oral lichen planus compared to healthy controls. Method. The study included 30 cutaneous lichen planus patients, 20 oral lichen planus patients, and 33 control subjects. Five milliliters of peripheral blood was obtained from each patient, and the serum was separated. IL-23 levels were determined using the ELISA kit, and the data were analyzed using the Mann–Whitney test. Results. IL-23 levels in the patient serum with oral lichen planus (P value ≤ 0.001) were significantly higher than in controls. Furthermore, there were significant differences in IL-23 serum levels in the patients with cutaneous lichen planus compared to the healthy controls (P value ≤ 0.001). Moreover, IL-23 serum levels were statistically different between patients with cutaneous lichen planus and patients with oral lichen planus (P value ≤ 0.001). Based on the mean concentration of interleukin-23, IL-23 levels were higher in the patients with oral lichen planus than in the patients with cutaneous lichen planus. Conclusions. Elevated serum IL-23 levels in the patients with oral lichen planus may indicate that IL-23 plays a crucial role in the pathogenesis of oral lichen planus. However, more research is needed with a larger sample size.

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.

Identification and Regulation of TCRαβ+CD8αα+ Intraepithelial Lymphocytes in Murine Oral Mucosa

TCRαβ⁺CD8αα⁺ intraepithelial lymphocytes (IELs) are abundant in gastrointestinal (GI) tract and play an important role in regulation of mucosal immunity and tolerance in the gut. However, it is unknown whether TCRαβ⁺CD8αα⁺ IELs exist in the oral mucosa and if yes, what controls their development. We here identified and characterized TCRαβ⁺CD8αα⁺ IELs from the murine oral mucosa. We showed that the number and function of TCRαβ⁺CD8αα⁺ IELs were regulated by TGF-β. We further revealed that oral TCRαβ⁺CD8αα⁺ IELs could be altered under systemic inflammatory conditions and by antibiotic treatment at the neonatal age of the mice. Our findings have revealed a previously unrecognized population of oral IELs that may regulate oral mucosal immune responses.

Increased Serum Level and High Tissue Immunoexpression of Interleukin 17 in Cutaneous Lichen Planus: A Novel Therapeutic Target for Recalcitrant Cases?

Background

Interleukin-17 is supposed to play an important role in the pathogenesis of oral lichen planus (OLP). However, there is scarce data in the literature on its significance in the cutaneous variant of the disease.

Objectives

To determine the serum level and tissue immunoexpression of IL-17 in cutaneous lichen planus (CLP).

Methods

Fifty-two adult patients with CLP, without any significant autoimmune or inflammatory conditions, were included in the first part of the study. The control group consisted of 27 age- and sex-matched healthy volunteers. Serum concentration of IL-17 was quantified using enzyme-linked immunosorbent assay (ELISA) kit. In the second part of the study, the tissue expression of IL-17 was assessed in archival paraffin-embedded biopsy specimens from CLP (n = 14) against normal control tissues (n = 11) using immunohistochemical assays. The expression was evaluated using Zeiss Axio Imager A2 light microscope. Positively stained cells were counted in 10 fields of view for biopsy specimen at 200x magnification, and the mean value was calculated.

Results

The serum level of IL-17 was significantly elevated in patients with CLP, compared with healthy volunteers (0.218 ± 0.221 ng/ml versus 0.126 ± 0.058 ng/ml, respectively; p = 0.025). No correlation was found between the serum concentration of IL-17 and patient age, gender, disease duration, extent of skin involvement, the presence or intensity of pruritus, and coexistence of mucosal lesions. In tissue samples from CLP lesions, significantly higher numbers of cells expressing IL-17 were found when compared to a healthy skin (p < 0.001).

Conclusion

Elevated serum concentration of IL-17 and high expression in a lesional skin support the hypothesis that IL-17 is implicated in the immunopathogenesis of CLP. These findings may constitute a premise for the future use of anti-IL-17 monoclonal antibodies in the treatment of severe and recalcitrant forms of CLP.

Potential roles of the CCL17-CCR4 axis in immunopathogenesis of oral lichen planus

BACKGROUND

Oral lichen planus (OLP) is a T cell-mediated chronic inflammatory disease. C-C chemokine receptor type 4 (CCR4) and its cognate C-C motif chemokine ligand 17 (CCL17) play a key role in T-cell activation and trafficking, but their implication in OLP pathogenesis has not been explored. Our study was designed to analyze the expression and function of the CCL17-CCR4 axis in OLP.

METHODS

The mRNA expression levels of CCL17 and CCR4 in the circulating T cells of OLP subjects were examined by quantitative real-time PCR. The protein levels of CCL17 and CCR4 in the peripheral blood of OLP subjects were detected by enzyme-linked immunosorbent assay (ELISA) and Simple Western assay, respectively. The functional relevance of increased expression of CCL17 and CCR4 in OLP was demonstrated in proliferation, apoptosis, and migration assays.

RESULTS

The mRNA and protein expression levels of CCL17 and CCR4 in the peripheral blood of patients with OLP were significantly upregulated compared with those of controls. CCL17 induced the migration of OLP T cells. In addition, blocking CCR4 with a small molecule CCR4 antagonist not only inhibited the proliferation and migration of OLP T cells but also promoted the apoptosis of OLP T cells.

CONCLUSION

Our findings indicate that the CCL17-CCR4 axis might be responsible for the inflammatory infiltration of T cells in OLP.

Interleukin-17 plays a role in pulp inflammation partly by WNT5A protein induction

OBJECTIVE

Our study aimed to investigate the role of interleukin (IL)-17 in dental pulp inflammation and the relationship between WNT5A and IL-17.

METHODS

Immunohistochemical staining was used to detect the expression of tumor necrosis factor-α (TNF-α), WNT5A and IL-17 in pulp tissues. Anti-IL-17 neutralizing antibody was used in rat pulpitis model and to study the role of IL-17 in pulpitis. TNF-α, WNT5A or IL-17 recombinant protein were used to treat human dental pulp cells. RT-PCR, Western blot, and Enzyme linked immunosorbent assay were used to detect the expression of mRNA and protein. Transwell assay was used to measure the migration of THP-1 cells, which is a human monocytic cell line.

RESULTS

IL-17 and WNT5A are co-expressed in TNF-α high-expressed region in human and rat pulpitis tissue. IL-17 mainly contributes to its positive regulatory role in inflammation through up regulate cytokines and mediated macrophages migration. Anti-IL-17 neutralizing antibody can suppress the inflammatory cell infiltration and TNF-α expression in dental pulpitis. TNF-α promotes the expression of IL-17 partly through WNT5A and WNT5A regulates IL-17 expression by mitogen-activated protein kinase (MAPK)-(P38 and ERK) pathway.

CONCLUSIONS

IL-17 acts as an inflammatory mediator in dental pulp inflammation. The expression of IL-17 can be partially regulated by WNT5A.

Comparative analysis of immune cell subsets in peripheral blood from patients with periodontal disease and healthy controls

Periodontitis is a chronic inflammatory disease caused by the colonization of teeth by the bacterial plaque biofilm and the resultant host immune responses in adjacent periodontal tissues. Disease severity can vary dramatically between patients with periodontitis, with some subjects displaying inflammation without bony destruction (gingivitis), while others experience chronic progressive or rapidly aggressive gingival connective tissue damage and bone loss. To determine whether peripheral immune dysregulation is associated with periodontitis, we performed extensive analysis of immune cell subsets in peripheral blood from patients with chronic or aggressive periodontitis versus periodontally healthy control subjects. Peripheral blood mononuclear cells (PBMC) from patients with chronic periodontitis or aggressive periodontitis and from periodontally healthy controls were analysed by 8-10-colour flow cytometry for the frequencies of various lymphocyte subsets, including interleukin (IL)-17-, interferon (IFN)-γ-, tumour necrosis factor (TNF)-α- and IL-10-producing cells, and the frequencies and phenotype of monocytes. Cytokine levels in serum from the different groups were determined by Luminex assay. We found no significant differences in the frequencies of major immune cell populations [CD4⁺ T cells, CD8⁺ T cells, γδ T cells, CD4⁺ CD45RO⁺ CD25⁺ CD127^low regulatory T cells (T_regs ), CD19⁺ B cells, CD14⁺ monocytes] or of cytokine-producing T cells, or in the phenotype of CD14⁺ monocytes in peripheral blood from these patient cohorts. Additionally, no significant differences were observed in serum levels of prototypical inflammatory cytokines. These results suggest that the local gingival inflammatory response is not reflected by obvious changes in major blood immune cell subset frequencies.

[Correlations between the T helper cell 17/regulatory T cells balance in peripheral blood of patients with oral lichen planus and clinical characteristics]

OBJECTIVE

This study aimed to investigate the ratio of T helper cell 17 (Th17) and regulatory T cells (Treg) in peripheral blood of oral lichen planus (OLP) and explore the pathogenesis of its possible role and significance.

METHODS

The peripheral blood samples were obtained from 33 patients with OLP (15 cases of reticular OLP and 18 cases of erosive OLP) and 17 healthy controls. The percentages of Th17 and Treg cells were detected by flow cytometry (FCM). Real-time fluorescence quantitative polymerase chain reaction (qPCR) technique was used to detect the expression levels of retinoid-related orphan nuclear receptor γt (RORγt) and forkhead box 3 (Foxp3).

RESULTS

The proportions of Th17, Treg cells, and their transcription factors (RORγt and Foxp3) in OLP were higher than those in the control groups (P<0.05). By contrast, in Treg cells and Foxp3, no significance was observed between erosive OLP and reticular OLP. Th17/Treg ratio increased in OLP. This ratio was significantly increased in erosive OLP compared with those in the control groups and reticular OLP (P<0.01). Nevertheless, no significance was noted between reticular OLP and control groups. Statistical analysis demonstrated positive correlations among Th17 cells, Th17/Treg, and clinical characteristics (r=0.66, P=0.00; r=0.66, P=0.00; r=0.52, P=0.00; r=0.50, P=0.00). Positive correlations also existed between Th17 and Treg cells (r=0.39, P=0.03).

CONCLUSIONS

Th17 cells, Treg cells, and their ratios all increased in the peripheral blood of OLP. Moreover, the imbalance inTh17/Treg may play a role in the pathogenesis of erosive OLP.

Grinspan syndrome with periodontitis: Coincidence or correlation?

Grinspan syndrome is a syndromic complex which comprises a triad of hypertension, diabetes, and oral lichen planus. It remains an enigmatic condition that whether it is separate entity or drug-induced lichenoid reaction emerging due to medications used to treat hypertension and diabetes. Diabetes is related to long-term hyperglycinemia leading to accelerated destruction of both nonmineralized connective tissue and bone leading to periodontitis. Moreover, there is also a possible link between cardiovascular disease and periodontitis. Here, we are presenting a case with the symptomatic triad fulfilling the diagnostic criteria of Grinspan syndrome. A 50-year-old female with type 2 diabetes mellitus and vascular hypertension came with the chief complaint of bleeding gums and severe burning sensation of the oral cavity. In addition, she was having generalized alveolar bone loss and clinical attachment loss. To the best of our knowledge, this coexistence has not been reported earlier. This needs further evaluation so that the preventive measures can be taken at early stage.

Overexpression and varied clinical significance of Th9 versus Th17 cells in distinct subtypes of oral lichen planus

OBJECTIVE

Oral lichen planus (OLP) presents with large numbers of T lymphocytes accumulating beneath the epithelium of the oral mucosa; however, its aetiology remains obscure. A potential role for an emerging novel T cell subset, Th9, in OLP has recently been suggested but remains to be clarified. The current aim was to investigate the expression and potential clinical significance of Th9 cells in distinct subtypes of OLP.

MATERIALS AND METHODS

Peripheral blood samples were collected from 41 OLP patients and 18 healthy controls (HCs). Flow cytometric analysis was used to detect the CD4+ T helper subset Th9 (IL-9⁺IL-17^-CD4⁺ Th cells) and Th17 (IL-9^-IL-17⁺CD4⁺ Th cells) expression levels.

RESULTS

Flow cytometry results showed significantly elevated levels of Th9 cells in reticular and erosive OLP compared to HCs. Th9 expression in erosive OLP was less than in reticular OLP, indicating that Th9 but not Th17 cells may play a predominant role in reticular disease. However, in erosive OLP patients, we found much higher levels of Th17 cells compared to reticular OLP patients and HCs, indicating that Th17 dominates in erosive OLP. Statistical analysis showed positive correlations of Th9 cells and Th17 cells in patients with reticular or erosive OLP but none in HCs.

CONCLUSIONS

Th9 and Th17 cells may take the predominant roles in reticular and erosive OLP respectively, and their numbers were positively correlated in reticular and erosive OLP patients. Elevated circulating Th9 cells may help maintain immune balance in OLP immunopathogenesis, which requires further investigation.

Altered expression of interleukin-17A and its targeting microRNAs in oral lichen planus: a pilot study

OBJECTIVE

To investigate the potential role of interleukin (IL)-17A and its targeting microRNAs (miRNAs) in oral lichen planus (OLP).

STUDY DESIGN

We compared the IL-17A expression levels in biopsies from patients with OLP (n = 50) against normal controls (n = 19) by using reverse transcription quantitative polymerase chain reaction (RT-qPCR) and Western blot analyses, identified the targeting miRNAs of IL-17A, and examined the miRNA expression levels in OLP.

RESULTS

IL-17A expression was significantly increased in patients with OLP compared with controls. The dual-luciferase reporter assay system demonstrated that miR-635 and miR-578 were the target miRNAs of IL-17A in human embryonic kidney 293 cells, which was consistent with predictions from bioinformatics software analyses. In contrast with IL-17A, the expression levels of miR-635 and miR-578 in OLP were significantly decreased compared with controls.

CONCLUSIONS

This pilot study found that low levels of miR-635 and miR-578 expression were associated with high expression of IL-17A, suggesting that IL-17A and its targeting miRNAs contribute to the pathogenesis of OLP.

Preliminary analysis of salivary microbiome and their potential roles in oral lichen planus

Several studies have explored the origin and development mechanism of oral lichen planus (OLP) with limited attention to the role of bacteria in the progression of this common oral disease. Here we utilized MiSeq sequencing of 16S rRNA gene amplicons to identify complex oral microbiota associated with OLP from saliva samples of two subtypes (reticular and erosive) of OLP patients and healthy controls. Our analyses indicated that the overall structure of the salivary microbiome was not significantly affected by disease status. However, we did observe evident variations in abundance for several taxonomic groups in OLP. Porphyromonas and Solobacterium showed significantly higher relative abundances, whereas Haemophilus, Corynebacterium, Cellulosimicrobium and Campylobacter showed lower abundances in OLP patients, as compared with healthy controls. In addition, we explored specific microbial co-occurrence patterns in OLP, and revealed significantly fewer linkers of Streptococcus comprising species in erosive OLP. Furthermore, the disease severity and immune dysregulation were also genus-associated, including with Porphyromonas that correlated to disease scores and salivary levels of interleukin (IL)-17 and IL-23. Overall, this study provides a general description of oral microbiome in OLP, and it will be useful for further investigation of their potential roles in the initiation and immune modulation of OLP.

Interleukin-17A Gene Variability in Patients with Type 1 Diabetes Mellitus and Chronic Periodontitis: Its Correlation with IL-17 Levels and the Occurrence of Periodontopathic Bacteria

Interleukin-17 contributes to the pathogenesis of type 1 diabetes mellitus (T1DM) and chronic periodontitis (CP). We analyzed IL-17A -197A/G and IL-17F +7488C/T polymorphisms in T1DM and CP and determined their associations with IL-17 production and occurrence of periopathogens. Totally 154 controls, 125 T1DM, and 244 CP patients were genotyped using 5' nuclease TaqMan(®) assays. Bacterial colonization was investigated by a DNA-microarray kit. Production of IL-17 after in vitro stimulation of mononuclear cells by mitogens and bacteria was examined by the Luminex system. Although no differences in the allele/genotype frequencies between patients with CP and T1DM + CP were found, the IL-17A -197 A allele increased the risk of T1DM (P < 0.05). Levels of HbA1c were significantly elevated in carriers of the A allele in T1DM patients (P < 0.05). Production of IL-17 by mononuclear cells of CP patients (unstimulated/stimulated by Porphyromonas gingivalis) was associated with IL-17A A allele (P < 0.05). IL-17A polymorphism increased the number of Tannerella forsythia and Treponema denticola in patients with CP and T1DM + CP, respectively (P < 0.05). IL-17A gene variability may influence control of T1DM and the "red complex" bacteria occurrence in patients with CP and T1DM + CP. Our findings demonstrated the functional relevance of the IL-17A polymorphism with higher IL-17 secretion in individuals with A allele.

Role of distinct CD4(+) T helper subset in pathogenesis of oral lichen planus

Oral lichen planus (OLP) is one of the most common chronic inflammatory oral mucosal diseases with T-cell-mediated immune pathogenesis. In subepithelial and lamina propria of OLP local lesions, the presence of CD4(+) T helper (CD4(+) Th) cells appeared as the major lymphocytes. These CD4(+) T lymphocytes can differentiate into distinct Th cell types such as Th1, Th2, Treg, Th17, Th22, Th9, and Tfh within the context of certain cytokines environment. Growing evidence indicated that Th1/Th2 imbalance may greatly participate into the cytokine network of OLP immunopathology. In addition, Th1/Th2 imbalance can be regulated by the Treg subset and also greatly influenced by the emerging novel CD4(+) Th subset Th17. Furthermore, the presence of novel subsets Th22, Th9 and Tfh in OLP patients is yet to be clarified. All these Th subsets and their specific cytokines may play a critical role in determining the character, extent and duration of immune responses in OLP pathogenesis. Therefore, we review the roles of distinct CD4(+) Th subsets and their signature cytokines in determining disease severity and susceptibility of OLP and also reveal the novel therapeutic strategies based on T lymphocytes subsets in OLP treatment.

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.

Clinical significance of IL-23 regulating IL-17A and/or IL-17F positive Th17 cells in chronic periodontitis

OBJECTIVE

To investigate the expression level and clinical significance of (IL-17A(+) and/or IL-17F(+)) Th17 cells under IL-23 regulation in patients of chronic periodontitis (CP) and healthy controls (HC).

MATERIALS AND METHODS

The whole peripheral blood samples were collected from 30 CP patients and 25 healthy controls. Flow cytometry was used to test the (IL-17A(+) and/or IL-17F(+)) Th17 expression level. Recombinant human IL-23 (rhIL-23) was used to detect Th17 differentiation and expansion. Correlation coefficient analysis between Th17 expression level and clinical parameters was analyzed by SPSS software.

RESULTS

Flow cytometry results showed that IL-17A(+)IL-17F(-) and IL-17A(-)IL-17F(+) Th17 were both increased in CP group than in HC group (P < 0.01), while, under recombinant human IL-23 (rhIL-23) stimulation, the number of IL-17A(+)IL-17F(-) Th17 cells was significantly increased in both CP and HC groups (P < 0.01). Interestingly, IL-17A(-)IL-17F(+) Th17 cells were only increased in CP group after rhIL-23 stimulation. Additionally, correlation coefficient analysis showed significant correlation between IL-17A(+)IL-17F(-) Th17 cell and attachment loss or probing depth (P < 0.05).

CONCLUSIONS

This study indicates that both the IL-17A(+)IL-17F(-) and IL-17A(-)IL-17F(+) Th17 cells may be involved in pathogenesis of periodontitis. The role of these Th17 cells in the disease pathogenesis needs to be further investigated.

Overexpression and selectively regulatory roles of IL-23/IL-17 axis in the lesions of oral lichen planus

Interleukin- (IL-) 23/IL-17 axis is a newly discovered proinflammatory signaling pathway and has been implicated in the pathogenesis of many chronic inflammatory and immune disorders. Here we investigated whether the IL-23/IL-17 axis was present and functional in the lesions of oral lichen planus (OLP), a chronic inflammatory disease affecting the oral mucosa. Using immunohistochemistry and quantitative PCR, we found that the subunits of IL-23 and IL-17 were overexpressed in OLP lesions than in normal oral mucosa tissues. In addition, the expressions of IL-23 and IL-17 are positively correlated in reticular OLP tissues. Results from in vitro studies revealed that exogenous IL-23 could increase the percentage of Th17 cells and IL-17 production in the CD4+T cells from reticular OLP patients. Furthermore, we also found that exogenous IL-17 could significantly enhance the mRNA expressions of β-defensin-2, -3, CCL-20, IL-8, and TNF-α, but not β-defensin-1, CXCL-9, -10, -11, CCL-5, and IL-6 in human oral keratinocytes. Taken together, our results revealed an overexpression pattern and selectively regulatory roles of IL-23/IL-17 axis in the OLP lesions, suggesting that it may be a pivotal regulatory pathway in the complex immune network of OLP lesions.

Inflammation-related cytokines in oral lichen planus: an overview

Cytokines are powerful mediators which play a central role in both innate and adapted immune responses. Aberrant productions of cytokines may lead to the onset of immune deficiency, allergy or autoimmunity, which are involved in the mechanisms of various immune-mediated inflammatory diseases. Oral lichen planus (OLP) is a chronic inflammation disease affecting the oral mucosa with unknown aetiology. Previous studies have described the abnormal expression patterns of various inflammation-related cytokines, such as IL-1, 2, 4, 5, 6, 8, 10, 12, 17, 18, TGF-β, IFN-γ and TNF-α, in lesions, saliva, serum and peripheral blood mononuclear cells from patients with OLP, which may reflect the immune dysregulation status and emerge as central players in the immunopathogenesis of OLP. Besides, the gene polymorphisms of several cytokines such as IFN-γ, TNF-α, IL-4, IL-10 have been found to be involved in the susceptibility of OLP. In this review, we gave a brief introduction of the characteristics and biological functions of these inflammation-related cytokines and summarized for the first time the current knowledge on the involvement of inflammation-related cytokines in OLP. Further research on the exact roles of these cytokines will aid the understanding of the pathogenesis and the identification of novel therapeutic approaches of OLP.

Oral lichen planus may enhance the expression of Th17-associated cytokines in local lesions of chronic periodontitis

OBJECTIVES

This study aims to compare the expression levels of interleukin (IL)-17 and IL-23 in local periodontal tissues from patients with both chronic periodontitis and oral lichen planus (CP-OLP), patients with chronic periodontitis (CP) only, patients with oral lichen planus (OLP) only, and healthy controls (HC).

MATERIALS AND METHODS

The periodontal tissues were collected from 15 CP-OLP patients, 15 CP patients, 15 OLP patients, and 10 healthy controls. Immunohistochemistry (IHC) and real-time quantitative PCR (qPCR) was performed to investigate the protein and mRNA expression level of IL-17 and IL-23 in periodontal lesions from these four groups.

RESULTS

IHC statistical analysis showed that the expression level of IL-17- and IL-23p19-positive cells significantly increased in CP-OLP group compared with that in CP (P < 0.01) and OLP groups (P < 0.05), showing intense staining reaction in local lamina propria lesions. Meanwhile, qPCR result showed higher IL-17 mRNA level in CP-OLP compared with that in CP and OLP groups and demonstrated a significant increase than OLP group (P < 0.05). Moreover, it was found that IL-17 mRNA expression level in erosive CP-OLP patients was significantly correlated with probing depth and attachment loss (P < 0.05).

CONCLUSIONS

This study indicated that there was an increased expression level of IL-17 and IL-23 in periodontal tissues from periodontitis patients with oral lichen planus, which might aggravate the inflammatory response in local lesions.

CLINICAL RELEVANCE

Oral lichen planus and chronic periodontitis may have interaction in disease pathogenesis, while IL-17 detection in local lesions may be helpful in identifying the disease severity in periodontitis patients with oral lichen planus.

Immunoexpression of interleukin-22 and interleukin-23 in oral and cutaneous lichen planus lesions: a preliminary study

Interleukin- (IL-) 22 is the signature cytokine of T-helper (Th) 22 cells, and IL-23 is required for IL-22 production. The objective of this study was to examine the immunoexpression of IL-22 and IL-23 in archival paraffin-embedded biopsy specimens from oral LP (n = 42) and cutaneous LP (n = 38) against normal control tissues. The results showed that the percentage of cells expressing IL-22 and IL-23 in LP were significantly higher in LP compared to controls, respectively (both P < 0.001). The correlation between IL-22 and IL-23 expression was significant (P < 0.05). Moreover, the percentage of cells expressing IL-22 and IL-23 in oral LP were significantly higher than cutaneous LP (P < 0.05). Collectively, our findings demonstrated that the increased expression of IL-22 and IL-23 in LP lesions could play roles in the pathogenesis of LP. Moreover, oral LP expressing IL-22 and IL-23 was higher than cutaneous LP, probably due to Th22 cells as an important component of oral mucosal host defense against oral microbiota and tissue antigens. This may be associated with the difference in clinical behaviour of the two variants of the disease.