Autocytotoxic T-cell clones in lichen planus

An Autopsy Case of Bronchiolitis Obliterans Associated With Oral Lichen Planus and Non-Hodgkin Lymphoma

We report the autopsy case of a 66-year-old woman with indolent B-cell non-Hodgkin lymphoma (NHL) who underwent repeated chemotherapy for 18 years. Two and a half years ago, she developed oral lichen planus and began corticosteroid treatment. Lichen planus recurred repeatedly with corticosteroid reduction. Obstructive ventilation impairment and respiratory failure had progressed two years ago. She was admitted to the hospital due to cytomegalovirus infection and died of respiratory failure. An autopsy revealed bronchiolitis obliterans, oral lichen planus, and recurrence of pre-existing NHL. This was a rare case of bronchiolitis obliterans with oral lichen planus and NHL.

A Rare Case of Lichen Planus Mimicking Secondary Syphilis: The Great Imitator Unveiled

Secondary syphilis, often referred to as "The Great Imitator," is a diagnostic challenge due to its ability to mimic a range of dermatological conditions. Accurate differentiation is critical, particularly in patients with immunocompromised states, as misdiagnosis can lead to inappropriate management. This case highlights a unique presentation of lichen planus resembling secondary syphilis. A 68-year-old female undergoing chemotherapy for breast cancer presented with asymptomatic pink, scaly plaques on her palms and mucosal patches on her tongue. Concern for secondary syphilis prompted a serologic workup, including a rapid plasma reagin (RPR) test, which was non-reactive. Physical examination revealed no cervical, axillary, or inguinal lymphadenopathy, a hallmark feature of secondary syphilis. A 3 mm punch biopsy of the palmar lesions showed findings characteristic of lichen planus, including hyperkeratosis, hypergranulosis, and a band-like lymphocytic infiltrate. Special stains for spirochetes were negative. The patient was treated with apremilast (Otezla®) 30 mg orally twice daily and clobetasol 0.05% cream applied twice daily. After two weeks, significant improvement in the lesions was observed. This case underscores the diagnostic complexities of lichen planus mimicking secondary syphilis. Secondary syphilis commonly presents with systemic symptoms and lymphadenopathy, which were absent in this patient. Histopathologic confirmation played a pivotal role in differentiating the two conditions. This case adds to the growing body of knowledge on atypical presentations of lichen planus in immunocompromised patients. Clinicians should maintain a broad differential diagnosis for palmoplantar and mucosal lesions. Histopathology remains a cornerstone in confirming the diagnosis and guiding appropriate management.

Lichen Planus: What is New in Diagnosis and Treatment?

Lichen planus (LP), an idiopathic, multifaceted chronic inflammatory disease with a heterogeneous clinical presentation, affects approximately 0.5-1% of the population. The various clinical manifestations of LP fall into three broad categories, namely cutaneous, appendageal, and mucosal, with further subclassification depending on the morphology and distribution patterns of individual lesions. There is mounting evidence that LP has systemic associations, including autoimmune conditions, glucose intolerance, dyslipidemia, and cardiovascular disorders. Cutaneous hypertrophic and mucosal forms of LP are at a heightened risk for malignant transformation. Familiarity with these potential associations in conjunction with long-term follow-up and regular screening could lead to a timely diagnosis and management of concomitant conditions. In addition, the frequent quality of life (QoL) impairment in LP underscores the need for a comprehensive approach including psychological evaluation and support. Several treatment strategies have been attempted, though most of them have not been adopted in clinical practice because of suboptimal benefit-to-risk ratios or lack of evidence. More recent studies toward pathogenesis-driven treatments have identified Janus kinase inhibitors such as tofacitinib, phosphodiesterase-4 inhibitors such as apremilast, and biologics targeting the interleukin-23/interleukin-17 pathway as novel therapeutic options, resulting in a dramatic change of the treatment landscape of LP. This contemporary review focuses on the diagnosis and management of LP, and places emphasis on more recently described targeted treatment options.

Network pharmacology and molecular docking analysis predict the mechanisms of Huangbai liniment in treating oral lichen planus

This study explored the mechanism of Huangbai liniment (HB) for the treatment of oral lichen planus (OLP) through network pharmacology and molecular docking techniques. The study identified HB' active ingredients, therapeutic targets for OLP, and associated signaling pathways. The chemical composition of HB was screened using the HERB database. The disease targets of OLP were obtained through the GeneCards and OMIM databases. A protein-protein interactions network was constructed with the String platform. Topological analysis was performed using Cytoscape software to identify core targets. Gene ontology and Kyoto encyclopedia of genes and genomes pathway enrichment analysis were performed using the Hiplot database, and the active ingredients and core targets were verified by molecular docking. Date analysis showed that the active composition of HB in the treatment of OLP were quercetin, wogonin, kaempferol, and luteolin. This survey identified 10 potential therapeutic targets, including TNF, CXCL8, IL-6, IL1B, PIK3R1, ESR1, JUN, AKT1, PIK3CA, and CTNNB1. Molecular docking revealed stable interactions between OLP' key targets and HB. These key targets were predominantly involved in the PI3K-Akt signaling pathway, AGE-RAGE signaling pathway, TNF signaling pathway, and HIF-1 signaling pathway. HB plays a crucial role in the treatment of OLP, acting on multiple targets and pathways, particularly the PI3K-Akt signaling pathway. It regulated biological processes like the proliferation of epithelial cells and lymphocytes and mediates the expression of transcription factors, cytokines, and chemokines. Therefore, this study provides a theoretical basis for the clinical trial and application of HB in the therapy of OLP.

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

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

Lichenoid mucocutaneous reactions associated with sintilimab therapy in a non-small cell lung adenocarcinoma patient: case report and review

The immune checkpoint inhibitor (ICI), anti-programmed cell death receptor-1 (PD-1) antibody, has gained widespread approval for treating various malignancies. Among the immune-related adverse reactions (irAEs) during ICI treatment, the lichenoid reaction is noteworthy. Sintilimab, a new PD-1 inhibitor, has secured approval in China for treating refractory non-Hodgkin's lymphoma, and phase I/II clinical trials for other solid tumors are ongoing both domestically and abroad. This paper presents a case of a mucocutaneous lichenoid reaction associated with sintilimab therapy, its diagnosis, and management. Our study, using multiplex immunofluorescence staining, reveals localized infiltration of CD4+ and CD8+ T lymphocytes in the subepithelial lamina propria region with upregulated PD-1 expression, implying an association between PD-1 expression upregulation and lichenoid reactions provoked by PD-1 monoclonal antibody. We provide a summary of clinical characteristics and treatment guidelines for lichenoid reactions induced by ICIs from previous reports, highlighting the success of a combined therapeutic regimen of oral antihistamines and topical corticosteroids in controlling symptoms without interrupting ICI treatment.

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.

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.

Characterization of Mucosal-Associated Invariant T Cells in Oral Lichen Planus

Oral lichen planus (OLP) is an inflammatory condition of unknown cause that has been associated with concurrent candidal infection. Mucosal-associated invariant T (MAIT) cells express the T cell receptor TCRVα7.2 and are activated by riboflavin intermediates produced by microbes. The interaction between MAIT cells, Candida, and OLP is unknown. This study aimed to determine mucosal-associated T cell presence in OLP and whether the abundance of these cells changed due to the presence of either Candida or symptoms, using multiplex immunohistochemistry (mIHC). Ninety formalin fixed-paraffin-embedded (FFPE) tissue samples were assessed using mIHC for the cellular markers CD3, interleukin 18 receptor one (IL18R1), TCRVα7.2, CD161, CD8, and major histocompatibility complex class I-related (MR-1) protein. The samples were stratified into five groups on the basis of clinical (presence/absence of symptoms) and microbiological (presence/absence of Candida) criteria. Results demonstrated the presence of MAIT cell phenotypes in OLP inflammatory infiltrate within the connective tissue. Significant differences existed between different OLP groups with the percentage of log(CD3+ CD161+) and log(CD3+ TCRVα7.2+) positive cells (p < 0.001 and p = 0.005 respectively). Significant differences also existed with the relative abundance of triple-stained log(CD3+ CD161+ IL18R1+) cells (p = 0.004). A reduction in log(CD3+ CD161+ IL18R1+) cells was observed in lesional tissue of patients with symptomatic OLP with and without Candida when compared to controls. When present in OLP, MAIT cells were identified within the connective tissue. This study demonstrates that mIHC can be used to identify MAIT cell phenotypes in OLP. Reduced percentage of log(CD3+ CD161+ IL18R1+) cells seen in symptomatic OLP with and without Candida suggests a role for these cells in OLP pathogenesis.

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.

The critical role of IFNγ in the epidermotropic migration of lymphocytes in oral lichen planus

INTRODUCTION

The chemokines play a crucial role in the recruitment of lymphocytes in oral lichen planus, and the activated epithelial cells are the main producers of the chemokines. However, the signals provoking chemokine secretion still remain to be elucidated.

METHODS

The global expression profile of chemokines in oral epithelial cell line induced by IFNγ was determined by microarray analysis. The gene and protein expression was validated in primary culture of oral epithelial cells, and the effects of IFNγ on regulating chemokine production were compared with that of TNFα and IL2. Moreover, the capability of primary culture of oral epithelial cells to attract peripheral lymphocytes in response to IFNγ was investigated in oral lichen planus patients, and the cell phenotype of the recruited lymphocytes was analyzed using flow cytometry.

RESULTS

IFNγ triggered the expression of multiple chemokines in the oral epithelial cells. The expression pattern of the chemokines closely resembled that in the epithelial cell layer of oral lichen planus lesions. Compared with IL2 and TNFα, IFNγ demonstrated a distinct maximal effect on the chemokines secretion in primary culture of oral epithelial cells. The migration of peripheral lymphocytes toward the culture supernatant of IFNγ-treated primary culture of oral epithelial cells was significantly enhanced in the oral lichen planus group compared to that in the healthy control group.

CONCLUSION

IFNγ plays an important role in the chemokine secretion and epidermotropic migration of lymphocytes in oral lichen planus.

Therapeutic strategies for oral lichen planus: State of the art and new insights

Oral lichen planus (OLP) is a chronic inflammatory disease of the oral mucosa. Several clinical subtypes of OLP have been reported, including the reticular and erosive one. On the one hand, reticular OLP is usually asymptomatic and is characterized by white streaks surrounded by well-defined erythematous borders. On the other hand, erosive OLP shows ulcerations and erosions surrounded by erythematous mucosa. While reticular OLP is relatively easy to control, erosive OLP is extremely painful and refractory to therapies, limiting the quality of life of the patients. In addition, treating erosive OLP is extremely tricky, and a gold standard treatment has not yet been established. However, several therapeutic approaches have been reported as effective, including systemic corticosteroids, systemic retinoids, and anti-interleukin (IL)-17/anti-IL-23 drugs. Indeed, our group and other several authors reported the effectiveness of anti-IL17, anti-IL12/23, and anti-IL23 agents in refractory OLP, highlighting the urgency of clinical studies on the use of anti-IL agents in OLP patients. In this paper, we reviewed the English- and German-language literature about therapeutic strategies for treating OLP, focusing on new systemic therapies for erosive OLP.

Expression and Significance of TNF-α and NF-κB/p65 in Cutaneous Lichen Planus

Purpose

The purpose of this study was to explore the expression of TNF-α and NF-κB/p65 in Lichen planus skin lesions and their correlation with the pathogenesis of Lichen planus.

Patients and Methods

The case group consisted of 30 individuals diagnosed with LP based on clinical and histopathologic examination. The control group consisted of 10 individuals from an Orthopedic Department with normal skin. TNF-α and NF-κB/p65 expression in skin tissue samples was detected by immunohistochemistry.

Results

The immunohistochemical results showed that TNF-α and NF-κB/p65 expression levels were significantly higher in LP skin lesions than normal skin tissues (P ≤ 0.05). Positive TNF-α staining mainly occurred in the cytoplasm of keratinocytes of the stratum granulosum, stratum spinosum, and stratum basale in the epidermis and lymphocytes in the superficial dermis. Positive NF-κB/p65 staining mainly occurred in the nucleus and cytoplasm of keratinocytes of the stratum spinosum and stratum basale in the epidermis and lymphocytes in the superficial dermis.

Conclusion

TNF-α and NF-κB/p65 are overexpressed in cutaneous LP. The two are positively correlated in LP, suggesting that they both play essential roles in the pathogenesis of LP.

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.

Langerhans Cells, T Cells, and B Cells in Oral Lichen Planus and Oral Leukoplakia

Although oral lichen planus (OLP) and oral leukoplakia (LPL) have different pathogenetic profiles, both may involve chronic inflammation. The aim of this observational study was to evaluate the inflammatory cell profiles of OLP and LPL. The inflammatory cell infiltrates in patients with OLP and LPL were analyzed for the presence of Langerhans cells (LCs; CD1a), T cells (CD3), and B cells (CD20), as well as for the proliferation marker Ki-67. Biopsied specimens from patients with OLP (N = 14) and LPL without dysplasia (N = 13) were immunohistochemically stained with antibodies directed against CD1a, CD3, CD20, and Ki-67, followed by quantitative analyses. A significant increase in the number of CD3⁺ cells and CD20⁺ cells was found in the submucosa of OLP, as compared to LPL (p < 0.01). Likewise, the number of CD3⁺ cells was significantly higher in the epithelium of OLP than of LPL (p < 0.05). No differences were found in the expression of Ki-67 and the number of CD1a⁺ cells between the two groups. Although an immune response is elicited in both conditions, there are differences at the cellular level between OLP and LPL. A more robust immune activation involving T cells and B cells is seen in OLP. The role of B cells in OLP needs to be further elucidated. Although the number of B cells in LPL is low, their role in the inflammatory response cannot be ruled out.

Immune mechanisms in oral lichen planus

Oral lichen planus (OLP) is a T-cell-mediated inflammatory disease of the oral mucosa that has been extensively researched over many years but as yet the mechanisms of pathogenesis are still not fully understood. Whilst the specific etiologic factors driving OLP remain ambiguous, evidence points to the development of a chronic, dysregulated immune response to OLP-mediating antigens presented by innate immune cells and oral keratinocytes leading to increased cytokine, chemokine and adhesion molecule expression. These molecules recruit T-cells and mast cells to the diseased site and orchestrate a complex interplay between cells that culminates in keratinocyte cell death, mucosal basement membrane destruction and long-term chronicity of the disease. The main lymphocytes involved are thought to be CD8+ cytotoxic and CD4+ Th1 polarised T-cells although recent evidence indicates the involvement of other Th subsets such as Th9, Th17 and Tregs, suggesting that a more complex immune cell relationship exists during the disease process. This review provides an overview of the immune mechanisms at play in OLP pathogenesis with particular emphasis on the role of the different Th subsets and how these recent discoveries may guide research toward identifying potential therapeutic targets.

Increased Level of Serum Wingless-Type Mouse Mammary Tumor Virus Integration Site Family Member 5a in Patients with Cutaneous Lichen Planus

Purpose

Methods

Results

Conclusion

Lichen Planus

Lichen planus (LP) is a T cell-mediated disease affecting the stratified squamous epithelia of the skin and/or mucus membrane. Histologically, the disease is characterized by a lichenoid inflammatory infiltrate and vacuolar degeneration of the basal layer of the epidermis. LP has three major subtypes: Cutaneous, mucosal and appendageal LP. Rarely, it may affect the nails in the absence of skin and/or mucosal changes. LP may also be induced by several drugs, typically anti-hypertensive medication or be associated with infections, particularly viral hepatitis. The diagnosis is based on the clinical presentation and characteristic histological findings. Although the disease is often self-limiting, the intractable pruritus and painful mucosal erosions result in significant morbidity. The current first-line treatment are topical and/or systemic corticosteroids. In addition, immunosuppressants may be used as corticosteroid-sparing agents. These, however are often not sufficient to control disease. Janus kinase inhibitors and biologics (anti-IL-12/23, anti-IL17) have emerged as novel future treatment options. Thus, one may expect a dramatic change of the treatment landscape of LP in the near future.

Reduced expression of programmed cell death 1 and programmed cell death ligand 1 in infiltrating inflammatory cells of lichen planus without administration of immune checkpoint inhibitors

Keratinocytes are the main targets of infiltrating T cells in the pathogenesis of lichen planus. However, the mechanisms of dense inflammatory infiltrates beneath the epidermis remain unknown. The aim of the present study was to clarify the roles of programmed cell death 1 (PD-1) and its ligand (PD-L1) in the pathogenesis of lichen planus. Immunohistochemistry of PD-1 and PD-L1 in 12 cases each of lichen planus and dermal-type erythema multiforme was performed. The expression of PD-1 and PD-L1 on infiltrating inflammatory cells, predominantly lymphocytes in lichen planus, was significantly less compared to that in dermal-type erythema multiforme. By dual immunofluorescence, the overlap between PD-1 and leukocyte common antigen, CD4, CD8, CD68, and factor XIIIa was limited and found in only a very small portion of lichen planus cells. Our data suggest that decreased expression of PD-1 and PD-L1 could play a role in accelerating inflammatory cell infiltration targeting the epidermis in the pathogenesis of lichen planus.

T cell-derived exosomes containing cytokines induced keratinocytes apoptosis in oral lichen planus

OBJECTIVE

Oral lichen planus (OLP) is a T cell-mediated inflammatory disease with uncertain etiology. Exosomes are cell-derived vesicles containing biological cargo, being associated with the development of multiple inflammatory diseases. The present study aims to investigate the role of T cell-derived exosomes in the pathogenesis of OLP.

METHODS

Exosomal marker CD63 was detected in OLP lesions by immunohistochemistry. Twenty-three cytokines in T cell-derived exosomes were assessed using luminex xMAP-based assay. After co-incubating with exosomes, the apoptosis of keratinocytes and the proliferation of Jurkat cells were assessed via flow cytometry and cell counting kit-8 assay, respectively.

RESULTS

CD63 was highly expressed in the lymphocyte infiltrated areas of OLP lesions. OLP T cell-derived exosomes contained upregulated interleukin-7, -10, -12, -17 and downregulated interleukin-1β, -5, and interferon-γ. Both exosomes from OLP patients and controls induced the apoptosis of keratinocytes and altered their morphology. Moreover, healthy control-derived exosomes markedly inhibited the proliferation of Jurkat cells, whereas OLP-derived exosomes exhibited no inhibitory effect.

CONCLUSIONS

OLP T cell-derived exosomes have an aberrant cytokine profile and could trigger the apoptosis of keratinocytes in vitro, which may be involved in the pathogenesis of OLP.

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.

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.

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.

Omega-3 polyunsaturated fatty acids: a promising approach for the management of oral lichen planus

BACKGROUND

Oral lichen planus (OLP) is a T-cell-mediated inflammatory disease with a risk of malignant transformation. Although the etiology of OLP is still uncertain, growing evidence suggests that oral microbiota, antigen-specific, and non-specific mechanisms are involved in the pathogenesis of OLP. Antigen-specific mechanisms include antigen presentation, T-cell activation, nuclear factor-kappa B signaling pathway, and cytokine secretion, while non-specific mechanisms consist of matrix metalloproteinases (MMP)-9 upregulation, psychological pressure, oxidative damage, aberrant expression of microRNAs (miRNAs), and autophagy. Till now, there is no cure for OLP, and the main purpose of OLP therapy is symptomatic control.

FINDING

Seafood and its derivative omega-3 polyunsaturated fatty acids (n-3 PUFAs) can suppress antigen presentation, T-cell activation, and nuclear factor-kappa B signaling pathway, modulate the overexpressed inflammatory cytokines, inhibit the expression of MMP-9, as well as regulate the expression of miRNAs and autophagy. And they are possible agents for ameliorating psychological disorder and oxidative damage. Moreover, n-3 PUFAs supplementation has a beneficial effect on preventing tumorigenesis.

CONCLUSION

n-3 PUFAs consumption may provide a non-toxic, inexpensive administration for OLP.

Impedance and Histologic Characteristics of the Sub-Laryngeal Esophagus Distinguish Eosinophilic Esophagitis From Other Esophageal Disorders

BACKGROUND & AIMS

The region of the esophagus 15-17 cm below the incisors, called the sub-upper esophageal sphincter (sub-UES), has not been characterized in adults with eosinophilic esophagitis (EoE) but appears different during endoscopy. We investigated how the sub-UES differs from the remaining esophagus in patients with EoE and aimed to determine whether these differences be used to distinguish patients with EoE from those with lichen planus.

METHODS

We performed a prospective study of 14 patients with EoE, 7 patients with lichen planus (based on presence of Civatte bodies, dysphagia, and/or narrow esophagus with thin esophageal mucosa without signs of EoE), and 20 patients undergoing upper endoscopy for upper gastrointestinal or with dysphagia but without features of EoE (controls) at a single medical center from 2015 through 2018. Biopsies from the distal, middle, and sub-UES regions of the esophagus were analyzed by histology, quantitative PCR, and immunohistochemistry. We measured mucosal impedance (MI) in all subjects at the sub-UES and 2 cm, 5 cm, and 10 cm from the gastro-esophageal junction.

RESULTS

Patients with EoE had significantly fewer eosinophils (median, 2 eosinophils/high-powered field [HPF]; range, 0-8 eosinophils/HPF) in sub-UES tissues compared with distal esophagus (median, 50 eosinophils/HPF; range, 22.5-60.8 eosinophils/HPF; P < .0001) or middle esophagus (median, 32 eosinophils/HPF; range, 19.3-60; P < .0001). Sub-UES tissues from patients with EoE had significantly less basal cell hyperplasia (P < .01), papillary elongation (P < .01), and dilated intercellular spaces (P < .01) than middle or and distal esophagus. MI in the sub-UES did not differ significantly between patients with EoE vs controls (P = .24), but was significantly lower in patients with lichen planus (median, 1344 ohms; range, 1046-1488) than patients with EoE (median, 2880 ohms; range, 2149-4858) (P < .001). mRNA and protein expression patterns did not differ significantly in the sub-UES of patients with EoE vs controls, except for expression of desmoglein-1, which was increased in sub-UES tissues from patients with EoE.

CONCLUSIONS

Sub-UES tissues from patients with EoE differ in numbers of eosinophils, histologic features, and MI compared to controls or patients with lichen planus. These features might help to distinguish these 2 diseases.

Fixed drug eruptions, bullous drug eruptions, and lichenoid drug eruptions

Drug reactions are among the most common reasons for inpatient dermatology consultation. These reactions are important to identify because discontinuation of the offending agent may lead to disease remission. With the rising use of immunomodulatory and targeted therapeutics in cancer care and the increased incidence in associated reactions to these drugs, the need for accurate identification and treatment of such eruptions has led to the development of the "oncodermatology" subspecialty of dermatology. Immunobullous drug reactions are a dermatologic urgency, with patients often losing a significant proportion of their epithelial barrier; early diagnosis is critical in these cases to prevent complications and worsening disease. Lichenoid drug reactions have myriad causes and can take several months to occur, often leading to difficulties identifying the offending drug. Fixed drug eruptions can often mimic other systemic eruptions, such as immunobullous disease and Stevens-Johnson syndrome, and must be differentiated from them for effective therapy to be initiated. We review the clinical features, pathogenesis, and treatment of immunobullous, fixed, and lichenoid drug reactions with attention to key clinical features and differential diagnosis.

Dermatologic Problems Commonly Seen by the Allergist/Immunologist

Allergists/immunologists see a variety of skin disorders, some of which have a known immunologic basis whereas others do not. We review the prevalence, etiology, clinical presentation, and effective and low-cost care of common dermatologic conditions seen in outpatient practices. Conditions discussed include pityriasis alba, seborrheic dermatitis, rosacea, acne, tinea infections, intertrigo, lichen planus, tinea versicolor, lichen simplex chronicus, scabies, pityriasis rosea, keratosis pilaris, and seborrheic keratosis. An understanding of frequently encountered cutaneous diseases and their therapies will help provide immediate access to treatment and improve the experience for both the affected patient and the clinician.

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.

Down-regulation of miRNA-27b-3p suppresses keratinocytes apoptosis in oral lichen planus

Oral lichen planus (OLP) is considered a precancerous lesion with no known cure. Recent studies reported that abnormal regulation of apoptosis was involved in the pathogenesis of OLP. Next generation sequencing was used to screen the candidate microRNAs and genes in biopsies from patients with OLP and healthy mucosa. Human oral keratinocytes were transfected into the related oligonucleotides of miR‐27b‐3p/cyclophilin D and their control groups. Apoptosis was detected by TdT‐mediated dUTP nick end labelling and flow cytometry. The levels of mRNA and protein were detected by quantitative PCR, Western blots, and enzyme‐linked immunosorbent assays, respectively. Luciferase assays were performed to detect the luciferase activities of miR‐27b‐3p and cyclophilin D. Here, we showed that basal epithelium apoptosis was reduced and the miR‐27b‐3p levels were decreased in clinical OLP samples. We also found that down‐regulation of miR‐27b‐3p inhibited epithelial keratinocyte apoptosis by up‐regulating cyclophilin D expression. Moreover, cyclophilin D increased the protein stability of Bcl2 through direct binding, and Bcl2 suppressed caspase9/3 activation and cytochrome C release. Taken together, these data showed that miR‐27b‐3p regulated keratinocyte apoptosis through cyclophilin D/Bcl2 signalling, suggesting the miR‐27b‐3p regulated the pathogenesis of OLP.

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

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

Phenotypic alteration of basal cells in oral lichen planus; switching keratin 19 and desmoglein 1 expression

In oral lichen planus, extracellular matrix and basal cells are damaged by T-lymphocytes. As a consequence, changes in expression of collagen fibers within the connective tissue and cytoskeletons of the epithelial tissue can be observed. With the goal of examining the characteristic changes undergone by basal cells as a consequence of T-lymphocytes damage in oral lichen planus, we investigated protein expression in the epithelial-connective junction. We selected 20 cases of oral lichen planus and 5 control samples of buccal mucosa. Subsequently, we divided the oral lichen planus cases into thin and thick parts based on the mean values of epithelial thickness from the control samples, and counted the positive rate of collagen IV, keratin 19, desmoglein 1, and Ki-67. Collagen IV immune-reactivity partially disappeared or thickened in oral lichen planus. The keratin 19 positive rate in oral lichen planus cases was significantly lower than in the controls. Desmoglein 1 positive rate of the thick part was significantly higher compared to the thin part of oral lichen planus. Thus, modifications in basal cells with both reduced keratin 19 expression and alterations of desmoglein 1 expression suggest that in oral lichen planus, as a consequence of cell injury or regeneration in the interface area, there is a disappearance of the "true basal cell nature".

Clinical features and management of oral lichen planus (OLP) with emphasis on the management of hepatitis C virus (HCV)-related OLP

Oral lichen planus (OLP) is a chronic inflammatory disease characterized by the occurrence of multiple, symmetrical lesions in the oral cavity. Hepatitis C virus (HCV) infection has been suggested as an etiological factor in OLP. The purpose of this review was to summarize the current literature regarding the treatment of OLP in patients with HCV infection. An electronic search of the PubMed database was conducted until January 2018, using the following keywords: OLP, HCV, corticosteroids, retinoids, immunomodulatory agents, surgical interventions, photochemotherapy, laser therapy, interferon, ribavirin, and direct-acting antivirals. We selected the articles focusing on the clinical features and treatment management of OLP in patients with/without HCV infection. Topical corticosteroids are considered the first-line treatment in OLP. Calcineurin inhibitors or retinoids can be beneficial for recalcitrant OLP lesions. Systemic therapy should be used in the case of extensive and refractory lesions that involve extraoral sites. Surgical intervention is recommended for isolated lesions. In patients with HCV, monotherapy with interferon (IFN)-α may either improve, aggravate or trigger OLP lesions, while combined IFN-α and ribavirin therapy does not significantly influence the progression of lesions. Direct-acting antiviral (DAA) therapy appears to be a promising approach in patients with HCV-related OLP, as it can improve symptoms of both liver disease and OLP, with fewer side effects. Nevertheless, for clinical utility of DAAs in OLP patients, further studies with larger sample sizes, adequate treatment duration, and long term follow-up are required.

Epstein-Barr Virus–Infected Plasma Cells Infiltrate Erosive Oral Lichen Planus

Epstein-Barr virus (EBV), in addition to its transforming properties, contributes to the pathogenesis of several inflammatory diseases. Here, we investigated its involvement in oral lichen planus (OLP), a common autoimmune-like disease of unknown etiopathogenesis that can display a malignant potential. EBV-infected cells (EBV+ cells) were sought in a large series of clinically representative OLPs ( n = 99) through in situ hybridization to detect small noncoding EBV-encoded RNAs. Overall, our results demonstrated that EBV was commonly found in OLP (74%), with significantly higher frequency (83%) in the erosive form than in the reticular/keratinized type mild form (58%). Strikingly, many erosive OLPs were massively infiltrated by large numbers of EBV+ cells, which could represent a large part of the inflammatory infiltrate. Moreover, the number of EBV+ cells in each OLP section significantly correlated with local inflammatory parameters (OLP activity, infiltrate depth, infiltrate density), suggesting a direct relationship between EBV infection and inflammatory status. Finally, we characterized the nature of the infiltrated EBV+ cells by performing detailed immunohistochemistry profiles ( n = 21). Surprisingly, nearly all EBV+ cells detected in OLP lesions were CD138+ plasma cells (PCs) and more rarely CD20+ B cells. The presence of EBV+ PCs in erosive OLP was associated with profound changes in cytokine expression profile; notably, the expression of key inflammatory factors, such as IL1-β and IL8, were specifically increased in OLP heavily infiltrated with EBV+ PCs. Moreover, electron microscopy–based experiments showed that EBV+ PCs actively produced EBV viral particles, suggesting possible amplification of EBV infection within the lesion. Our study thus brings conclusive evidence showing that OLP is commonly infiltrated with EBV+ PCs, adding a further puzzling element to OLP pathogenesis, given that PCs are now considered to be major regulatory immune cells involved in several autoimmune diseases (ClinicalTrials.gov NCT02276573).

Lichenoid Dermatitis of the Vulva: Diagnosis and Differential Diagnosis for the Gynecologic Pathologist

Inflammatory processes affecting the vulva may present a unique challenge due to location specific changes. Different factors are behind the intricacy in the presentation of vulvar dermatoses. First, the vulva is lined by different epithelia (hair-bearing keratinized epithelium, modified mucosa, and mucosa). Furthermore, among other factors, this organ is exposed to friction, occlusion, and trauma. Lastly, as there is a tendency to look for health care advice at an advanced stage of the disease, the lesion may be modified by secondary changes due to self-treatment. This article describes the clinical presentation and pathologic features of vulvar dermatoses with a lichenoid pattern and highlights practical points for their diagnoses.

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

BACKGROUND & AIMS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Triggers of oral lichen planus flares and the potential role of trigger avoidance in disease management

OBJECTIVE

Many patients with oral lichen planus (OLP) report triggers of flares, some of which overlap with triggers of other oral diseases, including oral allergy syndrome and oral contact dermatitis. The purpose of this study was to evaluate the prevalence of commonly reported triggers of OLP flares, their overlap with triggers of other oral diseases, and the potential role of trigger avoidance as a management strategy.

STUDY DESIGN

Questionnaire-based survey of 51 patients with biopsy-proven lichen planus with oral involvement seen in an academic dermatology specialty clinic and/or oral pathology clinic between June 2014 and June 2015.

RESULTS

Of the participants, 94% identified at least one trigger of their OLP flares. Approximately half of the participants (51%) reported at least one trigger that overlapped with known triggers of oral allergy syndrome, and 63% identified at least one trigger that overlapped with known triggers of oral contact dermatitis. Emotional stress was the most commonly reported trigger (77%). Regarding avoidance, 79% of the study participants reported avoiding their known triggers in daily life. Of those who actively avoided triggers, 89% reported an improvement in symptoms and 70% reported a decrease in the frequency of flares.

CONCLUSIONS

Trigger identification and avoidance can play a potentially effective role in the management of OLP.

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

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

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

OBJECTIVE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Clinical and Histopathologic Characterization of Canine Chronic Ulcerative Stomatitis

Canine chronic ulcerative stomatitis, also known as chronic ulcerative paradental stomatitis, is a painful condition of the oral cavity. The purpose of this study was to determine if there are commonalities in clinical and radiographic features among patients, whether the histopathologic evaluation might inform the pathogenesis, and whether the condition appears similar to human oral mucosal diseases. To do this, we prospectively collected clinical, radiographic, and histopathologic data from 20 dogs diagnosed with the disease. Clinical data were based on a clinical disease activity index, oral and periodontal examination parameters, and full-mouth dental radiographs. The histopathological and immunohistochemical data were based on oral mucosal samples obtained from erosive or ulcerated areas. Our findings revealed that canine chronic stomatitis is clinically characterized by painful oral mucosal ulcers of varying size, pattern, appearance, and distribution, most often associated with teeth with early periodontitis. Histologic examination revealed a subepithelial lichenoid band (interface mucositis) where B cells, T cells, and Forkhead-box protein 3 (FoxP3)- and interleukin-17-expressing cells were present. These cells might play a role in the underlying immune response and an immune-mediated pathogenesis is suspected. The clinical and histopathologic features of this chronic inflammatory mucosal disease in dogs resemble those of oral lichen planus in humans.

TGF-β Signal Transduction in Oro-facial Health and Non-malignant Disease (Part I)

The transforming growth factor-beta (TGF-β) family of cytokines consists of multi-functional polypeptides that regulate a variety of cell processes, including proliferation, differentiation, apoptosis, extracellular matrix elaboration, angiogenesis, and immune suppression, among others. In so doing, TGF-β plays a key role in the control of cell behavior in both health and disease. In this report, we review what is known about the mechanisms of activation of the peptide, together with details of TGF-β signal transduction pathways. This review summarizes the evidence implicating TGF-β in normal physiological processes of the craniofacial complex—such as palatogenesis, tooth formation, wound healing, and scarring—and then evaluates its role in non-malignant disease processes such as scleroderma, submucous fibrosis, periodontal disease, and lichen planus.

Distinct interferon-gamma and interleukin-9 expression in cutaneous and oral lichen planus

BACKGROUND

Cutaneous (CLP) and oral lichen planus (OLP) as the main subtypes of lichen planus (LP) present with different clinical manifestation and disease course, although their histopathologic features such as the band-like lymphocyte infiltrate and keratinocyte apoptosis are similar. So far, the underlying cellular and molecular mechanisms remain poorly understood.

OBJECTIVE

The aim of this study was to characterize and compare the in situ cellular infiltrates, cytokine expression profiles and apoptosis markers in CLP and OLP.

METHODS

Using immunofluorescence staining and laser scanning microscopy, we evaluated the cellular infiltrate (CD1a, CD3, CD4, CD8, CD21, CD57, CD123), cytokine expression (interleukin (IL)-1, IL-6, IL-9, IL-10, IL-17, IL-22, IL-23, tumour necrosis factor-α, transforming growth factor-β, interferon (IFN)-γ), and apoptosis markers (Fas, Fas ligand, cleaved caspase-3, TUNEL) of 21 anonymized biopsy specimens of LP (11 CLP, 10 OLP).

RESULTS

Among infiltrating cells mainly T cells and natural killer (NK) cells as well as plasmacytoid dendritic cells (DC) were observed. A predominance of CD8+ T cells was noted in OLP. In both CLP and OLP, T helper (Th)1, Th9, Th17, and Th22-type cytokines were expressed. The expression of IL-9, IFN-γ and IL-22 was higher in CLP compared to that of OLP (P = 0.0165; P = 0.0016; P = 0.052 respectively). Expression of Fas and Fas ligand as well as cleaved caspase-3-positive cells was observed in the epithelium of all LP samples.

CONCLUSIONS

The cell and cytokine patterns of CLP and OLP were partially distinct and generally resembled those reported for autoimmune diseases. The presence of CD8+ and NK cells as well as Fas/Fas ligand expression suggested that various pathways involved in keratinocyte apoptosis are relevant for LP. These results might help to establish targeted therapies for LP.