Inflammation-related cytokines in oral lichen planus: an overview

Expression and clinical significance of periostin in oral lichen planus

Oral lichen planus (OLP) is a chronic inflammatory lesion involving the oral mucosa, which has a high likelihood of progressing to cancer. The present study investigated the periostin expression in the mucosa and serum of patients with OLP and its correlation with serum cytokines. A total of 117 patients with OLP and 110 healthy controls were included in the study. The protein expression of periostin were measured in the OLP and normal oral mucosa by immunohistochemistry. ELISA was performed to measure the serum levels of periostin, tumour necrosis factor-α (TNF-α), interleukin (IL)-6, interferon-γ (IFN-γ), IL-4 and thymic stromal lymphopoietin (TSLP). Compared with the control group the OLP group had a significantly increased number of cases with high periostin expression in the oral mucosa and a significantly increased serum periostin level (P<0.05). Among all 117 OLP subjects, high periostin expression was associated with higher serum IL-6, TNF-α, TSLP and tissue mast cell density. High periostin expression was also significantly associated with a lower IFN-γ/IL-4 ratio (P<0.05). The present study concluded that periostin expression was increased in the oral mucosa and serum of patients with OLP and was associated with inflammatory response, T helper 2 cytokine-predominant immune imbalance, increased mast cell count and TSLP. The modulation of periostin may represent an attractive novel therapeutic target.

The measurement of serum TNF-α levels in patients with lichen planus

BACKGROUND

Lichen planus is a common mucocutaneous inflammatory skin disease with a multifactorial etiology. Cytokines play a key role in lichen planus pathogenesis. This study investigates the relationship between disease severity and levels of tumor necrosis factor-α (TNF-α), which is considered a primary cytokine that initiates cytotoxicity.

MATERIAL AND METHODS

Serum TNF-α levels were compared between a patient group (n = 34) and a control group (n = 20). TNF-α serum levels were measured using human TNF-α Enzyme-Linked Immunosorbent Assay (ELISA) test kits, and the two groups were statistically compared to each other.

RESULTS

Mean serum TNF-α levels were found to be significantly higher in the patient group than in the control group (p < 0.005). However, no significant association was observed between TNF-α levels and oral mucosal involvement (p > 0.005). No relationship was detected between TNF-α levels and patients' sex.

CONCLUSION

It is thought that TNF-α, a proinflammatory cytokine, may play an important role in the pathogenesis of lichen planus. TNF-α may be a simple and effective predictor to illustrate the inflammatory status in patients with lichen planus.

Inflammasome and Oral Diseases

One of the main steps in the development of the life in the earth is multicellularity. It enables cell differentiation and the development of morphological structures within an organism and is an essential factor in how to recognize friendly cells that are part of the multicellular organism and which foreign organisms can be harmful. Recognition includes devices such as the major histocompatibility complex (MHC), and the pattern recognition receptors (PRRs). PRRs are a group of proteins expressed by cells of the innate immune system that identify two classes of products: pathogen-associated molecular patterns (PAMPs), related to microbial pathogens, and damage-associated molecular patterns (DAMPs), associated with cell components that are released during cell damage or death. All these activate the inflammasome, which is a multiprotein oligomer that includes caspase 1, PYCARD, NALP, and caspase 5 (also known as caspase 11 or ICH-3). It is responsible for activation of inflammatory processes and has been shown to induce cell pyroptosis, a programmed cell death distinct from apoptosis, and promotes the maturation of the inflammatory cytokines interleukin 1β (IL-1β) and interleukin 18 (IL-18). We review whether inflammasome is related to diseases that can occur in the oral cavity. The mouth is always a possible environment for the development of pathological conditions because of the wide variety of microorganisms. Small variations in the equilibrium of the oral flora can cause disorders that could affect the organism in a systemic form. We provide data on periodontal disease, candidiasis, herpes virus, oral cancer, caries, and other oral diseases. There are very few papers that study this issue; therefore, we need more investigation and publications about inflammatory molecular processes, and more specifically, related to the inflammasome complex.

Oral keratinocytes synthesize CTACK: A new insight into the pathophysiology of the oral mucosa

The skin-associated chemokine CTACK plays a key role in many inflammatory conditions and could be instrumental in the pathophysiology of tissue-specific immunological diseases such as oral lichen planus (OLP). In this study, we investigated, by RT-PCR, ELISA, chemotaxis assays, and fluorescence-activated cell sorting (FACS), the production of CTACK in oral keratinocytes, its expression in tissues from normal and OLP patients, and its role in T-cell recruitment.CTACK was produced by the oral epithelium, and it affects chemotaxis of memory CLA+ cells to the oral epithelium. CTACK mRNA was expressed constitutively in primary oral epithelium and was increased during pro-inflammatory IFN-γ treatment. We found a constitutive production of CTACK at a protein level in oral primary cells that increased after IFN-γ treatment. Moreover, we confirmed that CTACK attracts memory T cells and those T cells that express CLA above the level of basal migration.

Serum cytokine profile and clinicopathological findings in oral lichen planus, oral lichenoid lesions and stomatitis

The objective of this study was to examine if clinical and histopathological variables in patients with oral lichen planus (OLP), oral lichenoid lesions (OLL), and generalized stomatitis display different cytokine profiles and if concomitant contact allergy influences this profile. Forty-nine patients and 29 healthy age- and gender-matched subjects were included. Demographic and clinical data immunohistochemical findings in mucosal specimens, results of contact allergy testing, and serum levels of tumor necrosis factor-α, interferon-γ, interleukin (IL)-6, IL-10, IL-12p40, and IL-12p70 were analyzed and compared between groups. Nineteen patients had OLP, primarily with ulcerative lesions on the buccal mucosa, 19 patients had OLL, and 11 patients had generalized stomatitis. All patients had oral symptoms, mainly stinging and burning. Nineteen patients and 10 healthy subjects had contact allergies, primarily to fragrance ingredients. Patient groups did not differ with regard to oral symptoms, clinical pattern of the lesions, or contact allergy. Serum cytokine levels did not differ between the different patient groups and were not related to histopathological findings. The patients had higher levels of IL-6 than the healthy subjects. Interferon-γ, IL-12p40, and IL-12p70 were below detection limit. Our findings indicate that OLP, OLL, and generalized stomatitis cannot be discriminated by means of the selected serum cytokines, and that the presence of concomitant contact allergy does not influence the cytokine expression.

Oral sampling methods are associated with differences in immune marker concentrations

OBJECTIVE

To determine whether the concentration and distribution of immune markers in paired oral samples were similar.

STUDY TYPE

Clinical research.

STUDY DESIGN

Cross-sectional study.

METHODS

Paired saliva and oral secretions (OS) samples were collected. The concentration of immune markers was estimated using Luminex multiplex assay (Thermo Fisher Scientific, Waltham, MA). For each sample, the concentration of respective immune markers was normalized to total protein present and log-transformed. Median concentrations of immune markers were compared between both types of samples. Intermarker correlation in each sampling method and across sampling methods was evaluated.

RESULTS

There were 90 study participants. Concentrations of immune markers in saliva samples were significantly different from concentrations in OS samples. Oral secretions samples showed higher concentrations of immunoregulatory markers, whereas the saliva samples contained proinflammatory markers in higher concentration.

CONCLUSION

The immune marker profile in saliva samples is distinct from the immune marker profile in paired OS samples.

LEVEL OF EVIDENCE

2b. Laryngoscope, 128:E214-E221, 2018.

Differential expression of STAT-3 in subtypes of oral lichen planus: a preliminary study

OBJECTIVE

This study aimed to examine the expression of signaling transduction proteins and their possible correlation with different clinical subtypes of oral lichen planus (OLP).

STUDY DESIGN

We examined the immunoexpression and phosphorylation status of 21 signaling transduction proteins of OLP (n = 10) and normal groups (n = 8) using PathScan analysis. Using immunohistochemistry, we detected expression of STAT-3 and p38 MAPK in tissues of OLP (n = 40) and normal controls (n = 10).

RESULTS

PathScan analysis showed that STAT-3 (Ser727) expression in normal control (N), reticular OLP (R-OLP) and erosive OLP (E-OLP) group was gradually elevated (R-OLP vs N, P = .001; E-OLP vs N, P < .001; E-OLP vs R-OLP, P = .002). Immunohistochemistry showed that STAT-3 expression in the epithelium of normal control, reticular OLP and erosive OLP was consistent with PathScan analysis (R-OLP vs N, P < .001; E-OLP vs N, P < .001; E-OLP vs R-OLP, P = .036). Both PathScan (P = .012) and immunohistochemistry (P < .001) showed that, p38 MAPK expression was significantly higher in OLP compared with normal controls. However, a significant difference was not seen between the reticular OLP and erosive OLP groups.

CONCLUSIONS

Our results indicate that STAT-3 may be involved in OLP development and progression and account for different clinical manifestations.

Experimental study on 1,25(OH)2 D3 amelioration of oral lichen planus through regulating NF-κB signaling pathway

OBJECTIVE

To explore the protective function of vitamin D (VD)/vitamin D receptor (VDR) on the development of oral lichen planus (OLP) and elaborate the underling mechanism of it.

METHODS

H&E staining, myeloid peroxidase (MPO) assays, quantitative PCR (qPCR), Western blotting, and Elisa were used to test the human biopsies and serum. QPCR, Western blotting, Elisa, and siRNA transfection were also performed in LPS-induced keratinocytes to observe the functions of vitamin D and VDR.

RESULTS

The lack of VDR in the diseased biopsies from OLP patients was associated with activated helper T-cell type 1 (Th1)-driven inflammatory response. Importantly, the status of serum 25-hydroxyvitamin D of OLP patients was reduced consistently. In a cultured cell model, 1,25(OH)₂ D₃ could downregulate excessive production of pro-inflammatory factors induced by lipopolysaccharide (LPS) in keratinocyte HaCat cells. Mechanistically, even though LPS-induced cytokines in keratinocytes were inhibited both by nuclear factor-κB (NF-κB) inhibitor and by activator protein 1 (AP-1) inhibitor, VDR-dependent 1,25(OH)₂ D₃ blocked the activation of phosphorylated-NF-κB p65 rather than c-Jun/c-Fos in the presence of LPS stimulation.

CONCLUSION

These results suggest that 1,25(OH)₂ D₃ plays an anti-inflammatory role in OLP by mediating NF-κB signaling pathway but not AP-1 signaling pathway with a VDR-dependent manner, predicting vitamin D supplement may be a potential strategy for the OLP management.

Association between polymorphisms in interleukins and oral lichen planus: A meta-analysis

BACKGROUND

More and more studies have suggested that single-nucleotide polymorphisms (SNPs) in interleukin (IL) genes are correlated with an increased risk of developing oral lichen planus (OLP). However, these results were inconsistent. Therefore, the aim of this meta-analysis is to retrieve and comprehensively analyze all related clinical studies to investigate the association of ILs gene polymorphisms with the OLP risk.

METHODS

PubMed, Embase, and the Cochrane Library were searched for eligible studies to evaluate the association between IL polymorphisms and the OLP. The odds ratios (ORs) and 95% confidence intervals (CIs) from each study were pooled to estimate the strength of the association. Statistical analyses were performed by using STATA software.

RESULTS

In all 6 studies, including 4 SNPs (IL6-174G/C, IL10-592C/A, IL10-819C/T, and IL10-1082G/A), 362 OLP patients and 622 non-OLP control subjects from five different countries were investigated. As for the IL6-174G/C, IL10-819C/T, and IL10-1082G/A, no evidence was found to support the association between SNP and OLP susceptibility in any genetic models. However, as for IL10-592C/A, a significant relationship between them was identified in all of comparison models (C vs A: OR = 0.724, 95% CI = 0.585-0.897, P = 0.003; CC vs AA: OR = 0.447, 95% CI = 0.276-0.722, P = 0.001; AC vs AA: OR = 0.585, 95% CI = 0.387-0.883, P = 0.011; CC+AC vs AA: OR = 0.544, 95% CI = 0.365-0.809, P = 0.003; CC vs AA+AC: OR = 0.715, 95% CI = 0.515-0.994, P = 0.046).

CONCLUSION

With the presently available evidence, this meta-analysis fails to show the statistical associations between IL6-174G/C, IL10-819C/T, and IL10-1082G/A and OLP susceptibility in any genetic models. However, the A allele and AA genotype in IL10-592C/A polymorphism may increase the risk of OLP. In the future, more well-designed studies with larger sample sizes are needed.

Clinical and Histopathologic Characterization of Canine Chronic Ulcerative Stomatitis

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

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

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Association of genetic polymorphisms in interferon-γ, interleukin-6 and transforming growth factor-β1 gene with oral lichen planus susceptibility

BACKGROUND

Oral lichen planus (OLP) is a premalignant mucocutaneous disease in which genetic factors and immune responses play a major role. Cytokines play an important role in the pathogenesis and disease progression of OLP. The aim of this study was to investigate the impact of gene polymorphisms of T helper cell subtype Th1 and Th2 cytokines, interferon-gamma (IFN-γ), interleukin-6 (IL-6) and transforming growth factor (TGF)-β1 on OLP susceptibility in a Saudi cohort.

METHODS

Forty two unrelated patients with OLP and 195 healthy controls were genotyped for IFN-γ (874A/T), IL-6 (174G/C) and TGF-β1 (509C/T) polymorphisms.

RESULTS

The frequency of genotype AT of IFN-γ (874A/T) was significantly higher while genotype AA was lower in OLP patients as compared to controls (P < 0.05). The frequency of T containing genotypes (AT + TT) was also higher in OLP patients as compared to that in controls (P = 0.003). The frequencies of allele T was higher while that of allele A lower in patients than the controls however the difference was not statistically significant (P = 0.07). There was no significant difference in the frequencies of alleles and genotypes of IL-6 (174G/C) and TGF-β1 (509C/T) polymorphisms between patient and control groups. These results indicated that genotype AT of IFN-γ (874A/T) polymorphism is associated with OLP risk and genotype AA is protective to OLP. On the other hand the polymorphisms IL-6 (174G/C) and TGF-β1 (509C/T) may not be associated with OLP risk in our population.

CONCLUSION

It is concluded that IFN-γ (874A/T) polymorphism is associated with the susceptibility of OLP, however further studies with large sample size involving different ethnic populations should be conducted to strengthen our results.

Phenotypically non-suppressive cells predominate among FoxP3-positive cells in oral lichen planus

BACKGROUND

Oral lichen planus (OLP) is a common T-cell-dominated oral chronic inflammatory disease occurring in periods of remission, quiescence, activity with pronounced inflammation, and acute ulceration. Cell infiltrates in OLP contain varying numbers of CD4⁺ T cells expressing the transcription factor FoxP3. FoxP3⁺ CD4⁺ T cells are, however, a heterogeneous cell population containing suppressive and non-suppressive cells, and their distribution in infiltrates from OLP is unknown.

METHODS

Biopsies were taken from normal oral mucosa (n = 8) and OLP lesions (n = 19), and a set of in situ methods for the determination of the functional phenotype of FoxP3⁺ CD4⁺ T cells was applied.

RESULTS

Numbers of FoxP3⁺ CD4⁺ T cells were highest in the atrophic form of the disease, yet low in the ulcerative form. The main FoxP3⁺ CD4⁺ T-cell population observed was FoxP3⁺ CD45RA^- CD25⁺ CD45RO⁺ and CD15s^- , a phenotype delineating a non-suppressive subset. Numbers of cells with an actively suppressing phenotype (FoxP3⁺ CD45RA^- CD25⁺ CD45RO⁺ and CD15s⁺ ) were, however, about twice as high in reticular lesions as compared with the atrophic form. Many FoxP3⁺ CD4⁺ T cells expressed T-bet, the hallmark transcription factor for IFN-γ-producing T cells, indicating that they may enhance immune and inflammatory responses rather than suppress them.

CONCLUSIONS

The absence of actively suppressing FoxP3⁺ CD4⁺ T cells may in part explain why OLP is a remarkably persisting condition, in spite of the presence of substantially high numbers of FoxP3⁺ CD4⁺ T cells. The findings emphasize that it is crucial to examine not only numbers but also functional phenotype of FoxP3⁺ CD4⁺ T cells in human tissues.

MicroRNAs in oral lichen planus and potential miRNA-mRNA pathogenesis with essential cytokines: a review

Oral lichen planus (OLP) is a potentially premalignant condition with unknown pathogenesis. Immune and inflammatory factors are thought to play important roles in the development of OLP, and cytokines, such as interferon (IFN)-γ and tumor necrosis factor (TNF)-α, can act as critical players in the immunopathogenesis of OLP. MicroRNAs (miRNAs) are closely correlated with cytokines in various inflammation-related diseases. In patients with OLP, miRNA-146a and miRNA-155 are increased in peripheral blood mononuclear cells, and numerous miRNAs have been shown to exhibit altered expression profiles in lesions. Although the microRNA-messenger RNA (miRNA-mRNA) network is thought to be involved in the development of OLP, in-depth studies are lacking. Here, we summarize current data on the mechanisms of action of miRNAs regulating typical cytokines in OLP, including interleukin (IL)-10, IL-17, IL-22, IFN-γ, and TNF-α, to study the genetic basis of the pathogenesis of OLP and to provide prospects of therapy.

TNF-α, TNF-β and IL-10 gene polymorphism and association with oral lichen planus risk in Saudi patients

Objectives

Oral lichen planus (OLP) is a chronic inflammatory oral mucosal disease. Cytokines play an important role in the pathogenesis and disease progression of OLP. Various reports have implicated cytokine gene polymorphisms in susceptibility to develop some immune mediated conditions including OLP. The purpose of this study was to investigate the association of tumor necrosis factor (TNF)-α, TNF-β and interleukin (IL)-10 gene polymorphisms with the OLP risk.

Material and Methods

Forty two unrelated patients with OLP and 211 healthy volunteers were genotyped for TNF-α (-308 G/A), TNF-β (+252A/G), IL-10 (-1082G/A), IL-10 (-819C/T), and IL-10 (-592C/A) polymorphisms.

Results

The frequencies of allele A and genotype GA of TNF-α (-308G/A) were significantly higher while allele G and GG genotypes were lower in OLP patients as compared to the controls (P<0.001). The frequency of GA genotype of TNF-β (+252A/G) was significantly higher in patients than in controls while the AA genotype was completely absent in OLP patients. These results indicated that allele A and genotype GA of TNF-α (-308G/A) as well as the GA genotype of TNF-β (+252A/G) polymorphisms are associated with OLP risk. The frequencies of alleles and genotypes of -1082G/A, -819C/T and -592C/A polymorphisms in IL-10 gene did not differ significantly between OLP patients and controls (P>0.05). However, haplotype ATA extracted from 1082G/A, -819C/T, -592C/A polymorphisms of IL-10 were more prevalent in OLP patients when compared to controls indicating its possible association with OLP susceptibility.

Conclusion

It is concluded that TNF-α (-308G/A), TNF-β (+252A/G) and IL-10 (-1082G/A, -819C/T and -592C/A) polymorphisms are associated with the susceptibility of OLP, thus giving additional support for the genetic basis of this disease.