Oral Lichen Planus

Role of Oral Microbiota Dysbiosis in the Development and Progression of Oral Lichen Planus

Oral lichen planus (OLP) is a chronic inflammatory autoimmune disease of the oral cavity with malignant potential affecting 1.01% of the worldwide population. The clinical patterns of this oral disorder, characterized by relapses and remissions of the lesions, appear on buccal, lingual, gingival, and labial mucosa causing a significant reduction in the quality of life. Currently, there are no specific treatments for this disease, and the available therapies with topical and systemic corticosteroids only reduce symptoms. Although the etiopathogenesis of this pathological condition has not been completely understood yet, several exogenous and endogenous risk factors have been proposed over the years. The present review article summarized the underlying mechanisms of action involved in the onset of OLP and the most well-known triggering factors. According to the current data, oral microbiota dysbiosis could represent a potential diagnostic biomarker for OLP. However, further studies should be undertaken to validate their use in clinical practice, as well as to provide a better understanding of mechanisms of action and develop novel effective intervention strategies against OLP.

Lichenoid Lesions of the Oral Mucosa

Lichenoid lesions involving the oral cavity present with an array of complex clinical manifestations and etiologies. The etiology ranges from local factors, systemic entities, and even autoimmune conditions. Several different types of lichenoid lesions may affect the oral cavity, and it is imperative that these are correctly diagnosed to ensure effective patient care. Lichenoid lesions such as chronic ulcerative stomatitis prove to be challenging as these are recalcitrant, present with overlapping features, require unique treatment and patients suffer a long time if not promptly diagnosed.

Outcome and long-term treatment protocol for topical tacrolimus in oral lichen planus

BACKGROUND AND OBJECTIVE

Topical tacrolimus has been shown to be beneficial in the treatment of oral lichen planus (OLP). However, long-term effects and its optimal application protocol with gradual reduction have not been studied. Accordingly, we analysed the clinical response of OLP to tacrolimus in our daily clinical practice with a focus on the optimal long-term therapeutic scheme.

METHODS

Retrospective analysis of all consecutive patients diagnosed with OLP and treated with topical tacrolimus (0.03% oral rinse) in a clinical setting between 2015 and 2020. The objective clinical response was measured by a 4-point scale (complete remission, major remission, partial remission and no response), and subjective impairment by a 3-point scale (severe, moderate and none).

RESULTS

Fifty-seven patients (74% women; median age: 66 years) were included. Fifty-six (98%) patients had prior treatment with topical steroids. After introduction of tacrolimus, objective remission (major or complete) was reached by 28%, 62%, 87% and 97% of patients after 3, 6, 12 and 24 months respectively. Subjective remission was reported by 16%, 48%, 69% and 83% after 3, 6, 12 and 24 months of treatment respectively. The treatment frequency could be gradually reduced from initially twice daily to once daily or less in 28%, 61%, 78% and 87% after 3, 6, 12 and 24 months respectively; 41% of patients completely suspended the treatment at one point, but 67% of them experienced a relapse after a median time of 3.3 months. Four patients (7%) developed a squamous cell carcinoma (SCC) during the observation period. Otherwise, there were only few and minor side-effects.

CONCLUSION

Topical tacrolimus can be an effective second-line therapy for OLP refractory to potent topical corticosteroids. The therapy frequency can often be reduced during the maintenance period. Both signs of clinical activity and subjective impairment should guide therapy. Regular follow-up is necessary to recognize possible SCC.

Oral lichenoid lesion in association with chemotherapy treatment for non-Hodgkin lymphoma or lichen planus? Review of the literature and report of two challenging cases

Background

The diagnosis of oral lichenoid lesions (OLL) remains a challenge for clinicians and pathologists. Although, in many cases, OLL cannot be clinically and histopathologically distinguishable from oral lichen planus (OLP), one important difference between these lesions is that OLL has an identifiable etiological factor, e.g. medication, restorative material, and food allergy. The list of drugs that can cause OLL is extensive and includes anti-inflammatory drugs, anticonvulsants, antihypertensives, antivirals, antibiotics, chemotherapeutics, among others. This work aimed to perform a literature review of OLL related to chemotherapy drugs and to report two cases of possible OLL in patients with B-cell and T-cell non-Hodgkin lymphomas in use of chemotherapy and adjuvant medications. We also discuss the challenge to clinically and histopathologically differentiate OLL and OLP.

Case presentation

In both cases, oral lesions presented reticular, atrophic, erosive/ulcerated, and plaque patterns. The diagnosis of OLL was initially established in both cases by the association of histopathology and history of onset of lesions after the use of medications. Although the patients have presented a significant improvement in the oral clinical picture for more than 2 years of follow-up, they still have some lesions.

Conclusion

A well-detailed anamnesis associated with the drug history, temporal relationship of the appearance of the lesions, and follow-up of patients are fundamental for the diagnosis of OLL related to drugs. Nevertheless, its differentiation from OLP is still a challenge.

Prevalence of oral lichen planus among north Indian population: a descriptive epidemiological study

The aim: oral lichen planus is a chronic inflammatory disease affecting the oral mucous membrane. It can present in various clinical forms: reticular, papular, plaque-like, atrophic, erosive and bullous. Though the exact etiology is not certain - autoimmunity, trauma, stress, and habits are considered as etiological factors. Oral lichen planus has been classified as a premalignant lesion. The present study aims to describe the prevalence of oral lichen planus in a sample of north Indian population. Materials and methods: the present study was conducted in the outpatient department of Dentistry, GMC Badaun. The parameters recorded were age, gender and site affected. The data was collected and analysed. Results: a total of 6263 patients reported to the outpatient department of dentistry out of which 43 patients were diagnosed with oral lichen planus. The overall prevalence of oral lichen planus was found to be 0.69 %. The mean age of disease presentation was 37.5 years. A higher prevalence of oral lichen planus was reported in females compared to males with a ratio of 1:1.15. Most affected site was found to be buccal mucosa bilaterally (58.14 %). Conclusion: the present study estimated the overall prevalence of oral lichen planus as well as its distribution according to age, gender and site in north Indian population. This could contribute to the precise assessment of the disease for better policy making for better treatment and management of oral lichen planus.

Fractal Dimension and Texture Analysis of Lesion Autofluorescence in the Evaluation of Oral Lichen Planus Treatment Effectiveness

BACKGROUND

Oral Lichen planus (OLP) is a chronic inflammatory disease. Topical steroids are used as the treatment of choice. The alternative is photodynamic therapy (PDT). The study aimed to fabricate optimal biodegradable matrices for methylene blue or triamcinolone acetonide because of a lack of currently commercially available carriers that could adhere to the mucous.

METHODS

The study was designed as a 12-week single-blind prospective randomized clinical trial with 30 patients, full contralateral split-mouth design. Matrices for steroid and photosensitizer and laser device were fabricated. Fractal and texture analysis of photographs, taken in 405, 450, 405 + 450 nm wavelength, of lesions was performed to increase the objectivity of the assessment of treatment.

RESULTS

We achieved two total responses for treatment in case of steroid therapy and one in the case of PDT. Partial response was noted in 17 lesions treated using local steroid therapy and 21 in the case of PDT. No statistically significant differences were found between the effectiveness of both used methods. Statistically significant differences in fractal dimension before and after treatment were observed only in the analysis of photographs taken in 405 + 450 nm wavelength.

CONCLUSIONS

Photodynamic therapy and topical steroid therapy are effective methods for treating OLP. Using a carrier offers the possibility of a more predictable and effective method of drug delivery into the mucous membrane. Autofluorescence enables the detection of lesions especially at the early stage of their development.

Horoscopic role of CD105 (Endoglin) in progression of oral lichen planus: An immunohistochemical study

Context

Role of CD105(Endoglin) in Pathogenesis and progression of OLP.

Aim

To assess the role of neoangiogenesis in the progression of OLP by determining the expression of CD105 in OLP and normal mucosa.

Settings and Design

The present study includes a total of 70 formalin-fixed paraffin-embedded blocks of which the study group comprises 50 tissue sections histopathologically confirmed as OLP. They were subdivided into two groups - Group I (Reticular OLP) and Group II (Erosive OLP) - 25 each. The control group (designated as Group III) included 20 sections of normal mucosa.

Materials and Methods

All the sections were 4 μm thick and stained with CD105 antibodies. After identifying areas of highest vascularity (hot spots) in low power (×10) magnification, individual microvessels were counted manually at high power (×40) magnification.

Statistical Analysis Used

Analysis of variance test was used to determine the difference of microvessel density (MVD) between variants of OLP and normal mucosa and Cohen's kappa statistic was used to check interobserver variability.

Results

CD105 staining showed a mean MVD of 1.31 ± 1.8 in the normal mucosa compared to 1.68 ± 1.4 and 4.14 ± 2.7 in the reticular and erosive variants, respectively, with a P = 0.000*, which is statistically significant (*P < 0.05 is statistically significant).

Conclusion

Based on our observations, it is evident that compared to normal mucosa, MVD is greater in lichen planus. Within the two variants of OLP, MVD is higher in Erosive variant compared with Reticular variant, foreshadowing the role of neoangiogenesis in the progression of OLP and its possible malignant transformation.

Oral Lichen Planus Associated With Lichen Planus Pigmentosus and Lichen Sclerosus in Monozygotic Twins

ABSTRACT

Lichen planus (LP) is a mucocutaneous immune-mediated disease of unknown etiology. It is more prevalent in women and usually occurs between the third and sixth decades of life. Oral lesions may or may not be associated with skin and genital lesions. Although the role of genetic factors is still undetermined, reports of LP in more than one family member are not uncommon. However, the occurrence of LP in monozygotic twins is rare. We report a rare case of 42-year-old female monozygotic twins presenting oral LP. This report is even rarer because one of the patients had cutaneous lesions of an unusual variant of LP (LP pigmentosus) and the other had an uncommon association with lichen sclerosus. The etiology and pathogenesis of LP are still uncertain. However, despite being rare, its occurrence in family members and monozygotic twins suggests that genetic factors are involved in its development.

Potential Metabolic Biomarkers for Early Detection of Oral Lichen Planus, a Precancerous Lesion

Background: Oral lichen planus (OLP) is a T-cell-mediated chronic inflammatory disorder and precancerous oral lesion with high incidence. The current diagnostic method of OLP is very limited and metabolomics may provide a new approach for quantitative evaluation.

Methods: The Ultra-Performance Liquid Chromatography-Quadrupole/Orbitrap High Resolution Mass Spectrometry (UHPLC-Q-Orbitrap HRMS) was applied to analyze the change of metabolites in serum of patients with OLP. A total of 115 OLP patients and 124 healthy controls were assigned to either a training set (n = 160) or a test set (n = 79). The potential biomarkers and the change of serum metabolites were profiled and evaluated by multivariate analysis.

Results: Totally, 23 differential metabolites were identified in the training set between OLP group and healthy group. Three prominent metabolites in receiver operating characteristic (ROC) were selected as a panel to distinguish OLP or healthy individuals in the test set, and the diagnostic accuracy was 86.1%.

Conclusions: This study established a new method for the early detection of OLP by analyzing serum metabolomics using UHPLC-Q-Orbitrap HRMS, which will help in understanding the pathological processes of OLP and identifying precancerous lesions in oral cavity.

Diagnostic Criteria of Oral Lichen Planus: A Narrative Review

Oral lichen planus (OLP) is a disease with unclear etiology or pathogenesis, categorized by the World Health Organization as oral lichenoid lesions (OLL; interface mucositis or lichenoid mucositis) into a group of potentially malignant disorders. The diagnosis of OLP is challenging because the clinical and histopathologic features are frequently seen in OLP, OLL and/or other mucosal diseases with lichenoid characteristics. Furthermore, OLP has a dynamic nature. Finally, an early and precise diagnosis can play a decisive role, allowing timely treatment and thus improving the patient quality of life. This article summarizes the state-of-the-art regarding OLP and OLL and discusses the challenges faced on making an accurate diagnosis, aiming to provide a practical guideline for the postgraduates and oral physicians in reaching the diagnosis of these lesions.

Chronic Oral Lesions

Chronic oral mucosal lesions can be associated with several mucocutaneous diseases. This article reviews the autoimmune and immune-mediated, reactive, genetic, and infectious diseases that may present with chronic oral and/or cutaneous manifestations and provides a rational approach to diagnosis and management.

The expression of Cathepsin L in oral lichen planus

Background

Malignant transformation of oral lichen planus (OLP) was reported particularly in erosive type, however, it remains inconclusive. Cathepsin L was shown to promote tumor growth and invasion in many cancers. Therefore, cathepsin L expression in erosive and non-erosive OLP compared with oral epithelial dysplasia and oral squamous cell carcinoma (OSCC) were investigated.

Methods

Thirty specimens of OLP (15 cases each of erosive and non-erosive OLP), 10 cases of oral epithelial dysplasia and 10 cases of OSCC were included. Ten healthy gingiva specimens were served as controls. All specimens were stained with cathepsin L antibody using immunohistochemistry technique.

Results

Cathepsin L was expressed in all OLP and OSCC cases. In oral epithelial dysplasia and healthy gingiva, the expression was found at 90% and 50% respectively. The percentage of positive cells was the highest in erosive OLP (27.26 ± 12.09%), followed by non-erosive OLP (20.85 ± 7.43%), OSCC (20.15 ± 15.70%), oral epithelial dysplasia (9.24 ± 7.00%) and healthy gingiva (2.27 ± 5.65%). Most of non-erosive OLP cases showed mild staining intensity while erosive OLP and OSCC showed moderate staining intensity. Cathepsin L was mainly expressed at basement membrane zone and inflammatory cells of OLP. In OSCC, the expression was found in tumor islands and keratin pearls. In oral epithelial dysplasia and normal gingiva, cathepsin L expressions were low and presented in scattered pattern in both epithelium and connective tissue.

Conclusion

According to the patterns of expression in this study, cathepsin L could be implicated in pathogenesis and severity of OLP.

Expression of nucleotide-binding oligomerization domain 1 and 2 in oral lichen planus

Background/purpose

Oral lichen planus (OLP) is a chronic inflammatory disease of oral mucosa. The present study investigated the expression of nucleotide-binding oligomerization domain (NOD), a pivotal sensor protein of the innate immune system, in OLP.

Materials and methods

Oral mucosal biopsies were collected from 20 patients with OLP and 6 individuals with normal oral mucosa (NOM). The expression of NOD1 and NOD2 was determined using RT-PCR and immunohistochemistry in OLP and NOM samples.

Results

The mRNA expression of NOD1 and NOD2 was significantly higher in the OLP group than in the NOM group. The protein expression of NOD1 was marginally upregulated in all mucosal layers in the OLP group compared with that of the NOM group; however, the differences were not significant. The expression of NOD2 was elevated in infiltrating lymphocytes of the submucosal layer in the OLP group compared with the NOM group, but was undetected in other inflammatory disease, inflammatory fibrous hyperplasia (IFH). This study revealed the upregulation of NOD2 mRNA and protein in the OLP group, but not in the NOM group.

Conclusion

These findings suggest that NOD2 may play an important role in the pathogenesis of OLP and represents a new diagnostic and treatment target.

Clinicopathologic data of individuals with oral lichen planus: A Brazilian case series

Background

The aim of the present series was to analyze the sociodemographic characteristics, clinicopathologic features, and oral health-related quality of life of 41 individuals with oral lichen planus (OLP).

Material and Methods

In a retrospective analysis (1998-2018), individuals with a clinical diagnosis of OLP from a referral service of Oral Medicine of Brazil were invited for follow-up. The individuals were assessed using the Oral Health Impact Profile-14 (OHIP-14) form. Histopathological data were reviewed according to the latest criteria proposed by the American Academy of Oral and Maxillofacial Pathology (AAOMP/2016).

Results

This series mainly consisted of females (70.7%) in their forties (31.7%). The buccal mucosa (68.2%) was the most commonly affected site. Reticular (56.1%) and erosive (34.3%) appearances were the most frequent. According to OHIP-14, individuals with OLP at multiple sites in the oral cavity showed worse values in the handicap domain and those who did not respond to corticosteroids showed a higher score on the psychological discomfort domain.

Conclusions

The findings of the present study, using the AAOMP/2016 criteria, agree with case series and retrospective studies reported in the literature. Besides, OLP in its more severe clinical forms had an influence on patient quality of life.

Key words:Diagnosis, epidemiology, oral lichen planus, oral mucosa, quality of life.

Role of mammary serine protease inhibitor on the inflammatory response in oral lichen planus

OBJECTIVES

Oral lichen planus (OLP) is a chronic inflammatory condition with an unclear pathological mechanism. IκB kinase α (IKKα)-regulated mammary serine protease inhibitor (MASPIN) has been shown to mediate inflammation, particularly in cancers. Here, we explored the expression of MASPIN in OLP and its role in the inflammatory response.

MATERIALS AND METHODS

Immunohistochemistry staining and reverse transcription-polymerase chain reaction assays were used to detect the subcellular localization and expression of MASPIN and IKKα in OLP and healthy control tissues. Levels of the inflammatory factors were compared with enzyme-linked immunosorbent assays. MASPIN and IKKα were overexpressed and silenced, respectively, in an inflammation model of human oral keratinocytes (HOKs) stimulated with lipopolysaccharide (LPS).

RESULTS

Mammary serine protease inhibitor expression was down-regulated, whereas IKKα expression was up-regulated in OLP tissues (p < 0.01). The levels of tumour necrosis factor-alpha and interleukin-6 in OLP tissues were increased compared to those of healthy controls (p < 0.01). MASPIN overexpression in LPS-stimulated HOK cells inhibited the levels of IKKα and the secretion of inflammatory cytokines. By contrast, IKKα silencing promoted the expression of MASPIN and inhibited the secretion of inflammatory cytokines.

CONCLUSION

Both MASPIN and IKKα are involved in the inflammatory process of OLP, suggesting potential therapeutic targets.

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.

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.

Reticular Oral Lichen Planus

Reticular oral lichen planus is a common clinical finding, often found incidentally on routine oral examination. Patients rarely complain of symptoms and the condition does not require treatment, as a result, biopsies and ancillary laboratory evaluation are seldom performed. We present a case of reticular oral lichen planus with a classic clinical presentation and characteristic histologic findings.

Cytokines, cortisol, and nitric oxide as salivary biomarkers in oral lichen planus: a systematic review

The etiopathogenesis of oral lichen planus (OLP) is still not fully elucidated, and it is believed that its development could involve a neuro-immune-endocrine profile. This systematic review investigated the relationship between cytokines, cortisol, and nitric oxide (NO) in the saliva of OLP patients. An electronic search was conducted in Pubmed/Medline, Scopus, LIVIVO, and Web of Science databases with no restriction of language to identify studies published up to December 2017. Data extraction was performed using the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines. A total of 140 articles were retrieved, and 32 articles fulfilled the inclusion criteria (cytokines = 17; cortisol = 9; NO = 6). The most studied cytokines in the saliva of OLP patients were interleukins IL-4, IL-6, IL-8, IFN-ү, and TNF-α, which were higher in OLP patients than in healthy controls (HC). Salivary cortisol was found to be higher in OLP than in HC in most (55.5%) of the selected studies, and all studies related to NO found higher levels of this marker in OLP than in HC. Despite controversial results, our review suggests that OLP patients have an increased inflammatory response, as indicated by the proinflammatory profile of salivary cytokines. In addition, we conclude that salivary cytokine and NO measurements may have significant diagnostic and prognostic potential for monitoring disease activity and therapeutic responses in OLP.

LPS-induced Vitamin D Receptor Decrease in Oral Keratinocytes Is Associated With Oral Lichen Planus

The suppressive function of vitamin D on oral lichen planus (OLP) have been documented previously. Vitamin D receptor (VDR) expression is down-regulated in OLP, but the molecular mechanism of its decrease and the related anti-inflammatory contributor of epithelial VDR signaling is unclear. Herein, we demonstrated that lipopolysaccharide (LPS) remarkedly down-regulated VDR expression of keratinocytes, and the reduced regulation was dependent on tumor necrosis factor alpha (TNFα)-miR-346 pathway. In human specimen studies, VDR levels of oral mucosal epithelia from OLP patients decreased substantially accompanied with robust TNFα and miR-346 induction, compared to the normal tissues. In addition, vitamin D/VDR signaling inhibited LPS-induced p53-upregulated modulator of apoptosis (PUMA) induction in keratinocytes via impeding nuclear factor-κB (NF-κB) activation, resulting in keratinocytes apoptosis reduction. Importantly, PUMA activity was up-regulated strongly in diseased epithelium, reversely correlated with VDR expression. Totally, our data indicate that LPS is responsible for VDR downregulation in oral keratinocytes, which is associated with OLP development.

Experimental study on 1,25(OH)2 D3 amelioration of oral lichen planus through regulating NF-κB signaling pathway

OBJECTIVE

To explore the protective function of vitamin D (VD)/vitamin D receptor (VDR) on the development of oral lichen planus (OLP) and elaborate the underling mechanism of it.

METHODS

H&E staining, myeloid peroxidase (MPO) assays, quantitative PCR (qPCR), Western blotting, and Elisa were used to test the human biopsies and serum. QPCR, Western blotting, Elisa, and siRNA transfection were also performed in LPS-induced keratinocytes to observe the functions of vitamin D and VDR.

RESULTS

The lack of VDR in the diseased biopsies from OLP patients was associated with activated helper T-cell type 1 (Th1)-driven inflammatory response. Importantly, the status of serum 25-hydroxyvitamin D of OLP patients was reduced consistently. In a cultured cell model, 1,25(OH)₂ D₃ could downregulate excessive production of pro-inflammatory factors induced by lipopolysaccharide (LPS) in keratinocyte HaCat cells. Mechanistically, even though LPS-induced cytokines in keratinocytes were inhibited both by nuclear factor-κB (NF-κB) inhibitor and by activator protein 1 (AP-1) inhibitor, VDR-dependent 1,25(OH)₂ D₃ blocked the activation of phosphorylated-NF-κB p65 rather than c-Jun/c-Fos in the presence of LPS stimulation.

CONCLUSION

These results suggest that 1,25(OH)₂ D₃ plays an anti-inflammatory role in OLP by mediating NF-κB signaling pathway but not AP-1 signaling pathway with a VDR-dependent manner, predicting vitamin D supplement may be a potential strategy for the OLP management.

Identification of the key genes implicated in the transformation of OLP to OSCC using RNA-sequencing

Oral lichen planus (OLP) is a chronic inflammatory disease that may transform to oral squamous cell carcinoma (OSCC), while its carcinogenesis mechanisms are not entirely clear. This study was designed to identify the important genes involved in the malignant transformation of OLP to OSCC. After RNA-sequencing, the differently expressed genes (DEGs) in OLP vs. normal and OSCC vs. normal groups, respectively, were identified by limma package in R language, and then clustering analysis were conducted by Pheatmap package in R language. Weighed gene co-expression network analysis (WGCNA) was performed for the DEGs to screen disease-associated modules. Using Cytoscape software, co-expression networks were constructed for the genes involved in the modules. Enrichment analysis was conducted for the genes involved in the co-expression networks using GOstat package in R language. Finally, quantitative real-time PCR (qRT-PCR) experiments were conducted to validate the key genes. There were, respectively, 223 and 548 DEGs in OLP vs. normal and OSCC vs. normal groups. WGCNA identified the blue modules for the DEGs in the two groups as disease-associated modules. Moreover, 19 common DEGs (including upregulated BCL9L, PER2 and TSPAN33, and downregulated GMPS and HES1) associated with both OLP and OSCC were identified. In the co-expression networks, BCL9L, HES1, PER2 and TSPAN33 might function in OLP via interactions (such as BCL9L-TSPAN33 and HES1-PER2). qRT-PCR analysis showed that BCL9L, PER2 and TSPAN33 were significantly upregulated, and GMP and HES1 were downregulated. These findings indicated that BCL9L, GMPS, HES1, PER2 and TSPAN33 affected the transformation of OLP to OSCC.

Identification of potential therapeutic target genes, key miRNAs and mechanisms in oral lichen planus by bioinformatics analysis

The study aimed to identify the potential target genes and key miRNAs as well as to explore the underlying mechanisms in the pathogenesis of oral lichen planus (OLP) by bioinformatics analysis. The microarray data of GSE38617 were downloaded from Gene Expression Omnibus (GEO) database. A total of 7 OLP and 7 normal samples were used to identify the differentially expressed genes (DEGs) and miRNAs. The DEGs were then performed functional enrichment analyses. Furthermore, DEG-miRNA network and miRNA-function network were constructed by Cytoscape software. Total 1758 DEGs (598 up- and 1160 down-regulated genes) and 40 miRNAs (17 up- and 23 down-regulated miRNAs) were selected. The up-regulated genes were related to nuclear factor-Kappa B (NF-κB) signaling pathway, while down-regulated genes were mainly enriched in the function of ribosome. Tumor necrosis factor (TNF), caspase recruitment domain family, member 11 (CARD11) and mitochondrial ribosomal protein (MRP) genes were identified in these functions. In addition, miR-302 was a hub node in DEG-miRNA network and regulated cyclin D1 (CCND1). MiR-548a-2 was the key miRNA in miRNA-function network by regulating multiple functions including ribosomal function. The NF-κB signaling pathway and ribosome function may be the pathogenic mechanisms of OLP. The genes such as TNF, CARD11, MRP genes and CCND1 may be potential therapeutic target genes in OLP. MiR-548a-2 and miR-302 may play important roles in OLP development.

Oral lichenoid lesions: distinguishing the benign from the deadly

Oral lichen planus is a chronic inflammatory disease of unknown etiology or pathogenesis with varied disease severity that waxes and wanes over a long period of time. Although a common oral mucosal disease, accurate diagnosis is often challenging due to the overlapping clinical and histopathological features of oral lichen planus and other mucosal diseases. Other immune-mediated mucocutaneous diseases can exhibit lichenoid features including mucous membrane pemphigoid, chronic graft-versus-host disease, and discoid lupus erythematosus. Reactive changes to dental materials or to systemic medications can mimic oral lichen planus both clinically and histologically. In these situations the clinical presentation can be useful, as oral lichen planus presents as a multifocal process and is usually symmetrical and bilateral. Dysplasia of the oral cavity can exhibit a lichenoid histology, which may mask the potentially premalignant features. Proliferative verrucous leukoplakia, an unusual clinical disease, can often mimic oral lichen planus clinically, requiring careful correlation of the clinical and pathologic features.

Treatment of recalcitrant erosive oral lichen planus and desquamative gingivitis with oral apremilast

BACKGROUND

Erosive oral lichen planus and desquamative gingivitis are uncommon but severe debilitating variants of oral lichen planus. Treatment of these presentations is difficult and challenging.

MAIN OBSERVATION

A 44-year-old woman was referred to the dermatology clinic with chronic painful lichen planus-related gingivitis and buccal erosions. She has failed multiple treatments including topical clobetasol and tacrolimus, intralesional corticosteroids and several systemic and immunosuppressive agents. Following completion of three months of treatment with oral apremilast at a dose of 30 mg twice daily, significant improvement was noted in her disease activity.

CONCLUSION

Oral apremilast may be a safe and effective treatment for erosive oral lichen planus.

Oral lichen planus preceding concomitant lichen planopilaris

Lichen planus (LP) is an immune-mediated mucocutaneous disorder with a wide array of clinical presentations. Oral lichen planus (OLP) is characterized clinically by striae, desquamation, and/or ulceration. Lichen planopilaris (LPP), a variant of LP, affects the scalp, resulting in perifollicular erythema and scarring of cutaneous surfaces accompanied by hair loss. The association between OLP and LPP has been reported previously with scant information on concomitant or sequential disease presentation. We describe a patient with concomitant OLP and LPP, and to the best of our knowledge, this is the first report on OLP preceding the onset of LPP.

Diagnosis of oral lichen planus: a position paper of the American Academy of Oral and Maxillofacial Pathology

Despite being one of the most common oral mucosal diseases and recognized as early as 1866, oral lichen planus (OLP) is still a disease without a clear etiology or pathogenesis, and with uncertain premalignant potential. More research is urgently needed; however, the research material must be based on an accurate diagnosis. Accurate identification of OLP is often challenging, mandating inclusion of clinico-pathological correlation in the diagnostic process. This article summarizes current knowledge regarding OLP, discusses the challenges of making an accurate diagnosis, and proposes a new set of diagnostic criteria upon which to base future research studies. A checklist is also recommended for clinicians to provide specific information to pathologists when submitting biopsy material. The diagnostic process of OLP requires continued clinical follow-up after initial biopsy, because OLP mimics can manifest, necessitating an additional biopsy for direct immunofluorescence study and/or histopathological evaluation in order to reach a final diagnosis.

Oral lichen planus to oral lichenoid lesions: Evolution or revolution

The diagnosis between different diseases may be impaired by clinical and histopathologic similarities, as observed in the oral lichen planus (OLP) and oral lichenoid lesion (OLL). Inspite of similar clinicopathological features; etiology, diagnosis and prognosis differ which mandates separation of OLL from OLP. Hence, it is essential for the oral physician and oral pathologist to be familiarized with the individual variations among clinicopathological features of OLP and OLL as well as to obtain a thorough history and perform a complete mucocutaneous examination in addition to specific diagnostic testing. The difficulties faced to establish the diagnosis between these two pathologies are widely investigated in the literature with a lack of definite conclusion. This review is an attempt to throw some light on these clinicopathologic entities with the aim to resolve the diagnostic dilemma.