Detection of fascin and CCR-7 positive mature dendritic cells in oral lichen planus

PA28γ induces dendritic cell maturation and activates T-cell immune responses in oral lichen planus

Oral lichen planus (OLP) is a common chronic inflammatory disease of the oral mucosa, the mechanism of its inflammatory progression has not yet been fully elucidated. PA28γ plays a significant role in a variety of immune-related diseases. However, the exact role of PA28γ in the pathogenesis of OLP remains unclear. Here, we demonstrated that PA28γ is overexpressed in epithelial cells and inflammatory cells of OLP tissues but has no significant relationship with OLP subtypes. Functionally, keratinocytes with high PA28γ expression could induce dendritic cell (DC) maturation and promote the T-cell differentiation into Th1 cells in response to the immune response. In addition, we found that a high level of PA28γ expression is associated with high numbers of infiltrating mature DCs and activated T-cells in OLP tissues. Mechanistically, keratinocytes with high PA28γ expression could promote the secretion of C-C motif chemokine (CCL)5, blocking CCL5 or/and its receptor CD44 could inhibit the induction of T-cell differentiation by keratinocytes with high PA28γ expression. In conclusion, we reveal that keratinocytes with high expression of PA28γ in OLP can induce DC maturation and promote T-cell differentiation through the CCL5-CD44 pathway, providing previously unidentified mechanistic insights into the mechanism of inflammatory progression in OLP.

Immunohistochemical evaluation of Langerhans cells in oral lichen planus and oral lichenoid lesions

OBJECTIVE

the aim of this study was to evaluate the density of Langerhans cells in oral lichen planus (OLP) and oral lichenoid lesions (OLL).

DESIGN

14 cases of OLP, 15 cases of OLL and 14 cases of oral inflammatory fibrous hyperplasia (OIFH), were selected for immunohistochemical analysis of CD1a, CD207 and S100 expression. The OIFH group was subdivided according to the presence (OIFHL n = 14) or absence (OIFHNL n = 14) of lichenoid inflammatory infiltrate. Positive cells were counted in intraepithelial and subepithelial areas. Results were analyzed by multivariate comparative analysis, correlation analysis, linear regression models and Student's T-test.

RESULTS

A significantly higher amount of CD207+ cells in OLL vs OLP was observed (p = 0.015). The prevailing reticular pattern observed was CD207^high for OLP (p = 0.0329). A statistically significant difference in the expression of CD1a and CD207 was observed for intraepithelial vs subepithelial areas (p = 0.024 and p=0.015, for CD1a and CD207, respectively). Significant correlations were also observed between the expression of CD1a + and CD207+ cells in the pathogenesis of OLP and OLL.

CONCLUSION

High levels of CD207+cells in OLP compared with OLL may help explain the differences in the immunopathogenesis of both diseases. Additionally, CD1a + and CD207+ cells appear to be more essential to immunopathogenesis of OLL than to the pathogenesis of OLP.

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.

Expression of CD1a by Langerhan's Cells in Oral Lichen Planus - A Retrospective Analysis

INTRODUCTION

Langerhan's Cells (LCs) are dendritic cells of the oral epithelium which play a role in a series of oral lesions from gingivitis to oral cancer. Oral Lichen Planus (OLP) is an oral mucosal T-lymphocyte mediated immunologic reaction to an unidentified putative antigen or allergen.

AIM

The aim of this study was to quantify the presence of immature LCs in OLP comparing them with normal epithelium.

MATERIALS AND METHODS

A retrospective study using 30 of OLP cases were conducted. Immunohistochemistry was performed using polyclonal anti-CD1a antibodies to identify LCs in 10 cases of normal tissue and 30 samples of OLP. The distribution of LCs among lesional tissue and normal mucosa was analysed using Mann-Whitney U test.

RESULTS

LC population in OLP was significantly higher when compared to the normal epithelium (p<0.001).

CONCLUSION

The increase in LCs indicates the active role played during the antigen detection in OLP and subsequent presentation to T-lymphocytes.

Cathepsin K expression is increased in oral lichen planus

BACKGROUND

Oral lichen planus (OLP) is an idiopathic T-cell-mediated mucosal inflammatory disease. Cathepsin K (Cat K) is one of the lysosomal cysteine proteases. It is involved in many pathological conditions, including osteoporosis and cancer. The expression and role of Cat K in OLP are unknown.

METHODS

Twenty-five oral mucosal specimens diagnosed histopathologically as OLP and fourteen healthy controls (HC) were used to study the immunohistochemical (IHC) expression of Cat K. Colocalization of Cat K with CD1a, Melan-A, CD68, CD45, mast cell tryptase (MCT), and Toll-like receptors (TLRs) 4 and 9 were studied using double IHC and/or immunofluorescence (IF) staining. Expression of Cat K was also evaluated in OLP tissue samples before and after topical tacrolimus treatment.

RESULTS

Cat K was expressed in a higher percentage of cells in the epithelial zone, and the staining intensity was stronger in the stroma in OLP compared to controls (P < 0.001). In OLP, Cat K was present mostly in melanocytes and macrophages and sporadically in basal keratinocytes, endothelial cells, and extracellularly. Cat K was found also in some fibroblasts in HC and OLP samples. Coexpression of Cat K and TLRs 4 and 9 was seen in some dendritic cells (presumably melanocytes) and macrophages. In OLP, tacrolimus treatment reduced the expression of Cat K in the epithelium but increased it in the stroma.

CONCLUSIONS

These results suggest that Cat K is involved in the pathogenesis of OLP. Cat K possibly takes part in the modulation of matrix molecules and cellular receptors.

Dendritic cells of the oral mucosa

The oral cavity contains distinct mucosal surfaces, each with its own unique distribution of dendritic cell (DC) subsets. In addition to tissue-specific properties, such organization might confer differential immune outcomes guided by tissue-resident DCs, which translate in the lymph node into an overall immune response. This process is further complicated by continual exposure and colonization of the oral cavity with enormous numbers of diverse microbes, some of which might induce destructive immunity. As a central cell type constantly monitoring changes in oral microbiota and orchestrating T-cell function, oral DCs are of major importance in deciding whether to induce immunity or tolerance. In this review, an overview of the phenotype and distribution of DCs in the oral mucosa is provided. In addition, the role of the various oral DC subsets in inducing immunity vs. tolerance, as well as their involvement in several oral pathologies is discussed.

Possible implication of local immune response in Darier's disease: an immunohistochemical characterization of lesional inflammatory infiltrate

Cell-mediated immunity is considered to be normal in Darier's Disease (DD), an inherited skin disorder complicated by skin infections. To date, there are no investigations on the local inflammatory infiltrate in DD skin lesions. In this immunohistochemical study we characterized and quantified it, making comparisons with two other inflammatory skin disorders, that is, pemphigus vulgaris (PV) and lichen ruber planus (LRP), and with the normal skin (NSk). We found a significant (P < .05) decrease of CD1a+ Langerhans cells (LCs) in DD, compared to PV, LRP, and NSk, and of CD123+ plasmacytoid dendritic cells (pDCs), compared to PV and LRP. We hypothesize that the genetic damage of keratinocytes might result in a loss of some subsets of dendritic cells and, consequently, in an impaired local immune response, which might worsen the infections that inevitably occur in this disease.