Overexpression and varied clinical significance of Th9 versus Th17 cells in distinct subtypes of oral lichen planus

ObjectiveOral lichen planus (OLP) presents with large numbers of T lymphocytes accumulating beneath the epithelium of the oral mucosa; however, its aetiology remains obscure. A potential role for an emerging novel T cell subset, Th9, in OLP has recently been suggested but remains to be clarified. The current aim was to investigate the expression and potential clinical significance of Th9 cells in distinct subtypes of OLP.Materials and methodsPeripheral blood samples were collected from 41 OLP patients and 18 healthy controls (HCs). Flow cytometric analysis was used to detect the CD4+ T helper subset Th9 (IL-9⁺IL-17⁻CD4⁺ Th cells) and Th17 (IL-9⁻IL-17⁺CD4⁺ Th cells) expression levels.ResultsFlow cytometry results showed significantly elevated levels of Th9 cells in reticular and erosive OLP compared to HCs. Th9 expression in erosive OLP was less than in reticular OLP, indicating that Th9 but not Th17 cells may play a predominant role in reticular disease. However, in erosive OLP patients, we found much higher levels of Th17 cells compared to reticular OLP patients and HCs, indicating that Th17 dominates in erosive OLP. Statistical analysis showed positive correlations of Th9 cells and Th17 cells in patients with reticular or erosive OLP but none in HCs.ConclusionsTh9 and Th17 cells may take the predominant roles in reticular and erosive OLP respectively, and their numbers were positively correlated in reticular and erosive OLP patients. Elevated circulating Th9 cells may help maintain immune balance in OLP immunopathogenesis, which requires further investigation.     

转录因子RORγτ和FOXP3在口腔扁平苔藓病损组织中的表达及意义

目的:口腔扁平苔藓(oral lichen planus,OLP)是一种发生于口腔黏膜的T淋巴细胞介导的自身免疫性疾病。辅助性T细胞(helper T lymphocytes, Th)在OLP的发病过程中具有重要作用,本研究旨在进一步探索OLP患者局部病损组织中辅助性T细胞亚群Th17细胞和Treg细胞的作用。方法:纳入43例OLP患者和13例健康志愿者。采用实时定量PCR法检测局部病损组织中Th17和Treg细胞的特征性转录因子RORγτ和FOXP3的表达,采用GraphPad Prism 5 软件对其表达差异进行统计学分析。结果:OLP局部病损组织中转录因子RORγτ和FOXP3的表达显著高于正常黏膜组织,而且均与OLP的临床分型密切相关。萎缩糜烂型OLP组病损组织中RORγτ/FOXP3比值显著高于网状型OLP组和健康对照组,而网状型OLP组的RORγτ/FOXP3比值虽然高于对照组,但差异无显著性。结论:Th17细胞和Treg细胞均参与OLP的局部免疫反应;同时,Th17/Treg失衡也参与了重症型OLP的致病过程,且表现为Th17细胞优势。     

Imbalance of Interleukin-17+ T-cell and Foxp3+ Regulatory T-cell Dynamics in Rat Periapical Lesions

Introduction

Interleukin (IL)-17⁺ T-helper (Th17) cells and Foxp3⁺ regulatory T (Treg) cells are CD4⁺ T-helper cells with reciprocal functions in immunology and bone metabolism. The present study aimed to investigate the expression dynamics of Th17 and Treg cells in rat periapical lesions as well as their correlation with bone resorption.

Methods

Experimental pulp exposures were made in the lower first molars of 28 Wistar rats to induce periapical lesions. Rats were killed on days 0, 7, 21, and 35. Mandibles were prepared for micro–computed tomography scanning, histologic observation, immunohistochemistry, enzyme histochemistry, and double immunofluorescence analysis.

Results

Through 3-dimensional and 2-dimensional measurements, the volume and area of periapical lesions visibly increased from day 7 to day 21 and then expanded slowly between days 21 and 35. IL-17–positive cells markedly increased from day 7 to day 35. However, Foxp3-positive cells remained at low levels until day 21 and then dramatically increased by day 35. The IL-17⁺/Foxp3⁺ ratio and number of osteoclasts simultaneously increased from day 7 to day 21 and then decreased on day 35. Finally, the distinct distribution of CD4⁺/IL-17⁺ Th17 and CD4⁺/Foxp3⁺ Treg cells was observed on days 7 and 35.

Conclusions

Our findings imply the imbalance of IL-17⁺ T cell and Foxp3⁺ Treg cell dynamics in induced periapical lesions, which may play an important role in periapical lesion progression.     

Immune mechanisms in oral lichen planus

Oral lichen planus (OLP) is a T cell-mediated inflammatory disease of the oral mucosa that has been extensively researched over many years but as yet the mechanisms of pathogenesis are still not fully understood. Whilst the specific aetiological factors driving OLP remain ambiguous, evidence points to the development of a chronic, dysregulated immune response to OLP-mediating antigens presented by innate immune cells and oral keratinocytes leading to increased cytokine, chemokine and adhesion molecule expression. These molecules recruit T cells and mast cells to the diseased site and orchestrate a complex interplay between cells that culminates in keratinocyte cell death, mucosal basement membrane destruction and long-term chronicity of the disease. The main lymphocytes involved are thought to be CD8+ cytotoxic and CD4+ Th1 polarised T cells although recent evidence indicates the involvement of other Th subsets such as Th9, Th17 and Tregs, suggesting that a more complex immune cell relationship exists during the disease process. This review provides an overview of the immune mechanisms at play in OLP pathogenesis with particular emphasis on the role of the different Th subsets and how these recent discoveries may guide research towards identifying potential therapeutic targets.     

Interleukin‐2, interleukin‐6 and T regulatory cells in peripheral blood of patients with Behçet’s disease and recurrent aphthous ulcerations

J Oral Pathol Med (2012) 41 : 73–79 Background: One of the factors involved in the pathogenesis of Behçet disease (BD) and recurrent aphthous ulcerations (RAU) is a cell‐mediated immune response in which several cytokines (interleukin‐2, interleukin‐6) and T regulatory cell (T reg cell) population seem to play a major role. The aim of this study was to measured the interleukin‐2 (IL‐2), interleukin‐6 (IL‐6) levels and analysis of CD4⁺ CD25⁺ Foxp‐3⁺ Treg cells in peripheral blood from patients with BD and RAU. In addition; we also analysed peripheral blood from healthy subjects for comparison. Methods: Thirty patients (15 men and 15 women) with BD, 30 patients (12 men and 18 women) with RAU and 15 healthy control subjects (nine men and six women) participated in the study. Analysis of CD4⁺ CD25⁺ Foxp‐3⁺ Treg cells, IL‐2 and IL‐6 levels have been measured in flow cytometry. Results: No statistical differences were observed in the serum levels of IL‐2 and IL‐6 between BD and RAU patients, and healthy subjects. Although there were no statistical differences in the number of CD4⁺ CD25⁺ Foxp‐3⁺ cells between groups, there were statistically significant differences in the number of CD4⁺ CD25^bright Treg cells. CD4⁺ CD25^bright Treg cells were significantly increased in BD and RAU patients compared to healthy subjects. Statistical analysis revealed no difference according to the number of CD4⁺ CD25^bright cells between BD and RAU patients. Conclusions: These results indicate that CD4⁺ CD25^bright T regulatory cells may be contributing factor in the pathogenesis of BD and RAU.     

口腔扁平苔藓外周血中辅助性T细胞/调节性T细胞平衡与临床特征相关性分析

目的 了解口腔扁平苔藓（OLP）患者外周血中辅助性T细胞17（Th17）与调节性T细胞（Treg）的平衡变化,探讨它们在OLP发病机制中的作用及意义。方法 选取17例正常组和33例OLP患者（网纹型15例,糜烂型18例）的外周血,应用流式细胞术（FCM）检测Th17、Treg细胞的表达水平,实时荧光定量聚合酶链反应（qPCR）检测它们的转录因子维甲酸相关孤核受体γt（RORγt）和叉头状转录因子3（Foxp3）mRNA的表达。结果 OLP外周血中Th17、Treg细胞及RORγt、Foxp3 mRNA表达均升高（P<0.05）,但Treg细胞和Foxp3 mRNA表达在OLP两型间差异无统计学意义。Th17/Treg比值在OLP中升高（P<0.05）,其中糜烂型OLP显著高于正常组及网纹型OLP（P<0.01）,但网纹型OLP与正常组相比差异无统计学意义。Spearman相关分析显示Th17细胞和Th17/Treg比值与体征计分、RAE计分存在正相关关系（r=0.66,P=0.00;r=0.66,P=0.00;r=0.52,P=0.00;r=0.50,P=0.00）;同时Th17细胞与Treg细胞也存在正相关关系（r=0.39,P=0.03）。结论 OLP外周血中Th17和Treg细胞以及它们的比例均增高,Th17/Treg失衡在糜烂型OLP的发病过程中起了一定作用。     

Effects of Calcium Hydroxide Intracanal Medications on T Helper (Th1, Th2, Th9, Th17, and Tfh) and Regulatory T (Treg) Cell Cytokines in Apical Periodontitis: A CONSORT RCT

IntroductionThis Consolidated Standards of Reporting Trials randomized clinical trial investigated T helper (Th1, Th2, Th9, Th17, and Tfh) and regulatory T (Treg) cell–type cytokines and their networks in apical periodontitis (AP). We also assessed the effects of calcium hydroxide [Ca(OH)2] intracanal medications (ICMs) on helper T and Treg cell–type cytokines.MethodsTwenty teeth with primary endodontic infection and apical periodontitis were randomly divided into two groups: Ca(OH)2 + saline solution (n = 10) and Ca (OH)2 + 2% chlorhexidine-gel (n = 10). Samples were collected from the periradicular tissue fluid (PTF) before (PTFs1) and after 14 days of ICMs (PTFs2). The Human High Sensitivity T Cell Panel was used to quantify target T-helper (Th)1: interelukin (IL)-2, IL-12, and interferon-gamma (IFN-γ); Th2: IL-4, IL-5, and IL-13; Th9: IL-9; Th17: IL-17; T follicular helper cells (Tfh): IL-21; and Treg-cell-type cytokine: IL-10.ResultsTh1-type cytokines were higher than Th2-type ones, at PTFs1. Positive (+) associations were found among all Th1-type cytokines and all Th2-type cytokines. There were negative (-) correlations between all Th1- and Th2-type cytokines. Size of radiolucent lesions and symptoms (tenderness to percussion and/or pain on palpation) were positively correlated with Th1-type cytokines, IL-17, and IL-21 but negatively correlated with Th2-type cytokines and IL-10 (all, P < .001). Both ICMs increased Th2-type cytokines and IL-10 (P < .05) and decreased Th1-type cytokines, IL-17, and IL-21 (P < .05), with no differences among them (P > .05).ConclusionsComplex T-cell cytokine networks are involved in AP. Both Ca(OH)2 ICMs effectively increased IL-4, IL-5, IL-10, and IL-13 and lowered IL-2, IL-12, IL-17, IL-21, and IFN-γ.     

OLP外周血中CD4＋CD25＋T细胞体外增殖及对CD4＋CD25-T细胞增殖的影响

目的：通过检测口腔扁平苔藓（OLP）患者外周血中CD4＋CD25＋T细胞的体外增殖及对CD4＋CD25＋T细胞增殖的影响,探讨调节性T细胞对OLP特异性细胞免疫的调节作用及其在该病发生中的意义。方法：通过免疫磁珠分离系统（MACS）分选OLP患者和健康志愿者外周血单个核细胞（peripheral blood mononuclear cell,PBMC）中的调节性T细胞（regulatory Tcell,Treg）和效应性T细胞（responder Tcell,Tresp）,采用流式细胞术检测其纯度、3H--脱氧胸腺嘧啶苷方法检测CD4＋CD25＋T细胞对CD4＋CD25＋T细胞增殖的影响,比较OLP患者和健康志愿者体内Treg细胞功能。结果：分选后健康对照组及OLP患者外周血中CD4＋CD25＋T细胞纯度均高于85％。无论是健康对照还是OLP患者的CD4＋CD25-T细胞均明显抑制CD4＋CD25-T细胞的增殖。与健康对照组相比,OLP组CD4＋CD25＋T细胞对CD4＋CD25-T细胞增殖的抑制作用显著降低旧〈0．01）。结论：调节性T细胞可能通过抑制OLP特异性细胞免疫应答促进疾病的发生发展。     

Kinetics of Th17‐related cytokine expression in experimentally induced rat periapical lesions

Th17‐related cytokines are essential factors in various pathological states, including inflammatory bone destruction. This study investigated the contribution of Th17‐related cytokines to the progress of experimentally induced rat periapical lesions. Periapical pathoses were induced by unsealed exposure of the pulp chamber of the lower first molars. A variety of immunocompetent cells, including CD68⁺ macrophages, Ia antigen⁺ cells and TCRαβ⁺ T cells, were observed in the lesions. The expression levels of Th17‐related cytokines, IL‐17 and IL‐23, and of pro‐inflammatory cytokines, IL‐1β and IL‐6, were significantly increased at 14 days (expansion stage) compared with normal periapical tissues. The expression levels of Foxp3, a regulatory T cell (Treg)‐related gene, and of IL‐10, an anti‐inflammatory cytokine, were higher at 28 days (chronic stage) than at 14 days. These findings suggest that Th17‐related cytokines may be primary contributors to the initiation of periapical bone destruction, and that lesion expansion may be regulated by anti‐inflammatory mediators.     

白细胞介素35对口腔扁平苔藓患者外周血辅助性T细胞17与调节性T细胞平衡的影响

目的探讨外源性白细胞介素(interleukin,IL)35对口腔扁平苔藓(oral lichen planus,OLP)患者外周血中辅助性T细胞17(helper T cell 17,Th17)与调节性T细胞(regulatory T cell,Treg)平衡的影响。方法选取2016年10至12月就诊于贵州医科大学附属医院口腔内科黏膜专科门诊的12例OLP患者外周血(OLP组)(男性1例,女性11例,26~68岁;其中非糜烂型OLP4例,糜烂型OLP 8例),同期收集贵州医科大学附属医院体检中心的13名健康人外周血(健康对照组)(男性1名,女性12名,20~68岁),无菌提取两组外周血单个核细胞,流式细胞术(flow cytometry,FCM)分选外周血CD4+T细胞,采用实时荧光定量PCR(quantitative real-time PCR,qPCR)检测两组外周血CD4+T细胞中Th17、Treg细胞特异转录因子维甲酸相关孤核受体γt(retinoic acid receptor-related orphan receptorγt,RORγt)、叉头状转录因子(forkhead box3,Foxp3)mRNA表达水平;将OLP患者外周血分选出的CD4+T细胞分为实验组与对照组,实验组加入重组人IL-35蛋白(recombinant human IL-35,rhIL-35),对照组加入等体积磷酸盐缓冲液,分别进行细胞体外培养,收集培养结束后的细胞,qPCR检测上述因子的表达水平。结果OLP组CD4+T细胞中Foxp3、RORγt mRNA的相对表达量[M(Q25,Q75)分别为0.15(0.09,0.30)和1.04(0.45,2.15)]均显著大于健康对照组[分别为0.04(0.02,0.06)和0.10(0.05,0.11)](Z=-4.134,P<0.01;Z=-3.699,P<0.01)。OLP组RORγt/Foxp3 mRNA比值[6.22(3.67,15.34)]显著大于健康对照组[2.50(1.24,5.23)](Z=-2.665,P=0.007)。OLP患者外周血实验组CD4+T细胞Foxp3 mRNA相对表达量[0.40(0.21,1.22)]显著大于对照组[0.15(0.11,0.26)](Z=-2.510,P=0.012),两组RORγt mRNA表达差异无统计学意义(P>0.05),实验组RORγt/Foxp3 mRNA比值[3.44(1.55,8.16)]显著小于对照组[6.22(4.43,12.21)](Z=-2.746,P=0.006)。结论OLP患者外周血中存在Th17细胞占优势的Th17/Treg平衡异常,外源性IL-35可通过促进Treg细胞扩增,实现对OLP患者外周血中Th17/Treg平衡的调节。     

Dysfunction of CD4+CD25high T regulatory cells in patients with recurrent aphthous stomatitis

Background: Recurrent aphthous stomatitis (RAS) is a chronic inflammatory disease of unknown etiology characterized by recurring formation of painful oral ulcers. RAS may result from oral epithelium damage caused by T‐cell‐mediated immune response. CD4⁺CD25⁺ T regulatory (Treg) cells suppress proliferation and effector functions of other immune cells, and therefore are crucial in regulating the immune response. Methods: We tested the function of peripheral CD4⁺CD25^high Treg cells in active RAS through their ability to inhibit proliferation and cytokine production of conventional CD4⁺ T cells. We also attempted to detect the presence of FOXP3 and indoleamine 2,3‐dioxygenase (IDO) mRNA in the lesional and non‐lesional oral mucosa of RAS patients and healthy individuals using real‐time PCR assay. Results: Treg cells derived from RAS patients were less efficient in the suppression of cytokine production of CD4⁺ T effector cells than Treg cells from healthy individuals. Moreover, in RAS, Treg cells were nearly twice less potent in the inhibition of CD4⁺CD25^? T cell proliferation than in healthy donors. Furthermore, we have demonstrated the decreased proportion of CD4⁺CD25⁺FOXP3⁺ Treg cells in peripheral blood of RAS patients compared with controls. We failed to detect FOXP3 mRNA, while IDO mRNA expression was decreased in non‐lesional mucosa biopsies from RAS patients compared with ulcer biopsies or normal mucosa from healthy donors. Conclusions: These findings suggest that CD4⁺CD25^high Treg cells are both functionally and quantitatively compromised in RAS and that decreased constitutive expression of IDO in oral mucosa in RAS may lead to the loss of local immune tolerance.     

Lymphocyte changes in peripheral blood,spleen, and liver in DMBA-induced squamous cell carcinoma of mouse cheek skin

The peripheral blood, spleen, and liver lymphocyte subsets of mice with experimental cheek skin carcinoma were determined. The carcinoma was induced by the topical application of 2% (w/v) 9,10-dimethyl-1,2-benzanthracene (DMBA) to cheek skin twice a week for 12 weeks, and it was examined macroscopically and histopathologically. The composition of lymphocyte subsets (T cells, B cells, CD4⁺ single-positive [SP] T cells, and CD8⁺SP T cells) in peripheral blood, spleen, and liver was determined by flow cytometry at 3-week intervals for up to 24 weeks. Spleens and livers were assessed by determining their content of natural killer (NK)T cells. The results showed histopathological progression of the skin lesions from papilloma to squamous cell carcinoma at week 12. Body weight was significantly reduced from weeks 15 to 24, and spleen weight was significantly increased at weeks 21 and 24, but liver weight was not significantly different from the control. The lymphocyte subset composition of peripheral blood showed significant elevation of T cells at weeks 6 and 9, followed by reduced levels at weeks 21 and 24, with significant reduction of B cells at weeks 6 and 9, followed by elevation at weeks 21 and 24. CD4⁺SP T-cell content was elevated at weeks 6, 9, and 12, and reduced at weeks 21 and 24. CD8⁺SP T-cell content was significantly reduced at weeks 6, 9, and 12, and elevated at weeks 21 and 24. The composition of the lymphocyte subsets in the spleen was similar to their composition in peripheral blood. The composition of both T and B cells in the liver was significantly different from that in the corresponding control group, but no significant differences were found in either CD4⁺SP or CD8⁺SP T cells. These findings revealed that the DMBA-induced cheek skin carcinoma in mice affected not only the lymphocyte subsets in peripheral blood, but the cells in the spleen and liver as well.     

Distribution of interleukin-2 receptor α-chain and cells expressing major histocompatibility complex class II antigen in chronic human periapical lesions

In situ distribution of CD2⁺ T-lymphocytes, CD4⁺ and CD8⁺ T-cell subsets, CD14⁺ macrophages, interleukin-2 receptor α-chain (IL-2Rα) and class II major histocompatibility complex antigen (major histocompatibility complex class II, HLA-DR) expressing cells were determined in 14 chronic human periapical granulomas by imrnunohistochemical method using monoclonal antibodies. CD2⁺ lymphocytes were rather evenly distributed within the classical granulation tissue and comprised 55% of the mononuclear cells. Macrophages were distributed all over the periapical area, but their proportion was much less than that of T lymphocytes. Both small, lymphocyte-like mononuclear cells and larger mononuclear cells resembling macrophages displayed mild to strong circumferential staining with the anti-HLA-DR antibody. The majority of lymphocytes expressed IL-2Rα indicating the activated state of T cells within the lesion.     

Pathogenesis of oral lichen planus – a review

J Oral Pathol Med (2010) 39 : 729–734 Oral lichen planus (OLP) is a T‐cell‐mediated chronic inflammatory oral mucosal disease of unknown etiology. OLP presents as white striations, white papules, white plaques, erythema, erosions, or blisters affecting predominantly the buccal mucosa, tongue and gingiva. Both antigen‐specific and non‐specific mechanisms are hypothesized to be involved in the pathogenesis of oral lichen planus (OLP). Antigen‐specific mechanisms in OLP include antigen presentation by basal keratinocytes and antigen‐specific keratinocyte killing by CD8⁺ cytotoxic T cells. Non‐specific mechanisms include mast cell degranulation and matrix metalloproteinase activation in OLP lesions. These mechanisms may combine to cause T cell accumulation in the superficial lamina propria, basement membrane disruption, intra‐epithelial T cell migration and keratinocyte apoptosis in OLP. The various hypotheses proposed for pathogenesis of oral lichen planus are discussed in this review.     

CD29 expression on CD4+ gingival lymphocytes supports migration of activated memory T lymphocytes to diseased periodontal tissue

The cell surface phenotypes of CD4⁺ cells extracted from inflammatory periodontal disease tissues were analyzed using two- and three-color immunofluorescence and flow cytometry. Cells extracted from both adult periodontal and localized juvenile periodontitis lesions showed a depressed CD4/CD8 ratio (1.0±0.1 adult periodontitis and 1.1 ±0.1 localized juvenile periodontitis) compared with cells recovered from normal/marginal gingivitis tissue (1.8 ±0.2) or with normal peripheral blood cells (2.1 ±0.1) or periodontal disease blood cells (2.1±0.1 and 1.7±0.1 for adult periodontitis and juvenile periodontitis, respectively). The monoclonal antibodies anti-2H4 and anti-4B4 were used to identify the CD45RA and CD29 antigens respectively on CD4⁺ T cells from the periodontal disease lesions. In peripheral blood, CD29⁺ cells accounted for 66–77% of the CD4⁺ population, and CD45RA⁺ cells accounted for 22–27% of the CD4⁺ subset. No differences in expression were found between peripheral blood lymphocytes from normal subjects and from periodontal disease patients. Two-color analyses of lymphocytes from periodontal diseased tissues showed that 87–89% of the CD4⁺ population were CD29⁺ and that 70–79% of the CD4⁺ cells were CD45RA⁺. Normal tissues contained significantly fewer CD4⁺CD29⁺ cells (56±4%) and CD4⁺CD45RA⁺ cells (40±4%) on average, and few, if any double-labelled cells could be accounted for. These data implied that a significant percentage of the CD4⁺ cells from the diseased tissues were both CD29⁺ and CD45RA⁺ and that these populations are found in quite different proportions in diseased periodontal tissue than in peripheral blood or nondiseased tissue. In further analyses using three-color cytometry the mean percentage of CD4⁺CD29⁺CD45RA⁺ lymphocytes extracted from periodontal disease lesions was 43±9% of the CD4⁺ population. These results suggest that CD4⁺ T lymphocytes in periodontal disease not only demonstrate varying levels of maturity but also that the accumulation of CD4⁺ T cells within the periodontal tissues maybe a result of increased adhesion and transendothelial migration.     

Serotype b of Aggregatibacter actinomycetemcomitans increases osteoclast and memory T‐lymphocyte activation

During periodontitis, alveolar bone resorption is associated with activation of T helper type 17 (Th17) lymphocytes and receptor activator of nuclear factor‐κB ligand (RANKL) ‐induced osteoclasts. We previously reported that serotype b of Aggregatibacter actinomycetemcomitans has a higher capacity to trigger Th17‐type differentiation and function in activated T lymphocytes and its lipopolysaccharide is a more potent immunogen compared with the other serotypes. This study aimed to investigate whether serotype b of A. actinomycetemcomitans induces higher Th17‐associated RANKL production, RANKL‐induced osteoclast activation, and antigen‐specific memory T lymphocyte proliferation. On naive CD4⁺ T lymphocytes stimulated with autologous dendritic cells primed with different A. actinomycetemcomitans serotypes, RANKL production, T‐bet, GATA‐3, RORC2 and Foxp3 expression, RORC2/RANKL intracellular double‐expression, TRAP⁺ osteoclast activation, and bone resorption were quantified. The frequency of proliferating memory T lymphocytes in response to A. actinomycetemcomitans serotypes was determined in periodontitis and healthy subjects. Naive CD4⁺ T lymphocytes stimulated by serotype b‐primed dendritic cells elicited higher levels of RANKL, RORC2, TRAP⁺ osteoclasts, and bone resorption than the same cells stimulated with the other serotypes. RANKL positively correlated and co‐expressed with RORC2. Memory T lymphocytes responding to serotype b were more frequently detected in periodontitis patients than healthy subjects. These results indicate that serotype b of A. actinomycetemcomitans is associated with higher production of RANKL and these increased levels are associated with Th17 lymphocyte induction, osteoclast activation, and bone resorption.     

Probiotics: A non-conventional therapy for oral lichen planus

Oral lichen planus (OLP) is a common T-cell mediated chronic inflammatory disease. Although the etiology is still unclear, present studies suggest that the composition of the oral microbiota and psychological problems are implicated in the etiology of OLP. The pathogenesis of OLP includes mainly antigen-specific and non-specific mechanisms. Antigen-specific mechanisms involve T-cell activation following antigen presentation and apoptosis of basal keratinocytes triggered by CD8⁺ cytotoxic T cells, while non-specific mechanisms consist of matrix metalloproteinase over-expression and mast cell degranulation in OLP lesions. Therapies for OLP are mainly used to control symptoms and a specific cure is not yet available. Probiotics are capable of modulating the immune response in a strain-specific manner. They are able to alleviate microbial infection and suppress T-cell activation, infiltration and proliferation, as well as suppress keratinocyte apoptosis and nuclear factor-kappa B signaling. Furthermore, probiotics can also modulate the production of inflammatory cytokines and microRNAs, inhibit MMP-9 expression and mast cell degranulation, and ameliorate psychological problems, all of which are involved in the pathogenesis of OLP. Therefore, we hypothesize that probiotics may be applicable to OLP as a safe, inexpensive and non-conventional therapy.     

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

Background: Dendritic cells (DC) play a crucial role in the pathogenesis of oral lichen planus (OLP) with respect to antigens presented to T cells. We performed immunohistochemical analysis to elucidate the process of activation of DC in OLP. Methods: Thirty biopsy specimens were obtained from the patients with OLP. The expressions of CD1a, Langerin, S‐100, fascin, chemokine receptor‐7 (CCR‐7), D2‐40, cyclooxygenase‐2 (COX‐2), and microsomal prostaglandin E synthase‐1 (mPGES‐1) in DC from OLP and disease free control were investigated using specific antibodies. The distribution and number (1 mm²) of DC were assessed in the intra‐epithelium and the submucosa specimens. Correlation between the number of DC and epithelium thickness was also determined. Result: Immature DC (Langerin⁺, CD1a⁺, and S‐100⁺) were identified in the epithelia from OLP patients and control, though the numbers of Langerin⁺ and CD1a⁺ positive cells were decreased in the OLP samples as compared to the control. Mature DC (fascin⁺) were identified in the submucosa specimens, not found in the epithelium from OLP or control. Double immunostaining revealed DC positive for fascin and CCR‐7 in the submucosa, which had migrated into D2‐40⁺ lymph vessels. Furthermore, keratinocytes expressed both Prostaglandin E₂ (PGE₂) converting enzymes, COX‐2, and mPGES‐1, indicating PGE₂ synthesis in the epithelial layer of the OLP specimens. Conclusion: Our results indicate that DC change from immature to mature in the epithelium and are then drawn out to the submucosa. We demonstrate that mature DC localized in the submucosa, it consequently migrates into lymph vessels. This maturation process of DC is an important immunopathological feature of OLP.