Intra-epithelial CD8+ T cells and basement membrane disruption in oral lichen planus

Impact of Topical Fluocinonide on Oral Lichen Planus Evolution: Randomized Controlled Clinical Trial

OBJECTIVE

To examine the impact of fluocinonide 0.05% gel formulation for the topical treatment of oral lichen planus (OLP).

METHODS

Through an RCT design, 47 patients with OLP were randomly allocated for topical OLP treatment with fluocinonide 0.05% (n = 23) or placebo (n = 24). Patients were examined for OLP symptoms, signs, disease severity, and extension score changes over 6-month follow-up.

RESULTS

After 6 months, in comparison with placebo, patients treated with fluocinonide experienced a significant reduction of OLP symptoms (p = 0.024), signs (p = 0.014), and OLP extension score (p = 0.028). The two-way ANOVA estimation models revealed that treatment with fluocinonide determined, at 6 months, a positive significant effect on the reduced OLP signs (p = 0.017), OLP symptoms (p = 0.026), and OLP extension score (p = 0.028). The multivariate regression analysis highlighted that anxiety, stress, and depression were significant predictors of every analyzed OLP outcome (p < 0.05 for each parameter) and that patients who had baseline anxiety, depression, and stress gained more benefits from fluocinonide at 6-month follow-up.

CONCLUSIONS

Topical fluocinonide 0.05% was more efficacious compared to placebo in reducing OLP outcomes at 6-month follow-up. Anxiety, depression, and stress were significant predictors of OLP outcomes and positively impacted the treatment with fluocinonide at 6 months.

Distinct Variations in Gene Expression and Cell Composition across Lichen Planus Subtypes

Lichen planus (LP) is a highly prevalent inflammatory skin disease. While various clinical subtypes have been defined, detailed comparisons of these variants are lacking. This study aimed to elucidate differences in gene expression and cellular composition across LP subtypes. Lesional skin biopsies from 28 LP patients (classical, oral, genital, and lichen planopilaris) and seven non-diseased skin controls (NDC) were analyzed. Gene expression profiling of 730 inflammation-related genes was conducted using NanoString. Immune cell compositions were assessed by multiplex immunohistochemistry. Gene expression profiles revealed unique inflammatory signatures for each LP subtype. Lichen planopilaris exhibited the most divergence, with downregulated gene expression and upregulation of complement pathway genes (C5-7), along with elevated M2 macrophages. Oral and genital LP demonstrated similar profiles with strong upregulation of TNF-related and Toll-like receptor-associated genes. Oral LP showed the highest upregulation of cytotoxicity-associated genes, as well as high numbers of CD8+ IL-17A+ (Tc17) cells (8.02%). Interferon gene signatures were strongly upregulated in oral and classical LP. The study highlights distinct differences in inflammatory gene expression and cell composition across LP subtypes, emphasizing the need for tailored therapeutic approaches.

Increased pathogenicity and pro-inflammatory capabilities of mucosal-associated invariant T cells involved in Oral Lichen Planus

BACKGROUND

Mucosal-associated invariant T (MAIT) cells assume pivotal roles in numerous autoimmune inflammatory maladies. However, scant knowledge exists regarding their involvement in the pathological progression of oral lichen planus (OLP). The focus of our study was to explore whether MAIT cells were altered across distinct clinical types of OLP.

METHODS

The frequency, phenotype, and partial functions of MAIT cells were performed by flow cytometry, using peripheral blood from 18 adults with non-erosive OLP and 22 adults with erosive OLP compared with 15 healthy adults. We also studied the changes in MAIT cells in 15 OLP patients receiving and 10 not receiving corticosteroids. Surface proteins including CD4, CD8, CD69, CD103, CD38, HLA-DR, Tim-3, Programmed Death Molecule-1 (PD-1), and related factors released by MAIT cells such as Granzyme B (GzB), interferon (IFN)-γ, tumour necrosis factor (TNF)-α, interleukin (IL)-17A, and IL-22 were detected.

RESULTS

Within non-erosive OLP patients, MAIT cells manifested an activated phenotype, evident in an elevated frequency of CD69+ CD38+ MAIT cells (p < 0.01). Conversely, erosive OLP patients displayed an activation and depletion phenotype in MAIT cells, typified by elevated CD69 (p < 0.01), CD103 (p < 0.05), and PD-1 expression (p < 0.01). Additionally, MAIT cells exhibited heightened cytokine production, encompassing GzB, IFN-γ, and IL-17A in erosive OLP patients. Notably, the proportion of CD103+ MAIT cells (p < 0.05) and GzB secretion (p < 0.01) by MAIT cells diminished, while the proportion of CD8+ MAIT cells (p < 0.05) rose in OLP patients with corticosteroid therapy.

CONCLUSIONS

MAIT cells exhibit increased pathogenicity and pro-inflammatory capabilities in OLP. Corticosteroid therapy influences the expression of certain phenotypes and functions of MAIT cells in the peripheral blood of OLP patients.

Mast cells in oral lichen planus and oral lichenoid lesions related to dental amalgam contact

The aim of this study was to analyze the expression of mast cell markers toluidine blue, c-kit, and tryptase and presence of mononuclear inflammatory cells in oral lichen planus (OLP) and oral lichenoid lesions related to dental amalgam. Nineteen specimens of OLP, OLLC, and healthy oral mucosa were selected. Mononuclear inflammatory cells were analyzed. Histochemical and immunohistochemical analyses were performed using toluidine blue, anti-c-kit and anti-tryptase reagents, and the results were quantified in areas A and B of connective tissue. Mast cells of all OLP and OLLC samples were positive for toluidine blue, c-kit, and tryptase. The density of toluidine blue+, c-kit+ and tryptase+ mast cells was higher in tissue with OLP and OLLC compared with healthy controls (p < 0.05). No difference was noted in mast cells density between OLP and OLLC (p > 0.05). The density of tryptase+ mast cells was higher in the subepithelial region (area A) than the region below it (Area B) in OLLC (p = 0.047). The mononuclear inflammatory cell density was higher in OLLC compared to OLP, but without statistical significance (p > 0.05). A positive statistical correlation was found between mononuclear immune cells and density of c-kit+ and tryptase+ mast cells in OLP (r = 0.943 and r = 0.886, respectively). Our data demonstrate that the etiopathogenesis process of OLP and OLLC modulates the expansion and degranulation of mast cells; mast cells density, however, was similar between OLP and OLLC. The distribution of mast cells appears to vary along the lamina propria.

Non-Coding RNAs as Potential Targets for Diagnosis and Treatment of Oral Lichen Planus: A Narrative Review

Oral lichen planus (OLP) is a chronic inflammatory disease that is characterized by the infiltration of T cells into the oral mucosa, causing the apoptosis of basal keratinocytes. OLP is a multifactorial disease of unknown etiology and is not solely caused by the malfunction of a single key gene but rather by various intracellular and extracellular factors. Non-coding RNAs play a critical role in immunological homeostasis and inflammatory response and are found in all cell types and bodily fluids, and their expression is closely regulated to preserve normal physiologies. The dysregulation of non-coding RNAs may be highly implicated in the onset and progression of diverse inflammatory disorders, including OLP. This narrative review summarizes the role of non-coding RNAs in molecular and cellular changes in the oral epithelium during OLP pathogenesis.

METTL14-upregulated miR-6858 triggers cell apoptosis in keratinocytes of oral lichen planus through decreasing GSDMC

Oral lichen planus (OLP), a chronic inflammatory disorder, is characterized by the massive cell apoptosis in the keratinocytes of oral mucosa. However, the mechanism responsible for triggering oral keratinocyte apoptosis is not fully explained. Here, we identify that Gasdermin C (GSDMC) downregulation contributes to apoptosis in human oral keratinocytes. Mechanistically, we describe that activated nuclear factor kappa B (NF-κB) pathway induces overexpression of methyltransferase-like 14 (METTL14), which increases N6-adenosine methylation (m6A) levels in the epithelial layer of OLP. m6A modification is capable of regulating primary miR-6858 processing and alternative splicing, leading to miR-6858 increases. miR-6858 can bind and promote GSDMC mRNA degradation. Forced expression of GSDMC is able to rescue cell apoptosis in human oral keratinocyte models resembling OLP. Collectively, our data unveil that m6A modification regulates miR-6858 production to decrease GSDMC expression and to trigger keratinocyte apoptosis in the context of OLP.

Skin-infiltrating T cells display distinct inflammatory signatures in lichen planus, bullous pemphigoid and pemphigus vulgaris

Introduction

We here thought to dissect the inflammatory signature in lesions of three skin disorders, which show a common adaptive immune response against autoantigens of the skin but are characterized by diverging clinical phenotypes. Pemphigus vulgaris (PV) and bullous pemphigoid (BP) are type-2-dependent, IgG autoantibody-driven blistering disorders of mucous membranes and skin, which target desmoglein (Dsg)3 and bullous pemphigoid (BP)180, respectively. In contrast, lichen planus (LP) is a common chronic inflammatory disease of the skin and mucous membranes with a pronounced dermal T cell infiltrate. We previously identified peripheral type 1 and 17 T cell responses against Dsg3 and BP180 in a cohort of LP patients strongly suggesting that the underlying inflammatory T cell signature may drive the evolving phenotype.

Methods

Paraffin-embedded skin biopsies from well-characterized patients with LP (n=31), BP (n=19), PV (n=9), and pemphigus foliaceus (PF) (n=2) were analysed. Areas with the most prominent inflammatory infiltrate were excised with punch biopsies and tissue microarrays (TMA) containing multiple biopsies were created. Using multicolor immunofluorescence, the inflammatory infiltrate was stained with antibodies against multiple cellular markers, i. e. CD3ϵ, CD4, CD15, TCR-δ, the cytokine IL-17A, and the transcription factors, T-bet and GATA-3.

Results

In LP, there was a higher number of CD4+ T cells expressing T-bet compared to GATA-3. In contrast, CD4+ T cells in PV and BP skin lesions more frequently expressed GATA-3 than T-bet. IL-17A+ cells and IL-17A+ T cells were found to a similar extent in all the three disorders. IL-17A+ granulocytes were more predominant in BP than in LP or PV. Of note, the majority of IL-17A+ cells in LP were neither T cells nor granulocytes.

Discussion

Our findings in inflammatory skin infiltrates clearly show a predominant type 1 signature in LP in contrast to a preponderance of type 2 T cells in PV and BP. In contrast to LP, granulocytes and to a much lesser extent CD3+ T cells were a cellular source of IL-17A in BP and PV. These data strongly suggest that different inflammatory cell signatures drive evolving clinically diverse phenotypes of LP, PV and BP despite common target antigens of the skin.

Human papilloma virus-16-specific CD8+ T-cell expansions characterize different clinical forms of lichen planus and not lichen sclerosus et atrophicus

Lichen planus (LP) is a cutaneomucosal chronic inflammatory disease characterized by a CD8+ cytotoxic T-lymphocytes (CTL) infiltrate. In erosive oral LP, we found HPV16-specific activated CTL in lesions, supporting a pathogenic contribution of HPV16. Here, we investigated whether a similar scenario occurs in other clinical forms of LP and in lichen sclerosus et atrophicus (LSA), another chronic disease also affecting the mucosa and/or the skin. Blood CTL from LP and LSA patients expressed significant higher levels of granzyme B, perforin and CD107a proteins than healthy donors. Expansions of TCRVß3+ CTL, with presence of TCR clonotypes identical to those previously detected in erosive oral LP, were found both in blood and mucosal/skin lesions of LP, and not of LSA patients. These expansions were enriched with HPV16-specific CD8+ T-cells as shown by their recognition of the E711-20 immunodominant epitope. In LSA patients, the peripheral repertoire of CTL was oligoclonal for TCRVß6+ CTL. Finally, although patients with LP and LSA have developed antibodies against HPV16 capsid L1, antibodies against HPV16 E6 were only observed in patients with LP. Overall, our data collectively suggest an involvement of HPV16-specific CTL in different clinical forms of LP, not only in erosive oral LP, while a different scenario operates in LSA.

Analysis of the response to two pharmacological protocols in patients with oral lichen planus: A randomized clinical trial

OBJECTIVE

To evaluate the effectiveness of two different therapies on oral lichen planus (OLP) treatment through the analysis of OLP symptoms and signs and to analyze the risk of side effects related to the adopted protocols.

METHODS

Thirty-eight patients with OLP were selected according to van der Meij and van der Waal clinical and histopathological criteria. Through a randomized design, 19 patients received Tacrolimus 0.1% ointment (T group) and 19 an anti-inflammatory mouthwash (M group) composed of calcium hydroxide 10%, hyaluronic acid 0.3%, umbelliferone, and oligomeric proanthocyanidins. The patients were examined on a regular basis for OLP symptoms, signs, and disease severity score changes over a 3-month follow-up period.

RESULTS

Both treatments were effective in the reduction of OLP signs and symptoms. However, at 3 months (T3), in comparison with the M group, T group patients showed significantly lower mean values of OLP signs (p = 0.035), symptoms (p = 0.045), and disease severity scores (p = 0.041). Moreover, the Spearman test showed that there was a significant correlation between OLP signs and symptoms at each follow-up session in all patients.

CONCLUSIONS

Both treatments demonstrated a significant approach to control OLP. However, tacrolimus determined a more effective improvement in OLP signs and symptoms compared to anti-inflammatory mouthwash at 3-month follow-up.

Association of oral candidiasis with oral lichen planus in patients using corticosteroid therapy - Meta-analysis

Oral lichen planus (OLP) is a chronic inflammatory disease that commonly affects the skin and mucous membranes. There is a difference of opinion among clinicians about whether OLP has been associated with oral candidiasis. Nonetheless, in OLP patients, the oral candidiasis prevalence rate ranges from 7.7 to 16.6%, as established through biopsy findings, whereas 37-50% of the prevalence rate has been noticed in culture findings. Oral candidiasis has been linked to several local and systemic factors, including salivary gland dysfunction, dental prostheses, topical or inhaled corticosteroids, smoking, and the use of systemic medications. The aim was to highlight the association of Candida in patients diagnosed with OLP, correlate the use of steroid therapy, and enumerate the factors of using steroid therapy as implicated causes for oral candidiasis. A search was made using search engines such as PubMed, Scopus, Cochrane Database of Systematic Reviews, Science Citation Index, NIH Public Access, and Clarivate Analytics (Figure 1). The keywords using the research option for this field were "Oral Candidiasis" AND "Oral Lichen planus" or "Candidiasis" AND "Corticosteroids" or "Topical Corticosteroids" AND Oral Lichen planus or "Inhalation Corticosteroids" AND "Candidiasis" or "Oral Lichen planus" AND "Corticosteroids." The database search was made for the duration of 1991 to -2021 (Table 1). Additional articles were obtained regarding the literature on OLP and oral candidiasis and were considered background material. The incidence of oral candidiasis and associated lichen planus following steroid therapy enlisted by various authors has been addressed. According to the results of this study, there is a positive correlation between the presence of oral candidiasis in the OLP's patients treated with corticosteroids. Finally, this meta-analysis concluded that there is a positive correlation between the presence of Candida species in OLP and steroid medication.

Updates on immunological mechanistic insights and targeting of the oral lichen planus microenvironment

Oral lichen planus (OLP) is a chronic immune inflammatory disease that is an oral potentially malignant disorder (OPMD), occurs in the oral mucosa and affects approximately 0.5% to 4% of the general population. There are usually five types of OLP: reticular/papular, plaque-like, atrophic/erythematous, erosive/ulcerative, and bullous. Furthermore, the chance of causing oral squamous cell carcinoma (OSCC) is 1.4%. Although the etiology of OLP is still unknown, accumulating evidence supports that immune dysregulation may play a vital role in the pathogenesis of OLP, especially the massive production of various inflammatory cells and inflammatory mediators. In this review, we focus on the relationship between OLP and its immune microenvironment. We summarize current developments in the immunology of OLP, summarizing functional cell types and crucial cytokines in the OLP immune microenvironment and the underlying mechanisms of key signaling pathways in the OLP immune microenvironment. We highlight the application potential of targeted immune microenvironment therapy for OLP.

Lymphocyte and CD62E expression in lichen planus and lichenoid reaction

Background

It is difficult to distinguish the clinical and histopathological aspects of oral lichen planus lesions from those of oral lichenoid reaction. Some criteria were proposed to distinguish them, mainly because they have different biological behaviors. The aim of the present study was to compare the lymphocyte population and the expression of E-selectin between these lesions.

Methods

Participants with a clinical diagnosis of oral lichen planus (GOLP) and oral lichenoid reaction (GOLR) who needed to perform a biopsy were selected. The tissue was frozen and immunostaining was performed for CD3/CD4, CD3/CD8, CD4/CLA, CD8/CLA, and CD62E. The analysis of each immunostaining was accomplished using the ImageJ program.

Results

In total, 25 participants with oral lichen planus and 11 with oral lichenoid reaction were seen. In the evaluation of CD3 + CD4+/CD3 + and CD3 + CD8+/CD3 + proportions, there was a higher percentage of these cells in the oral lichen planus group when compared with the oral lichenoid reaction group (p = 0.027 and p = 0.038 respectively). The average number of CLA + lymphocytes for CD4+/CLA + and CD8+/CLA + in both groups was not statistically significant (p = 0.840; d = 0.363). In GOLP, the number of CD4 + CLA+/E-selectin and CD8 + CLA+/E-selectin was not statistically significant (p = 0.951 and p = 0.454 respectively); neither in GOLR (p = 0.454 and p = 0.989 respectively).

Conclusion

Our results indicate that CD3 + CD4+, CD3 + CD8+, CD4 + CLA+, CD8 + CLA + lymphocytes and E-selectin are present in both lesions. However, the proportion of CD3 + CD4+/CD3 + and CD3 + CD8/CD3 + cells is higher in the oral lichen planus group when compared with the oral lichenoid reaction group, suggesting that these cells may be important for the etiopathogenic mechanism of these lesions.

JAK inhibitors in lichen planus: A review of pathogenesis and treatments

Lichen planus (LP) is an auto-inflammatory skin disorder identified by a presence of T-cell lymphocytes at the dermal-epidermal junction. It is hypothesized that the INF-γ/CXCL10 axis fulfills a major role in the onset and persistence of chronic inflammation in LP. Since Janus kinases (JAKs) are involved in the transduction of INF-γ signals, they may be good targets for LP treatment. Several case reports and case series described the safety and efficacy of upadacitinib (2 articles), tofacitinib (6 articles), baricitinib (4 articles), and Ruxolitinib (1 Article) in the treatment of LP variants. The predominant variants that JAK inhibitors improved were lichen planopilaris, nail LP, and erosive LP. Considering the role of the JAK pathway in LP pathogenesis and the evidence provided by these reports, it seems JAK inhibitors would be effective therapeutic agents for LP treatment. Hence, these agents should be trialed and evaluated further.

Infiltration of Mature KLRG1 Expressing Cytotoxic T Cells in Oral Lichen Planus

BACKGROUND

Oral lichen planus (OLP) is a chronic inflammatory disease affecting oral mucosa. Its pathogenesis includes T cell infiltration. T cells may be naïve or in response to antigen stimulation, progress through differentiation stages. The differentiated states of T cells in OLP mucosa have not previously been reported.

METHODS

Available OLP microarray gene expression data from Gene Expression Omnibus were analyzed for markers of T cell cytotoxicity. Immunohistochemical studies of T cell subset markers CD4 and CD8 and the T cell differentiation marker killer cell lectin-like receptor G1 (KLRG1) were performed on paraffin embedded formalin fixed oral mucosa biopsy samples from 10 patients with OLP.

RESULTS

Gene expression analysis of OLP oral mucosa samples disclosed increased transcript expression of KLRG1, CD8A, and granzyme K (GZMK). By immunohistochemistry, prominent CD4 + and CD8 + T cell infiltration was seen in all patient samples. KLRG1 + T cells were abundant, constituting a mean of 51% (range 40-65%) of the number of CD8 + T cells. KLRG1 + T cells localized at the epithelium and lamina propria junction, infiltrating both basal and intraepithelial regions and adjacent to both basal and intraepithelial keratinocytes.

CONCLUSIONS

OLP oral mucosa T cell infiltration includes KLRG1 + highly differentiated cytotoxic T cells, suggesting continued antigen exposure driving T cells to a highly differentiated phenotype. The known phenotype of these cells, together with microarray detected increases in cytotoxic molecules, suggests that highly differentiated cytotoxic T cells contribute to oral mucosa injury in OLP.

Oral lichen planus: comparative efficacy and treatment costs-a systematic review

Objective

To compare the reported efficacy and costs of available interventions used for the management of oral lichen planus (OLP).

Materials and methods

A systematic literature search was performed from database inception until March 2021 in MEDLINE via PubMed and the Cochrane library following PRISMA guidelines. Only randomized controlled trials (RCT) comparing an active intervention with placebo or different active interventions for OLP management were considered.

Results

Seventy (70) RCTs were included. The majority of evidence suggested efficacy of topical steroids (dexamethasone, clobetasol, fluocinonide, triamcinolone), topical calcineurin inhibitors (tacrolimus, pimecrolimus, cyclosporine), topical retinoids, intra-lesional triamcinolone, aloe-vera gel, photodynamic therapy, and low-level laser therapies for OLP management. Based on the estimated cost per month and evidence for efficacy and side-effects, topical steroids (fluocinonide > dexamethasone > clobetasol > triamcinolone) appear to be more cost-effective than topical calcineurin inhibitors (tacrolimus > pimecrolimus > cyclosporine) followed by intra-lesional triamcinolone.

Conclusion

Of common treatment regimens for OLP, topical steroids appear to be the most economical and efficacious option followed by topical calcineurin inhibitors. Large-scale multi-modality, prospective trials in which head-to-head comparisons interventions are compared are required to definitely assess the cost-effectiveness of OLP treatments.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12903-022-02168-4.

Metal Allergy Mediates the Development of Oral Lichen Planus via TSLP-TSLPR Signaling

Metal allergy is a T-cell-mediated delayed type of hypersensitive reaction. The pathogenetic mechanisms underlying the allergy are unclear, although the condition has been reported to be related to oral lichen planus (OLP), despite an absence of immunological studies to support this relationship. In this study, histopathological samples of OLP patients were examined to compare the metal allergy-positive and -negative groups, with a focus on the network of epidermal keratinocytes and T cells induced by thymic stromal lymphopoietin (TSLP) and its receptor, TSLPR. Infiltration of T cells into the epithelium was revealed to be higher in the OLP lesions of metal allergy-positive patients than in those of metal allergy-negative patients. Moreover, TSLP-TSLPR signaling and TNF-α production were higher in the epithelial tissue samples of the metal allergy-positive patients than in the metal allergy-negative patients. Metal allergy is associated with both increased expressions of TSLP in keratinocytes and increased TNF-α levels in the epithelium. We propose that this would promote the accumulation of T cells at the lesion site, contributing to the formation of the disease. These results suggest that metal allergy may be an aggravating factor in the pathogenesis of OLP.

Tobacco Use and Oral Health

This review outlines the important oral implications of tobacco use. The lining of the mouth (oral mucosa), if exposed to tobacco and its products in a susceptible individual, can develop benign, potentially malignant, and malignant tumours. Treatment and prognosis depend on tumour type, how early it is detected, its size and site in the oral cavity and whether it has spread. Advanced oral squamous cell carcinoma (OSCC) has a 20% 5-year survival rate. Tobacco use also increases the risk of periodontitis, peri-implantitis, caries, alveolar osteitis and halitosis. Although less life threatening than OSCC, these tobacco related conditions create a substantial financial and health burden for individuals and society. Dental practitioners routinely examine the oral cavity for signs of mucosal and tooth changes, are experienced in recognising variations from normal and have established management and referral pathways. They are also ideally positioned to provide brief interventions to assist their patients to quit smoking.

Effects of cold physical plasma on oral lichen planus: An in vitro study (Effects of CAP on OLP)

OBJECTIVES

In the search for more effective and safe treatment avenues, we investigated cold physical plasma as a new treatment modality for therapy of oral lichen planus (OLP).

MATERIAL AND METHODS

Healthy and diseased human mucosal tissue samples with a size of 3 mm in diameter obtained from OLP patients were subjected to plasma treatment ex vivo or were left untreated. Tissue sections were quantified for immune-infiltration of CD4+ , CD8+ , CD45RA+ , and CD45R0+ T cells. Moreover, the tissues' inflammatory profile was assessed by analyzing 12 different cytokines in the surrounding media.

RESULTS

A significantly increased infiltrate of CD8+ and CD45-R0+ T cells was detected in OLP tissue samples when compared to healthy tissue. A higher concentration of interleukin (IL) 1β, IL6, IL8, and granulocyte macrophage-colony stimulating factor (GM-CMF) was detected in OLP samples compared to healthy mucosal tissue. For all cytokines and chemokines investigated, 23 out of 24 comparisons showed a decrease in tendency (significant for IL1β, IL2, IL10, and GM-CSF) in response to plasma treatment. In ex vivo-treated tissue, a decrease of T-cell infiltrate in OLP lesions compared with healthy tissue was observed.

CONCLUSION

Our findings suggest cold physical plasma can be a promising therapeutic option for OLP that requires further validation in vivo.

The possible involvement of granulysin mediated cytotoxicity in keratinocytes disruption in lichen planus

Lichen planus is a chronic mucocutanous disorder histopathologically characterized with a keratinocytes apoptosis, subsequent basal cell layer liquefaction and accumulation of the inflammatory infiltrate in papillary dermis. A formation of apoptotic bodies in basal cell layer is due to a cytotoxic lymphocyte attack to the basal keratinocytes. It has been demonstrated that the cytotoxic molecules included in this attack are perforin and granzyme B. Both molecules are found upregulated in CD8+ lymphocytes that are in close contact to keratinocytes. However, their amount is lower in lichen planus than in other skin disease characterized by liquefaction and vacuolar degeneration of the basal epidermal layer. This could speculate about other cytotoxic molecule such as granulysin that could mediate keratinocyte apoptosis. Therefore, in this article we hypothesize about the crucial role of granulysin molecule in keratinocytes killing that could contribute to a lichen planus pathogenesis.

Treatment trends in oral lichen planus and oral lichenoid lesions (Review)

Oral lichen planus (OLP) is a chronic inflammatory disease, associated with altered cell-mediated immunological function. It has long-term evolution, repeated exacerbations, sometimes painful and resistant to treatment, even all of these, OLP significantly affects patient's life quality. Not least, OLP is accompanied by an increased risk of malignant transformation. A wide spectrum of therapeutic options is available, but none are curative. In this review, 58 structured studies on the clinical symptomatology and treatment strategy of OLP were analyzed. The literature research was performed according to the criteria of the PRISMA system. This study summarizes current knowledge regarding management of OLP and oral lichenoid lesions, discusses the challenges of choosing an adequate treatment and, in attempt to improve the quality of patient life, trying to describe a therapeutic algorithm that takes into consideration the clinical features of the disease. Current OLP therapy aims at eliminating all mucosal-related lesions, reduce symptomatology and decrease the risk of oral cancer and include corticosteroids, immunomodulatory agents, retinoids, ultraviolet irradiation and/or laser therapy.

Correlation of VEGF and MMP-2 levels in oral lichen planus: An in vivo immunohistochemical study

BACKGROUND

This study aimed to investigate the relation between vascular endothelial growth factors (VEGF) and matrix metalloproteinase-2 (MMP-2) in different oral lichen planus (OLP) forms compared to control patients.

METHODS

Biopsies from 60 patients were selected and equally distributed as follows: reticular/popular OLP (R/PLP), atrophic/erosive OLP (A/ELP) patients, healthy subjects (Control). All biopsies were immune-histochemical stained and statistically analyzed for VEGF and MMP-2 expression.

RESULTS

Immune-expression of VEGF was significant between OLP and control (P-value <0.001). OLP showed a higher epithelial expression of VEGF in A/ELP compared to R/PLP (15.19 ± 2.53). In connective tissue (CT), R/PLP showed a higher VEGF expression (11.57 ± 2.32) compared to A/ELP (9.87 ± 2.48); (p < 0.001), with no significant difference (P-value ≥ 0.05). A significant epithelial expression of MMP-2 was seen in A/ELP compared to R/PLP (21.32 ± 7.08). R/PLP showed a higher expression of MMP-2 (20.45 ± 6.28) in CT compared to A/ELP group (17.66 ± 6.94), with a non-significant difference (P-value = 1.000). In A/ELP, a positive correlation between VEGF and MMP-2 was detected in CT, r = 0.761, with a weak correlation was noticed in epithelium r = 0.163. A negative correlation was noted between VEGF and MMP-2 in R/PLP in CT, r = -0.368, with a moderate positive correlation in epithelium, r = 0.655.

CONCLUSION

MMP-2 and VEGF protein profiles support a role in the pathogenesis of OLP. Based the MMP-2 and VEGF findings in the A/ELP group, this pathway may have a role in the malignant transformation of these lesions. Both observations invite further study.

IFN-γ enhances cell-mediated cytotoxicity against keratinocytes via JAK2/STAT1 in lichen planus

Lichen planus (LP) is a chronic debilitating inflammatory disease of unknown etiology affecting the skin, nails, and mucosa with no current FDA-approved treatments. It is histologically characterized by dense infiltration of T cells and epidermal keratinocyte apoptosis. Using global transcriptomic profiling of patient skin samples, we demonstrate that LP is characterized by a type II interferon (IFN) inflammatory response. The type II IFN, IFN-γ, is demonstrated to prime keratinocytes and increase their susceptibility to CD8⁺ T cell-mediated cytotoxic responses through MHC class I induction in a coculture model. We show that this process is dependent on Janus kinase 2 (JAK2) and signal transducer and activator of transcription 1 (STAT1), but not JAK1 or STAT2 signaling. Last, using drug prediction algorithms, we identify JAK inhibitors as promising therapeutic agents in LP and demonstrate that the JAK1/2 inhibitor baricitinib fully protects keratinocytes against cell-mediated cytotoxic responses in vitro. In summary, this work elucidates the role and mechanisms of IFN-γ in LP pathogenesis and provides evidence for the therapeutic use of JAK inhibitors to limit cell-mediated cytotoxicity in patients with LP.

Dyslipidemia in Lichen Planus: A Case-control Study

Objective:

Lichen planus (LP) is a chronic inflammatory disease that affects the skin, mucous membranes, scalp and nails. It has been reported that diabetes mellitus and dyslipidemia prevalence were higher in patients with LP. However, most of these reports were retrospective, database search, which included patients who were on lipid-lowering drugs. This study aims to conduct a prospective case-control study to investigate the association between LP and dyslipidemia.

Methods:

Methods: This study was conducted on 49 patients with LP (mucosal or cutaneous) and 99 healthy controls. All patients were subjected to clinical and histological examination, whereas controls were subjected to clinical examination. The variables analyzed were age, sex, tobacco consumption, hypertension, lipid profiles and fasting blood glucose.

Results:

Results: Serum levels of triglycerides, total cholesterol and LDL cholesterol were higher in patients with LP. However, there was no significant difference between patients with LP and controls. No significant differences between LP patients and controls were observed with the average age, sex, tobacco consumption and hypertension.

Conclusion:

Conclusion: This prospective case-control study demonstrated that dyslipidemia was more common among patients with LP. Physicians should be aware of this association and consider screening them for dyslipidemia.

The immunopathogenesis of oral lichen planus-Is there a role for mucosal associated invariant T cells?

Oral lichen planus (OLP) is a chronic, T-cell-mediated, immune condition of unknown cause. OLP may present with painful symptoms requiring treatment, as well as lesions outside the oral cavity. It is likely that what initiates the OLP disease process is a complex interaction of host susceptibility and environmental triggers. While it is possible that OLP represents a true autoimmune condition against an epithelial autoantigen, the mechanisms that lead to this immune dysregulation are still poorly understood. In this review article, we discuss current concepts relating to the immunopathogenesis of OLP, as well as the potential contributory roles the oral microbiota and mucosal-associated invariant T (MAIT) cells.

Effect of sonic versus manual supervised toothbrushing on both clinical and biochemical profiles of patients with desquamative gingivitis associated with oral lichen planus: A randomized controlled trial

OBJECTIVES

The aim of this randomized, parallel-design, clinical trial was to investigate the effectiveness of an intensive plaque control programme with sonic versus manual toothbrushing on clinical outcomes and gingival crevicular fluid (GCF) levels of matrix metalloproteinases (MMP) in desquamative gingivitis (DG) patients.

METHODS

A total of 32 patients affected by DG secondary to oral lichen planus (OLP) were consecutively recruited and randomly assigned to a test (n = 16) and control (n = 16) group. Both groups were enrolled in an intensive control programme comprising supragingival scaling and polishing, and brush-specific instructions for a period of 8 weeks. The treatment of interest (test) was the use of a sonic-powered toothbrush, and the standard treatment (control) was the utilization of a soft-bristle manual toothbrush for twice-daily home oral hygiene procedures. Periodontal parameters, patient-centred outcomes, MMP-1 and MMP-9 GCF levels were evaluated at baseline and 8 weeks after starting the programme.

RESULTS

The plaque control programme resulted in statistically significant reduction in periodontal parameters with consequent improvement in the clinical features, painful symptoms and severity of DG lesions in both groups (all P < 0.001). When a sonic toothbrush was used, there was a more significant decrease in clinical indices, mucosal disease scores and GCF levels of MMP-1 and MMP-9.

CONCLUSIONS

This clinical trial reported the effectiveness of a combined protocol based on professional oral hygiene and supervised toothbrushing in OLP patients with DG. The daily use of a sonic toothbrush would seem to perform better in the short term.

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.

Evaluating the role of tissue microRNA-27b as a diagnostic marker for oral lichen planus and possible correlation with CD8

BACKGROUND

MicroRNA-27b (miR27b) is a small, non-coding RNA that is involved in physiological keratinocyte differentiation and regulating inflammatory processes. We performed this study to investigate the value of miR27b as a diagnostic marker for oral lichen planus (OLP) and the correlation between CD8 (cytotoxic T-cell marker) and miR27b tissue expression in OLP patients.

METHODS

Forty participants (including 20 OLP patients and 20 controls) underwent oral biopsy. The obtained specimens were examined by immunostaining and quantitative RT-PCR for CD8 and miR27b tissue expression, respectively. We used the Spearman rank correlation test to evaluate the correlation between both variables.

RESULTS

Our analysis showed that in comparison with healthy tissues, OLP tissue samples exhibited significantly higher CD8 levels (P < 0.01), as well as a significant downregulation of miR27b expression (P < 0.0001). Upon comparing different OLP subgroups, no significant difference was detected in terms of miR27b expression; however, the tissue levels of CD8 varied significantly (highest in the erosive subgroup and lowest in the papular/plaque/reticular subgroup). The Spearman rank analysis showed a negative correlation between tissue expression of miR27b and CD8; however, this was not statistically significant (P > 0.05). Further, the receiver operating characteristic curve of tissue miR27b as an OLP biomarker revealed 100% sensitivity and 65% specificity at cutoff value of 4.4.

CONCLUSION

This study demonstrated increased CD8 levels and downregulation of miR27b in OLP tissues, compared to healthy tissues. Moreover, it revealed the potential of miR27b as an OLP disease biomarker. The possible negative correlation between CD8 and miR27b tissue expression requires further investigation in larger studies.

Effect of a structured plaque control on MMP-1 and MMP-9 crevicular levels in patients with desquamative gingivitis associated with oral lichen planus

OBJECTIVES

No data are available in the literature on the extent to which the immune host-response and bacterial-elicited inflammation separately contributes to the increase in gingival crevicular fluid (GCF) levels of inflammatory biomarkers in patients affected by desquamative gingivitis (DG) secondary to oral lichen planus (OLP). The aim of this study was to investigate the effect of a structured plaque control intervention on GCF levels of MMP-1 and MMP-9 in OLP patients with DG and to compare them with those of non-OLP patients.

MATERIALS AND METHODS

The study population consisted of 18 unrelated Caucasian patients with DG, while 18 periodontally healthy subjects were recruited for the control group. Periodontal parameters and GCF biomarker amounts were evaluated at baseline and 2 months after a structured plaque control intervention, comprising professional oral hygiene sessions, manual toothbrushing, and interdental cleaning advice, only for DG patients. Determination of MMP-1 and MMP-9 levels was carried out by means of an enzyme-linked immunosorbent assay.

RESULTS

Plaque control program led to improvement in all examined clinical parameters and resulted in significant decrease in GCF total amount and concentration of MMP-1 and MMP-9 in comparison to baseline (p < 0.001). However, MMP-1 and MMP-9 levels in DG patients were still significantly higher than those in the healthy control group (p < 0.01).

CONCLUSIONS

These findings would seem to support an intrinsic upregulated expression of MMPs in DG patients that is exacerbated by bacterial plaque.

CLINICAL RELEVANCE

The present outcomes provide further scientific grounds for the importance of strict professional oral hygiene sessions in DG patients.

Bullous lichen planus - a review

Bullous lichen planus is a rare variant of lichen planus. It is characterized by vesicles or bullae, which usually develop in the context of pre-existing LP lesions. It is often misdiagnosed and should be differentiated from other subepidermal bullous diseases especially lichen planus pemphigoides. The diagnosis is based on clinical suspicion and is confirmed by histopathology and immunofluoresence. The clinical features of bullous lichen planus include typical lichen planus lesions, accompanied by the formation of bullae on the affected or perilesional skin. This is evident on histology, with alteration of the dermo-epidermal junction and intrabasal bullae as a consequence of extensive inflammation. The histologic features in conjunction with the negative immunofluoresence indicate that bullous lichen planus is a form of "hyper-reactive lichen planus" rather than a distinct entity. There is no standard treatment of bullous lichen planus. Topical and systemic corticosteroids, dapsone and acitretin have been described as effective choices.

Clinical Assessment of the Efficiency of Low Level Laser Therapy in the Treatment of Oral Lichen Planus

BACKGROUND:

Oral lichen planus (OLP) is a chronic inflammatory disease of the oral mucosa of uncertain etiology.

AIM:

To evaluate the effect of using low level laser therapy (LLLT (970 nm Siro laser Advance) for the treatment of symptomatic (OLP).

SUBJECTS AND METHODS:

The present study was conducted on ten patients suffering from persistent oral lichen planus (OLP). Patients were treated with diode laser (970nm) for the symptomatic relief of pain and burning sensation. The patients were assessed before, during and after the completion of the laser treatment which was done twice weekly for two successive months with maximum of ten sessions. The assessment was performed using visual analogue scale (VAS) and clinical investigation for each patient.

RESULTS:

Detailed significant reduction in lesion size and showed complete remission of burning sensation and pain. No reported complications or therapy side effects were observed in any of the treated patients.

CONCLUSION:

Diode laser therapy seems to be an effective adjunctive treatment modality for relieving pain and clinical symptoms of OLP.

Oral Lichen Planus: An Update on Etiology, Pathogenesis, Clinical Presentation, Diagnosis and Management

The mouth is a mirror of health or disease, a sentinel or early warning system. The oral cavity might well be thought as a window to the body because oral manifestations accompany many systemic diseases. In many instances, oral involvement precedes the appearance of other symptoms or lesions at other locations. Oral lichen planus (OLP) is a chronic mucocutaneous disorder of stratified squamous epithelium of uncertain etiology that affects oral and genital mucous membranes, skin, nails, and scalp. LP is estimated to affect 0.5% to 2.0% of the general population. This disease has most often been reported in middle-aged patients with 30-60 years of age and is more common in females than in males. The disease seems to be mediated by an antigen-specific mechanism, activating cytotoxic T cells, and non-specific mechanisms like mast cell degranulation and matrix metalloproteinase activation. A proper understanding of the pathogenesis, clinical presentation, diagnosis of the disease becomes important for providing the right treatment. This article discusses the prevalence, etiology, clinical features, oral manifestations, diagnosis, complications and treatment of oral LP.

Immunohistochemical expression of cathepsin L in atopic dermatitis and lichen planus

Background:

Cathepsin L is a member of papain superfamily. It seems to promote T-cell survival, selection maturation in the thymus and enhance the antigen presentation. Cathepsin L plays an important role in tumor necrosis factors (TNF-α) induced cell death. Also it degrades the tight junction between cornedesomses in the epidermis. Elevated expression of cathepsin L has been found in many inflammatory and neoplastic diseases.

Objective:

The aim of this study was to determine immunohistochemical expression of cathepsin L in atopic dermatitis (AD) and lichen planus (LP) patients in order to evaluate its role in the pathogenesis of both diseases.

Materials and Methods:

This study included 15 patients with AD (Group I), 15 patients with LP (Group II), in addition to 10 healthy skin specimens served as controls (Group III). Punch biopsies were taken from lesional skin of the patients and controls for immunohistochemical detection of cathepsin L expression.

Results:

Highly significant increase was found in cathepsin L expression in AD and LP patients compared to controls [P = 0.001].

Conclusion:

Cathepsin L could be implicated as an important protease in the pathogenesis of AD and LP. It could be a useful marker for assessing AD severity.

Foxp3 gene expression in oral lichen planus: a clinicopathological study

CD4+CD25+ Forkhead‑box protein 3 (Foxp3+) regulatory T cells are important in oral lichen planus (OLP). The present study aimed to investigate Foxp3 expression in CD4+CD25+ T cells of peripheral blood mononuclear cells and oral lesions in patients diagnosed with OLP, who were grouped as OLP subtype, duration and relapse. Using quantitative polymerase chain reaction (qPCR), western blotting and immunohistochemistry, Foxp3 expression levels in explants of oral lesions and CD4+CD25+ T cells from 32 patients with OLP were measured and compared, with 10 healthy subjects as the control group. Foxp3 mRNA expression levels in the explants of oral lesions and circulating CD4+CD25+ T cells in patients with OLP were significantly higher than those in the control group (P<0.05). In patients with clinically erosive lesions, Foxp3 mRNA expression was significantly lower in circulating CD4+CD25+ T cells and tissue explants compared to patients with reticular lesions (P<0.01 and P<0.05, respectively), and lowest in patients with a history of OLP of >1 year or with a history of relapse (P<0.05 and P<0.01, respectively). Foxp3 protein levels in reticular OLP were significantly higher than those in erosive OLP and the control group. The incidence of Foxp3 protein expression in OLP tissues was 36.24±18.92 and 10.44±6.51% in normal oral mucosa (P=0.019). Atrophic/erosive OLP lesions showed a higher proportion of Foxp3‑expressing cells than that of reticular OLP lesions (P<0.05). This study indicated that Foxp3 expression in patients with OLP is associated with the severity and duration of the disorder, suggesting altered immune suppression in the development, clinical course and responsiveness to treatment.

Oral lichen planus: focus on etiopathogenesis

Lichen planus is a chronic mucocutaneous inflammatory disease, which frequently affects the oral mucosa of white females over 40 years old. Its aetiology remains uncertain and the pathogenesis is still the object of much speculation. The present paper presents the most well known antigens, and describes the action of different cells and proteins associated with the development of that disease, as well as the possible agents involved with its malignant transformation. Different external agents, especially virus, and internal agents, like stress, and the heat shock protein antigen expression, associated or not, can alter the basal keratinocytes of the oral mucosa making them susceptible to apoptosis by CD8(+) cytotoxic T cell as well as activate matrix metalloproteinase and mast cell degranulation, which produce a great range of inflammatory mediators and cytokines determining the clinical onset of the disease. Regarding carcinogenesis, since it is a complex process and presents multifactorial origin, it is believed that there may be a synergism between intrinsic, such as inflammation mediators, and extrinsic agents (tobacco, alcohol, viral infections) for the OLP malignant transformation to occur. However, further studies are needed to better understand the origin, pathogenesis and process of malignant transformation of OLP.

Oral lichen planus: An update on pathogenesis and treatment

Oral lichen planus (OLP) is a chronic inflammatory disease that affects the mucus membrane of the oral cavity. It is a T-cell mediated autoimmune disease in which the cytotoxic CD8+ T cells trigger apoptosis of the basal cells of the oral epithelium. Several antigen-specific and nonspecific inflammatory mechanisms have been put forward to explain the accumulation and homing of CD8+ T cells subepithelially and the subsequent keratinocyte apoptosis. A wide spectrum of treatment modalities is available, from topical corticosteroids to laser ablation of the lesion. In this review, we discuss the various concepts in the pathogenesis and current treatment modalities of OLP.

Altered expression of HSP70 in oral lichen planus

Background:

Oral lichen planus (OLP), a well-known mucocutaneous lesion has been the center of debate regarding its obscure etiopathogenesis. Recent highlight has been placed on the role of autoimmunity and a sect of constitutional molecules, the native chaperones HSP70, proposed to be important in the onset and progress of disease.

Aim:

To substantiate a potential role of HSP70 in the pathogenesis of oral lichen planus.

Settings and Design:

The study involved immunohistochemical (IHC) analyses in a laboratory under monitored conditions. It was a retrospective study on clinically and histopathologically confirmed specimens.

Materials and Methods:

30 samples of confirmed cases of OLP were selected and grouped on the basis of the thickness of the epithelial layer into atrophic, normal (classical) and acanthotic. An immunohistochemical analysis of the expression of HSP70 protein was done, followed by a quantitative and qualitative analysis of the stained layers.

Statistical Analyses:

A Z test was performed to estimate the difference observed between two sample proportions. The statistics was given at 1% level of significance i.e. P<0.01.

Results:

An increased expression of HSP70 was noted in the basal and suprabasal cells of the epithelium of OLP. A higher count and intensity of HSP70 expression was seen in the basal layer of the epithelium. Greater expression was noted in the epithelium of the atrophic group.

Conclusion:

The expression pattern of HSP70 positively implicates it in the pathogenesis of OLP.

Mast cells distribution and variations in epithelium thickness and basement membrane in oral lichen planus lesion and oral lichenoid reaction

Background:

Oral lichen planus (OLP) is a chronic mucocutaneous lesion with unknown etiology. Oral lichenoid lesions (OLL) comprise a family of lesions with different etiologies. Both lesions have similar clinical and histopathologic characteristics although their management is different. Differential diagnosis between OLP and OLL has always been a major challenge.

Materials and Methods:

In this prospective analytical study, the role of mast cells in pathogenesis of these lesions was investigated by evaluation of 52 patients with clinical and histopathological diagnosis of OLP (26 cases) and OLL (26 cases) based on WHO criteria, and by applying a more accessible staining methods, Hematoxylin and Eosin, toluidine blue (histochemistry) and Periodic Acid Schiff staining. In order to distinguish these two lesions, number of mast cells and thickness of epithelium and basement membrane were measured using light microscopy. Data were analyzed by SPSS software using t-test method (P<0.001).

Results:

No significant difference was observed between the total numbers of mast cells of two groups (P=0.148), but a statistically significant difference was detected between degranulated mast cells in two groups (P<0.001). A significant difference was also observed between the thickness of epithelium in two groups (P<0.001), although no difference was seen between basement membrane thickness in these lesions.

Conclusion:

Number of degranulated mast cells in reticular layer of corium in lichenoid lesions was more than that of OLP. This implies that despite the increase in number of these cells, in both groups of diseases, the role of these cells has not been the same in pathogenesis of the diseases. Moreover, the epithelium thickness was lower in lesions of OLP compared to lesions of oral lichenoid, so this parameter may be a useful criterion together with other histopathological and clinical finding to discriminate these lesions. However, discrepancy of basement membrane thickness can not be a reliable criterion. Finally we suggest more accessible staining methods which are reliable for differentiation of these two lesions.

Serum level of matrix metalloproteinase-3 in patients with oral lichen planus

BACKGROUND

Oral Lichen planus (OLP) is a chronic lesion of the oral mucosa with unknown origin. Basement membrane changes are common in OLP and may be mediated by proteases such as matrix metalloproteinase (MMPs) and mast cell chymase. The aim of our study was to evaluate the level of serum MMP-3 in OLP com-pared to normal individuals and assess its clinical significance.

METHODS

Thirty four serum samples from patients diagnosed with OLP (12 males, 22 females, age: 42.2±10.8 years) and 34 serum samples from healthy control subjects (11 males, 23 females, age: 42.5±13.3 years) were collected and MMP-3 concentration was measured by ELISA.

RESULTS

The serum MMP-3 level in OLP patients was higher (21.64±24.31 ng/ml) compared with healthy con-trols (16.52±23.63 ng/ml), but showed no statistically significant difference. A statistically significant difference was demonstrated between the two types of OLP, being more pronounced in the erosive/atrophic form 6).

CONCLUSION

The different clinical appearances of OLP are associated with significant differences in MMP-3 serum level.