Potential implication of serum lipid levels as predictive indicators for monitoring oral lichen planus.

Compelling evidence indicates that dyslipidemia is positively associated with oral lichen planus (OLP). The types and magnitude of lipid metabolism disturbance in peripheral blood of OLP patients have been investigated in different studies. Yet, consensus on how these different lipid components varied in levels for the development of OLP lesions has not been reached so far. Herein, a total of 8 eligible studies were recognized, which enrolled 533 cases of OLP and 499 healthy controls. The analysis showed that the average total triglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) levels were considerably higher, and high-density lipoprotein cholesterol (HDL-C) levels were significantly lower in OLP patients compared to healthy controls. Collectively, the lipid profile panel maybe serve as the potential predictive indicator for screening OLP.

TYK2 inhibition with deucravacitinib ameliorates erosive oral lichen planus.

Erosive oral lichen planus (OLP) is a challenging disease. This T cell driven disorder frequently shows a treatment unresponsive course and strongly limits patients' quality of life. The disease lacks FDA or EMA approved drugs for its treatment and the efficacy of the commonly administered treatments (i.e. topical and systemic steroids, steroid sparing agents) is often only partial. Although the etiopathogenesis of the disease still needs to be fully elucidated, recent advances helped to identify interferon-É£ (IFN-É£) as a pivotal cytokine in OLP pathogenesis, thus making the interference with its signalling a therapeutic target. Janus kinase (JAK) inhibitors therefore gained relevance for their inhibitory effect on IFN-É£ signalling. While some drugs such as abrocitinib, upadacitinib, tofacitinib directly interfere with IFN-É£ signalling through blockade of JAK1 and/or JAK2, deucravacitinib, a selective TYK-2 inhibitor indirectly interferes on IFN-É£ activation through interference with interleukin (IL)-12, a potent promotor for Th1/IFN-É£ responses. This mechanism of action makes deucravacitinib a candidate drug for the treatment of OLP. Here we provide initial evidence that deucravacitinib 6 mg daily has a beneficial effect in three patients with oral OLP.

Integrative Approaches for the Diagnosis and Management of Erosive Oral Lichen Planus.

Erosive oral lichen planus (EOLP) represents a significant challenge in dental and medical management due to its chronic inflammatory nature, painful symptoms, and impact on quality of life. This study aims to evaluate the current diagnostic approach with novel non-invasive techniques, such as dermoscopy, and also the landscape of treatment options for EOLP, focusing on its efficacy, safety, and the challenges that it present in clinical practice. Through a comprehensive literature review, we explored the use of topical corticosteroids, systemic immunosuppressants, biologics, and Janus kinase (JAK) inhibitors in treating EOLP, alongside examining patient compliance, psychological impacts, and the risk of adverse effects and recurrence. Our findings reveal that while topical corticosteroids are the cornerstone of EOLP treatment, offering symptomatic relief, their long-term use is limited by side effects and tolerance development. Systemic therapies and biologics provide alternatives for refractory cases but necessitate careful adverse effect monitoring. JAK inhibitors show promise as an innovative treatment avenue but require more evidence on long-term safety and efficacy. This study highlights the necessity of personalized treatment approaches due to the variable disease course and response to treatment, underscoring the importance of a multidisciplinary strategy in managing EOLP. The complexity of EOLP treatment, compounded by its psychological and quality of life impacts, demands ongoing research into targeted therapies, the establishment of standardized treatment protocols, and the development of effective outcome measures to improve patient care and treatment outcomes.

γδ T cells in oral diseases.

OBJECTIVE: γδ T cells are a distinct subset of unconventional T cells, which link innate and adaptive immunity by secreting cytokines and interacting with other immune cells, thereby modulating immune responses. As the first line of host defense, γδ T cells are essential for mucosal homeostasis and immune surveillance. When abnormally activated or impaired, γδ T cells can contribute to pathogenic processes. Accumulating evidence has revealed substantial impacts of γδ T cells on the pathogenesis of cancers, infections, and immune-inflammatory diseases. γδ T cells exhibit dual roles in cancers, promoting or inhibiting tumor growth, depending on their phenotypes and the clinical stage of cancers. During infections, γδ T cells exert high cytotoxic activity in infectious diseases, which is essential for combating bacterial and viral infections by recognizing foreign antigens and activating other immune cells. γδ T cells are also implicated in the onset and progression of immune-inflammatory diseases. However, the specific involvement and underlying mechanisms of γδ T cells in oral diseases have not been systematically discussed. METHODS: We conducted a systematic literature review using the PubMed/MEDLINE databases to identify and analyze relevant literature on the roles of γδ T cells in oral diseases. RESULTS: The literature review revealed that γδ T cells play a pivotal role in maintaining oral mucosal homeostasis and are involved in the pathogenesis of oral cancers, periodontal diseases, graft-versus-host disease (GVHD), oral lichen planus (OLP), and oral candidiasis. γδ T cells mainly influence various pathophysiological processes, such as anti-tumor activity, eradication of infection, and immune response regulation. CONCLUSION: This review focuses on the involvement of γδ T cells in oral diseases, with a particular emphasis on the main functions and underlying mechanisms by which γδ T cells influence the pathogenesis and progression of these conditions. This review underscores the potential of γδ T cells as therapeutic targets in managing oral health issues.

Histologic and Histomorphometric Comparative Study of Oral Lichen Planus Versus Oral Lichenoid Reaction.

Aim: Oral lichen planus (OLP) is a T-cell-mediated chronic inflammatory disease classified as an oral potentially malignant disorder (OPMD) and increased transformation risk to oral cancer. Oral lichenoid reactions (OLRs) share the clinical manifestations of OLP. This study aimed to determine histomorphometric changes in OLPs and OLRs in comparison to the healthy control, which helps to plan for the establishment of diagnostic criteria. Materials and Methods: This cross-sectional prospective study was conducted on a total of 75 tissue-embedded paraffin-block samples, including OLPs (n = 25), OLR cases (n = 25), and healthy control individuals (n = 25). The study groups were compared by chi-squared, Fisher's exact, and one-way ANOVA tests. A p-value less than 0.05 was considered statistically significant. Results: Comparison of the nuclear area and cellular area showed a statistically significant difference between study groups in basal and parabasal layer (P < 0.05). Comparison of the nuclear-to-cytoplasm ratio showed a statistically significant difference between study groups in basal (P < 0.05) but not in the parabasal region (P = 0.681). Conclusion: We showed a significant difference in the nuclear and cellular area, nuclear-to-cytoplasm ratio between OLPs and OLRs, and healthy controls, but there was no statistically significant difference between OLPs and OLRs. Thus, these parameters cannot be applied to differentiate diagnoses between OLPs and OLRs.

A Comparative Study of the Treatment of Oral Premalignant Lesions with Surgical Excision and Medical Therapy.

Introduction: Potentially malignant oral epithelial lesions are a group of oral conditions with an altered morphological state of the normal mucosal lining and include different lesions such as leukoplakia, erythroplakia, submucosal fibrosis, and lichen planus. Aim: To compare the outcome of premalignant oral lesions after medical therapy consisting of submucosal intralesional injection of triamcinolone with hyaluronidase and surgical excision. Materials and Methods: This was a comparative prospective interventional study and the study was conducted among 50 patients presented to the Department of Otorhinolaryngology with premalignant oral lesions from the year 2020 to 2022. Patients were divided into two groups by random allocation, group A was treated with medical therapy, and Group B was treated with surgical excision and followed for a minimum of 6 months and the outcome has been categorized. Results: All patients were divided into two groups-group A and group B, group A consisted of 22 (44%) patients who were given medical therapy, and group B consisted of 28 (56%) patients who underwent surgical excision. In group A, the clinical response was seen in 8 (36.36%) and in group B, the clinical response was seen in 18 (64.29%) patients. Conclusion: Surgical excision was found to be better with more cases of clinical response (64.29%) when compared to medical treatment (36.36%) with a p value of 0.0497 which is significant whereas malignant transformation was almost equal in medical therapy and surgical treatment which was 13.64% and 14.28%, respectively.

Evaluation of the Effectiveness of Amlexanox in the Treatment of Erosive Oral Lichen Planus: A Clinical Experience from a Tertiary Care Center.

Aim: This comparative study evaluated the effectiveness and safety profile of topical amlexanox and triamcinolone for the management of erosive oral lichen planus (EOLP). Materials and Methods: This prospective, observational study included 21 patients diagnosed clinically and histopathologically with EOLP and categorized into two groups. Subjects in the two groups were prescribed topical amlexanox and triamcinolone, respectively, for 4 weeks. The area of the erosive lesion and burning sensation was measured at baseline, at the end of the first, 2second, and fourth week. These outcome measures were documented and statistically analyzed. The statistical analyses were performed using the IBM SPSS Statistics version 22. Analysis for age distribution was done by independent sample t test. Analysis of sex distribution was done by chi-square test. Variations within a single group for both the outcome parameters were calculated by Wilcoxon signed rank test. (P < 0.05 statistically significant). Results: A total of 30 erosive sites were evaluated in 21 patients over a 4-week duration. The most common site was the buccal mucosa in both groups (23 of 30; 76.67% of total lesions assessed), followed by the tongue (5 of 30; 16.67% of total lesions assessed), the palate (1 of 30; 3.33% of total sites assessed), and the maxillary attached gingiva (1 of 30; 3.33% of total sites assessed). Group 1 (amlexanox) was comprised of 11 subjects, whereas Group 2 (triamcinolone) was comprised of 10 subjects. Pre and posttreatment comparison revealed no statistically significant difference (P = 0.756; 0.512, respectively), for the area of the erosion and burning sensation. Intragroup analysis showed that in Groups 1 and 2, there was a statistically significant reduction in the measures posttreatment (P < 0.05). Conclusions: Amlexanox provides an earlier onset of pain relief in the treatment of EOLP, whereas providing a comparable reduction in the erosive area compared with triamcinolone. Topical amlexanox appears to be as effective as triamcinolone and is a promising alternative in the management of the erosive lichen planus with minimal adverse effects.

Efficacy of Clobetasol Propionate (0.05%), Amlexanox (5%), and Triamcinolone Acetonide (0.1%) in the Treatment of Oral Lichen Planus.

Objectives: This study aimed to compare the efficiencies of 0.05% clobetasol propionate, 0.1% triamcinolone acetonide, and 5% amlexanox in the management of oral lichen planus (OLP). Material and Method: A total of 120 patients diagnosed with oral lichen planus were equally divided into three groups and treated with 0.05% clobetasol propionate (group A), 0.1% triamcinolone acetonide (group B), and 5% amlexanox (group C) topical medicaments. The patients were evaluated for pain using the visual analog scale (VAS) and erosive lesion. Results: There was a statistically significant decrease in the VAS pain scale score from day 1 to day 15 in all of the tested groups. There was also a reduction in the erosive area on the right and left buccal mucosa on the 15th day with all three tested drugs. Triamcinolone acetonide (0.1%) was effective in reducing the erosive lesions on buccal mucosa when compared with 0.05% clobetasol propionate and 5% amlexanox. Conclusion: Clobetasol propionate, triamcinolone acetonide, and amlexanox were effective in treating OLP patients.

Evaluation of the Function of Vitamin D in Treating Oral Lichen Planus.

Objectives: The objective of the current research was to evaluate the role of vitamin D in the management of oral lichen planus. Materials and Method: Based on their vitamin D levels, 90 individuals with oral lichen planus were equally divided into three groups. Deficient subjects received oral vitamin D supplementation. Result: The majority of improvements were observed in patients who were taking vitamin D supplements. It was discovered that the data comparison was statistically considerable. Conclusion: It was determined that vitamin D was crucial for the management of oral lichen planus.

Efficacy of Aloe Vera, Amlexanox (5%), and Triamcinolone Acetonide (0.1%) in the Management of Oral Lichen Planus.

Objective: This research assessed the efficiencies of aloe vera, 0.1% triamcinolone acetonide, and 5% amlexanox in the management of OLP. Materials and Methods: A total of 120 participants diagnosed with oral lichen planus (OLP) were equally divided into three groups and treated with: aloe vera, (Group A), 0.1% triamcinolone acetonide (Group B), and 5% amlexanox (Group C) topical medicaments. The patients were evaluated for pain, using the visual analogue scale (VAS). They were also evaluated for ulcerative lesion type and erosive area on days 1, 7, and 15 of the study. Results: There was a statistically considerable decrease in the VAS pain scale score, reduction in the erosive area on buccal mucosa, and healing of ulcer from day 1st to 15th day with all three tested drugs. Conclusion: All drugs used in this study; aloe vera, triamcinolone acetonide, and amlexanox were effective in treating OLP patients.

What can we learn from treatments of oral lichen planus?

Oral lichen planus (OLP), a T-lymphocyte-mediated disease of the oral mucosa, has a complex pathogenesis that involves a number of factors. The disease is characterized by recurrent episodes and requires continuous follow up, and there is no curative treatment available. Erosive lichen planus, among others, has a risk of malignant transformation and requires standardized treatment to control its progression. Different clinical subtypes of oral lichen planus require appropriate treatment. Pharmacological treatments are the most widely available and have the greatest variety of options and a number of novel pharmacological treatments are presented as highlights, including JAK enzyme inhibitors. The second is photodynamic therapy, which is the leading physiological treatment. In addition, periodontal treatment and psychological treatment should not be neglected. In this review, we briefly discuss the most recent developments in therapies for oral lichen planus after summarizing the most widely used clinical treatments, aiming to provide different proposals for future clinical treatment.

Oral lichen planus among patients from Lublin Region in relation to 25-hydroxy-vitamin D3 serum level.

INTRODUCTION AND OBJECTIVE: Lichen planus is a chronic inflammatory skin disease involving the mucous membrane of the oral cavity. It is postulated that different factors play a role in the occurrence of the disease and may activate the immune system, thus influencing the development of lichen planus. Vitamin D is a steroid prohormone with multiple systemic effects. OBJECTIVE: The aim of this study was to assess oral lichen planus against 25-hydroxy-vitamin D3 serum level. Vitamin D takes an active part in the pathogenesis of immunisation diseases, may have also a beneficial effect on oral health. MATERIAL AND METHODS: The clinical picture of lichen planus was analyzed according to the concentration of 25-hydroxy-vitamin D3. Patients were given a questionnaire interview which included questions about the co-existence of systemic diseases, subjective complaints, and information relating to the individual course of the disease. In the next stage of the study, patients were underwent a physical examination. Laboratory determinations of the concentration of 25-hydroxy-vitamin D3 were also performed. RESULTS: The mean vitamin D concentration in patients with lichen planus in the oral cavity was 14.37 ± 4.95 ng/ml. An insufficient level (10-30 ng/ml) was detected in 84.91% of the examined patients, whereas a deficiency (< 10 ng/ml) was observed in 15.09% of those patients. None of the analyzed patients had vitamin D level in the range of established clinical standards. A substantially lowered vitamin D level was found in patients reporting bleeding and pain of the gums. CONCLUSIONS: The study enhances relationship between reduced levels of vitamin D3 and lichen planus in patients with oral lesions. Thus, vitamin D3 control and supplementation may play an important role in the treatment of lichen planus.

Exploring the prevalence and risk factors of benign and premalignant oral lesions in an adult population from Northern Spain: a pilot study.

OBJECTIVE: The goal was to identify the lifestyle risk factors associated with benign and potentially malignant oral disorders. METHOD AND MATERIALS: The study enrolled first-time patients from the Oral Pathology Section, volunteers from Oviedo, and first-time patients from University of Oviedo dental clinic. Patients underwent a survey that included sociodemographic information, lifestyle habits, and medical history. Then, a comprehensive examination of the oral mucosa was conducted. Univariate and multivariate logistic regression were conducted using R software. RESULTS: Among the 183 participants, the most prevalent lesions were varicose veins (43.2%), cheek/lip biting (34.97%) and coated tongue (33.3%). Among the OPMDs (16.4%), oral lichen planus (OLP, 12.64%) and leukoplakia (3.3%). Tobacco was associated with melanotic pigmentation (OR 3.87, p= 0.001) and coated tongue (OR 5.90, p= 0.001). Longer intervals since last check-up were associated with traumatic keratosis (OR 2.05, p=035). Age and heavy smoking were found to have higher risk of developing an OPMD (OR 1.04, p=0.035 and OR 7.35, p=0.028 respectively). CONCLUSIONS: Our data should be considered when organizing public health programs focused on the detection and screening of heavy smokers. It is also important to strengthen the oral pathology units in universities as reference centres for students to acquire the necessary knowledge for their diagnosis and treatment, while simultaneously promoting awareness of this risk factor for oral precancer among the general population.

Association between Vitamin D Receptor Polymorphism and Susceptibility to Oral Lichen Planus and Oral Squamous Cell Carcinoma.

Introduction: Oral squamous cell carcinomas (OSCC) comprise 90-95% of oral cancers. Early diagnosis improved the survival rate of OSCC patients to 80-90%. Oral lichen planus (OLP) is a chorionic inflammatory disease with malignancy potential. The vitamin D receptor (VDR) plays a critical role in the pathogenesis of oral cancer. This study aimed to determine the association between VDR rs7975232 (Apa I) polymorphism and potential susceptibility to OLP and OSCC risks. Materials and Methods: In this prospective case-control study, a total of 120 blood samples were obtained from OSCC patients (n=29), OLP (n=50), and controls (n=40). VDR rs7975232 polymorphism was studied using the Polymerase Chain Reaction Restriction Fragment Length Polymorphism (PCR-RFLP) method. Statistical analysis was performed with SPSS Version 23 software. Data were expressed as means ± standard deviation (SD). Age, sex, allelic frequency, and genotyping were compared using the chi-square test. A p-value of less than 0.05 was regarded as statistically significant. The disease risk was estimated by Odds ratio (OR) with a 95% confidence interval. Results: A significant age difference was observed between the controls and the OSCC group (p=0.001). A significant difference was observed in Aa and aa genotypes compared with AA between OSCCs and controls. Moreover, dominant (p<0.001), additive (p<0.001), and allelic (p=0.001) models were different between groups. Conclusion: There was a positive association between rs7975232 VDR polymorphism and susceptibility to OSCC. More experimental evidence must reveal the possible association between rs7975232 and the risk of OLP in a larger cohort.

Oral lichen planus in children: A systematic review / Liquen plano oral en niños: una revisión sistemática

Background: Oral Lichen Planus is a common chronic inflammatory disease of the oral mucosa. The prevalencein adults ranges between 0.5% and 2%, while in children is reported to be about 0,03%. Clinical features of OralLichen Planus could be variable in both adults and children, ranging from painless white hyperkeratotic lesions topainful erythematous atrophic ones.Actually, there are no systematic reviews in the literature on OLP in children, whereby this paper aims to sum-marize all the pathophysiological aspects and identify all cases described in the literature of Oral Lichen Planusin children, reporting their clinical characteristics.Material and Methods: A systematic review of the literature was performed in online databases including PubMed,Scopus, Web of Science, Science Direct, EMBASE. In addition, in order to identify reports not otherwise identifi-able, an analysis of the gray literature was performed on google scholar and in Open Gray.Results: By literature analysis, it emerged that most cases were reported from India. The mean age at time of diag-nosis of the disease was 11 years, ranging from 3 to 17 years. The most frequent pattern was the reticular patternfollowed by plaque-like, erosive, atrophic, sclerosus, and bullous. The buccal mucosa was the most involved oralsite, followed by the tongue, lips and gingiva.Conclusions: Although Oral Lichen Planus in children is rare, it may cause oral discomfort and need to be dif-ferentiated from other oral white lesions and/or chronic ulcers.(AU)

Inflammatory cytokines mediating the effect of oral lichen planus on oral cavity cancer risk: a univariable and multivariable mendelian randomization study.

BACKGROUND: While observational studies and experimental data suggest a link between oral lichen planus (OLP) and oral cavity cancer (OCC), the causal relationship and the role of inflammatory cytokines remain unclear. METHODS: This study employed a univariable and multivariable Mendelian Randomization (MR) analysis to investigate the causal relationship between OLP and the risk of OCC. Additionally, the potential role of inflammatory cytokines in modulating this association was explored. Instrumental variables were derived from genetic variants associated with OLP (n = 377,277) identified in Finngen R9 datasets, with 41 inflammatory cytokines as potential mediators, and OCC (n = 4,151) as the outcome variable. Analytical methods including Inverse Variance Weighted (IVW), Weighted Median, MR-Egger, and MR-PRESSO were utilized to assess the causal links among OLP, inflammatory cytokines, and OCC risk. Multivariable MR (MVMR) was then applied to quantify the mediating effects of these cytokines in the relationship between OLP and increased OCC risk. RESULTS: MR analysis provided strong evidence of a causal relationship between OLP (OR = 1.417, 95% CI = 1.167-1.721, p < 0.001) and the risk of OCC. Furthermore, two inflammatory cytokines significantly influenced by OLP, IL-13 (OR = 1.088, 95% CI: 1.007-1.175, P = 0.032) and IL-9 (OR = 1.085, 95% CI: 1.005-1.171, P = 0.037), were identified. Subsequent analysis revealed a significant causal association only between IL-13 (OR = 1.408, 95% CI: 1.147-1.727, P = 0.001) and higher OCC risk, establishing it as a potential mediator. Further, MVMR analysis indicated that IL-13 (OR = 1.437, 95% CI = 1.139-1.815, P = 0.002) mediated the relationship between OLP and OCC, accounting for 8.13% of the mediation. CONCLUSION: This study not only elucidates the potential causal relationship between OLP and the risk of OCC but also highlights the pivotal mediating role of IL-13 in this association.

Immunophenotypic and Gene Expression Analyses of the Inflammatory Microenvironment in High-Grade Oral Epithelial Dysplasia and Oral Lichen Planus.

BACKGROUND: Oral lichen planus (OLP) and oral epithelial dysplasia (OED) present diagnostic challenges due to clinical and histologic overlap. This study explores the immune microenvironment in OED, hypothesizing that immune signatures could aid in diagnostic differentiation and predict malignant transformation. METHODS: Tissue samples from OED and OLP cases were analyzed using immunofluorescence/immunohistochemistry (IF/IHC) for CD4, CD8, CD163/STAT1, and PD-1/PDL-1 expression. RNA-sequencing was performed on the samples, and data was subjected to CIBERSORTx analysis for immune cell composition. Gene Ontology analysis on the immune differentially expressed genes was also conducted. RESULTS: In OED, CD8 + T-cells infiltrated dysplastic epithelium, correlating with dysplasia severity. CD4 + lymphocytes increased in the basal layer. STAT1/CD163 + macrophages correlated with CD4 + intraepithelial distribution. PD-1/PDL-1 expression varied. IF/IHC analysis revealed differential immune cell composition between OED and OLP. RNA-sequencing identified upregulated genes associated with cytotoxic response and immunosurveillance in OED. Downregulated genes were linked to signaling, immune cell recruitment, and tumor suppression. CONCLUSIONS: The immune microenvironment distinguishes OED and OLP, suggesting diagnostic potential. Upregulated genes indicate cytotoxic immune response in OED. Downregulation of TRADD, CX3CL1, and ILI24 implies dysregulation in TNFR1 signaling, immune recruitment, and tumor suppression. This study contributes to the foundation for understanding immune interactions in OED and OLP, offering insights into future objective diagnostic avenues.

Successful Treatment of Erosive Lichen Planus With Tofacitinib: A Case Series and Review of the Literature.

Lichen planus (LP) is an inflammatory disease that affects the skin, hair, nails and mucous membranes. Erosive LP is a chronic and difficult-to-treat subtype of lichen planus, characterized by lesions on mucosal surfaces, particularly in the oral and genital areas. The prevalence of erosive LP has not been determined. To date, treatment has consisted of surgical intervention, photodynamic therapy, laser therapy, and systemic or topical drugs, including steroids and immunomodulatory agents. LP usually need longer periods of treatment and are known as precancerous lesions with a 0.4% to 12% conversion rate. In addition, nearly 25% of patients who develop erosive LP of the vulva are resistant to topical corticosteroids, which are the first choice of treatment. This study reports 6 cases with a mean age of 3.33 years, who were diagnosed with erosive LP lesions and previously failed in treatment with local, intralesional, and systemic steroids, and hydroxychloroquine. These patients were then treated with 10 mg of tofacitinib per day. Interestingly, with the new treatment, the patients' mean overall satisfaction score was 9.16 out of 10 (range: 8-10), the mean pain relief score was 9.16 out of 10 (range: 9-10) and patients' symptom improvement also began an average of 1.33 months after starting treatment (range: 1-2.5 months).

Oral mucosal changes in tight junction proteins in patients with oral lichen planus.

OBJECTIVE: This study aimed to investigate the expression of tight junction, its distribution pattern in oral lichen planus samples and its potential association with the severity of oral lichen planus. MATERIALS AND METHODS: Cross-sectional study designs were conducted. Transcriptome sequencing was conducted using oral mucosal tissues from 22 patients with oral lichen planus and 11 healthy controls. Immunohistochemistry and quantitative reverse transcription PCR were performed to verify the expression of claudin-1, claudin-4, occludin and zonula occludens-1 in oral mucosal tissues from another 30 patients with oral lichen planus and 26 healthy controls. The relationship between tight junction protein expression and oral lichen planus severity was explored using correlation analysis. RESULTS: 5603 and 2475 differentially expressed genes were upregulated and downregulated respectively, in oral lichen planus tissues. KEGG analysis showed that tight junctions including CLDN1, CLDN4, OCLN and TJP1 were downregulated in oral lichen planus. Claudin-1, claudin-4, occludin and zonula occludens-1 expression was verified to be significantly lower in oral lichen planus. Furthermore, correlation analyses showed that decreased occludin expression was positively related to oral lichen planus severity. CONCLUSION: Decreased expression of TJ barrier proteins may be associated with the development of oral lichen planus.