Oral lichen planus: focus on etiopathogenesis

Oral lichen planus: a novel staging and algorithmic approach and all that is essential to know

Lichen planus (LP) is a chronic autoimmune disease. Oral lesions may occur in isolation or in combination with other affected muco-cutaneous sites. Oral LP (OLP) may present as one of the various manifestations of LP or may present as a disease sui generis with a broad range of severity. Despite this disease targeting the oral mucosa, its great impact on quality of life is underrated. In this article, we provide an updated review of the pathophysiology and epidemiology of OLP and offer guidance for its diagnosis and management. We also propose an algorithmic approach to the clinical forms of OLP and a novel staging system to facilitate management decisions.

Vitamin D receptor genetic polymorphisms are associated with oral lichen planus susceptibility in a Chinese Han population

BACKGROUND

Vitamin D receptor (VDR) is involved in multiple immune-mediated disorders including oral lichen planus (OLP). This study investigated the association between VDR gene polymorphisms and the risk of OLP.

METHODS

In total, 177 OLP patients and 207 healthy participants were recruited from the Affiliated Hospital of Stomatology, Nanjing Medical University. Eight single nucleotide polymorphisms (SNPs: rs731236, rs739837, rs757343, rs2107301, rs2239185, rs7975232, rs11574129 and rs11568820) in the VDR gene were selected and genotyped.

RESULTS

The results showed that OLP risk was increased in subjects with the rs2239185 TT genotype (Recessive model: adjusted Odd ratio(OR) = 2.68, 95% Confidence interval(CI) = 1.28-5.62, P = 0.009) and rs7975232 CC genotype (Recessive model: adjusted OR = 2.25, 95% CI = 1.10-4.58, P = 0.026). Moreover, rs2239185 and rs7975232 (P < 0.01) showed significant cumulative effects on OLP risk.Haplotype analysis showed that the CC haplotype (rs2239185-rs7975232) was associated with an increased risk of OLP (OR = 3.11, 95% CI = 1.42-6.83, P = 0.005), compared with the AC haplotype.

CONCLUSION

The rs2239185 and rs7975232 variants of VDR may influence OLP susceptibility, and VDR gene polymorphisms may be candidate susceptibility regions for OLP in a Chinese Han population.

Could photodynamic therapy be utilized as a treatment modality for oral lichen planus?

BACKGROUND

Oral lichen planus (OLP) is a chronic inflammatory disease. There is no standard treatment modality for OLP. Recently, photodynamic therapy (PDT) has been advocated as a new treatment modality for OLP.

AIM

The aim of the present study is to compare the effect of PDT using methylene blue (MB) as a photosensitizer to the effect of topical corticosteroids in the treatment of erosive OLP lesions.

MATERIALS AND METHODS

Our study included 20 patients with erosive OLP. Patients were divided into two groups. The study group included 10 patents which received MB-PDT. Patients were instructed to use MB as mouth path for 5 min. After 10 min, we applied focal red light on OLP lesions (wavelength 660 nm, Intensity 100-130 m W/cm2) for 2 min. The PDT was applied twice a week for four weeks. In the control group, 10 patients were instructed to apply topical betamethasone valerate ointment 100 mg on OLP lesion three times per day for four weeks. Subjective, objective scores and lesion size were recorded at time zero, after 2 weeks and after 4 weeks from the start of treatments.

RESULTS

Both groups showed statistically significant differences between time zero and the 4^th week of treatment in subjective, objective scores and the area of the lesions. MB-PDT showed a higher degree of improvement than topical corticosteroids between time zero and the 4^th week of treatment.

CONCLUSION

Photodynamic therapy can be used as a treatment for erosive OLP. PDT offers improvement of OLP subjective and objective scores without major side effects.

Metabolic changes during malignant transformation in primary cells of oral lichen planus: Succinate accumulation and tumour suppression

Oral squamous cell carcinoma (OSCC) is usually diagnosed at late stages, which leads to high morbidity. There are evidence that chronic inflammation (eg oral lichen planus [OLP]) was a risk factor of OSCC, but often misdiagnosed or ignored until invasion and metastasis. By applying precision medicine, the molecular microenvironment variations and relevant biomarkers for the malignant transformation from OLP to OSCC can be fully investigated. Several studies pointed out that the metabolic pathway were suppressed in OSCC. However, it remains unclear how the systemic profile of the metabolites change during the malignant transformation. In this study, we examined and compared the mucosa samples from 11 healthy individuals, 10 OLP patients and 21 OSCC patients. Based on the results, succinate, a key metabolite of the tricarboxylic acid cycle pathway, was accumulated in the primary cultured precancerous OLP keratinocytes and OSCC cells. Then, we found that succinate activated the hypoxia‐inducible factor‐1 alpha (HIF‐1α) pathway and induced apoptosis, which could also be up‐regulated by the tumour suppressor lncRNA MEG3. These results suggested the critical roles of succinate and MEG3 in the metabolic changes during malignant transformation from OLP to OSCC, which indicated that succinate, HIF1α and downstream proteins might serve as new biomarkers of precancerous OLP for early diagnosis and therapeutic monitoring. In addition, succinate or its prodrugs might become a potential therapy for the prevention or treatment of OSCC.

Cytokines Levels and Salivary Microbiome Play A Potential Role in Oral Lichen Planus Diagnosis

Oral lichen planus (OLP) is a chronic Th1-mediated inflammatory mucocutaneous disease of the skin and oral mucosa that can have various clinical presentations. Lesions are usually bilateral and often painful. While cutaneous Lichen Planus (LP) lesions are self-limiting, the oral lesions are chronic and rarely remissive. The diagnosis of oral lichen planus (OLP) is often challenging, and confirmation by histopathological criterion is generally advised. The aim of our study was to identify the cytokines present in OLP-suggestive lesions and in non-specific inflammatory lesions (NSIL) used as controls. Moreover, assess cytokines protein levels and oral microbiota composition in whole saliva samples. Histopathological analysis, immunohistochemistry and gene expression were used as techniques to analyze the oral mucosal tissue samples. ELISA was conducted to analyze salivary cytokine levels and 16S rRNA sequencing was used to determine the salivary microbiome. As a result we observed larger number of infiltrated lymphocytes (p = 0.025), as well, more T CD4 lymphocytes in the epithelial tissue (p = 0.006) in OLP samples compared to NSIL. In addition, the OLP samples displayed more apoptotic cells compared to NSIL (p = 0.047). Regarding the cytokine analysis, IFN-γ and IL-33 were more expressed in OLP lesions than in NSIL samples (p < 0.001; p = 0.026). Furthermore, our results demonstrated higher levels of IFN-γ protein expression in the saliva of OLP group compared to controls (p = 0.0156). We also observed noted differences in the oral microbiota composition between OLP and NSIL saliva samples. In conclusion, OLP lesions presented larger numbers of apoptotic and inflammatory cells, higher levels of IFN-γ and IL-33 compared to NSIL, and these lesions also differ regarding oral microbiota composition. These results are consistent with the Th-1-mediated chronic inflammation nature of oral lichen planus investigated lesions and displayed unique features that could be used as a diagnostic tool.

Mucocutaneous Diseases

Mucocutaneous diseases affecting the oral cavity are predominantly immune mediated or inflammatory. Three of the most common and clinically significant conditions are reviewed in this article: lichen planus, pemphigus vulgaris, and mucous membrane pemphigoid. Because oral manifestations may be the first or only manifestation of mucocutaneous diseases, oral health professionals play a critical role in the early diagnosis and multidisciplinary management of these conditions.

Evaluation of depression, anxiety and stress levels in patients with oral lichen planus

The pathogenesis of oral lichen planus (OLP) remains to be fully elucidated; however, certain psychoneurological factors may influence the onset and exacerbation of OLP. The aim of the present study is to evaluate the intensity of negative emotions in patients with OLP. A cross-sectional, questionnaire-based study was performed. The sample consisted of 52 subjects, comprising 26 patients with OLP (OLP group) and 26 controls (CTRL group). The Depression Anxiety Stress Scale 21 (DASS-21) was used for psychometric evaluation. The patients were also asked about their attitude toward the disease, treatment, and interference of the disease on daily life. The mean level of depression was 12.54 ± 6.6 in the OLP group and 7.69 ± 5.22 in the CTRL group (P = 0.006). The mean level of anxiety was 11.15 ± 7.95 in the OLP group and 6.62 ± 4.86 in the CTRL group (P = 0.018). The mean stress levels were 8.69 ± 7.06 and 3.85 ± 3.18 in the OLP and CTRL groups, respectively (P = 0.003). Severe and very severe scores of depression and very severe scores of anxiety and stress were present in the OLP group, whereas these emotions were normal in the majority of controls. Depression, stress, and anxiety may be involved in the pathogenesis and course of OLP.

Severity of oral lichen planus and oral lichenoid lesions is associated with anxiety

OBJECTIVES

Oral lichen planus (OLP) and oral lichenoid lesions (OLL) are chronic inflammatory diseases whose symptoms can impair patient's quality of life (QoL). Psychological factors seem to play an important role in these diseases. This study aimed to determine the impact of oral health and anxiety levels on the QoL of patients with OLP and OLL.

PATIENTS AND METHODS

This was a cross-sectional study composed of OLP and OLL patients and a control group matched by age and sex with no autoimmune/inflammatory or malignant oral lesions. Anxiety levels and oral health impact on QoL were assessed using the Hamilton Anxiety Scale (HAM-A) and the Oral Health Impact Profile-14 (OHIP-14), respectively. The instruments were filled through personal interview before starting the treatment for oral lesions.

RESULTS

A total of 87 patients diagnosed with OLP (n = 45) and OLL (n = 42), and 87 controls were included in the study. Statistical differences were observed for the psychic and somatic anxiety dimensions between severities of diseases. Patients with OLP or OLL had higher scores for the OHIP-14 dimensions physiological discomfort and social limitation compared with controls. In addition, higher scores for physical pain, physical disability, social disability, and handicap were detected among patients with greater severity.

CONCLUSION

Greater severity of OLP and OLL seems to be associated with increased levels of anxiety, higher scores of oral health impact profile, and decreased QoL.

CLINICAL RELEVANCE

Patients with severe OLP/OLL may benefit from additional therapeutic treatments, such as psychological and/or psychiatric management, concomitant to treatment specific to oral lesions.

Oxidative Stress and Oral Mucosal Diseases: An Overview

BACKGROUND

Reactive oxygen species (ROS) and free radicals are physiologically produced during cellular metabolism. When their balance is disrupted in favor of ROS, a condition called oxidative stress occurs. Oxidative stress represents a widespread phenomenon involved in several pathological conditions. The aim of the present review was to report current knowledge on oxidative stress related to oral mucosal diseases.

MATERIALS AND METHODS

Articles from 2000 to 2018 were selected for relevance, validity and quality, from results obtained in PubMed, MEDLINE and Google Scholar using the following search terms: oxidative stress and oral lichen, oral pemphigus, aphthous stomatitis, oral leukoplakia, oral cancer, oral squamous cell carcinoma and oral carcinoma. All articles were independently screened for eligibility by the authors.

RESULTS

This narrative review integrates extensive information from all relevant published studies focusing on oxidative stress in oral mucosal diseases. We outline the pathogenetic function of oxidative stress in the most frequent inflammatory, potentially malignant and malignant diseases of the oral mucosa and provide detailed findings from human research.

CONCLUSION

Although variability in findings between individual studies exists, it justifies the conclusion that oxidative stress is a significant process in the oral mucosal diseases pathogenesis.

Relationship of infiltrating intraepithelial T lymphocytes in the diagnosis of oral lichen planus versus oral epithelial dysplasia: a pilot study

OBJECTIVE

The aim of this study was to identify the type and distribution of CD4+ and CD8+ T lymphocytes in oral mucosal specimens to potentially distinguish between underlying alterations or patterns in oral epithelial dysplasia and oral lichen planus.

STUDY DESIGN

This pilot study included 10 archived tissue samples that were received at the University of North Carolina Oral and Maxillofacial Pathology Laboratory and were diagnosed as oral lichen planus and moderate to severe epithelial dysplasia. Dual staining with CD4 and CD8 antibodies was carried out on each case. Slides were scanned in the Aperio ScanScope FL (Leica Biosystems, Wetzlar, Germany) and archived. Histomorphometric analysis was performed to detect inflammatory cells expressing CD4 and CD8 biomarkers in the epithelial and connective tissue regions.

RESULTS

No differences were found in the amount and ratio of CD4+/CD8+ lymphocytes among the 3 groups analyzed; however, the intraepithelial CD8+ lymphocyte distribution was strikingly different between lichen planus and moderate to severe epithelial dysplasia.

CONCLUSIONS

The localization of CD8+ cells can be potentially useful as an adjunctive diagnostic procedure to distinguish oral epithelial dysplasia from other inflammatory entities, such as lichen planus.

Oral lichen-planus-associated fibroblasts acquire myofibroblast characteristics and secrete pro-inflammatory cytokines in response to Porphyromonas gingivalis lipopolysaccharide stimulation

Background

Oral lichen planus (OLP) is a chronic inflammatory oral mucosal disease in which comprehensive inflammation-related cytokines are involved. These cytokines are commonly produced by immune cells and specific nonimmune cells including keratinocytes, endothelial cells and fibroblasts. This raises the question of whether fibroblasts in OLP lesions contribute to the inflammatory process upon inflammatory simulation.

Methods

Primary cultured Oral lichen-planus-associated fibroblasts (OLP AFs, n = 5) and normal buccal mucosal fibroblasts (NFs, n = 5) were examined by immunohistochemistry, Western blotting and reverse transcription-polymerase chain reactions (RT-PCR). Various inflammatory mediators were evaluated with a multiplex assay. Differences among groups were assessed using a Student’s test or repeated measures one-way ANOVA, as appropriate.

Results

OLP AFs express significantly higher levels of α-smooth muscle actin (α-SMA) than NFs, indicating the presence of myofibroblasts. Myofibroblasts secrete Interleukin (IL)-6, IL-8, and tumor necrosis factor-α (TNF-α) in response to Porphyromonas gingivalis lipopolysaccharide (pg. LPS).

Conclusion

OLP AFs demonstrated α-SMA expression and secreted pro-inflammatory cytokines in response to pg. LPS stimulation.

Electronic supplementary material

The online version of this article (10.1186/s12903-018-0656-6) contains supplementary material, which is available to authorized users.

Role of miR-155 in immune regulation and its relevance in oral lichen planus

Oral lichen planus (OLP) is a chronic mucosal inflammatory disease. The World Health Organization has described it as a potentially malignant condition. The pathogenesis of OLP remains to be fully elucidated, but extensive evidence suggests that immunologic and inflammatory factors have important roles. MicroRNAs (miRs), which are small non-coding RNAs, have been reported to be involved in OLP. In particular, miR-155 is significantly upregulated in patients with OLP. miR-155 has numerous functions and is closely linked to inflammation and immune system regulation. However, in-depth studies of the mechanisms via which miR-155 is involved in OLP are currently insufficient. Considering the close association between miR-155 and immune regulation as well as the importance of immune factors in OLP, the role of miR-155 in the immune system was herein summarized with a focus on OLP. The present review provides a basis for further study of the molecular mechanisms underlying the development and progression of OLP.

Dietary Fatty Acids and Other Nutrients in Relation to Inflammation and Particularly to Oral Mucosa Inflammation. A Literature Review

Oral mucosa is site of inflammatory process development. When they are chronic, they provide a microenvironment based on cytokines and inflammatory mediators that contribute to cancer initiation, progression, invasion, and metastasis. Certain dietary fatty acids (FAs) have immunomodulatory, inflammatory, and antiinflammatory effects. This review examined the literature on inflammation, mainly referred to the oral mucosa, and its association with dietary FAs and other nutrients. A Pubmed search of studies published in English until June 2018 was carried out. N-3 FAs have shown immunomodulatory and antiinflammatory activity in certain human diseases. These FAs and their mediators may inhibit inflammation, angiogenesis, and cancer via multiple mechanisms. Studies on cellular models of murine and human intestinal mucosa indicate association between dietary n-3 FA intake and the inflammatory state of mucosa membranes. Nevertheless scarce information on the association between dietary FAs and oral inflammation could be found. Based on the evidence, we hypothesize that n-3 FAs reduce the oral mucosa inflammation thus decreasing the risk of developing precancerous lesions and cancer. Molecular and clinical studies referred to this topic should be carried out as a contribution to the oral cancer prevention.

Black pepper and its bioactive constituent piperine: promising therapeutic strategies for oral lichen planus

Oral lichen planus (OLP) is a common T cell-mediated chronic inflammatory disease with malignant potential and unclear etiology. The present study suggests that antigen-specific mechanisms in which dentritic cells, T lymphocytes and NF-κB signaling pathway play critical roles, are involved in the pathogenesis of OLP. Additionally, it has been indicated that altered expression of cyclooxygenase 2 (COX-2) and imbalanced oxidant-antioxidant status as well as psychological issue may act as promoters to the development of OLP. Therapies for OLP are primarily aimed to control symptoms and a specific cure is not yet available. Black pepper and its principle bioactive compound piperine have been reported to possess remarkable pharmacological activities. Not only has piperine been evidenced to exhibit repressive effects on the maturation of dentritic cells, the proliferation, activation and function of T lymphocytes as well as the NF-κB signaling pathway, but also to suppress the overproduction of COX-2 and weaken the oxidative stress. Furthermore, piperine might be a possible agent for alleviating psychological disorders and preventing carcinogenesis. Given all these into consideration, piperine may be a novel and effective therapeutic strategy for OLP.

Efficacy of photobiomodulation on oral lichen planus: a protocol study for a double-blind, randomised controlled clinical trial

INTRODUCTION

Oral lichen planus (OLP) is an idiopathic chronic mucocutaneous disease with a wide range of clinical manifestations, including white reticular patches, erosive/ulcerative and atrophic lesions, both associated with intense symptomatology. Topical corticosteroids are commonly used as standard therapy. However, patients frequently present relapses after the discontinuation of treatment as well as developing resistance to corticosteroid therapy. Photobiomodulation (PBM) has been shown to be a potential therapeutic tool to treat inflammatory disorders, including OLP. The aim of this study was to compare the efficacy of PBM (660 nm) with corticosteroid therapy with clobetasol propionate 0.05% for the treatment of OLP.

METHODS AND ANALYSIS

Forty-four patients with symptomatic and histopathological diagnosis of OLP will be randomised into two experimental groups in a double-blind manner: control group (n=22): clobetasol propionate 0.05%+placebo PBM, and experimental group (n=22): PBM (λ=660 nm, power 100 mW, radiant exposure: 177 J/cm² and 0.5J per point)+placebo gel. Laser will be applied 2×/week for 1 month and clobetasol propionate three times a day for 30 days and the same for placebo treatments. The primary variable (pain) and the secondary variables (clinical score, evaluation of functional scores, clinical resolution, OLP recurrence, quality of life and anxiety and depression) will be evaluated at the baseline, once a week during treatment (depending on the variables) and after 30 days and 60 days of follow-up. Pain will be evaluated using visual analogue scale and clinical characteristics will be scored using the Thongprasom Index. The quality of life and anxiety and depression will be evaluated by Oral Health Impact Profile-14 questionnaire and by Hospital Anxiety and Depression Scale for anxiety scale, respectively. The serum and salivary levels of interleukin (IL)-6, IL-10, IL-1β, INF-γ and tumour necrosis factor-α will be evaluated by ELISA at baseline and at the end of treatment.

ETHICS AND DISSEMINATION

This protocol was approved (#2.375.410) by the Nove de Julho University (UNINOVE) Research Ethics Committee. The data gathered using this protocol will be published in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

NCT03320460.

Epstein-Barr virus is not detected in mucosal lichen planus

Background

Lichen planus (LP) is a chronic inflammatory, immunological, mucocutaneous disease can affect skin, genital and oral mucosa. Oral lichen planus (OLP) is the most common noninfectious, chronic inflammatory oral disease affecting 1-2% of the general adult population. World Health Organization (WHO) classifies OLP as a potentially malignant disorder. Epstein Barr virus or human herpesvirus-4, is a member of the herpes virus family and one of the most ubiquitous viruses known to human, infecting approximately 90% of the world’s adult population. The virus often infects B lymphocytes resulting in a wide spectrum of mucocutaneous and systemic diseases, ranging from mild lesions to aggressive malignancies. The aim of this study was to investigate expression of the EBV encoded RNAs EBER1 and EBER2 in oral and genital lichen planus and compare results with normal tissues in situ hybridization which is considered the golden standard for detection of EBER.

Material and Methods

A total of 68 biopsies, 25 oral LP, 26 genital LP, 10 oral controls and finally 7 genital controls were analysed using situ hybridization.

Results

All samples had RNA as shown by the control slide, whereas no case contained neither EBER1 nor EBER2.

Conclusions

Based on results from our study EBV is not involved in aetiology of lichen planus.

Key words:Mucosal lichen planus, Epstein - Barr virus.

Chicken or the Egg: Microbial Alterations in Biopsy Samples of Patients with Oral Potentially Malignant Disorders

Oral carcinogenesis often leads to the alteration of the microbiota at the site of the tumor, but data are scarce regarding the microbial communities of oral potentially malignant disorders (OPMDs). Punch biopsies were taken from healthy and non-healthy mucosa of OPMD patients to analyze the microbiome using metagenome sequencing. In healthy oral mucosa biopsies the bacterial phyla Firmicutes, Fusobacteria, Proteobacteria, Actinobacteria and Bacteroidetes were detected by Ion Torrent sequencing. The same phyla as well as the phyla Fibrobacteres and Spirochaetes were present in the OPMD biopsies. On the species level, there were 10 bacterial species unique to the healthy tissue and 35 species unique to the OPMD lesions whereas eight species were detected in both samples. We observed that the relative abundance of Streptococcus mitis decreased in the OPMD lesions compared to the uninvolved tissue. In contrast, the relative abundance of Fusobacterium nucleatum, implicated in carcinogenesis, was elevated in OPMD. We detected markedly increased bacterial diversity in the OPMD lesions compared to the healthy oral mucosa. The ratio of S. mitis and F. nucleatum are characteristically altered in the OPMD lesions compared to the healthy mucosa.

MicroRNA-17-92 cluster promotes the proliferation and the chemokine production of keratinocytes: implication for the pathogenesis of psoriasis

Keratinocytes are the main epidermal cell type that constitutes the skin barrier against environmental damages, which emphasizes the balance between the growth and the death of keratinocytes in maintaining skin homeostasis. Aberrant proliferation of keratinocytes and the secretion of inflammatory factors from keratinocytes are related to the formation of chronic inflammatory skin diseases like psoriasis. MicroRNA-17-92 (miRNA-17-92 or miR-17-92) is a miRNA cluster that regulates cell growth and immunity, but the role of miR-17-92 cluster in keratinocytes and its relation to skin diseases have not been well investigated. In the present study, we initially found that miR-17-92 cluster promoted the proliferation and the cell-cycle progression of keratinocytes via suppressing cyclin-dependent kinase inhibitor 2B (CDKN2B). Furthermore, miR-17-92 cluster facilitated the secretion of C-X-C motif chemokine ligand 9 (CXCL9) and C-X-C motif chemokine ligand 10 (CXCL10) from keratinocytes by inhibiting suppressor of cytokine signaling 1 (SOCS1), which enhanced the chemotaxis for T lymphocytes formed by keratinocytes. In addition, we detected increased expression of miR-17-92 cluster in psoriatic lesions and the level of lesional miR-17-92 cluster was positively correlated with the disease severity in psoriasis patients. At last, miR-17-92 cluster was increased in keratinocytes by cytokines through the activation of signal transducers and activators of transcription 1 (STAT1) signaling pathway. Our findings demonstrate that cytokine-induced overexpression of miR-17-92 cluster can promote the proliferation and the immune function of keratinocytes, and thus may contribute to the development of inflammatory skin diseases like psoriasis, which implicates miR-17-92 cluster as a potential therapeutic target for psoriasis and other skin diseases with similar inflammatory pathogenesis.

Salivary proteomics in lichen planus: A relationship with pathogenesis?

OBJECTIVES

Oral lichen planus is a chronic, T-cell-mediated, inflammatory disease that affects the oral cavity. The oral lichen planus pathogenesis is still unclear, however, the main evidence is that the mechanisms of activation of different T lymphocyte pathway induce apoptosis with an increase in Th1 and Th17 subtypes cells, triggered by the release of cytokines. This study analysed saliva proteomics to identify protein markers that might be involved in the pathogenesis and development of the disease.

MATERIAL AND METHODS

Proteins differentially expressed by oral lichen planus and healthy controls were screened using mass spectrometry; the proteins found in oral lichen planus were subjected to bioinformatics analysis, including gene ontology and string networks analysis. The multiplex analysis validation allowed the correlation between the proteins identified and the involved cytokines in Th17 response.

RESULTS

One hundred and eight proteins were identified in oral lichen planus, of which 17 proteins showed a high interaction between them and indicated an association with the disease. Expression of these proteins was correlated with the triggering of cytokines, more specifically the Th17 cells.

CONCLUSION

Proteins, such as S100A8, S100A9, haptoglobin, can trigger cytokines and might be associated with a pathological function and antioxidant activities in oral lichen planus.

How general dentists could manage a patient with oral lichen planus

BACKGROUND

The literature hardly contains information on how patients suffering from oral lichen planus could be managed by dentists.

MATERIAL AND METHODS

Based on the limited available literature and particularly on the long-term clinical and histopathological experience of one of the authors, suggestions on how dentists could manage patients with oral lichen planus have been put forward.

RESULTS

In most cases, the dentist should be able to establish a correct diagnosis. Occasionally, the dentist may call upon a specialist, usually an oral medicine specialist or an oral and maxillofacial surgeon for confirmation of the diagnosis, possibly a biopsy procedure, and management of the patient in case of severe symptoms. Proper patient information is of utmost importance in the management.

CONCLUSIONS

General dentists can be expected to manage the majority of patients with oral lichen planus. Some patients may need to be referred for diagnostic purposes to a specialist; this is also the case for the rare patient with severe symptoms, possibly requiring systemic treatment.

Efficacy of photodynamic therapy in the treatment of symptomatic oral lichen planus: A systematic review

BACKGROUND

The aim of this study was to systematically review the efficacy of photodynamic therapy (PDT) in the management of symptomatic oral lichen planus (OLP).

MATERIALS AND METHODS

PubMed/MEDLINE, Scopus, and ISI Web of knowledge were searched until July 2017, using the following keywords: OLP, erosive lichen planus, lichen planus, and PDT.

RESULTS

Five clinical studies were included. The risk of bias was considered high in 4 studies and moderate in 1 study. The efficacy of PDT was compared with topical corticosteroids in all included studies. Laser wavelengths, duration of irradiation, and power density ranged between 420-660 nm, 30 seconds to 10 minutes, and 10-500 mW/cm² , respectively. All studies reported PDT to be effective in the management of symptomatic OLP. Two studies reported PDT to be as effective as corticosteroids, 1 study reported a better efficacy of PDT compared to corticosteroids, whereas 2 studies found PDT to be inferior to corticosteroids.

CONCLUSIONS

The limited available evidence suggests that PDT is an effective treatment option for the management of OLP. However, due to the limited number of studies included in this review and heterogeneity among these studies, more well-designed clinical trials with adequate sample sizes are highly warranted.

Biomolecules in the treatment of lichen planus refractory to corticosteroid therapy: Clinical and histopathological assessment

BACKGROUND

Local deficit of several biomolecules have been described in oral lichen planus (OLP). Such a deficit impairs cellular functions and cell-matrix communication.

PURPOSE

Assess the efficacy of the local application of autologous biomolecules in the treatment of erosive OLP.

MATERIALS AND METHODS

In this study, the use of plasma rich in growth factors (PRGF) as a source of blood-derived and autologous growth factors and proteins were tested in erosive oral lichen planus refractory to corticosteroids. Histopathological features of the disease were also analysed at the time of diagnosis. Clinical data were the number of recurrences and achievement of pain reduction and complete healing of the lesions. A total of 10 patients with erosive OLP refractory to treatment by corticosteroids were included in the study. All patients were females with a mean age of 48±12years.

RESULTS

A complete remission of the disease was achieved after one infiltration of PRGF in 8 patients. Only 2 patients required a total of 2 infiltrations to heal. Hydropic degeneration of the epithelium basal layer, band-like subepithelial lymphocytic infiltration and fibrin deposits in the epithelium were observed in all patients. Interestingly plasma cells were present in 2 patients. All patients presenting plasma cells healed after only one PRGF infiltration. However, 2 patients out of 6 (no plasma cells) required 2 infiltrations.

CONCLUSIONS

The local administration of autologous local factors could overcome the deficit of biomolecular clues and thus improve cell functions and restore cell-matrix communication.

Porphyromonas gingivalis lipopolysaccharide induces over production of CC chemokine ligand 2 via toll-like receptor-4 in oral lichen planus

BACKGROUND

We recently reported that the CC chemokine ligand 2 (CCL2)-CC receptor 2 (CCR2) axis was involved in the pathogenesis of oral lichen planus (OLP). However, the exact mechanism for the high expression of CCL2 in OLP specimens is not clear. Therefore, this study was designed to investigate the potential role of the toll-like receptor 4 (TLR-4) pathway in overproduction of CCL2 in OLP lesions.

METHODS

Immunohistochemical staining and real-time RT-PCR were used to detect TLR-4, CCL2, and CCR2 expression in OLP lesions. Then, gingival epithelial cells from OLP lesions were established and treated with Porphyromonas gingivalis (P. gingivalis) lipopolysaccharide (LPS). CCL2 expression in epithelial cells was determined by Western blotting and real-time RT-PCR. In some experiments, TAK-242, a specific inhibitor of TLR-4, was used to block the TLR-4 pathway before cells were stimulated with LPS.

RESULTS

We found that TLR-4 was significantly increased in the epithelium of OLP specimens, compared with controls. Moreover, LPS can induce the over production of CCL2 in epithelial cells of OLP, in vitro. TAK-242 effectively eliminated the increase in CCL2 expression induced by LPS by blocking the TLR-4/NF-κB pathway. In addition, we again confirmed that expression of CCL2 and CCR2 was increased in OLP specimens.

CONCLUSION

Increased TLR-4 expression contributes to the upregulated expression of CCL2 in the epithelium of OLP lesions, which suggests that oral bacteria participate in the pathogenesis of OLP via the TLR-4 pathway.

Differential expression of STAT-3 in subtypes of oral lichen planus: a preliminary study

OBJECTIVE

This study aimed to examine the expression of signaling transduction proteins and their possible correlation with different clinical subtypes of oral lichen planus (OLP).

STUDY DESIGN

We examined the immunoexpression and phosphorylation status of 21 signaling transduction proteins of OLP (n = 10) and normal groups (n = 8) using PathScan analysis. Using immunohistochemistry, we detected expression of STAT-3 and p38 MAPK in tissues of OLP (n = 40) and normal controls (n = 10).

RESULTS

PathScan analysis showed that STAT-3 (Ser727) expression in normal control (N), reticular OLP (R-OLP) and erosive OLP (E-OLP) group was gradually elevated (R-OLP vs N, P = .001; E-OLP vs N, P < .001; E-OLP vs R-OLP, P = .002). Immunohistochemistry showed that STAT-3 expression in the epithelium of normal control, reticular OLP and erosive OLP was consistent with PathScan analysis (R-OLP vs N, P < .001; E-OLP vs N, P < .001; E-OLP vs R-OLP, P = .036). Both PathScan (P = .012) and immunohistochemistry (P < .001) showed that, p38 MAPK expression was significantly higher in OLP compared with normal controls. However, a significant difference was not seen between the reticular OLP and erosive OLP groups.

CONCLUSIONS

Our results indicate that STAT-3 may be involved in OLP development and progression and account for different clinical manifestations.

Does the corticotropin-releasing hormone system play a role in the pathogenesis of lichen planus?

Introduction

Lichen planus (LP) is a chronic inflammatory disease, where the psychogenic factors seem to play an important role in the pathogenesis.

Aim

To determine the expression of corticotropin-releasing hormone (CRH) receptor type 1 (CRH-R1) in LP.

Material and methods

Thirty-two LP patients and 17 age/gender-matched controls were included in the study. Detailed information about the disease and body surface area (BSA) covered by the lesions was recorded. Immunohistochemically, the expression of CRH-R1 was stained in the lesional skin of patients with LP and in the control group.

Results

The comparison of CRH-R1 expression showed a statistically significant difference between LP patients and the controls (p < 0.05). Additionally, we did not observe any correlation between BSA and staining intensity in LP patients.

Conclusions

Our study showed an increase in CRH-R1 expression in LP lesions. These results support the participation of the cutaneous CRH/CRH-R1 system in the pathogenesis of LP skin lesions.

Mucin 5B in saliva and serum of patients with oral lichen planus

Oral lichen planus (OLP) is among the most common oral diseases. Its etiopathogenesis has yet to be clearly identified. OLP patients complain of mouth dryness. This study aimed to assess the level of Mucin 5B in OLP patients with xerostomia. This study was conducted on 30 OLP patients and 30 healthy individuals. In addition to patient complaint of mouth dryness, xerostomia was assessed by tongue blade and lipstick tests. Stimulated and unstimulated saliva were collected in plastic vials by spitting method. Level of Mucin 5B was measured by ELISA. Unstimulated saliva flow was significantly lower in OLP patients (P = 0.0001). Stimulated saliva flow was not significantly different between the two groups (P > 0.05). Level of Mucin 5B in unstimulated saliva was significantly lower in OLP group (P = 0.0001) while it was not significantly different in stimulated saliva of the two groups (P > 0.05). Level of Mucin 5B was significantly higher in serum of OLP patients (P = 0.016). Both saliva flow and level of Mucin 5B decrease in OLP patients. Since Mucin 5B is effective for wetting and lubrication of the oral cavity, this result can suggest a possible reason for mouth dryness in OLP patients.

No detection of Merkel cell polyomavirus in oral lichen planus: Results of a preliminary study in a French cohort of patients

Oral lichen planus (OLP) is a chronic inflammatory disease considered as a CD8+ T lymphocyte-mediated autoimmune reaction, which may be triggered by undetermined virus. Recent reports have described the detection of Merkel cell polyomavirus (MCPyV) DNA in oral samples from healthy patients and in patients with different forms of oral cancers. We therefore investigated in a prospective way whether MCPyV was detectable in oral lesions of patients with active OLP. Our preliminary results do not support the hypothesis that OLP may be triggered by MCPyV infection. Further studies are needed to evaluate the involvement of other human polyomaviruses in OLP pathogenesis.

A genome-wide association scan of biological processes involved in oral lichen planus and oral squamous cell carcinoma

BACKGROUND

In this study, the molecular mechanisms underlying malignant transformation from oral lichen planus (OLP) to oral squamous cell carcinoma (OSCC) were examined.

METHODS

High-throughput sequencing of long noncoding RNAs (lncRNAs) and mRNAs of normal subjects and patients with OLP and OSCC was conducted. RNA-seq reads were mapped, lncRNA and mRNA transcripts were assembled, and expression levels were estimated. The targets of lncRNAs were predicted. Finally, Gene Ontology (GO) and pathway enrichment analyses of differentially expressed genes (DEGs) and lncRNA targets were performed.

RESULTS

High-quality sequence data were generated and the mapping ratios for OSCC, normal, and OLP samples were high. In total, 820, 656, and 582 DEGs were obtained from OPL vs. normal, OSCC vs. normal, and OSCC vs. OPL, respectively. A total of 1721 known lncRNAs and 133 predicted lncRNAs and targets were obtained. Keratinization was significantly enriched by OSCC-related DEGs, but not OPL-related DEGs. The pathway of olfactory transduction was enriched by OPL- and OSCC-related DEGs. Defense response to virus and viral carcinogenesis were enriched by DEGs and lncRNA targets in all comparisons. GO term related to the metabolic process was enriched by lncRNA targets in the OPL vs normal comparison, and antigen processing and presentation via MHC class I was significantly enriched by lncRNA targets in the other 2 comparisons.

CONCLUSION

Keratinization and MHC class I antigen processing and presentation were activated during the malignant transformation from OLP to OSCC. Additionally, the olfactory transduction pathway may be important for OSCC.

Genome-Wide Association Study Identifies Risk Variants for Lichen Planus in Patients With Hepatitis C Virus Infection

BACKGROUND & AIMS

There is a close relationship between hepatitis C virus (HCV) infection and lichen planus, a chronic inflammatory mucocutaneous disease. We performed a genome-wide association study (GWAS) to identify genetic variants associated with HCV-related lichen planus.

METHODS

We conducted a GWAS of 261 patients with HCV infection treated at a tertiary medical center in Japan from October 2007 through January 2013; a total of 71 had lichen planus and 190 had normal oral mucosa. We validated our findings in a GWAS of 38 patients with HCV-associated lichen planus and 7 HCV-infected patients with normal oral mucosa treated at a medical center in Italy.

RESULTS

Single-nucleotide polymorphisms in NRP2 (rs884000) and IGFBP4 (rs538399) were associated with risk of HCV-associated lichen planus (P < 1 × 10^-4). We also found an association between a single-nucleotide polymorphism in the HLA-DR/DQ genes (rs9461799) and susceptibility to HCV-associated lichen planus. The odds ratios for the minor alleles of rs884000, rs538399, and rs9461799 were 3.25 (95% confidence interval, 1.95-5.41), 0.40 (95% confidence interval, 0.25-0.63), and 2.15 (95% confidence interval, 1.41-3.28), respectively.

CONCLUSIONS

In a GWAS of Japanese patients with HCV infection, we replicated associations between previously reported polymorphisms in HLA class II genes and risk for lichen planus. We also identified single-nucleotide polymorphisms in NRP2 and IGFBP4 loci that increase and reduce risk of lichen planus, respectively. These genetic variants might be used to identify patients with HCV infection who are at risk for lichen planus.

Increased salivary aldehyde dehydrogenase 1 in non-reticular oral lichen planus

Background

Oral lichen planus is a potentially malignant disorder. One of the malignant transformation markers is cancer stem cells. One of the proposed marker for the detection of cancer stem cells's in head and neck cancer is aldehyde dehydrogenase. Recently it is shown that aldehyde dehydrogenase 1 expression in tissue samples is associated with oral lichen planus malignant transformation.

Objective

This study evaluates salivary aldehyde dehydrogenase 1 in oral lichen planus.

Method

Thirty patients and 30 age and sex-matched healthy volunteers were recruited. Oral lichen planus was diagnosed based on the modified World Health Organization criteria. Subjects in the case group were divided into reticular and non-reticular forms. Unstimulated salivary samples were collected at 10-12 AM. Saliva concentrations of aldehyde dehydrogenase 1 were measured by ELISA.

Results

The differences between aldehyde dehydrogenase levels in the oral lichen planus group compared with the control group were not significant but aldehyde dehydrogenase in non-reticular oral lichen planus was significantly higher than that of the reticular form.

Limitations of the study

This is a cross-sectional study, thus longitudinal studies in oral lichen planus may present similar or different results.

Conclusions

The mechanism of malignant transformation in oral lichen planus is not defined. Previous analyses revealed that the aldehyde dehydrogenase 1 expression is significantly correlated with increased risk of transformation. This finding is consistent with our results because in the erosive and ulcerative forms of oral lichen planus, which have an increased risk of transformation, salivary aldehyde dehydrogenase 1 was overexpressed. A higher salivary aldehyde dehydrogenase level in non-reticular oral lichen planus can be a defensive mechanism against higher oxidative stress in these groups. Aldehyde dehydrogenase may be one of the malignant transformation markers in oral lichen planus. Further studies are needed for introducing aldehyde dehydrogenase as a prognostic indicator in certain lesions.

The use of topical corticosteroides in the treatment of oral lichen planus in Spain: A national survey

Background

Explore the treatment of oral lichen planus with topical corticosteroids by the healthcare professionals in Spain.

Material and Methods

A questionnaire targeted health professionals who treat OLP, in particular maxillofacial surgeons, dermatologist and dentist. The dissemination of the questionnaires was conducted through professional associations and dental and medical societies. The questionnaire was previously evaluated by means of a cognitive pre-test procedure to ensure that the questions were opportune and appropriate, understandable and acceptable among the professionals.

Results

Of the 890 questionnaires sent a total of 190 questionnaires were answered by 90 dentists, 60 dermatol gists and 40 by maxillofacial surgeons. The most frequent treatment was 0.1% triamcinolone acetonide in orobase 3 times a day. The effectiveness of the topical corticosteroid treatment was 6.68 (SD= 2.26) in a scale of 1 to 10. The 30% of the dentists and 10.49% of maxillofacial surgeons combined treatment with other drugs. The most frequent one (80%) was nystatin (100,000 IU per millimetre). Dermatologists did not use other treatments in combination with corticosteroids.

Conclusions

There is a need for national guidelines in treatment for oral lichen planus (treatment criteria, drug, dose, treatment time and method of application of corticosteroid) that can be applied by all professionals who treat this disease.

Key words:Oral lichen planus, topical corticosteroids, triamcinolone acetonide, questionnaire.

Identifying the association between interleukin-6 and lichen planus: A meta-analysis

Numerous studies have examined the association between interleukin-6 and the pathogenesis of lichen planus (LP)/oral LP (OLP) in various populations; however, there is a lack of systematic analysis. The aim of the present study was to assess this association more precisely, thus a meta-analysis was performed. Case-control studies, which were published up to December 2015, were obtained from PubMed, Embase and the China National Knowledge Infrastructure databases. Data were extracted and pooled mean differences (MDs) with 95% confidence intervals (CIs) were calculated. Ultimately, eight studies were included, comprising 299 LP/OLP cases and 231 control subjects. Overall, the pooled MD for IL-6 was 16.24 (95% CI, 9.84-22.64; I²=99% for heterogeneity). In the subgroup analysis by ethnicity, a significant increase of the IL-6 expression level was identified among Asian individuals, but not in Caucasian individuals. Thus, IL-6 may be significant in the pathogenesis of LP. However, further studies are required to validate these associations.

Immunohistochemical detection of Mycoplasma salivarium in oral lichen planus tissue

BACKGROUND

Oral lichen planus (OLP) is a T-cell-mediated inflammatory disease; however, its exact etiology is unknown. Hyperkeratosis is often observed in OLP lesions. Previous studies have revealed the localization of Mycoplasma salivarium in the epithelial cells of oral leukoplakia with hyperkeratosis. Herein, we investigated the presence of M. salivarium in OLP tissue by immunohistochemistry to determine the causative factor of OLP.

METHODS

Forty-one formalin-fixed, paraffin-embedded samples obtained from 31 patients with OLP were examined. Ten samples of normal-appearing oral mucosa were used as controls. Immunohistochemistry (IHC) was performed using anti-M. salivarium monoclonal antibodies.

RESULTS AND CONCLUSIONS

Mycoplasma salivarium was detected in the epithelium and lymphocyte infiltrate area in 24 of 41 OLP samples (58.5%). The bacteria were intracellularly localized in epithelial cells, while it was unclear whether they were also localized in lymphocyte cells or in the extracellular spaces among the lymphocytes in the subepithelial lymphocyte infiltrate area. Little or no staining was observed in the epithelium in the normal-appearing mucosa samples. Sawtooth rete ridge formation was observed in 21 OLP samples (51.2%), and a significant positive correlation between sawtooth rete ridge formation and IHC positivity was demonstrated. However, the role of M. salivarium in the epithelium and lamina propria of OLP tissue remains unknown.

Clinical profile of 108 cases of oral lichen planus

Oral lichen planus (OLP) is a T cell-mediated chronic inflammatory disease with a varied clinical presentation. The present clinical study was carried out to clarify the demographic and clinical profile of 108 patients with OLP. The patients were identified based on the diagnostic criteria proposed by van der Meij et al. (2003) modified from the WHO (1978) clinical and histopathologic definition of OLP. Information such as age, gender, clinical presentation and type of OLP, site of involvement, symptoms, extraoral involvement, history of systemic disease, familial occurrence and risk factors like chewing and smoking tobacco, chewing betel quid, alcohol consumption were obtained. Mean age of OLP patients was 45.4 years, and among the identified patients, 70.4% were females. The most frequent clinical type was the reticular form (80.6%). The OLP lesions were symptomatic in 77.8% of the patients. The buccal mucosa was the most affected site (87.9%) and multiple oral lesions were observed in 41.7% of the patients. Among the OLP patients, 36.1% and 4.7% reported chewing tobacco and smoking tobacco, respectively. Histopathologically, epithelial dysplasia was seen in two cases. The chronic nature of OLP warrants patient education, psychological support and long-term follow up. (J Oral Sci 58, 43-47, 2016).