Regulatory T-cells and IL17A+ cells infiltrate oral lichen planus lesions

The Mechanism of Immune Intervention by Iguratimod in Oral Lichen Planus Patients: An In Vitro Experimental Study

BACKGROUND

Oral lichen planus (OLP) is a T cell-mediated immune disease. Iguratimod (IGU) is a novel immunomodulatory agent for rheumatoid arthritis. No studies have been reported on the mechanism of IGU in the treatment of OLP, which deserves investigation.

METHODS

Samples were collected from two batches of non-erosive OLP, erosive OLP (EOLP) patients and healthy control subjects. In the first batch, the effects of IGU or the same volume of dimethyl sulfoxide (DMSO) on proliferation, apoptosis and migration of peripheral blood T lymphocytes (PBL T) were examined by CCK-8, flow cytometry and transwell assay respectively. The levels of IL-6, IL-17, TNF-α, TGF-β and IL-10 were measured by enzyme-linked immunosorbent assay. In the second batch, the percentages of Th17 and Treg cells were determined by flow cytometry in peripheral blood mononuclear cells after IGU or DMSO stimulation.

RESULTS

Compared with the control, IGU promoted apoptosis and inhibited migration, but had no significant effect on the proliferation of PBL T in OLP. IL-6, IL-17 and TNF-α were decreased in OLP. TGF-β and IL-10 showed an upward trend in the IGU-treated EOLP. IGU decreased Th17 in OLP and reduced Th17/Treg ratio in EOLP. The percentage of Treg cells showed an upregulated trend but the difference was not statistically significant.

CONCLUSION

IGU may intervene in the immune response of OLP by affecting functions of PBL T, improving the balance of Th17/Treg and regulating related cytokines.

Function of unconventional T cells in oral lichen planus revealed by single-cell RNA sequencing

OBJECTIVE

We intended to map the single-cell profile of OLP, explore the molecular characteristics of unconventional T cells in OLP tissues.

METHODS

Buccal mucosa samples from OLP patients and healthy individuals were used to prepare single-cell suspension. Single-cell RNA sequencing was used to analyze the proportion of all the cells, and the molecular characteristics of unconventional T cells. Immunohistochemical staining was used to detect the expression of unconventional T cells marker genes.

RESULTS

The cell clusters from buccal mucosa were categorized into immune cells, fibroblasts, endothelial cells, and epithelial cells. Unconventional T cells with phenotype of CD247+TRDC+NCAM1+ were identified. Immunohistochemical staining revealed higher expression of unconventional T cell marker genes in OLP tissue, predominantly in the lamina propria. In OLP, unconventional T cells are in a unique stress response state, exhibited enhanced NF-κB signaling and apoptosis inhibition, enhanced heat shock protein genes expression, weakened cytotoxic function. A large number of ligand-receptor pairs were found between unconventional T cells and other cells, particularly with fibroblasts and endothelial cells.

CONCLUSIONS

This study mapped the single-cell profile of OLP, delineated the molecular characteristics of unconventional T cells in OLP, and uncovered that these unconventional T cells are in a stress response state.

Rapid qPCR-based quantitative immune cell phenotyping in mouse tissues

The immune microenvironment plays an important role in the regulation of diseases. The characterization of the cellular composition of immune cell infiltrates in diseases and respective models is a major task in pathogenesis research and diagnostics. For the assessment of immune cell populations in tissues, fluorescence-activated cell sorting (FACS) or immunohistochemistry (IHC) are the two most common techniques presently applied, but they are cost intensive, laborious, and sometimes limited by the availability of suitable antibodies. Complementary rapid qPCR-based approaches exist for the human situation but are lacking for experimental mouse models. Accordingly, we developed a robust, rapid RT-qPCR-based approach to determine and quantify the abundance of prominent immune cell populations such as T cells, helper T (Th) cells, cytotoxic T cells, Th1 cells, B cells, and macrophages in mouse tissues. The results were independently validated by the gold standards IHC and FACS in corresponding tissues and showed high concordance.

Upregulation of IL-37 in epithelial cells: A potential new mechanism of T cell inhibition induced by tacrolimus

Oral lichen planus (OLP) is a chronic T cell-mediated mucocutaneous disease characterized by T cell infiltration at the connective tissue-epithelium interface. Traditionally, topical corticosteroids are used as the first-line drugs to treat OLP. However, long-term use of corticosteroids may lead to drug tolerance, secondary candidiasis, and autoimmune adrenal insufficiency. Although topical tacrolimus has often been recommended for short-term use in corticosteroid-refractory OLP, the precise role of tacrolimus in epithelial cells remains elusive. This study showed that tacrolimus could directly upregulate the expression of IL-37 in human gingival epithelial cells by promoting the TGF-βRI/Smad3 pathway independently of calcineurin inhibition and MAPKs. In contrast, dexamethasone, one of the corticosteroids, did not have the same effect. Moreover, IL-37 could inhibit the proliferation of activated T cells and the secretion of effector cytokines and alleviate epithelial cell apoptosis and death caused by activated T cells ina co-culturesystem. Furthermore, compared with healthy controls, IL-37 and p-Smad3 levels significantly increased in the oral mucosa affected by OLP, especially in the epithelium. IL-37 might have mediated a negative feedback mechanism to curb excessive inflammation in OLP. However, the expression of IL-37 was not associated with the infiltration of CD8+ T cells and Tregs in OLP, implying that IL-37 might mostly affect T cell activation rather than T cell differentiation and migration. Overall, this study discovered a potential novel mechanism by which tacrolimus might indirectly inhibit T cell-mediated immune damage by upregulating IL-37 in human gingival epithelial cells.

Targeting Th17 cells: a promising strategy to treat oral mucosal inflammatory diseases

With the improved quality of life, oral health is under increased pressure. Numerous common oral mucosal diseases, such as oral lichen planus(OLP) and gingivitis, are related to the destruction of the oral immune barrier. The cytokines secreted by T-helper 17 (Th17) cells are essential for maintaining oral immune homeostasis and play essential roles in immune surveillance. When antigens stimulate the epithelium, Th17 cells expand, differentiate, and generate inflammatory factors to recruit other lymphocytes, such as neutrophils, to clear the infection, which helps to maintain the integrity of the epithelial barrier. In contrast, excessive Th17/IL-17 axis reactions may cause autoimmune damage. Therefore, an in-depth understanding of the role of Th17 cells in oral mucosa may provide prospects for treating oral mucosal diseases. We reviewed the role of Th17 cells in various oral and skin mucosal systemic diseases with oral characteristics, and based on the findings of these reports, we emphasize that Th17 cellular response may be a critical factor in inflammatory diseases of the oral mucosa. In addition, we should pay attention to the role and relationship of "pathogenic Th17" and "non-pathogenic Th17" in oral mucosal diseases. We hope to provide a reference for Th17 cells as a potential therapeutic target for treating oral mucosal inflammatory disorders in the future.

The potential roles of Th17 cells in the pathogenesis of oral lichen planus

BACKGROUND

Oral lichen planus (OLP) is a T cell-mediated chronic autoimmune disease, whose pathogenesis and etiology are not entirely understood. OLP is characterized by subepithelial lymphocyte infiltration and elevated intra-epithelial lymphocytes. The majority of lamina propria lymphocytes are CD4⁺ T cells. CD4⁺ helper T (Th) cells play a crucial role in activating CD8⁺ cytotoxic T cells (CTLs) through interactions and cytokine production. Th1 and Th2 cells are well-accepted to be associated with OLP pathogenesis. However, OLP treatment is challenging yet, the more information we have about the pathology of OLP, the easier it will be treated. With the discovery of Th17 cells in recent years and the demonstration of their role in autoimmune disease, many researchers started to investigate the role of Th17 in the pathogenesis of OLP.

METHODS

To make up this review, studies covering the role of TH17 in different types of lichen planus were selected from major databases.

RESULTS

As we review in this article, Th17 cells and their signature cytokines play an important role in OLP pathogenesis. As well, utilizing some anti-IL-17 antibodies showed promising results in improving the disease; however, more studies are still needed to better understand and treat OLP.

Salivary expression of lncRNA DQ786243 and IL-17 in oral lichen planus: case-control study

Background

A growing number of studies has investigated IL-17 in OLP. However, its exact role and interactions are not fully determined. In addition, the literature investigating its salivary expression is limited. The scarcity in the literature studying lncRNAs was noticed, particularly with regards to correlating them with cytokines in OLP. In the current study, the salivary expression of lncRNA DQ786243 and IL-17 was assessed among different forms of OLP.

Methods

The study included 52 participants in four equal groups: reticular OLP, erythematous OLP, ulcerative OLP, and control group. All eligible OLP patients underwent conventional oral examination, along with basic charting of their demographic data, pain intensity using a visual analogue scale, and clinical evaluation using the Thongprasom et al. scale. The salivary expression of lncRNA DQ786243 and IL-17 was evaluated for all participants using qRT-PCR. Unstimulated whole saliva samples were used. Data were analyzed for statistical significance.

Results

No statistically significant difference was observed when comparing the mean age and gender distribution of the studied groups. A statistically significant difference was detected when comparing pain and clinical scores in the three OLP forms. The highest expression of both salivary biomarkers was noticed in ulcerative OLP, followed by erythematous OLP and reticular OLP, then the controls, with a significant difference between the studied groups. Upon comparing the salivary expression of DQ786243 in ulcerative and erythematous OLP, no significant difference was detected. No significant difference was detected when comparing salivary expression of IL-17 in erythematous OLP to the other OLP forms.

Conclusions

The salivary expression of lncRNA DQ786243 and IL-17 was upregulated in OLP compared to healthy individuals. Besides, their expression increased when the severity of OLP was at its highest level in ulcerative OLP. There was a positive correlation between DQ786243 and IL-17.

Trial registration The protocol was registered at ClinicalTrials.gov (NCT04503824). The date of registration is 07/08/2020.

Probiotics as Potential Biological Immunomodulators in the Management of Oral Lichen Planus: What's New?

Oral lichen planus (OLP) is a T cell-mediated chronic inflammatory disorder with multifactorial aetiology and malignant transformation potential. Despite the treatments so far identified, new tailored and safe specific measures are needed. Recently, human microbiota imbalance has been linked to several immune-mediated diseases, opening new therapeutic perspectives for probiotics; besides their ability to directly interact with the host microbiota, they also display a strain-specific immune-modulatory effect. Thus, this non-systematic review aims to elucidate the molecular pathways underlying probiotic activity, mainly those of Lactobacilli and Bifidobacteria and their metabolites in OLP pathogenesis and malignant transformation, focusing on the most recent in vitro and in vivo research evidence. Findings related to their activity in other immune-mediated diseases are here included, suggesting a probiotic translational use in OLP. Probiotics show immune-modulatory and microbiota-balancing activities; they protect the host from pathogens, hamper an excessive effector T cell response, reduce nuclear factor-kappa B (NF-kB) signalling and basal keratinocytes abnormal apoptosis, shifting the mucosal response towards the production of anti-inflammatory cytokines, thus preventing uncontrolled damage. Therefore, probiotics could be a highly encouraging prevention and immunotherapeutic approach for a safer and more sustainable OLP management.

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

OBJECTIVES

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

MATERIAL AND METHODS

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

RESULTS

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

CONCLUSION

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

Lichen planus - a clinical guide

Lichen planus (LP) is a chronic lichenoid inflammatory disorder of the skin, mucosa and of the appendages. LP is classically characterized by the presence of a rich infiltration of inflammatory T cells, which migrate in the upper part of the dermis, arranged in a band-like pattern. Different sub types of the disease have been so far described. Albeit LP is clinically well defined, the disease still represents a therapeutic enigma. Especially with regard to mucosal or scalp affecting LP types, which often present a recalcitrant and treatment unresponsive course, efficacious therapeutic options are still lacking. Thus, LP represents a disease with a high psychosocial burden. Yet, development in the deciphering of LP pathogenesis reveals possible new druggable targets, thus paving the way for future therapeutic options. In this clinical guide, we summarize the current clinical knowledge and therapeutic standards and discuss the future perspective for the management of LP.

The inflammation in cutaneous lichen planus is dominated by IFN-ϒ and IL-21-A basis for therapeutic JAK1 inhibition

Cutaneous lichen planus (CLP) and psoriasis (PSO) are both common chronic inflammatory skin diseases for which development of new treatments requires the identification of key targets. While PSO is a typical Th17/IL-17-disorder, there is some evidence that Th1/IFN-ɣ dominate the inflammatory process in CLP. Nonetheless, the immunopathogenesis of CLP is not fully explained and key immunological factors still have to be recognized. In this study, we compared the immune signature of CLP lesions with the well-characterized inflammation present in PSO skin. First, we analysed the histological and immunohistological characteristics of CLP and PSO. Second, we assessed the cytokine expression (IL1A, IL1B, IL4, IL6, IL8, IL10, IL17A, IL19, IL21, IL22, IL23A, IL13, IFNG, TNF, IL12A, IL12B and IL36G) of lesional skin of CLP with PSO by qPCR. Histology revealed a similar epidermal thickness in CLP and PSO. Immunohistochemically, both diseases presented with an inflammatory infiltrate mainly composed by CD3⁺ CD4⁺ T cells rather than CD3⁺ CD8⁺ . Importantly, mRNA analysis showed a distinct cytokine signature: while levels of IL12B, IL1A, IL6 and IL23 were similar between the two groups, the characteristic PSO-associated cytokines IL8, IL17A, IL22, IL19 and IL36G were expressed at very low levels in CLP. In contrast, CLP lesional skin was dominated by the expression of IFNG, IL21, IL4, IL12A and TNF. Immunohistochemistry confirmed the dominance of IL-21, IFN-ɣ and also pSTAT1 in the dermal infiltrate of CLP, while IL-17A was more present in PSO. Collectively, this study improves our understanding of the immunological factors dominating CLP. The dominating cytokines and signalling proteins identified suggest that anti-cytokine therapeutics like JAK inhibitors may be beneficial in CLP.

Increased Serum Level and High Tissue Immunoexpression of Interleukin 17 in Cutaneous Lichen Planus: A Novel Therapeutic Target for Recalcitrant Cases?

BACKGROUND

Interleukin-17 is supposed to play an important role in the pathogenesis of oral lichen planus (OLP). However, there is scarce data in the literature on its significance in the cutaneous variant of the disease.

OBJECTIVES

To determine the serum level and tissue immunoexpression of IL-17 in cutaneous lichen planus (CLP).

METHODS

Fifty-two adult patients with CLP, without any significant autoimmune or inflammatory conditions, were included in the first part of the study. The control group consisted of 27 age- and sex-matched healthy volunteers. Serum concentration of IL-17 was quantified using enzyme-linked immunosorbent assay (ELISA) kit. In the second part of the study, the tissue expression of IL-17 was assessed in archival paraffin-embedded biopsy specimens from CLP (n = 14) against normal control tissues (n = 11) using immunohistochemical assays. The expression was evaluated using Zeiss Axio Imager A2 light microscope. Positively stained cells were counted in 10 fields of view for biopsy specimen at 200x magnification, and the mean value was calculated.

RESULTS

The serum level of IL-17 was significantly elevated in patients with CLP, compared with healthy volunteers (0.218 ± 0.221 ng/ml versus 0.126 ± 0.058 ng/ml, respectively; p = 0.025). No correlation was found between the serum concentration of IL-17 and patient age, gender, disease duration, extent of skin involvement, the presence or intensity of pruritus, and coexistence of mucosal lesions. In tissue samples from CLP lesions, significantly higher numbers of cells expressing IL-17 were found when compared to a healthy skin (p < 0.001).

CONCLUSION

Elevated serum concentration of IL-17 and high expression in a lesional skin support the hypothesis that IL-17 is implicated in the immunopathogenesis of CLP. These findings may constitute a premise for the future use of anti-IL-17 monoclonal antibodies in the treatment of severe and recalcitrant forms of CLP.

Malignant transformation in oral lichen planus and lichenoid lesions: a 14-year longitudinal retrospective cohort study of 829 patients in New Zealand

OBJECTIVE

The aim of this study was to identify the rate of malignant transformation in a longitudinal cohort of patients with oral lichen planus and oral lichenoid lesion (OLP/OLL) and to assess the associations between clinicopathologic aspects and malignant transformation.

STUDY DESIGN

Data were taken from the records of 829 patients histologically diagnosed with OLP/OLL in the years 2005 to 2018.

RESULTS

Of the study patients, 548 (66.1%) were females and 281 (33.9%) were males. The average age at diagnosis was 57.3 years. The hyperplastic type was the most frequent (58.5%). Most patients had multiple sites of involvement, with the buccal mucosa being the most frequent site of biopsy. Oral epithelial dysplasia developed in 5 (0.6%) patients with a previous histologic diagnosis of OLP/OLL and developed oral squamous cell carcinoma (OSCC) in 23 patients (2.8%) during the follow-up period. The atrophic/ulcerative forms are 25.8 times more likely to progress to OSCC compared with the hyperplastic types (hazard ratio [HR] 25.8; P < .05). The HR increases by 5% with every year of age (HR 1.05; 95% confidence interval; P < .05).

CONCLUSIONS

In our study, oral epithelial dysplasia developed in less than 1% of patients with OLP/OLL, and OSCC in 2.8%during the follow-up period. The atrophic/ulcerative forms are 25.8 times more likely to progress to OSCC compared with the hyperplastic types. The HR increases by 5% with every year of age.

A Cross-Sectional Study of Oral Lichen Planus Associated With Thyroid Diseases in East China

Objective: To investigate the prevalence of thyroid diseases in patients with oral lichen planus (OLP) and to explore the correlation between the two diseases. Methods: A cross-sectional study was conducted to investigate the history of thyroid disease in 585 patients with oral lichen planus diagnosed in the Department of Oral Mucosal Diseases of the Ninth People's Hospital, Shanghai Jiaotong University, School of Medicine from June 2017 to April 2018 and in 10,441 normal people in an epidemiological survey conducted by endocrinology department of Ninth People's Hospitalin eastern China from 2014 to 2015. Personal medical history of thyroid disease was obtained through questionnaire and thyroid function was also tested. Results: Of the 585 patients with OLP, 190 (32.48%) had thyroid disease (excluding coexistence of multiple thyroid diseases), 62 (32.6%) had thyroid nodules, and 71 (37.4%) had Hashimoto's thyroiditis. Hyperthyroidism was diagnosed in six patients (3.2%), hypothyroidism in seven patients (3.7%), and thyroid cancer in 11 patients (5.8%). The prevalence of Hashimoto's thyroiditis was significantly higher in patients with oral lichen planus than in the general population. The probability of thyroid disease was significantly higher in women with OLP than in men with OLP (P < 0.001). Conclusion: OLP is associated with a high probability of developing thyroid disease, especially Hashimoto's thyroiditis. In the management of OLP patients, especially in female patients, thyroid disease must be screened.

Immunopathogenesis of canine chronic ulcerative stomatitis

Canine Chronic Ulcerative Stomatitis is a spontaneously occurring inflammatory disease of the oral mucosa. An immune-mediated pathogenesis is suspected though not yet proven. We have recently reported on the clinical and histologic features, and identification of select leukocyte cell populations within the lesion. A clinical and histologic similarity to oral lichen planus of people was proposed. In the present study, these initial observations are extended by examining lesions from 24 dogs with clinical evidence of chronic ulcerative stomatitis. Because dogs with chronic ulcerative stomatitis often have concurrent periodontal disease, we wondered if dental plaque/biofilm may be a common instigator of inflammation in both lesions. We hypothesized that dogs with chronic ulcerative stomatitis would exhibit a spectrum of pathologic changes and phenotype of infiltrating leukocytes that would inform lesion pathogenesis and that these changes would differ from inflammatory phenotypes in periodontitis. Previously we identified chronic ulcerative stomatitis lesions to be rich in FoxP3+ and IL17+ cells. As such, we suspect that these leukocytes play an important role in lesion pathogenesis. The current study confirms the presence of moderate to large numbers of FoxP3+ T cells and IL17+ cells in all ulcerative stomatitis lesions using confocal immunofluorescence. Interestingly, the majority of IL17+ cells were determined to be non-T cells and IL17+ cell frequencies were negatively correlated with severity on the clinical scoring system. Three histologic subtypes of ulcerative stomatitis were determined; lichenoid, deep stomatitis and granulomatous. Periodontitis lesions, like stomatitis lesions, were B cell and plasma cell rich, but otherwise differed from the stomatitis lesions. Direct immunofluorescence results did not support an autoantibody-mediated autoimmune disease process. This investigation contributes to the body of literature regarding leukocyte involvement in canine idiopathic inflammatory disease pathogenesis.

Cytokines Levels and Salivary Microbiome Play A Potential Role in Oral Lichen Planus Diagnosis

Oral lichen planus (OLP) is a chronic Th1-mediated inflammatory mucocutaneous disease of the skin and oral mucosa that can have various clinical presentations. Lesions are usually bilateral and often painful. While cutaneous Lichen Planus (LP) lesions are self-limiting, the oral lesions are chronic and rarely remissive. The diagnosis of oral lichen planus (OLP) is often challenging, and confirmation by histopathological criterion is generally advised. The aim of our study was to identify the cytokines present in OLP-suggestive lesions and in non-specific inflammatory lesions (NSIL) used as controls. Moreover, assess cytokines protein levels and oral microbiota composition in whole saliva samples. Histopathological analysis, immunohistochemistry and gene expression were used as techniques to analyze the oral mucosal tissue samples. ELISA was conducted to analyze salivary cytokine levels and 16S rRNA sequencing was used to determine the salivary microbiome. As a result we observed larger number of infiltrated lymphocytes (p = 0.025), as well, more T CD4 lymphocytes in the epithelial tissue (p = 0.006) in OLP samples compared to NSIL. In addition, the OLP samples displayed more apoptotic cells compared to NSIL (p = 0.047). Regarding the cytokine analysis, IFN-γ and IL-33 were more expressed in OLP lesions than in NSIL samples (p < 0.001; p = 0.026). Furthermore, our results demonstrated higher levels of IFN-γ protein expression in the saliva of OLP group compared to controls (p = 0.0156). We also observed noted differences in the oral microbiota composition between OLP and NSIL saliva samples. In conclusion, OLP lesions presented larger numbers of apoptotic and inflammatory cells, higher levels of IFN-γ and IL-33 compared to NSIL, and these lesions also differ regarding oral microbiota composition. These results are consistent with the Th-1-mediated chronic inflammation nature of oral lichen planus investigated lesions and displayed unique features that could be used as a diagnostic tool.

Esophageal Lichen Planus Is Associated With a Significant Increase in Risk of Squamous Cell Carcinoma

Esophageal lichen planus (ELP) is a chronic inflammatory process characterized by apoptotic activity of cytotoxic CD8+ T cells on basal keratinocytes as well as regulatory and helper T cells.^1-3 Due to chronic inflammation, malignant transformation may be a concern and has been documented in case reports.^4,5 We describe the occurrence of esophageal cancer in ELP patients from a large tertiary patient population.

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

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

Insulin-like growth factor 1 exhibits the pro-autophagic and anti-apoptotic activity on T cells of oral lichen planus

BACKGROUND

Oral lichen planus (OLP) is an autoimmune mucocutaneous disease characterized by T cell infiltrating in microenvironment. T cell-mediated immune dysfunctions are of importance in the pathogenesis of OLP. Insulin-like growth factor 1 (IGF1) has profound effects on maintenance of immune functions; however, its specific mechanism in OLP remains unknown. This study aims to explore how IGF1 regulates T-cell immune functions in OLP.

METHODS

IGF1 in OLP lesions was stained by immunohistochemistry and immunofluorescence. Additionally, proliferation, apoptosis and autophagy of T cells were examined after stimulation with IGF1 for 24 h, respectively. Z-VAD-FMK, a pan-caspase inhibitor, was used to explore IGF1-mediated crosstalk between apoptosis and autophagy. The modulation of IGF1 on ERK and PI3K/mTOR pathway was also analyzed.

RESULTS

IGF1 was increased in OLP lesions and was remarkably co-located with T cells. IGF1 significantly enhanced T-cell proliferation, suppressed apoptosis and induced autophagic flux. Moreover, autophagy was induced by apoptosis inhibitor, Z-VAD-FMK, thereby reducing death of T cells. IGF1 could facilitate Z-VAD-FMK-induced autophagy and then decrease proportion of apoptotic T cells. IGF1-treated T cells also showed elevated phosphorylation of ERK, PI3K and mTOR.

CONCLUSIONS

IGF1 inhibited apoptosis and promoted autophagy in T cells, potentially contributing to the pathogenesis of OLP.

Analysis of Immunologic Function Changes in Lichen Planus After Clinical Treatment

BACKGROUND Lichen planus (LP) is a common chronic superficial skin lesion that causes chronic or sub-acute inflammatory disorders. LP can affect the oral cavity, skin, mucous membrane, and other body parts, and features include repeat attacks and long duration, leading to lower quality of life. This study aimed to analyze the changes of immunologic function before and after treatment of LP. MATERIAL AND METHODS Thirty cutaneous LP patients were selected. Peripheral blood was collected in the morning before and after treatment. Peripheral blood mononuclear cells (PBMCs) were isolated by density gradient method. Flow cytometry was used to detect T cell subpopulation CD4⁺ T cells and CD8⁺ T to calculate CD4⁺ T/CD8⁺ T ratio. Enzyme-linked immunosorbent assay (ELISA) was adopted to detect the helper T-cell (Th) factor IL-2, IFN-γ, IL-4, IL-6, IL-17, and IL-22 levels. RESULTS Compared with before treatment, the expressions of CD4⁺ T cells and CD8⁺ T cells were decreased, while the proportion of CD4⁺ T/CD8⁺ T were significantly elevated after treatment. IL-2 and IFN-γ secretion were markedly increased, whereas IL-4, IL-6, IL-17, and IL-22 were significantly reduced after treatment (P<0.05). CONCLUSIONS LP treatment reduces the distribution of CD4⁺ T cells and CD8⁺ T cells, and promotes the changes of Th1, Th2, and Th17 cytokines secretion.

IL-25 promotes Th2-type reactions and correlates with disease severity in the pathogenesis of oral lichen planus

OBJECTIVE

The aim of the present study was to investigate the correlation between IL-25 expression and disease severity, and the potential immunoregulatory role of IL-25 expression in oral lichen planus (OLP).

MATERIALS AND METHODS

The oral mucosal tissue samples obtained from OLP patients and healthy controls (HCs) were analyzed for IL-25 expression by real-time quantitative PCR (qPCR) and immunohistochemistry. Recombinant IL-25 was used to stimulate OLP patient-derived CD4 + T cells, and then IL-4 secretion and mRNA expression were evaluated by ELISA and qPCR, respectively. The efficiency of the siRNA-mediated knockdown of IL-25R expression in oral keratinocytes was determined by qPCR and Western blotting. Human oral keratinocyte cells were cultured with the recombinant human cytokines IL-25, IL-17 A and IL-17 F. The production of associated cytokines by keratinocytes was determined by qPCR. Statistical analyses of quantitative data were performed using SPSS software.

RESULTS

The IL-25 and IL-4 mRNA levels were elevated and correlated significantly with each other in specific OLP subtype lesions compared to HCs, while the numbers of IL-25 positive cells were also increased in local OLP lesions as compared to HCs. In vitro culture with recombinant IL-25 could significantly promote CD4 + T cells from both subtypes of OLP to produce IL-4 mRNA and remarkably elevate supernatant IL-4 levels in reticular OLP CD4 + T cell cultures, which may be attributed to the elevated expression of IL-25R in local OLP lesions. Statistical analyses demonstrated that the simultaneously increased levels of IL-4, CXCL8 and CCL20 in keratinocytes were induced by IL-25 but not IL-17 A or IL-17 F. Decreasing IL-25R subunit expression by siRNA-mediated knockdown significantly blocked the expression of all cytokine-produced inflammatory mediators in oral keratinocytes.

CONCLUSIONS

In OLP lesions, IL-25 can function to mediate the Th2 response in specific disease subtypes, which may be an important cause of OLP disease chronicity and persistent inflammation.

[Correlations between the T helper cell 17/regulatory T cells balance in peripheral blood of patients with oral lichen planus and clinical characteristics]

OBJECTIVE

This study aimed to investigate the ratio of T helper cell 17 (Th17) and regulatory T cells (Treg) in peripheral blood of oral lichen planus (OLP) and explore the pathogenesis of its possible role and significance.

METHODS

The peripheral blood samples were obtained from 33 patients with OLP (15 cases of reticular OLP and 18 cases of erosive OLP) and 17 healthy controls. The percentages of Th17 and Treg cells were detected by flow cytometry (FCM). Real-time fluorescence quantitative polymerase chain reaction (qPCR) technique was used to detect the expression levels of retinoid-related orphan nuclear receptor γt (RORγt) and forkhead box 3 (Foxp3).

RESULTS

The proportions of Th17, Treg cells, and their transcription factors (RORγt and Foxp3) in OLP were higher than those in the control groups (P<0.05). By contrast, in Treg cells and Foxp3, no significance was observed between erosive OLP and reticular OLP. Th17/Treg ratio increased in OLP. This ratio was significantly increased in erosive OLP compared with those in the control groups and reticular OLP (P<0.01). Nevertheless, no significance was noted between reticular OLP and control groups. Statistical analysis demonstrated positive correlations among Th17 cells, Th17/Treg, and clinical characteristics (r=0.66, P=0.00; r=0.66, P=0.00; r=0.52, P=0.00; r=0.50, P=0.00). Positive correlations also existed between Th17 and Treg cells (r=0.39, P=0.03).

CONCLUSIONS

Th17 cells, Treg cells, and their ratios all increased in the peripheral blood of OLP. Moreover, the imbalance inTh17/Treg may play a role in the pathogenesis of erosive OLP.