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

Prevalence of anxiety, depression, sleeping problems, cognitive impairment, and suicidal ideation in people with autoimmune skin diseases

BACKGROUND

Autoimmune skin diseases (ASDs) such as psoriasis and vitiligo, in addition to causing visible skin symptoms, are closely associated with psychological health issues. However, a comprehensive understanding of the prevalence of these psychological comorbidities in affected individuals is lacking. This study aims to identify the prevalence of anxiety, depression, sleeping problems, cognitive impairment, and suicidal ideation in people with ASDs.

METHOD

PubMed, MEDLINE, Web of Science, and Cochrane Library searches were conducted from 1993 to May 2024. Observational studies reporting prevalence data for anxiety, depression, sleeping problems, cognitive impairment, and suicidal ideation among people with ASDs were included in the analysis. The Newcastle-Ottawa scale was used to evaluate the quality of studies.

RESULTS

The study included 114 studies from 37 countries including 823,975 participants. The estimated pooled prevalence of anxiety in patients with ASDs was 33.3% (95% CI: 27.3-29.3%). The estimated pooled prevalence of depression was 33.7% (95% CI: 29.2-38.1%). The estimated pooled prevalence of sleeping problems was 45.0% (95% CI:31.6-58.4%). The estimated pooled prevalence of cognitive impairment and suicidal ideation was 30.8% (95% CI:15.0-46.7%) and 21.6% (95% CI:13.4-29.8%), respectively. The most common mental disorder in patients with systemic lupus erythematosus and psoriasis was sleeping problems at 55.9% (95% CI: 35.6-76.1%, I2 = 97%) and 39.0% (95% CI: 21.1-56.9%, I2 = 99%).

CONCLUSION

Among patients with ASDs, anxiety, depression, sleeping problems, cognitive impairment, and suicidal ideation were common. The most prevalent mental disorder among patients with systemic lupus erythematosus and psoriasis was sleeping problems. Those with ASDs may experience considerable psychological burdens, and integrated mental health support is necessary for their treatment.

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

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

Assessment of TNF-α (-857 C/T) gene polymorphism in oral lichen planus disease: A case-control study

Background and aims

Oral lichen planus (OLP) is an inflammatory mucocutaneous disorder with an immune-mediated pathogenesis. The tumor necrosis factor-α (TNF-α) level in the serum of OLP patients is significantly higher than in the control group. TNF-α-857 C/T polymorphism can be related to the increased TNF-α level in blood circulation. This study investigated the relationship between TNF-α (-857 C/T) polymorphism and OLP patients in an Iranian population.

Methods

Saliva samples were taken from 200 people, including 100 patients with OLP and 100 healthy people who did not have significant differences in age and sex. Then, DNA was extracted from them and the TNF-α (-857 C/T) genotype was identified using the polymerase chain reaction with confronting two-pair primers method. Statistical Package for the Social Sciences version 16 software analyzed the results.

Results

The frequency of C/C, C/T, and T/T genotypes of the TNF-α-857 C/T polymorphism in the patient group were 78%, 18%, and 4%, respectively, and in the control group were 72%, 23%, and 5%, respectively. The differences between the two groups regarding allele (χ 2  =  0.97, p  = 0.32) and genotype (χ 2  =  0.96, p  = 0.62) frequency among the studied population were insignificant.

Conclusion

This study showed that the difference in the frequency of single nucleotide polymorphism TNF-α-857 C/T polymorphism in the patient and control group had no significant relationship with the increased OLP incidence. Also, no significant association was observed between allele and genotype frequency of TNF-α (-857 C/T) with OLP subtypes.

Crossroads between Skin and Endocrine Glands: The Interplay of Lichen Planus with Thyroid Anomalies

In this narrative review, we aimed to overview the interplay between lichen planus (LP) and thyroid conditions (TCs) from a dual perspective (dermatologic and endocrine), since a current gap in understanding LP-TC connections is found so far and the topic is still a matter of debate. We searched PubMed from Inception to October 2023 by using the key terms "lichen planus" and "thyroid", (alternatively, "endocrine" or "hormone"). We included original clinical studies in humans according to three sections: LP and TC in terms of dysfunction, autoimmunity, and neoplasia. Six studies confirmed an association between the thyroid dysfunction (exclusively hypothyroidism) and LP/OL (oral LP); of note, only one study addressed cutaneous LP. The sample size of LP/OLP groups varied from 12-14 to 1500 individuals. Hypothyroidism prevalence in OLP was of 30-50%. A higher rate of levothyroxine replacement was identified among OLP patients, at 10% versus 2.5% in controls. The highest OR (odd ratio) of treated hypothyroidism amid OLP was of 2.99 (p < 0.005). Hypothyroidism was confirmed to be associated with a milder OLP phenotype in two studies. A single cohort revealed a similar prevalence of hypothyroidism in LP versus non-LP. Non-confirmatory studies (only on OLP, not cutaneous LP) included five cohorts: a similar prevalence of hypothyroidism among OLP versus controls, and a single cohort showed that the subjects with OLP actually had a lower prevalence of hypothyroidism versus controls (1% versus 4%). Positive autoimmunity in LP/OLP was confirmed in eight studies; the size of the cohorts varied, for instance, with 619 persons with LP and with 76, 92, 105, 108, 192, 247, and 585 patients (a total of 1405) with OLP, respectively; notably, the largest control group was of 10,441 individuals. Four clusters of approaches with respect to the autoimmunity in LP/OLP were found: an analysis of HT/ATD (Hashimoto's thyroiditis/autoimmune thyroid diseases) prevalence; considerations over the specific antibody levels; sex-related features since females are more prone to autoimmunity; and associations (if any) with the clinical aspects of LP/OLP. HT prevalence in OLP versus controls was statistically significantly higher, as follows: 19% versus 5%; 12% versus 6%; and 20% versus 9.8%. A single study addressing LP found a 12% rate of ATDs. One study did not confirm a correlation between OLP-associated clinical elements (and OLP severity) and antibody values against the thyroid, and another showed that positive TPOAb (anti-thyroperoxidase antibodies) was more often found in erosive than non-erosive OLP (68% versus 33%). Just the reverse, one cohort found that OLP subjects had a statistically significantly lower rate of positive TPOAb versus controls (9% versus 15%). Five case-control studies addressed the issue of levothyroxine replacement for prior hypothyroidism in patients that were diagnosed with OLP (no study on LP was identified); three of them confirmed a higher rate of this treatment in OLP (at 8.9%, 9.7%, and 10.6%) versus controls. In conclusion, with regard to LP/OLP-TC, we note several main aspects as practical points for multidisciplinary practitioners: OLP rather than LP requires thyroid awareness; when it comes to the type of thyroid dysfunction, mostly, hypothyroidism should be expected; female patients are more prone to be associated with ATDs; a potential higher ratio of OLP subjects taking levothyroxine was found, thus a good collaboration with an endocrinology team is mandatory; and so far, OLP individuals have not been confirmed to be associated with a higher risk of thyroid nodules/cancer.

Cathepsins in oral diseases: mechanisms and therapeutic implications

Cathepsins are a type of lysosomal globulin hydrolase and are crucial for many physiological processes, including the resorption of bone matrix, innate immunity, apoptosis, proliferation, metastasis, autophagy, and angiogenesis. Findings regarding their functions in human physiological processes and disorders have drawn extensive attention. In this review, we will focus on the relationship between cathepsins and oral diseases. We highlight the structural and functional properties of cathepsins related to oral diseases, as well as the regulatory mechanisms in tissue and cells and their therapeutic uses. Elucidating the associated mechanism between cathepsins and oral diseases is thought to be a promising strategy for the treatment of oral diseases and may be a starting point for further studies at the molecular level.

Anxiety and depression in keratotic oral lichen planus: a multicentric study from the SIPMO

OBJECTIVES

Oral lichen planus with exclusive keratotic reticular, papular, and/or plaque-like lesions (K-OLP) is a clinical pattern of OLP that may be associated with a complex symptomatology and psychological alteration. The aim of the study was to evaluate the prevalence of anxiety (A) and depression (D) in patients with K-OLP, analyzing the potential predictors which can affect mental health status.

METHODS

Three hundred K-OLP patients versus 300 healthy controls (HC) were recruited in 15 Italian universities. The Numeric Rating Scale (NRS), Total Pain Rating Index (T-PRI), and Hamilton Rating Scales for Depression and for Anxiety (HAM-D and HAM-A) were administered.

RESULTS

The K-OLP patients showed statistically higher scores in the NRS, T-PRI, HAM-D, and HAM-A compared with the HC (p-value < 0.001**). A and D were found in 158 (52.7%) and 148 (49.3%) K-OLP patients. Strong linear correlations were identified between HAM-A, HAM-D, NRS, T-PRI, and employment status and between HAM-D, HAM-A, NRS, T-PRI, employment status, and female gender. Multivariate logistic regression revealed that HAM-D and HAM-A showed the greatest increase in the R2 value for A and D in the K-OLP patients, respectively (DR2 = 55.5% p-value < 0.001**; DR2 = 56.5% p-value < 0.001**).

CONCLUSIONS

The prevalence of A and D is higher in the K-OLP patients compared with the HC, also found in K-OLP subjects without pain, suggesting that the processing of pain may be in a certain way independent of the processing of mood.

CLINICAL RELEVANCE

Mood disorders and pain assessment should be carefully performed in relation to K-OLP to obtain a complete analysis of the patients.

Risk of Prediabetes and Diabetes in Oral Lichen Planus: A Case-Control Study according to Current Diagnostic Criteria

OBJECTIVE

To estimate the prevalence of prediabetes and diabetes in patients with oral lichen planus (OLP).

METHODS

Prospective cohort, including consecutive patients diagnosed clinically and histologically with OLP from 2018 to 2022. Patients and controls were matched by age and gender. Fasting plasma glucose value collection from all patients. Multivariate regression analysis evaluated the relationship between prediabetes and diabetes variables according to current diagnostic criteria.

RESULTS

The sample comprised 275 patients (207 women; 75.3%), mean age 59.60 ± 12.18 years for both groups. Prediabetes was diagnosed according to the American Diabetes Association (ADA, 100-125 mg/dL), in 21.45% of OLP patients (59/275) and 14.55% (40/275) of control patients (p = 0.035). Patients with the atrophic-erosive form exhibited stronger association with taking oral antidiabetics (p = 0.011). Multivariate analysis showed that being over >60 years and having a cutaneous location was associated with ≥3 sites (OR 1.81 and OR 2.43). ADA prediabetes and oral antidiabetics drugs increased the probability of OLP (OR 1.60 (1.04-2.51), p = 0.03 and OR 2.20 (1.18-4.69), p = 0.017) after adjustment for sex and age.

CONCLUSIONS

Because glycemia 100-125 mg/dL was associated with OLP, testing serum fasting plasma glucose seems reasonable in order to prevent development of diabetes and deal with possible complications until new studies are complete.

Single-cell immune profiling reveals immune responses in oral lichen planus

Introduction

Oral lichen planus (OLP) is a common chronic inflammatory disorder of the oral mucosa with an unclear etiology. Several types of immune cells are involved in the pathogenesis of OLP.

Methods

We used single-cell RNA sequencing and immune repertoire sequencing to characterize the mucosal immune microenvironment of OLP. The presence of tissue-resident memory CD8+ T cells are validated by multiplex immunofluorescence.

Results

We generated a transcriptome atlas from four OLP biopsy samples and their paired peripheral blood mononuclear cells (PBMCs), and compared them with two healthy tissues and three healthy PBMCs samples. Our analysis revealed activated tissue-resident memory CD8+ T cells in OLP tissues. T cell receptor repertoires displayed apperant clonal expansion and preferrential gene pairing in OLP patients. Additionally, obvious BCR clonal expansion was observed in OLP lesions. Plasmacytoid dendritic cells, a subtype that can promote dendritic cell maturation and enhance lymphocyte cytotoxicity, were identified in OLP. Conventional dendritic cells and macrophages are also found to exhibit pro-inflammatory activity in OLP. Cell-cell communication analysis reveals that fibroblasts might promote the recruitment and extravasation of immune cells into connective tissue.

Discussion

Our study provides insights into the immune ecosystem of OLP, serving as a valuable resource for precision diagnosis and therapy of OLP.

Serum and salivary cytokines in patients with oral lichen planus treated with Photobiomodulation

OBJECTIVES

To evaluate the serum and salivary levels of IL-1β, IL-6, IL-17A, TNF-α, IL-4, and IL-10 in patients with oral lichen planus (OLP) treated with Photobiomodulation (PBM) and clobetasol propionate 0.05%.

MATERIAL AND METHODS

Thirty-four OLP patients were randomized into two groups: Control (clobetasol propionate 0.05%) and PBM (660 nm, 100 mW, 177 J/cm2 , 5 s, 0.5 J per point). Serum and saliva were collected at baseline and at the end of treatment (after 30 days) and evaluated using ELISA. The cytokine results were correlated with pain, clinical subtypes, and clinical scores of OLP.

RESULTS

IL-1β, IL-6, IL-17A, TNF-α, and IL-4 levels were higher in saliva in relation to serum. IL-1β was the most concentrated cytokine in saliva, and a positive correlation with the severity of OLP was noticed. After treatment with corticosteroid, IL-1β in saliva decreased significantly. No modulation of all cytokines was observed after PBM.

CONCLUSION

IL-1β appears to be an important cytokine involved in OLP pathogenesis. In addition, the mechanisms of action of PBM do not seem to be linked to the modulation of pro or anti-inflammatory cytokines at the end of treatment. It is possible that this events occurred early during treatment.

[Esophageal Lichen Planus - An Underdiagnosed Disease]

An involvement of the esophagus in patients with lichen planus was described for the first time in 1982. Ever since, it has been seen as a rarity. However, studies over the last 10 years have shown a higher prevalence than expected. It may even be supposed that esophageal lichen planus (ELP) is more common than eosinophilic esophagitis. ELP mostly affects middleaged women. The principal symptom is dysphagia. Endoscopically, ELP is characterized by denudation and tearing of the mucosa, trachealization and hyperkeratosis and esophageal stenosis may occur in patients with long courses of the disease. Histologic findings including mucosal detachment, T-lymphocytic infiltrate, intraepithelial apoptosis (civatte bodies) and dyskeratosis are crucial. Direct immunofluorescence shows fibrinogen deposits along the basement membrane zone. So far, there is no well-established therapy but a treatment with topic steroids is effective in 2/3 of the patients. Common therapy of lichen planus of the skin seems to be ineffective for treatment of ELP. Symptomatic esophageal stenosis should be endoscopically dilated. ELP joins the group of "new" immunologic diseases of the esophagus.

Der Lichen planus des Ösophagus – Eine unterschätzte Erkrankung

Eine Beteiligung des Ösophagus bei der Hauterkrankung Lichen planus wurde erstmals 1982 beschrieben und fast 30 Jahre lang als eine Rarität angesehen. Untersuchungen der letzten 10 Jahre aber zeigen, dass diese Erkrankung weniger selten ist als angenommen. Es ist sogar anzunehmen, dass der ösophageale Lichen planus (Esophageal Lichen planus, ELP) häufiger ist als die Eosinophile Ösophagitis (EoE). Die Ösophagusbeteiligung betrifft meist Frauen im mittleren Alter. Das Hauptsymptom ist eine Dysphagie. Endoskopisch erkennt man in der Speiseröhre eine charakteristische Schleimhautablösung, eine Trachealisierung, und gelegentlich Hyperkeratosen und bei langem Bestehen auch Stenosen. Wegweisend ist die Histologie mit einer subepithelialen Ablösung sowie einem bandförmigen Infiltrat aus T-Lymphozyten, dem Nachweis von apoptotischen Keratinozyten (Civatte Bodies) und Dyskeratosen. Die direkte Immunfluoreszenz zeigt Fibrinogen-Ablagerungen entlang der Basalmembran. Eine etablierte Therapie gibt es bisher nicht. Die Behandlung mit topischen Steroiden ist in ⅔ der Fälle wirksam. Eine Therapie wie beim klassischen Lichen planus scheint unwirksam zu sein. Bei symptomatischen Stenosen kann eine Dilatation indiziert sein. Der ELP reiht sich in die Gruppe der „neuen“ immunologisch vermittelten Erkrankungen des Ösophagus ein.

Comprehensive Insight into Lichen Planus Immunopathogenesis

Lichen planus is a chronic disease affecting the skin, appendages, and mucous membranes. A cutaneous lichen planus is a rare disease occurring in less than 1% of the general population, while oral illness is up to five times more prevalent; still, both forms equally impair the patient's quality of life. The etiology of lichen planus is not entirely understood. Yet, immune-mediated mechanisms have been recognized since environmental factors such as hepatitis virus infection, mechanical trauma, psychological stress, or microbiome changes can trigger the disease in genetically susceptible individuals. According to current understanding, lichen planus immunopathogenesis is caused by cell-mediated cytotoxicity, particularly cytotoxic T lymphocytes, whose activity is further influenced by Th1 and IL-23/Th-17 axis. However, other immunocytes and inflammatory pathways complement these mechanisms. This paper presents a comprehensive insight into the actual knowledge about lichen planus, with the causal genetic and environmental factors being discussed, the immunopathogenesis described, and the principal effectors of its inflammatory circuits identified.

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.

Esophageal lichen planus: Current knowledge, challenges and future perspectives

Lichen planus (LP) is a frequent, chronic inflammatory disease involving the skin, mucous membranes and/or skin appendages. Esophageal involvement in lichen planus (ELP) is a clinically important albeit underdiagnosed inflammatory condition. This narrative review aims to give an overview of the current knowledge on ELP, its prevalence, pathogenesis, clinical manifestation, diagnostic criteria, and therapeutic options in order to provide support in clinical management. Studies on ELP were collected using PubMed/Medline. Relevant clinical and therapeutical characteristics from published patient cohorts including our own cohort were extracted and summarized. ELP mainly affects middle-aged women. The principal symptom is dysphagia. However, asymptomatic cases despite progressed macroscopic esophageal lesions may occur. The pathogenesis is unknown, however an immune-mediated mechanism is probable. Endoscopically, ELP is characterized by mucosal denudation and tearing, trachealization, and hyperkeratosis. Scarring esophageal stenosis may occur in chronic courses. Histologic findings include mucosal detachment, T-lymphocytic infiltrations, epithelial apoptosis (Civatte bodies), dyskeratosis, and hyperkeratosis. Direct immuno-fluorescence shows fibrinogen deposits along the basement membrane zone. To date, there is no established therapy. However, treatment with topical steroids induces symptomatic and histologic improvement in two thirds of ELP patients in general. More severe cases may require therapy with immunosuppressors. In symptomatic esophageal stenosis, endoscopic dilation may be necessary. ELP may be regarded as a precancerous condition as transition to squamous cell carcinoma has been documented in literature. ELP is an underdiagnosed yet clinically important differential diagnosis for patients with unclear dysphagia or esophagitis. Timely diagnosis and therapy might prevent potential sequelae such as esophageal stenosis or development of invasive squamous cell carcinoma. Further studies are needed to gain more knowledge about the pathogenesis and treatment options.

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

Background

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

Case presentation

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

Conclusion

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

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.

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.

Expression of Cathepsin B and Cystatin A in Oral Lichen Planus

Objective:

Cathepsin B (Cat-B), a cysteine protease, and cystatin A (Cys-A), a protease inhibitor, are involved in the immune response. This study determined Cat-B and Cys-A expression in oral lichen planus (OLP) by immunohistochemistry.

Materials and Methods:

Thirty specimens each of OLP and healthy gingiva (HG) were included. The expression pattern, the number of positive cells, the staining intensity, and the immunoreactive score (IRS) of Cat-B and Cys-A were investigated. The data were analyzed by using unpaired t-test, Chi-square, and Spearman’s rank correlation.

Results:

The Cat-B expression in OLP was observed as cytoplasmic staining in the epithelial cells, whereas Cys-A expression was exhibited in the nucleus and cytoplasm of the epithelium. An increase in Cat-B staining intensity was also observed in the basal cells. Conversely, the high staining intensity of Cys-A was observed in the stratum spinosum, but not the stratum basale. In HG, Cat-B expression demonstrated a relatively consistent intensity in the epithelial layer. The Cys-A expression in HG was similar to OLP with a lower staining intensity. The mean percentage of positive cells and the IRS score of Cat-B and Cys-A in OLP were significantly higher than HG (P < 0.05). There was no correlation between Cat-B and Cys-A levels in OLP. Interestingly, Cat-B expression in erosive OLP was greater than in non-erosive OLP (P < 0.05).

Conclusion:

The Cat-B and Cys-A expression in OLP was more outstanding than in HG, suggesting possible roles for the process of OLP pathogenesis. In addition, Cat-B expression may be an indicator of the disease severity.

Prevalence and risk of chronic kidney disease in oral lichen planus: a large cross-sectional study from eastern China

Background

Oral lichen planus (OLP) is a chronic inflammatory mucocutaneous disease which is frequently associated with comorbidities such as diabetes and cardiovascular diseases. However, little is known about the association of OLP with impaired kidney function. To elucidate the possible association of chronic kidney disease (CKD) with OLP and its severity, this study investigated the prevalence of CKD as well as its risk factors in patients with OLP.

Methods

A large prospective cross-sectional study of 1,021 patients with OLP was carried out using questionnaires and laboratory tests available from an oral medicine clinic at a university in eastern China. According to the Kidney Disease: Improving Global Outcomes (KDIGO) diagnostic guideline, CKD was classified based on the estimated glomerular filtration rate (eGFR, <60 mL/min/1.73 m²) or urinary albumin to creatinine ratio (UACR, >30 mg/g).

Results

The prevalence of CKD in the patients with OLP in this study was 14.3% (95% CI, 12.3–16.6%), which was higher than that in the general Chinese population (10.8%; 95% CI, 10.2–11.3%). The mean values of serum creatinine, eGFR, UACR, and urine N-acetyl-β-D-glucosidase in patients with CKD were significantly higher than those in patients without CKD (all P<0.01). Pearson’s correlation analysis revealed that CKD stage and UACR were positively correlated with the severity of OLP (both P<0.001). Importantly, multivariate regression analysis revealed that age ≥58 years old, female sex, and hypertension were independent risk factors for incident CKD and abnormal UACR (>30 mg/g) in patients with OLP (all P<0.01).

Conclusions

This study has reported for the first time that CKD is a comorbidity in patients with OLP. The occurrence and staging of incident CKD are associated with OLP and its severity.

The Characteristics of Patients with Oral Lichen Planus and Malignant Transformation-A Retrospective Study of 271 Patients

Introduction: Oral lichen planus (OLP) is a chronic inflammatory disease with an unknown etiology rating among oral potentially malignant disorder. The aim of the study was to determine the epidemiological and clinical characteristics of the patients with OLP and rate of malignant transformation. Patients and methods: Data were obtained from the medical records of 271 patients referred to the Oral Medicine Unit at the University Hospital in Hradec Králové diagnosed with oral lichen planus in the period of 2003–2020. The records were retrospectively analyzed. The following clinical data were retrieved from the medical charts: gender, age, systemic diseases, alcohol and tobacco consumption, localization/clinical appearance of lesions, distribution of the lesions, presence of the symptoms, treatment provided and malignant transformation. Results: A total of 271 charts of patients with confirmed diagnosis of OLP were retrospectively analyzed, of whom, 66.4% (180/271) were women and 33.6% (91/271) were men. The mean age of the patients was 56.0 (18.2–85.0) years. The median follow-up of all patients was 15.2 months. Overall, 2 patients (2/271, 0.74%) meeting the above-mentioned criteria for malignant transformation were identified during the follow-up period. Both patients suffered from erosive type OLP and developed squamous cell carcinoma of the tongue. Conclusions: This retrospective study is in concordance with other studies showing the similar profile and clinical features of the patients with OLP. Malignant transformation rate was 0.74%.

Diabetes mellitus and oral lichen planus: A systematic review and meta-analysis

OBJECTIVE

To undertake a meta-analysis of the association of Oral Lichen Planus (OLP) with diabetes, two diseases with an important impact on public health and the economy, but the evidence of which about their association is inconsistent.

METHODS

Relevant studies were localized by searching MEDLINE, EMBASE, Conference Proceedings, and other databases from inception to October 2020, without restrictions. The reference lists of included studies and of related reviews were also inspected. Global pooled odds ratios were calculated, and predefined subgroup analyses were performed. The heterogeneity between studies and publication bias was assessed and sensitivity analysis was carried out.

RESULTS

Thirty-two studies were included in the meta-analysis. Pooled ORs showed a moderate association between diabetes and OLP [OR: 1.87 (95%CI: 1.57, 2.34)]. The association is limited to studies carried out on adults only [OR: 2.12 (95%CI: 1.75, 2.57)] and is observed in all study designs. Globally, the heterogeneity was low to moderate. Studies carried out in European populations show a stronger association of diabetes and OLP than Asiatic studies [OR: 2.49 (95%CI: 1.87, 3.32) and 1.60 (95%CI: 1.25, 2.03), respectively].

CONCLUSIONS

Diabetes and OLP are moderately associated. Systematic diagnosis of diabetes in OLP patients could prove useful.

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

ABSTRACT

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

[Esophageal Lichen Planus - an Underdiagnosed Disease]

An involvement of the esophagus in patients with lichen planus was described for the first time in 1982. Ever since, it has been seen as a rarity. However, studies over the last 10 years have shown a higher prevalence than expected. It may even be supposed that esophageal lichen planus (ELP) is more common than eosinophilic esophagitis. ELP mostly affects middle-aged women. The principal symptom is dysphagia. Endoscopically, ELP is characterized by denudation and tearing of the mucosa, trachealization and hyperkeratosis and esophageal stenosis may occur in patients with long courses of the disease. Histologic findings including mucosal detachment, T-lymphocytic infiltrate, intraepithelial apoptosis (civatte bodies) and dyskeratosis are crucial. Direct immunofluorescence shows fibrinogen deposits along the basement membrane zone. So far, there is no well-established therapy but a treatment with topic steroids is effective in 2/3 of the patients. Common therapy of lichen planus of the skin seems to be ineffective for treatment of ELP. Symptomatic esophageal stenosis should be endoscopically dilated. ELP joins the group of "new" immunologic diseases of the esophagus.

Corticosteroid delivery using oral mucosa equivalents for the treatment of inflammatory mucosal diseases

Oral lichen planus (OLP) is an immune‐mediated disease of the oral mucosa with idiopathic aetiology. It is frequently treated with topical corticosteroids (applied as gels, mouthwashes, or sprays); however, the mucosal exposure times of topical corticosteroids are short because of removal by the constant flow of saliva and mechanical forces. In this study we used cell monolayers, as well as oral mucosal equivalents (OMEs) containing activated T‐cells, to examine corticosteroid potency and delivery of clobetasol‐17‐propionate from a novel electrospun mucoadhesive patch. The OMEs displayed tight junctions, desmosomes, hemidesmosomes, and an efficient permeability barrier. Following application of corticosteroids to cells cultured as monolayers, the degree of cytotoxicity measured correlated to the level of potency recognized for each corticosteroid; by contrast, OMEs were largely unaffected by corticosteroid treatment. Permeation of clobetasol‐17‐propionate into and through the OMEs was time‐ and dose‐dependent, regardless of whether this corticosteroid was delivered in liquid form or from a mucoadhesive patch, and both liquid‐ and patch‐delivered clobetasol‐17‐propionate significantly reduced the secretion of interleukin‐2 by activated T‐cells. This study confirms that OMEs are more suitable models than cell monolayers for evaluating toxicity and drug delivery. After topical exposure, clobetasol‐17‐propionate accumulated in OMEs at a higher level than betamethasone‐17‐valerate and hydrocortisone‐17‐valerate, and exerted its immunosuppressive actions following application via the patch delivery system, highlighting the efficacy of this mode of drug delivery to treat OLP.

The role of CD68+ and CD163+ macrophages in immunopathogenesis of oral lichen planus and oral lichenoid lesions

Macrophages are phagocytic cells with essential participation in immunological events of the oral cavity. However, the role of these cells in oral lichen planus (OLP) and oral lichenoid lesions (OLL) remains unclear. The present study aimed to evaluate the density of macrophages in OLP and OLL, and to compare it with that of oral inflammatory fibrous hyperplasia (OIFH) (control group). 14 cases of OLP, 14 cases of OLL and 14 cases of OIFH were selected for immunohistochemical analysis of CD68⁺ (M1) and CD163⁺ (M2) macrophage expression. CD68⁺ and CD163⁺ macrophages densities were measured in the intraepithelial and subepithelial areas. The statistical tests used were multivariate analysis of variance, as well as a correlation and linear regression. OLP has more CD68+ macrophages when comparing with OLL (p = 0.001) and OIFH (p = 0.045). There is a very strong relationship between the macrophages types (p < 0.0001) in OLP and OLL. The linear regression showed that to OLL development (p < 0.0001/R^2' = 0.9584), the presence of different types of macrophages are more essential than to OLP (p < 0.0001/R^2' = 0.8983). However, in the OLP these dependencies are also largely. CD68⁺ macrophages may be associated with immunopathogenesis of OLP, indicating a pro-inflammatory activity and regulatory role in the type of T-cell response. Besides, CD68⁺ macrophages can cooperate in the diagnosis of OLP. These results are essential to future studies that seek a therapeutic target for OLP and OLL.

Psychological profile and unexpected pain in oral lichen planus: A case-control multicenter SIPMO studya

OBJECTIVES

To analyze psychological profiles, pain, and oral symptoms in patients with oral lichen planus (OLP).

MATERIALS AND METHODS

300 patients with keratotic OLP (K-OLP; reticular, papular, plaque-like subtypes), 300 patients with predominant non-keratotic OLP (nK-OLP; erythematosus atrophic, erosive, ulcerative, bullous subtypes), and 300 controls were recruited in 15 universities. The number of oral sites involved and oral symptoms were recorded. The Numeric Rating Scale (NRS), Total Pain Rating Index (T-PRI), Hamilton Rating Scales for Depression and for Anxiety (HAM-D and HAM-A), Pittsburgh Sleep Quality Index (PSQI), and Epworth Sleepiness Scale (ESS) were administered.

RESULTS

The OLP patients, especially the nK-OLP, showed higher scores in the NRS, T-PRI, HAM-D, HAM-A and PSQI compared with the controls (p-value < .001** ). A positive correlation between the NRS, T-PRI, HAM-A, HAM-D, and PSQI was found with the number of oral symptoms and number of oral sites involved. Pain was reported in 67.3% of nK-OLP and 49.7% of K-OLP cases with poor correspondence between the site of lesions and the site of the symptoms.

CONCLUSIONS

Mood disorders are frequently associated with OLP with an unexpected symptomatology correlated with the number of oral symptoms and with the extension of disease suggesting a peripheral neuropathy.

MAIT cells, guardians of skin and mucosa?

Mucosal Associated Invariant T (MAIT) cells are evolutionary conserved innate-like T cells able to recognize bacterial and fungal ligands derived from vitamin B biosynthesis. These cells are particularly present in liver and blood but also populate mucosal sites including skin, oral, intestinal, respiratory, and urogenital tracts that are in contact with the environment and microbiota of their host. Growing evidence suggests important involvement of MAIT cells in safeguarding the mucosa against external microbial threats. Simultaneously, mucosal MAIT cells have been implicated in immune and inflammatory pathologies affecting these organs. Here, we review the specificities of mucosal MAIT cells, their functions in the protection and maintenance of mucosal barriers, and their interactions with other mucosal cells.

The attentive focus on T cell-mediated autoimmune pathogenesis of psoriasis, lichen planus and vitiligo

T cell-mediated autoimmune skin diseases develop as a result of the aberrant immune response to the skin cells with T cells playing a central role. These chronic inflammatory skin diseases encompass various types including psoriasis, lichen planus and vitiligo. These diseases show similarities in their immune-pathophysiology. In the last decade, immunomodulating agents have been very successful in the management of these diseases thanks to a better understanding of the pathophysiology. In this review, we will discuss the immunopathogenic mechanisms and highlight the role of T lymphocytes in psoriasis, lichen planus and vitiligo. This study could provide new insights into a better understanding of targeted therapeutic pathways and biological therapies.

The association between Epstein-Barr virus and oral lichen planus: A systematic review and meta-analysis

BACKGROUND

Oral lichen planus (OLP) is a relatively common inflammatory disease, with unclear etiology. A number of studies have linked Epstein-Barr virus (EBV) with OLP. The present systematic review and meta-analysis aimed to evaluate the available evidence regarding the potential association between EBV and OLP.

METHODS

Online databases (PubMed, Scopus, Web of Science, ProQuest, and Google Scholar) were searched from date of inception till May 2020. Studies were included if they met the following criteria: 1) observational studies that assessed the relationship between EBV and OLP, 2) the study comprised OLP patients and control subjects, 3) diagnosis of OLP was confirmed histopathologically, and 4) articles were in English. Studies without control groups, experimental studies, case reports, and reviews were excluded. The fixed-effects model was performed for meta-analyses using RevMan 5.3 software.

RESULTS

A total of 10 studies comprising 386 OLP cases and 304 controls were included. Of these, only 8 studies were eligible for the meta-analysis. The results of the quality assessment showed that only 2 studies were of high quality, while the remaining studies were of moderate quality. The results of the pooled eight studies revealed a significant positive association between EBV and OLP (OR = 4.41, 95% CI: [2.74, 7.11], P < .0001).

CONCLUSION

The results of the present systematic review suggest that EBV infection is statistically associated with increased risk of OLP. However, these results are preliminary, and high-quality, large-scale studies are warranted to further explore the potential role of EBV in the pathogenesis of OLP.

Altered expression of CCN1 in oral lichen planus associated with keratinocyte activation and IL-1β, ICAM1, and CCL5 up-regulation

BACKGROUND

Emerging evidence indicates that CCN1 is a novel inflammation-regulated mediator involved in the pathogenesis of some immune-mediated inflammatory diseases. The objective of this study was to investigate the preliminary roles of CCN1 and its related cytokines IL-1β, CCL5, and ICAM1 in oral lichen planus (OLP).

METHODS

CCN1 expression levels in biopsies from OLP patients against normal oral mucosa (NOM) using immunohistochemistry (42 OLP vs 9 NOM) and RT-qPCR (20 OLP vs 20 NOM) were compared, respectively. The correlation of CCN1 and IL-1β, CCL5, and ICAM1 expression was examined by RT-qPCR in tissue samples and an in vitro cell culture system using keratinocyte HaCaT cells incubated with lipopolysaccharides.

RESULTS

Immunohistochemistry showed that CCN1 protein mainly expressed in the cytoplasm of epithelial keratinocytes of OLP. Consistently, RT-qPCR revealed that mRNA expression of CCN1 was increased in OLP compared with NOM (P < .05) and positively correlated with the high expression of IL-1β, ICAM1, and CCL5 (P < .001), respectively. Importantly, an in vitro study showed that keratinocyte proliferation significantly (P < .05) increased by CCN1 stimulation. Moreover, IL-1β, ICAM1, and CCL5 expression in keratinocytes stimulated by CCN1 was increased (P < .05), respectively.

CONCLUSIONS

This preliminary study for the first time reported that altered expression of CCN1 was associated with high expression of IL-1β, ICAM1, and CCL5 in OLP. And we demonstrated CCN1 promoted keratinocyte activation, as well as IL-1β, ICAM1, and CCL5 production in keratinocytes. Our data indicated that the potential role of CCN1 and its related cytokines was involved in the pathogenesis of OLP.

Possible Mechanisms Involved in the Cooccurrence of Oral Lichen Planus and Hashimoto's Thyroiditis

Oral lichen planus (OLP) is a chronic inflammatory oral mucosal disorder mediated by T cells, with a multifactorial etiology. Hashimoto's thyroiditis (HT) is a common autoimmune disease characterized by hypothyroidism. Although many clinical studies conducted over the past several decades have reported the cooccurrence of OLP and HT, the underlying mechanism remains unclear. This review summarizes potential mechanisms that might be involved in the cooccurrence of OLP and HT. We find that OLP and HT share a common or overlapping pathogenesis in terms of immune, heredity, environmental, and hormonal factors, which might cause cooccurrence. Furthermore, considering the latency of HT, a routine screen for thyroid diseases, particularly HT, is suggested for confirmed OLP patients.