The inhibitory effect of PUVA on the immunity of experimental dermatophytosis in guinea pigs

Summary The effect of topical PUVA on the disease course and immunity of T. mentagrophytes dermatophytosis was investigated in guinea pigs. Animals which had been inoculated on nontreated skin showed mild erythematous lesions with scaling in a few days and then developed the most intense reaction between days 10 and 14. The lesions resolved completely by the third week. On the other hand, animals which had been inoculated on the PUVA-treated sites showed only mild squamous, erythematous lesions until the fourth postinfective week, when the intense reaction began to appear. Complete regression was observed by the fifth week in these animals. Trichophytin tests performed on the 14th day were positive in the guinea pigs of nontreated group, while negative in the PUVA-treated animals. The latter group revealed a positive reaction on the fifth week. PUVA did not show inhibitory effect on the sensitization by intracutaneous injection of trichophytin antigen. The PUVA treatment depleted the ATPase-positive Langerhans' cells. These results indicate that PUVA treatment suppresses the immunity of dermatophytosis and delays the spontaneous resolution of the lesions, and suggest that the Langerhans' cell is involved in the development of cell-mediated immunity in experimental dermatophytosis.     

The ATPase-staining of Langerhans cells in previously stored skin tissues.

The ATPase-staining of Langerhans cells is usually done on fresh, unfixed biopsy specimens. In the present study, we attempted to stain these cells in previously stored tissues of guinea pig skin. The ATPase activity disappeared after freezing or preservation in formalin or ethanol. In contrast, tissue specimens which had been stored in physiological saline at 4 degrees C stained as well as fresh cells even after 14 days.     

Mast cell density in psoriatic skin. The effect of PUVA and corticosteroid therapy

Summary Numbers and volume fractions of mast cells in nonlesional and chronic lesional skin of psoriatic patients were compared with those of normal control skin. Mast cell densities were similar in psoriatic nonlesional and normal control skin. The superficial dermis of lesional psoriatic skin contained more mast cells than either normal or nonlesional psoriatic skin. Neither PUVA nor corticosteroid treatment for 3–4 weeks significantly reduced mast cell numbers or volume fractions in lesional skin, although both treatments clinically and histologically markedly improved the lesions. The results indicate that the initiation of the healing process in psoriatic plaques is not correlated with the mast cell density. The remaining high mast cell density may be normalized later, or after a longer therapy.     

The ELAM-1 ligand sialosyl-Lex is present on Langerhans cells isolated from stratified epithelium

In this study we show the expression of the newly identified carbohydrate ligand, sialosyl-Le(X) on Langerhans cells. The receptor for sialosyl-Le(X) is the endothelial leukocyte adhesion molecule-1 (ELAM-1) present on activated endothelial cells. Using flow cytometry, Langerhans cells were selected due to positivity for an antibody against CD1a and low orthogonal light scatter. The CD1a antigen stained by the OKT6 antibody is considered a maturational marker of Langerhans cells in agreement with the specific labeling of dendritic cells in the epithelium only. Double immunostaining (OKT6/anti-sialosyl-Le(X)) using flow cytometry and immunohistochemistry demonstrated that almost all OKT6-positive cells in normal stratified epithelium expressed sialosyl-Le(X). Conversely, by immunohistochemistry of oral epithelium with acute inflammation, additional dendritic cells negative for OKT6 were found to express sialosyl-Le(X). In addition, sialosyl-Le(X)-positive but not OKT6-positive dendritic cells were found in the submucosa. These findings indicate that the carbohydrate antigen sialosyl-Le(X) is expressed earlier than the CD1a antigen in the maturation of the Langerhans cell lineage. Future studies should aim at investigating the importance of adhesion between sialosyl Le(X) and ELAM-1 in epithelial recruitment of Langerhans cells.     

In vivo activation of langerhans cells and dendritic epidermal T cells in the elicitation phase of murine contact hypersensitivity

Langerhans cells (LCs) and dendritic epidermal T cells (DETCs) constitute the skin immune system. To demonstrate the kinetics of in vivo activation of murine LCs and DETCs in the elicitation phase of contact hypersensitivity, we measured the cell area positively stained for I-A and gammadeltaT-cell receptor (or Thy-1.2), respectively, under a fluorescence microscope at various time intervals after topical application of dinitrofluorobenzene. The fluorescence-positive area of LCs increased in parallel with that of DETCs at 1 h and 24 h, indicating the biphasic activation of LCs and DETCs. Early activation was hapten-specific and often exhibited close LC-to-DETC apposition. Experiments with in vivo administration of neutralizing anticytokine antibodies revealed that none of interferon (IFN)-gamma, tumour necrosis factor (TNF)-alpha and interleukin (IL)-1beta were involved in the induction of early activation of LCs and DETCs, while TNF-alpha and IL-1beta mediated late activation of LCs, and IFN-gamma and IL-1beta mediated that of DETCs. Our results indicate that LCs and DETCs are synchronously and biphasically activated in the epidermis during the elicitation phase of contact hypersensitivity and suggest that different mechanisms may control early and late activation.     

The presence of IgE molecules on epidermal langerhans cells in patients with atopic dermatitis

Summary Skin sections of clinically involved and clinically normal-looking skin from patients with atopic dermatitis were incubated with anti-human IgE antibodies using the indirect immunoperoxidase technique. Apart from positive dermal anti-IgE staining, positive epidermal anti-IgE staining was also observed. The morphology of the epidermal staining cells suggested the involvement of dendritic cells. This was confirmed by positive immuno-double labelling with OKT6 and anti-IgE. This phenomenon seemed to be specific for atopic dermatitis since skin sections from normal nonatopic controls, patients with allergic asthma, contact dermatitis, and schistosomiasis showed no epidermal anti-IgE staining. To further elucidate the nature of the epidermal anti-IgE staining cells, epidermal cell suspensions were prepared from clinically involved skin from patients with atopic dermatitis. These cell suspensions also showed positive anti-IgE staining cells and positive immuno-double labelling with OKT6 and anti-IgE. Immunogold electron microscopy with anti-IgE on epidermal cell suspensions from patients with atopic dermatitis showed gold particles on the cell membranes of cells containing Birbeck granules, being Langerhans' cells. Epidermal cell suspensions from normal non-atopic controls were negative. The presence of IgE molecules on epidermal Langerhans' cells, which seems to be specific for patients with atopic dermatitis, provides an explanation for the high frequency of positive patch test reactions to inhalant allergens.     

The influence of topical dermatological treatment modalities on epidermal Langerhans cells and contact sensitization in mice

The influence of the widely used topical dermatological treatment modalities anthralin, coal tar and pyrogallol on surface markers of epidermal Langerhans cells and contact sensitization was studied and compared with that of a PUVA treatment. A common effect of all dermatological therapies tested was inhibition of Langerhans cell ATPase, whereas an effect on MHC class II antigens was found only after PUVA or tar treatment. The induction of contact hypersensitivity was inhibited only by PUVA, and not by the other treatments. These results show that various forms of topical therapy influence surface markers and immunological function of epidermal Langerhans cells differently.     

Effects of UVB on fascin expression in dendritic cells and Langerhans cells

BACKGROUND: Fascin is an actin-binding protein that regulates the rearrangement of cytoskeletal elements and their interactions with the cell membrane. Previous studies have indicated that fascin expression is enhanced in DC upon maturation and plays a critical role in T cell activation. Ultraviolet irradiation exerts immunosuppressive effects. OBJECTIVE: We examined the effects of UVB irradiation on the interaction of DC/LC with T cells through fascin. METHOD: Murine bone marrow-derived DC (BM-DC) were induced by recombinant murine GM-CSF and LPS, and UVB irradiation was applied prior to supplementation with LPS. I-A(+) cells (Langerhans cells (LC)) in the epidermal cell suspensions were exposed to UVB irradiation at the beginning of the 24-h culture. BM-DC and LC were analysed by immunohistochemical staining and flow cytometric analyses. To evaluate the effects of UVB irradiation on DC-T cell binding, we examined the clustering of BM-DC with allogeneic CD4(+) T cells under a confocal microscope. RESULTS: Fascin expression in BM-DC and LC was decreased by UVB irradiation. Furthermore, UVB irradiation reduced the ability of BM-DC to cluster with allogeneic CD4(+) T cells. Polarization of fascin and filamentous actin (F-actin) at the point of contact of BM-DC with T cells was also disturbed by UVB irradiation. CONCLUSION: These results suggest that the suppression of fascin expression by UVB irradiation down-regulates the rearrangement of the cytoskeleton and, thereby, antigen presentation in DC/LC.     

Lack of effect of oral selenite on p53 associated gene expression during TL01 therapy of psoriasis patients

Selenium (Se) has protective properties against ultraviolet (UV)-induced changes in skin cells in vitro but little is known about such activity in human subjects. In the present study, seven patients with psoriasis ingested 400 microg of sodium selenite daily during a 4 week course of whole-body narrow-band UVB (TL01) therapy while six more psoriasis patients, similarly irradiated, ingested a placebo. Skin biopsies, collected at the start and end of the phototherapy were analysed for phosphorylated p53, Fas, Bcl-2, Bax and oxidized guaninosine, and for numbers of Langerhans and sunburn cells. Following the TL01 therapy, no significant difference was observed for any of these markers when the Se group was compared with the placebo group of patients, although p53 and Bcl-2 expression decreased in the Se supplemented group.     

表没食子儿茶素没食子酸酯减轻UVB诱导的朗格汉斯细胞凋亡作用

目的 研究中波紫外线(UVB)对人表皮朗格汉斯细胞(LC)的光损伤作用以及绿茶活性成分表没食子儿茶素没食子酸酯(EGCG)的光保护作用。方法 采用密度梯度离心和免疫磁珠的方法分离纯化人表皮LC,将分离纯化的LC随机分为对照组、30 mJ/cm² UVB辐射组以及辐射后加用200μg/mL EGCG处理组,4h后以PI染色并经流式细胞仪检测细胞凋亡率。结果 30 mJ/cm² UVB辐射组的凋亡率明显高于对照组,EGCG干预组的凋亡率低于单纯UVB辐射组,但仍高于非照射对照组;且辐射后S期细胞数明显增加。几乎没有G₂/M期的细胞,EGCG处理辐射细胞后,S期细胞数减少。结论 UVB可诱导人表皮LC凋亡,而EGCG具有一定的保护作用。     

咪喹莫特对尖锐湿疣皮损朗格汉斯细胞的影响

目的探讨外用咪喹莫特治疗尖锐湿疣可能的机制。方法咪喹莫特治疗前、后对30例尖锐湿疣患者分别取同一部位皮损,采用免疫组化法检测其CD1a的表达,并以Motic彩色医学图文分析系统,对阳性细胞进行定量分析。15名正常男性的包皮作为对照。结果光学显微镜及Motic彩色医学图文分析显示,用药前患者皮损中CD1a+朗格汉斯细胞(LC)数量与用药后皮损及正常皮肤比较,均明显减少(P0.05);而用药后患者皮损中CD1a+LC的数量与正常皮肤比较差异无统计学意义(P0.05)。治疗前尖锐湿疣皮损中典型的LC少见,咪喹莫特治疗后,皮损中形态正常的LC增多。结论尖锐湿疣皮损中LC功能的恢复可能是咪喹莫特治疗尖锐湿疣的机制之一。     

银屑病患者角质形成细胞对朗格汉斯细胞免疫刺激功能的影响

为探讨银屑病患者皮损处角质形成细胞对朗格汉斯细胞（LCs）免疫刺激功能的影响，从健康者外周血分离单核细胞，经IL－4＋GM－CSF＋TGF－β1培养5天后分化发育为1Cs,再加入银屑病患者角质形成细胞培养上清继续培养2天，然后通过Leica显微镜观察其形态；通过混合淋巴细胞反应分析其种T的刺激功能。结果显示，以健康人角质形成细胞上清为对照，LCs经银屑病患者角质形成细胞上清培养2天后，拥有不规则突起的细胞明显较正常组增多。同时，其刺激T淋巴细胞增殖的能力也增强。结果表明，银屑病患者角质形成细胞上清培养的LCs表现出较强的免疫刺激功能，并在银屑病相关的免疫反应过程中发挥了重要作用，提示这可能与银屑病患者角质形成细胞表达的某些因子有关。     

The role of cutaneous dendritic cells in the immunopathogenesis of atopic dermatitis

We review the immunology of atopic dermatitis (AD) and focus attention on the role of cutaneous dendritic cells. AD is a complex immune-mediated skin disorder characterized by the recruitment of both CD4+ and CD8+ T cells into the skin. T-helper (Th) 2-type cytokines are dominant in acute AD skin, while both Th1- and Th2-type cytokines are present in chronic AD. Cutaneous dendritic cells, which are present in increased numbers within AD skin, are believed to play a key part in the activation of T cells in the skin. They may also help to determine the pattern of cytokines produced by activated effector T cells.     

温热对HPV感染皮肤中朗格汉斯细胞的影响

目的 探讨不同温热条件处理后的正常皮肤/尖锐湿疣皮损组织中朗格汉斯细胞（LC）的形态、数量及迁移。方法 利用37 ℃、42 ℃、45 ℃不同的温热条件处理置于培养液中的离体尖锐湿疣皮损（16例）和正常皮肤组织（15例），采用免疫组化和流式细胞分析方法测定LC形态、数量和迁移的变化。结果 表皮中LC数量随着温度的增高而减少，正常皮肤组织表皮内LC数量分别为：782.40 ± 114.88（37 ℃），649.44 ± 119.40（42 ℃），510.88 ± 118.64（45 ℃）；疣体组织表皮内LC数量分别为：646.04 ± 135.67 （37 ℃）、489.38 ± 118.19 （42 ℃）、387.93 ± 110.15 （45 ℃ ）；LC树突变短、减少或消失。温热促进LC迁移至培养液中。不同温度下，游走的LC表达CD1a的数量不同，正常皮肤组织游走至培养液中LC表达CD1a的比率分别是0.19% ± 0.18%（37 ℃），0.89% ± 0.19%（42 ℃），1.59% ± 0.28%（45 ℃）；尖锐湿疣组织分别为0.62% ± 0.31%（37 ℃），2.31% ± 0.54%（42 ℃），6.33% ± 0.98%（45 ℃）。结论 温热能够促进LC的迁移，籍此有可能增强LC在免疫应答中的抗原提呈作用。     

Demonstration of the high-affinity IgE receptor (FcɛRI) on Langerhans cells of oral mucosa

Abstract Langerhans cells in the skin have recently been shown to bind IgE molecules via a high-affinity IgE receptor. Using two specific antibodies, 29C6 and 6F7, against the α-chain of the high-affinity IgE receptor we here demonstrate that Langerhans cells express this receptor in oral mucosa. A specific antibody. Tül, against the low-affinity IgE receptor showed only low expression of this receptor. High-affinity binding for IgE may be important for induction and support of Langerhans cell-dependent transepithelial IgE-mediated allergic reactions and inflammation.