Autoimmune disorders in oral lichen planus: systematic review and meta-analysis

Thyroid Dysfunction and Oral Lichen Planus: Evidence From Two-Sample Mendelian Randomization Analysis

INTRODUCTION AND AIMS

Epidemiological studies have shown that the association between thyroid dysfunction (TD) and oral lichen planus (OLP) is controversial, and the causal relationship remains ill-defined. This study aims to investigate their probable mutual causality using bidirectional Mendelian randomization (MR) analyses.

METHODS

We extracted genetic instruments for OLP and 10 phenotypes of TD from the genome-wide association studies database. The inverse variance weighted method was primarily used to evaluate the bidirectional causal relationship between TD and OLP. The results' robustness was verified by sensitivity analysis (Cochran's Q test, MR-Egger intercept, and leave-one-out test). Bonferroni correction threshold (0.05/10) was applied to determine significant differences.

RESULTS

Forward MR analysis indicated that Hashimoto's thyroiditis (HT) was suggestively linked to a higher likelihood of developing OLP (P = .0077), while hypothyroidism significantly increased the risk of OLP occurrence (P = .0002). The reverse MR study found that OLP was suggestively related to the occurrence of hyperthyroidism (P = .0126) and thyroid cancer (P = .0244). Furthermore, OLP was found to significantly increase the risk of HT (P = 3.47 × 10-⁸), Graves' disease (P = 1.03 × 10-⁵), hypothyroidism (P = 1.08 × 10-⁸), and elevated thyroid-stimulating hormone levels (P = 1.99 × 10-⁶). No major pleiotropy or heterogeneity was detected (P > .05).

CONCLUSION

These findings suggest that hypothyroidism significantly increases the risk of OLP, while OLP may contribute to the development of autoimmune thyroid disorders, particularly HT, Graves' disease, hypothyroidism, and thyroid-stimulating hormone. These findings highlight the complex interaction between endocrine and immune systems, emphasizing the need for further research into shared molecular pathways and potential clinical implications.

CLINICAL RELEVANCE

This study provides a genetic foundation for understanding the relationship between TD and OLP, which aids early screening and diagnosis and informs therapy development.

Association Between Autoimmune Thyroid disease and Oral Lichen Planus: A Multi-Omic Genetic Analysis

OBJECTIVE

The oral mucosa mirrors a range of latent systemic disorders, with potential clinical associations noted between autoimmune thyroid disease (AITD) and oral lichen planus (OLP). This study aims to explore the genetic relationship and underlying mechanisms mediating these conditions.

METHODS

A 2-step Mendelian randomization (MR) analysis was conducted to elucidate the genetic relationship and mediating factors between AITD and OLP. Linkage disequilibrium score regression was employed to assess heritability and genetic correlations among phenotypes, followed by genetic colocalization analysis to discern shared genetic variants. A transcriptome-wide association study (TWAS) was also performed to pinpoint gene expression profiles.

RESULTS

Genetically predicted AITD is associated with an increased risk of OLP (OR[95% CI]: 1.44[1.19,1.74], P=1.61 × 10-4), potentially mediated by hypothyroidism. There is strong evidence of colocalization between AITD and OLP, with a shared PTPN22 gene variant driving this association. TWAS further identified RNASET2 and FGFR1OP within the HLA region as high-confidence shared genes for both conditions.

CONCLUSION

Our study provides novel evidence of a possible genetic association between AITD and OLP. These findings highlight the critical role of endocrine alterations in maintaining oral immune homeostasis, though further research is warranted to validate our findings.

Clinical predictors of disease severity in oral lichen planus

BACKGROUND

The limited understanding of factors influencing the disease progression of oral lichen planus (OLP) poses challenges in delivering effective and personalized treatment for this condition, known to increase the risk of oral cancer and have an adverse impact on patients' quality of life.

OBJECTIVES

To systematically identify clinical predictors of disease severity in patients with OLP.

METHODS

This cross-sectional and single-site prospective study was conducted between December 2021 and February 2024 in the Departments of Oral Medicine and Oral & Maxillofacial Surgery (Aberdeen Royal Infirmary, Aberdeen, UK). Patients presenting with OLP aged 18 years or older diagnosed using Van der Meij and Van der Waal criteria were eligible for the study. Out of a total of 270 eligible patients with OLP presenting consecutively to the outpatient clinics during the study period, 89 patients agreed to participate and were enrolled into the study. Participants demographic and relevant clinical data, namely medical history, smoking status, alcohol consumption, perceived stress levels, oral hygiene status and haematological and biochemical parameters, including full blood count, haematinics and vitamin D, were recorded. The outcome measure was OLP disease severity measured as the Oral Disease Severity Score (ODSS), Gingival ODSS and the Reticular/hyperkeratotic, Erosive/erythematous, Ulcerative (REU scoring system).

RESULTS

In total, 89 participants were recruited into the study. The median age of the study population was 66 (interquartile range 58-73) years, and 65 (73%) patients were women. The median total ODSS score was 10 (range 0-44). After adjustment for confounding factors, patients with lichen planus affecting skin or other mucosal sites had a 5.76-unit higher OLP severity score [B = 5.76, 95% confidence interval (CI) = 0.74-10.78, P = 0.03] than those without extraoral involvement as measured by the ODSS. Patients with insufficient vitamin D exhibited a 5.49-unit increase in disease severity (B = 5.49, 95% CI = 1.13-9.84, P = 0.01) compared with those with adequate vitamin D levels.

CONCLUSIONS

This study identified the importance of cutaneous and/or genital lichen planus in phenotyping OLP disease severity. We also highlight the role of vitamin D as a significant predictor of disease severity of OLP, suggesting the importance of adequate vitamin D levels in patient management.

Association Between Oral Lichen Planus and Thyroid Disease: A Cross-Sectional Study

Background: In recent years, various authors have suggested a potential association between oral lichen planus (OLP) and thyroid disease (TD), although other studies have failed to confirm a significant relationship. The available literature presents inconsistent and sometimes contradictory findings. Additionally, other conditions-such as anxiety and depression, hypertension, diabetes mellitus, and dyslipidemia-have also been linked with OLP. Methods: A cross-sectional study was conducted involving 120 participants, comprising 60 patients diagnosed with OLP and 60 controls. Medical histories related to TD and other comorbidities were collected for both groups. Results: The prevalence of TD among the OLP patients was 20%, compared to 6.7% in the control group. The most frequently observed thyroid disorder was hypothyroidism, identified in 13.3% of the patients with OLP. Statistically, there was a moderate probability of an association between OLP and TD (p = 0.054). No statistically significant associations were found between OLP and hypertension (p = 0.378), type 2 diabetes mellitus (p = 0.550), dyslipidemia (p = 0.562), anxiety (p = 0.959), or depression (p = 0.532). Conclusions: Although the association between OLP and TD remains inconclusive, our findings suggest a moderate statistical probability of a relationship.

Laboratory investigation of the association between oral lichen planus and Hashimoto's thyroiditis

BACKGROUND

Previous studies have shown some relationship between oral lichen planus (OLP) and certain systemic comorbidities. The aim of this study was to investigate laboratory parameters between cases of Hashimoto's thyroiditis (HT) concomitant with OLP and cases of HT only.

METHODS

This case-control study comprised 59 HT patients with OLP and 76 without OLP, all of whom had 5 serum thyroid-related indicators, including thyroid peroxidase antibody (TPOAb), thyroglobulin antibody (TGAb), thyroid stimulating hormone (TSH), free triiodothyronine (FT3), and free thyroxine (FT4).

RESULTS

Compared to cases of HT only, female predominance, presence of thyroid nodules, positive TGAb, and higher FT3/FT4 ratio were mainly observed in cases of HT concomitant with OLP (all P < 0.05). Multivariate regression analysis revealed that presence of thyroid nodules (odds ratio [OR], 10.328; 95% confidence interval [CI], 2.564-41.604), positive TGAb (OR, 6.936; 95%CI, 2.024-23.765), and higher FT3/FT4 ratio (OR, 2.577; 95%CI, 1.377-4.823) were associated significantly (all P < 0.005) with higher risk of OLP occurrence in 135 HT patients. Notably, these significant associations were not found among 30 male patients but did among 105 female patients in regression analysis.

CONCLUSION

This retrospective study revealed that presence of thyroid nodule, positive TGAb, and high FT3/FT4 ratio as risk factors were significantly associated with OLP occurrence risk in female patients with HT. This suggests that female patients suffering from HT, particularly who presented with the risk factors, should be informed about the risk of OLP development and the need for oral mucosal examination to screen for lichen lesions.

The dual role of diabetes on oral potentially malignant disorders

BACKGROUND

Observational studies suggest a link between diabetes and oral potentially malignant disorders (OPMDs), such as oral lichen planus (OLP) and oral leukoplakia (OLK). The causal relationship, as well as the type of diabetes that promotes OPMDs development, remains unclear. This Mendelian randomization (MR) study estimated the causal effects of diabetes-related traits on OPMDs.

METHODS

Large-scale genome-wide association study data on type 1 diabetes (T1D), type 2 diabetes (T2D), fasting glucose (FG), fasting insulin (FI), glycated hemoglobin (HbA1c), OLP, OLK, and actinic cheilitis (AC) were used. Causal effects were assessed using inverse-variance weighted (IVW), weighted median, and MR-Egger methods. Multivariable MR analyses evaluated the independent roles of these traits, with extensive sensitivity analyses.

RESULTS

Genetic susceptibility to T1D (IVW OR = 1.09, 95% CI 1.02-1.17, P = 0.007) and T2D (IVW OR = 0.91, 95% CI 0.86-0.97, P = 0.002) showed protective effects against AC. T1D was associated with an increased risk of OLP (IVW OR = 1.09, 95% CI 1.02-1.17, P = 0.007). The effect of T1D on AC and OLP remained robust after adjusting for FI, FG, and HbA1c, while T2D's effect on AC was not significant when considering these glycemic traits. No potential pleiotropy was detected (P > 0.05).

CONCLUSIONS

T1D may have a causal role in the development of OLP independent of glycemic traits, emphasizing the need for routine oral examinations in T1D patients. Conversely, genetically predicted T1D and T2D are significantly associated with a reduced risk of AC, challenging previous assumptions and offering new insights into the relationship between diabetes and OPMDs. Further extensive investigations are required to address the limitations of this study and to clarify these associations.

Distinct Immunological Features Compared to Lichen Planus and Oral Lichen Planus

Purpose

Lichen planus (LP) and oral lichen planus (OLP) share clinical and histological similarities, yet their distinct immunopathological mechanisms make differentiation and management challenging. Clarifying these differences is essential for accurate diagnosis and treatment. This study aimed to investigate the systemic immune profile of OLP using single-cell transcriptomics, identifying distinct immune cell subsets and signaling pathways contributing to its chronic inflammatory state. Additionally, it sought to compare the inflammatory lesion microenvironments of OLP and LP by analyzing key immune pathways and cellular interactions.

Methods

Peripheral blood mononuclear cells (PBMCs) were obtained from 16 OLP patients and 5 healthy controls. Single-cell transcriptomic data from PBMCs and lesion tissues of OLP and LP were analyzed to profile immune and inflammatory signatures. Key molecular findings were validated using independent datasets and enzyme-linked immunosorbent assays (ELISA).

Results

Prostaglandin D2 synthase (PTGDS), a pivotal enzyme in prostaglandin metabolism, emerged as a diagnostic marker with elevated expression in NK cells from OLP patients. Additionally, a novel CXCR4 high-TSC22D3 high CD4 cytotoxic T cell subset with enhanced cytotoxicity was identified, potentially contributing to OLP pathogenesis. OLP blood samples also demonstrated significant upregulation of TNF and TLR signaling in NK cells, indicating a heightened chronic inflammatory state. Comparative tissue analysis revealed intensified TNF-driven inflammation and a disrupted HIF1A- vascular endothelial growth factor (VEGF) interactions in OLP, contrasting with LP's robust VEGF-mediated angiogenesis.

Discussion

These findings highlight distinct immunopathogenic mechanisms between OLP and LP. The upregulation of PTGDS in NK cells and CXCR4 high-TSC22D3 high CD4 cytotoxic T cells in PBMCs indicates systemic immune dysregulation in OLP, while tissue-level differences suggest impaired vascular remodeling and chronic inflammation. These insights underscore the need for targeted immunomodulatory therapies.

Conclusion

This study identifies distinct immune signatures that differentiate OLP from LP, highlighting potential therapeutic targets that require further validation for personalized treatment strategies.

Annual review of selected scientific literature: A report of the Committee on Scientific Investigation of the American Academy of Restorative Dentistry

The Scientific Investigation Committee of the American Academy of Restorative Dentistry offers this review of select 2023 dental literature to briefly touch on several topics of interest to modern restorative dentistry. Each committee member brings discipline-specific expertize in their subject areas that include (in order of appearance here): prosthodontics; periodontics, alveolar bone, and peri-implant tissues; dental materials and therapeutics; occlusion and temporomandibular disorders; sleep-related breathing disorders; oral medicine, oral and maxillofacial surgery, and oral radiology; and dental caries and cariology. The authors have focused their efforts on presenting information likely to influence the daily dental treatment decisions of the reader with an emphasis on current innovations, new materials and processes, emerging technology, and future trends in dentistry. With the overwhelming volume of literature published daily in dentistry and related disciplines, this review cannot be comprehensive. Instead, its purpose is to inform and update interested readers and provide valuable resource material for those willing to subsequently pursue greater detail on their own. Our intent remains to assist colleagues in navigating the tremendous volume of newly minted information produced annually. Finally, we hope readers find this work helpful in providing evidence-based care to patients seeking healthier and happier lives.

History of Breast Cancer in Patients with Oral Lichen Planus: A Case-Control Study

Objectives: The purpose of this study was to determine the association between oral lichen planus (OLP) and the history of cancer outside of oral cavity and the predominance of its location. Methods: This case-control study included 600 OLP patients and 600 control subjects evaluated in the same section, matched for age and sex to the OLP patients. OLP patients were diagnosed clinically and histologically. Initially, the prevalence of the most frequent types of cancers was described. A Pearson chi-squared test model was used to determine the association of cancer history and OLP. It was considered statistically significant whether p value was ≤0.05. The final multivariate regression model was built after applying a backward selection method to the complete multivariate model considering the odds ratio (OR) with a 95% confidence interval (CI). Results: The history of cancer was significantly associated with OLP regardless of age, sex, tobacco and or alcohol use in both univariate [OR = 2.26 (95%CI: 1.26-4.24); p = 0.008] and multivariate analyses [OR = 2.21 (95%CI: 1.21-4.19); p = 0.012]. According to the location of cancer, there was an association between OLP and history of breast cancer [OR = 3.71 (95%CI = 1.03-13.38); p = 0.032]. Conclusions: This case-control study suggests a higher frequency of cancer, particularly breast cancer, among patients with OLP compared to the control group. Due to the study's design and sample limitations, these findings should be interpreted cautiously. Future longitudinal, multi-institutional studies with rigorous control for cancer history and other confounding factors are essential to further explore the association between OLP and cancer, particularly breast cancer.

Correlations between lichen planus and autoimmune diseases: a Mendelian randomization study

Previous observational studies have found that lichen planus (LP) is associated with autoimmune diseases. To determine the association between LP and 15 autoimmune diseases, we applied the Mendelian randomization (MR) approach, which uses genetic variants as a tool to improve causal inference. We performed a two-sample MR with the genetic instruments identified for 15 autoimmune diseases. Genome-wide association study (GWAS) data was sourced from the IEU Open GWAS database. The instrumental variables (IVs) for LP (1865 cases and 212,242 non-cases) were genetic variations highly associated (P < 5 × 10-6) with LP in the European population. To calculate causal effects, odds ratios (ORs) with 95% confidence intervals (CIs) are employed. MR showed that the genetic risk of psoriasis was positively associated with atopic dermatitis (OR [95%CI] = 0.964[0.936, 0.992], PIVW = 0.013), ankylosing spondylitis (OR [95%CI] = 0.879[0.774, 0.999], PIVW = 0.047) and Type 1 diabetes (OR [95%CI] = 1.074[1.008, 1.145], PIVW = 0.027). These results didn't exhibit horizontal pleiotropy, and "leave-one-out" analysis demonstrated result stability. The MR study indicates a causal relationship between atopic dermatitis, ankylosing spondylitis and Type 1 diabetes in Europe. Further research is necessary to clarify the biological mechanisms that underlie these associations.

Efficacy of antimalarials in oral lichen planus: A systematic review

OBJECTIVE

To evaluate whether hydroxychloroquine (HCQ) or chloroquine (CQ) are effective for the treatment of oral lichen planus (OLP).

MATERIALS AND METHODS

A literature search was conducted in four databases. Clinical studies investigating the effect of HCQ/CQ in patients with OLP were included.

RESULTS

Eleven studies were included. Four were RCTs and seven quasi-experimental studies. The studies included 390 patients diagnosed with OLP, of which 326 and 7 received HCQ and CQ, respectively. 46 patients received topical dexamethasone, 5 placebo and 6 griseofulvin as controls. Five studies assessed pain, and all of them obtained pain reduction with the use of HCQ. Six studies reported objective clinical improvement of OLP with the use of HCQ. Five studies that used a subjective scale obtained that 24%-100% of the patients achieved a complete/almost complete improvement of OLP lesions and its symptomatology. The most frequent side effects were vision problems, gastric discomfort, rash, nauseas, headaches, skin pigmentation, and elevated kidney function. 17 patients had to withdraw from the studies.

CONCLUSIONS

Current evidence is scarce to confirm HCQ as a therapeutic option for OLP. More RCTs are needed to compare its efficacy with topical corticosteroids and to evaluate whether HCQ reduces relapses of OLP.

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.

Role of Vitamin D in Oral Lichen Planus: A Case Control Study

BACKGROUND

It has been reported that vitamin D deficiency may be associated with the development of oral lichen planus (OLP). Given the high prevalence of vitamin D deficiency in many countries, we sought to determine whether it constitutes a comorbidity of OLP.

METHODS

One hundred and twenty patients clinically and histologically diagnosed with OLP were evaluated for their serum vitamin D levels. The results were compared to results from a control series of the same number of subjects matched for age and sex.

RESULTS

Vitamin D deficiency was diagnosed in 45% (n = 54) of OLP patients and in 26.7% (n = 32) of the control group. Vitamin D supplements were being taken by 32 (26.7%) OLP patients and 15 (12.5%) subjects in the control group. A multivariate logistic regression model showed that OLP was associated with vitamin D deficiency [OR: 2.24 (1.28-3.98, p = 0.005)] and vitamin D supplementation [OR: 2.51 (1.25-5.22, p = 0.011)], even after controlling for confounding variables such as sex, age ≤60>, tobacco, and alcohol.

CONCLUSION

The association between OLP patients and vitamin D deficiency or vitamin D supplementation suggests that further research might explore the benefits of vitamin D supplements in managing OLP patients.

A Molecular Hypothesis on Malignant Transformation of Oral Lichen Planus: A Systematic Review and Meta-Analysis of Cancer Hallmarks Expression in This Oral Potentially Malignant Disorder

We aimed to qualitatively and quantitatively analyze, through a systematic review and meta-analysis, the current evidence on the differential expression of the hallmarks of cancer in oral lichen planus (OLP) samples, in order to know the earliest molecular mechanisms that could be involved in the malignant transformation of this oral potentially malignant disorder. We searched MEDLINE/PubMed, Embase, Web of Science, and Scopus for studies published before November 2023. We evaluated the methodological quality of studies and carried out meta-analyses to fulfill our objectives. Inclusion criteria were met by 110 primary-level studies, with 7065 OLP samples, in which the expression of 104 biomarkers were analyzed through immunohistochemistry. Most OLP samples showed sustained cell proliferation signaling (65.48%, 95%CI = 51.87-78.02), anti-apoptotic pathways (55.93%, 95%CI = 35.99-75.0), genome instability (48.44%, 95%CI = 13.54-84.19), and tumor-promoting inflammation events (83.10%, 95%CI = 73.93-90.74). Concurrently, OLP samples also harbored tumor growth suppressor mechanisms (64.00%, 95%CI = 53.27-74.12). In conclusion, current evidence indicates that molecular mechanisms promoting hyperproliferative signaling, an antiapoptotic state with genomic instability, and an escape of epithelial cells from immune destruction, are developed in LP-affected oral mucosa. It is plausible that these events are due to the actions exerted by the chronic inflammatory infiltrate. Malignant transformation appears to be prevented by tumor suppressor genes, which showed consistent upregulation in OLP samples.

Familial oral lichen planus: A new risk group for oral cancer?

OBJECTIVE

The familial type of oral lichen planus (OLP) is rare, with a paucity of data regarding its clinical significance. Our objective was to characterize patients with familial OLP.

METHODS

Families with at least two members diagnosed with OLP were included. Clinical and demographic data and medical history were recorded.

RESULTS

Twenty families, 19 Jewish and 1 Arab, were identified. Of the Jewish families, 57.8% were non-Ashkenazi, originating mainly from central Asia. Of those with OLP there were 14 males and 23 females with an average age of 49.1. Dyslipidemia, cardiovascular, and thyroid disorders (27.7%, 22.2%, and 16.6%, respectively) were the most common comorbidities. Five patients from five distinct families had oral cancer, two with second primary.

CONCLUSIONS

To the best of our knowledge, this is the largest study describing familial OLP. The predominant and common ethnicity of the families with multiple members diagnosed with OLP may imply an ethnic tendency. The higher tendency of hypothyroidism and the high percentage of OSCC among familial OLP patients might be connected to familial OLP and the latter suggests that this population is predisposed to malignant transformation. Thus, this group should be considered as a high-risk group.

Oral and non-oral lichen planus show genetic heterogeneity and differential risk for autoimmune disease and oral cancer

Lichen planus (LP) is a T-cell-mediated inflammatory disease affecting squamous epithelia in many parts of the body, most often the skin and oral mucosa. Cutaneous LP is usually transient and oral LP (OLP) is most often chronic, so we performed a large-scale genetic and epidemiological study of LP to address whether the oral and non-oral subgroups have shared or distinct underlying pathologies and their overlap with autoimmune disease. Using lifelong records covering diagnoses, procedures, and clinic identity from 473,580 individuals in the FinnGen study, genome-wide association analyses were conducted on carefully constructed subcategories of OLP (n = 3,323) and non-oral LP (n = 4,356) and on the combined group. We identified 15 genome-wide significant associations in FinnGen and an additional 12 when meta-analyzed with UKBB (27 independent associations at 25 distinct genomic locations), most of which are shared between oral and non-oral LP. Many associations coincide with known autoimmune disease loci, consistent with the epidemiologic enrichment of LP with hypothyroidism and other autoimmune diseases. Notably, a third of the FinnGen associations demonstrate significant differences between OLP and non-OLP. We also observed a 13.6-fold risk for tongue cancer and an elevated risk for other oral cancers in OLP, in agreement with earlier reports that connect LP with higher cancer incidence. In addition to a large-scale dissection of LP genetics and comorbidities, our study demonstrates the use of comprehensive, multidimensional health registry data to address outstanding clinical questions and reveal underlying biological mechanisms in common but understudied diseases.

Hypertension in oral lichen planus: A systematic review and meta-analysis

OBJECTIVES

To perform a systematic review and meta-analysis in order to qualitatively and quantitatively evaluate the prevalence and magnitude of the association of hypertension in patients with oral lichen planus (OLP).

METHODS

MEDLINE, Embase, Scopus, and Web of Science databases were searched for studies published before May 2022, not restricted by publication language or date. The methodological quality and risk of bias of primary-level studies were critically assessed. Meta-analyses were performed, as well as meta-regression, stratified, sensitivity and small-study effects analyses, a Galbraith (radial) plot, and trial sequential analysis. Quality of evidence was evaluated using GRADE system.

RESULTS

104 studies, including 16,587 patients, met the inclusion criteria. The results show that patients who suffer from OLP have a high prevalence of hypertension (PP = 24.17%, 95% CI = 21.45-27.00), with a low quality of evidence. A significant association between hypertension and oral lichen planus was also reported (OR = 1.28, 95% CI = 1.01-1.63, p = 0.04), showing a moderate quality of evidence.

CONCLUSIONS

Patients with OLP could be at an increased risk of suffering from hypertension which is probably due to multiple factors. Healthcare practitioners involved in OLP management should be aware of this comorbidity in order to apply suitable measures and make referrals if hypertension is suspected, although further research is needed.

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.

An Evidence-Based Update on the Potential for Malignancy of Oral Lichen Planus and Related Conditions: A Systematic Review and Meta-Analysis

A systematic review and a meta-analysis is presented on published articles on the malignant transformation of oral lichen planus (OLP) and related conditions, which, based on current evidence, updates an earlier systematic review published by our research group that included publications until November 2018. In this updated study (Nov-2023) we searched MEDLINE, Embase, Web of Science, and Scopus. We evaluated the methodological quality of studies (QUIPS tool) and carried out meta-analyses. The inclusion criteria were met by 101 studies (38,083 patients), of which, 20 new primary-level studies (11,512 patients) were published in the last 5 years and were added to our updated study. The pooled malignant transformation ratio was 1.43% (95% CI = 1.09-1.80) for OLP; 1.38% (95% CI = 0.16-3.38) for oral lichenoid lesions; 1.20% (95% CI = 0.00-4.25) for lichenoid reactions; and 5.13% (95% CI = 1.90-9.43) for OLP with dysplasia. No significant differences were found between the OLL or LR groups and the OLP subgroup (p = 0.853 and p = 0.328, respectively), and the malignant transformation was significantly higher for the OLP with dysplasia group in comparison with the OLP group (p = 0.001). The factors that had a significant impact with a higher risk of malignant transformation were the presence of epithelial dysplasia, a higher methodological quality, the consumption of tobacco and alcohol, the location of lesions on the tongue, the presence of atrophic and erosive lesions, and infection by the hepatitis C virus. In conclusion, OLP behaves as an oral potentially malignant disorder (OPMD), whose malignancy ratio is probably underestimated as a consequence essentially of the use of inadequate diagnostic criteria and the low methodological quality of the studies on the subject.

Possible interplay of diabetes mellitus and thyroid diseases in oral lichen planus: A pooled prevalence analysis

The existence of a comorbidity between diabetes mellitus (DM) as well as between thyroid diseases (TD) and oral lichen planus (OLP), respectively, was substantially demonstrated. However, there is not enough attention to the concurrent status of both TD and DM in OLP patients. Herein, this short communication aimed to compare 1) the prevalence of DM when TD was concurrently investigated and that of DM when TD status was ignored; 2) the prevalence of TD when DM was concurrently investigated and that of TD when DM status was ignored in the studies. The pooled prevalence (9.86 %; 95 % confidence intervals [CI], 9.22-10.53 %) of DM when TD was concurrently investigated was significantly higher than that (8.13 %; 95%CI, 8.03-9.12 %) when TD status was not investigated in OLP patients. The pooled prevalence (12.48 %; 95%CI, 11.77-13.22 %) of TD when DM was concurrently investigated was significantly higher than that (10.45 %; 95%CI, 9.52-11.46 %) when DM status was not investigated in OLP patients. Thus, it is logical to presume for the first time that there is possible interplay of DM and TD in OLP occurrence. TD and DM should serve as important confounding factors each other in clinical investigation on OLP and associated comorbidities.

Risk factors for the development of oral precancerous lesions in a cohort of 293 oral lichen planus patients with or without chronic periodontitis in southern Taiwan

Background/purpose

Oral lichen planus (OLP) may contribute to the risk of chronic periodontitis, and no reports have shown whether OLP patients with periodontitis have a greater risk of oral precancerous lesions, Candida infection or other clinicopathological diseases. This study aimed to assess the risk factors for the development of oral precancerous lesions in a cohort of 293 OLP patients with or without chronic periodontitis in southern Taiwan.

Materials and methods

The current study recruited 293 OLP patients without preexisting periodontitis at a tertiary institution from 1995 to 2018. The patients were divided into two groups based on the presence or absence of periodontitis. The study compared various clinical and pathological characteristics between the two groups, and also estimated the odds ratio (OR) and the 10-year cumulative risk of chronic periodontitis in OLP patients using logistic regression models and Kaplan‒Meier analysis methods, respectively.

Results

After adjusting for age and gender, the significant contributors to oral precancerous lesions in OLP patients (P < 0.05) were periodontal disease (OR = 2.24) and the male gender (OR = 7.52). Betel nut consumption (OR = 2.61), smoking (OR = 2.46), and candidiasis infection (OR = 3.02) also showed significant associations. Older OLP patients had a lower lesion risk, while a longer OLP duration heightened the periodontal disease likelihood.

Conclusion

The present study demonstrated that coexisting periodontal disease increases the likelihood of developing precancerous lesions in patients with OLP. Periodontal management with oral hygiene care and quitting betel nut consumption and smoking can reduce the risk.

Oral lichen planus and related lesions. What should we accept based on the available evidence?

Recent new terminologies have been proposed for lesions in the sphere of oral lichen planus (OLP) that theoretically present unique aetiological, clinical, prognostic or management characteristics different from those of the so-called typical forms of OLP. We aimed to critically analyse what concepts and terminologies related to OLP should we accept based on the available evidence. A review of the literature was carried out in order to critically analyse the concepts and terminologies related to OLP. New concepts and terminologies include oral lichenoid lesions; contact lichenoid reactions, drug lichenoid reactions or those in the context of graft-versus-host disease; chronic ulcerative stomatitis; lichen planus pemphigoid; and some lesions that are difficult to categorise, such as OLP with features of proliferative verrucous leukoplakia and lichenoid lesions of the upper labial mucosa. A multidisciplinary, multicontinent working group has recently published a guideline with recommendations for modifying definitions and terminologies associated with a disease, among which a reasoned, evidence-based justification for the proposed change is considered essential. An in-depth analysis of the newly proposed terms for OLP-related lesions shows that many of them are not justified. In this paper, we set out our position on the basis of the existing evidence on the appropriateness of the use of these new terms.

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.

Experimental and clinical trial investigations of phyto-extracts, phyto-chemicals and phyto-formulations against oral lichen planus: A systematic review

ETHNOPHARMACOLOGICAL RELEVANCE

Bio-assay guided phytoextracts and derived phytoconstituents reported having multipotent biological activities and nearly 60-80% of the global population still using natural regimens as an alternative therapeutic source. This study focused on the ethnopharmacological and experimental evidence of natural remedies that are effective in treating oral lichen planus (OLP), a chronic T-cell mediated autoimmune disease that is associated with oral cancer transmission.

AIM OF THE REVIEW

A number of studies have shown that antioxidants and antiinflammatory phytoextracts and phyto-constituents are effective against OLP. In this systematic review, we summarize the details of experimentally assessed ancient Traditional Chinese Medicine (TCM), Indian Ayurveda or Ayurvedic Medicine, and Japanese Kampo Medicine (JKM) regimens (crude extracts, individual phytochemicals, and phyto-formulations) that reduce oral lesion, severity index and pain associated with OLP based on studies conducted in vivo, in vitro, and in randomized controlled trials (RCTs).

MATERIALS AND METHODS

Experimental, clinical and RCT investigation reports were gathered and presented according to PRISMA-2020 format. Briefly, the information was obtained from PubMed, ScienceDirect, Wiley journal library, Scopus, Google Scholar with ClinicalTrials.gov (a clinical trial registry database operated by the National Library of Medicine in the United States). Further, individual phytochemical structures were verified from PubChem and ChemSpider databases and visualized by ChemDraw 18.0 software.

RESULTS

We summarized 11 crude phytoextracts, 7 individual phytochemicals, 9 crude formulations, 8 specific TCM and JKM herbal cocktails, and 6 RCTs/patents corroborated by multiple in vitro, in vivo and enzyme assay methods. Briefly, plants and their family name, used plant parts, reported phytochemicals and their chemical structure, treatment doses, and duration of each experiment were presented more concisely and scientifically.

CONCLUSION

Documentation of evidence-based natural ethnomedicines or remedies could be useful for promoting them as potential, cost-effective and less toxic alternatives or as complementary to commonly prescribed steroids towards the control of OLP.

Hallmarks of Cancer Expression in Oral Lichen Planus: A Scoping Review of Systematic Reviews and Meta-Analyses

Oral lichen planus (OLP) is a common chronic inflammatory disease of unknown etiology and likely autoimmune nature that is currently considered an oral potentially malignant disorder, implying that patients suffering from this process are at risk of developing oral cancer in their lifetime. The molecular alterations that develop in OLP and that make the affected oral epithelium predisposed to malignancy are unknown, although, as in other autoimmune diseases (ulcerative colitis, primary biliary cirrhosis, etc.), they may be linked to oncogenesis-promoting effects mediated by the inflammatory infiltrate. So far there is no in-depth knowledge on how these hallmarks of cancer are established in the cells of the oral epithelium affected by OLP. In this scoping review of systematic reviews and meta-analyses the state of evidence based knowledge in this field is presented, to point out gaps of evidence and to indicate future lines of research. MEDLINE, Embase, Cochrane Library and Dare were searched for secondary-level studies published before October 2022. The results identified 20 systematic reviews and meta-analyses critically appraising the hallmarks tumor-promoting inflammation (n = 17, 85%), sustaining proliferative signaling (n = 2, 10%), and evading growth suppressors (n = 1, 5%). No evidence was found for the other hallmarks of cancer in OLP. In conclusion, OLP malignization hypothetically derives from the aggressions of the inflammatory infiltrate and a particular type of epithelial response based on increased epithelial proliferation, evasion of growth-suppressive signals and lack of apoptosis. Future evidence-based research is required to support this hypothesis.