Number Of Langerhans Cells Research Articles

The interferon-rich skin environment regulates Langerhans cell ADAM17 to promote photosensitivity in lupus.

The autoimmune disease lupus erythematosus (lupus) is characterized by photosensitivity, where even ambient ultraviolet radiation (UVR) exposure can lead to development of inflammatory skin lesions. We have previously shown that Langerhans cells (LCs) limit keratinocyte apoptosis and photosensitivity via a disintegrin and metalloprotease 17 (ADAM17)-mediated release of epidermal growth factor receptor (EGFR) ligands and that LC ADAM17 sheddase activity is reduced in lupus. Here, we sought to understand how the lupus skin environment contributes to LC ADAM17 dysfunction and, in the process, differentiate between effects on LC ADAM17 sheddase function, LC ADAM17 expression, and LC numbers. We show through transcriptomic analysis a shared IFN-rich environment in non-lesional skin across human lupus and three murine models: MRL/lpr, B6.Sle1yaa, and imiquimod (IMQ) mice. IFN-I inhibits LC ADAM17 sheddase activity in murine and human LCs, and IFNAR blockade in lupus model mice restores LC ADAM17 sheddase activity, all without consistent effects on LC ADAM17 protein expression or LC numbers. Anti-IFNAR-mediated LC ADAM17 sheddase function restoration is associated with reduced photosensitive responses that are dependent on EGFR signaling and LC ADAM17. Reactive oxygen species (ROS) is a known mediator of ADAM17 activity; we show that UVR-induced LC ROS production is reduced in lupus model mice, restored by anti-IFNAR, and is cytoplasmic in origin. Our findings suggest that IFN-I promotes photosensitivity at least in part by inhibiting UVR-induced LC ADAM17 sheddase function and raise the possibility that anifrolumab ameliorates lupus skin disease in part by restoring this function. This work provides insight into IFN-I-mediated disease mechanisms, LC regulation, and a potential mechanism of action for anifrolumab in lupus.

Immunohistochemical analysis of chronic and recurrent dermatophytosis.

Dermatophytosis has assumed epidemic proportions with rising resistance, recalcitrance and recurrence, especially in tropical regions. While various factors contribute to high prevalence worldwide, yet little is known about the interactions between host defence mechanisms and dermatophytes, particularly in chronic and recalcitrant dermatophytosis. We aimed to compare the population of various immune cells in specimens of chronic recurrent dermatophytosis and those with acute superficial dermatophytosis. We investigated the density of various immune cells-Langerhans cells (CD1a+), macrophages (CD68+), dermal dendrocytes (Factor XIIIa+) in the skin of chronic dermatophytosis patients and those with successfully resolved lesions (controls). Langerhans cells were significantly decreased in the epidermis of patients, both in affected and unaffected areas in comparison with controls. In the dermis, however, no differences in the density of immune cells (macrophages and fibroblasts) were observed. The limited sample size and immune cells evaluated could be expanded further in future research. These results indicate that the decreased number of Langerhans cells could be a potential risk factor for the development of chronic and recurrent dermatophytosis.

Yinxieling decoction ameliorates psoriasis by regulating the differentiation and functions of Langerhans cells via the TGF-β1/PU.1/IL-23 signal axis.

Langerhans cells (LCs) play a critical role in skin immune responses and the development of psoriasis. Yinxieling (YXL) is a representativeChinese herbal medicine for the treatment of psoriasis in South China. It was found to improve psoriasis without obvious side effects in the clinic. Here we attempted to clarify whether and how YXL regulates the differentiation and functions of LCs in Imiquimod (IMQ)-induced psoriasis in vivo and induced LCs in vitro. The Psoriasis Area Severity Index (PASI) score was used to evaluate the efficacy of YXL for IMQ-induced psoriasis-like mice. Flow cytometry was utilized to analyze the effects of YXL, to regulate the differentiation, migration, maturation, and antigen presentation of LCs. The results show that YXL significantly alleviated skin inflammation, as reduced in PASI score and classic psoriasis characteristics in pathological sections. Although there was no effect on the proportion of total DCs in the skin-draining lymph nodes, the expression of epidermal LCs and its transcription factor PU.1 were both markedly inhibited. LCs were also prevented from migrating from epidermal to skin-draining lymph nodes and mature. In addition, the number of LCs carrying antigens in the epidermis increased, which suggested that YXL could effectively prevent LCs from presenting antigens. In vitro, YXL had a significant impact on inhibiting the differentiation of LCs. Further data showed that YXL decreased the relative expression of transforming growth factor-β (TGFβ) messenger RNA (mRNA) and interleukin-23 (IL-23) mRNAs. Thus, YXL alleviates psoriasis by regulating differentiation, migration, maturation, and antigen presentation via the TGFβ/PU.1/IL-23 signal axis.

New insights into the role of the oral leukoplakia microenvironment in malignant transformation.

Oral leukoplakia is the most frequent and potentially malignant lesion of the oral cavity. Although dysplasia grading remains the main factor for risk assessment, challenges persist in determining the exact risk of transformation, and the literature has focused on studying alternative biomarkers. The interaction between dysplastic epithelial cells and the microenvironment starts early, and the communication is mainly mediated by lymphocytes, inflammatory factors, fibroblasts, and the extracellular matrix, leading to dysplastic progression. Leukoplakia-infiltrating leukocytes (LILs) and leukoplakia-associated fibroblasts (LAFs) play crucial roles in the dysplastic microenvironment. The immune response is related to intraepithelial T lymphocyte infiltration, mechanisms of immunosuppression coordinated by regulatory T cells, M2 macrophage polarization, and increased numbers of Langerhans cells; in contrast, fibroblastic and extracellular matrix factors are associated with increased numbers of pro-tumorigenic myofibroblasts, increased expression of metalloproteinases vs. decreased expression of TIMPs, and increased expression of chemokines and other inflammatory mediators. The microenvironment offers insights into the progression of leukoplakia to carcinoma, and understanding the complexity of the oral microenvironment in potentially malignant diseases aids in determining the risk of malignant transformation and proposing new therapeutic alternatives.

Influence of Organ Culture on the Characteristics of the Human Limbal Stem Cell Niche

Organ culture storage techniques for corneoscleral limbal (CSL) tissue have improved the quality of corneas for transplantation and allow for longer storage times. Cultured limbal tissue has been used for stem cell transplantation to treat limbal stem cell deficiency (LSCD) as well as for research purposes to assess homeostasis mechanisms in the limbal stem cell niche. However, the effects of organ culture storage conditions on the quality of limbal niche components are less well described. Therefore, in this study, the morphological and immunohistochemical characteristics of organ-cultured limbal tissue are investigated and compared to fresh limbal tissues by means of light and electron microscopy. Organ-cultured limbal tissues showed signs of deterioration, such as edema, less pronounced basement membranes, and loss of the most superficial layers of the epithelium. In comparison to the fresh limbal epithelium, organ-cultured limbal epithelium showed signs of ongoing proliferative activity (more Ki-67+ cells) and exhibited an altered limbal epithelial phenotype with a loss of N-cadherin and desmoglein expression as well as a lack of precise staining patterns for cytokeratin ((CK)14, CK17/19, CK15). The analyzed extracellular matrix composition was mainly intact (collagen IV, fibronectin, laminin chains) except for Tenascin-C, whose expression was increased in organ-cultured limbal tissue. Nonetheless, the expression patterns of cell–matrix adhesion proteins varied in organ-cultured limbal tissue compared to fresh limbal tissue. A decrease in the number of melanocytes (Melan-A+ cells) and Langerhans cells (HLA-DR+, CD1a+, CD18+) was observed in the organ-cultured limbal tissue. The organ culture-induced alterations of the limbal epithelial stem cell niche might hamper its use in the treatment of LSCD as well as in research studies. In contrast, reduced numbers of donor-derived Langerhans cells seem associated with better clinical outcomes. However, there is a need to consider the preferential use of fresh CSL for limbal transplants and to look at ways of improving the limbal stem cell properties of stored CSL tissue.

Non-Calcifying/Langerhans Cell-Rich Calcifying Epithelial Odontogenic Tumour: A Critical Review of the Rare and Distinctive Entity.

The study aims to analyse the non-calcifying/Langerhans cell rich (NCLC) subtype of calcifying epithelial odontogenic tumour (CEOT). METHOD: The features of cases of the NCLC subtype of CEOT noted in the English literature by PubMed as well as 3 new cases were reviewed. Overall, twenty-one cases were noted. Many were women in the fourth to sixth decades (male-to-female ratio =1 to 2). Radiologically, the lesion is often unilocular with resorption of the affected teeth. Nineteen of the 21 cases occurred in the maxilla, especially the anterior portion. On pathological examination, epithelial cells are noted in non-calcifying amyloid-rich fibrous stroma. The main differential diagnosis is the amyloid subtype of central odontogenic fibroma. Immunohistochemical studies revealed the tumour epithelial cells were positive for cytokeratins and p63 and contained CD1a, S-100, and langerin-positive Langerhans cells. On a median follow-up of 2 years, one patient had a recurrence one year after curettage. The NCLC subtype of CEOT is unique as it contains significant numbers of Langerhans cells and has clinicopathological features distinctive from classic CEOT.

Novel characterization of CXCR4 expressing cells in uninfected and herpes simplex virus-1 infected corneas

PurposeTo characterize CXCR4-expressing cells in uninfected and herpes simplex virus-1 (HSV-1) infected corneas. MethodsThe corneas of C57BL/6J mice were infected with HSV-1 McKrae. The RT-qPCR assay detected CXCR4 and CXCL12 transcripts in uninfected and HSV-1-infected corneas. Immunofluorescence staining for CXCR4 and CXCL12 protein was performed in the frozen sections of herpes stromal keratitis (HSK) corneas. Flow cytometry assay characterized the CXCR4-expressing cells in uninfected and HSV-1-infected corneas. ResultsFlow cytometry data showed CXCR4 expressing cells in the separated epithelium and stroma of uninfected corneas. In the uninfected stroma, CD11b + F4/80+ macrophages are the predominant CXCR4-expressing cells. In contrast, most CXCR4 expressing cells in the uninfected epithelium were CD207 (langerin)+, CD11c+, and expressed MHC class II molecule, documenting the Langerhans cells (LCs) phenotype. After corneal HSV-1 infection, CXCR4 and CXCL12 mRNA levels increased significantly in HSK corneas than in uninfected corneas. Immunofluorescence staining showed CXCR4 and CXCL12 protein localization in the newly formed blood vessels in the HSK cornea. Furthermore, the infection resulted in LCs proliferation, causing an increase in their numbers in the epithelium at 4 days post-infection (p.i.). However, by 9-day p.i., the LCs numbers declined to the counts observed in naïve corneal epithelium. Our results also showed neutrophils and vascular endothelial cells as the prominent CXCR4-expressing cell types in the stroma of HSK corneas. ConclusionsTogether, our data demonstrate the expression of CXCR4 on resident antigen presenting cells in the uninfected cornea and on infiltrating neutrophils and newly formed blood vessels in the HSK cornea.

Immunoexpression of CD1a and Histopathology in Lesional and Non Lesional Skin in Psoriasis: A Cross-sectional Study

Introduction: Psoriasis is a long-lasting autoimmune disease mediated by T-lymphocytes and dendritic cells. Langerhans cells are a unique population of dendritic cells found in the epidermis, where they can be identified by Cluster of Differentiation 1a (CD1a) positivity. They play an important role in the pathogenesis of psoriasis. Aim: To evaluate the utility of immunoexpression of CD1a in the early diagnosis of psoriasis and to study the histopathology of skin biopsies from clinically diagnosed cases of psoriasis. Materials and Methods: A cross-sectional study was conducted from September 2017 to August 2019 at Gandhi Hospital, Secunderabad, Telangana, India. Skin biopsies were taken from 50 patients with psoriasis from the Outpatient Department (OPD). Histopathological features in early psoriasis were studied, and CD1a immunoexpression in lesional, perilesional, and distant skin was analysed. The data were analysed using Student’s t-test with the Statistical Package for the Social Sciences (SPSS) software. Results: Half of the cases were found in two age groups: 51-60 years (15 patients, 30%) and 11-20 years (10 patients, 20%). The majority of the cases were males (36 patients, 72%). Most of the biopsies were taken from the lower limb (24 patients, 48%), followed by the back (13 patients, 26%). In this study, the average number of CD1a positive Langerhans cells was highest (54.92±5.26) in perilesional skin compared to lesional skin (30±3.96), which was statistically significant (p-value=0.04). Conclusion: Based on the observations in this study, a strong positive reaction of CD1a in perilesional skin can be used to diagnose psoriasis in the early clinical stages, before full-blown clinical psoriatic plaques have appeared. Early diagnosis may prompt physicians to initiate treatment early

Course and structure of corneal nerve fibers in patients with primary open-angle glaucoma

PURPOSE. T o analyze the course and structure of corneal nerve fibers (CNF) in patients with different stages of primary open-angle glaucoma (POAG), and to determine possible correlations with the available diagnostic indicators of glaucoma progression. METHODS. The study included 48 patients (48 eyes) diagnosed with stages I–IV POAG at the age of 33 to 75 years. In addition to standard examination methods, all patients underwent static perimetry with Humphrey Field Analyzer II, optical coherence tomography (OCT) of the optic disc, measurement of biomechanical properties of the fibrous membrane of the eye, as well as laser confocal microscopy of the cornea on HRT III device with corneal adapter Cornea Rostock. RESULTS. There were positive correlations of medium strength between the indices of basic nerve fiber length (r = 0.64 and r = 0.63; p < 0.05) and density (r = 0.6 and r = 0.65; p < 0.05) with perimetry data (MD and PSD) and retinal nerve fiber thickness measured with OCT of the optic disc (r = 0.65 and r = 0.61; p < 0.05). Nerve fiber anisometry and symmetry coefficients depended on glaucoma stage (r = 0.62 and r = 0.65; p < 0.05). An increase in the number and density of Langerhans cells and an increase in the length of their processes were detected. A reliable correlation (r = 0.63) was found between glaucoma stage and corneal inflammatory response. The immune etiology of the glaucoma process considered by several authors may be a reason of an increase in the number and density of macrophages during the progression of POAG. CONCLUSION. Laser confocal microscopy can be used as an additional diagnostic method for patients with different stages of POAG.

Corneal confocal microscopy in patients with distal symmetric polyneuropathy compared to controls.

Diabetic neuropathy (DN) is a very common clinical condition throughout the world. The diagnostic tests currently recommended have low sensitivity, such as electromyography, or are invasive, such as skin biopsy. New techniques have been developed to identify the early involvement of the peripheral nerve. With the advent of corneal confocal microscopy (CCM), a reduction in corneal innervation in patients with DN has been observed. To compare, through CCM, diabetic patients with symptomatic distal symmetric polyneuropathy (DSP) and controls. In the present study, through CCM, we compared the morphological changes in the sub-basal epithelial corneal plexus of 35 diabetic patients with symptomatic DSP with 55 controls. Moreover, we sought to determine a pattern of change regarding the severity stages of DSP, comparing the clinical, laboratory, and nerve-conduction (NC) variables. Differences between the control and diabetic groups were observed for the following variables, respectively: age (44.9 ± 13.24 years versus 57.02 ± 10.4 years; p < 0.001); fiber density (29.7 ± 10.2 versus 16.6 ± 10.2; p < 0.001); number of fibers (4.76 ± 1.30 versus 3.14 ± 1.63; p < 0.001); number of Langerhans cells (4.64 ± 8.05 versus 7.49 ± 10.3; p = 0.035); tortuosity (p < 0.05); and thickness (p < 0.05). Furthermore, inverse relationships were found regarding fiber density and age (p < 0.01) and fiber density and the severity of the disease (p < 0.05). A positive relationship between the conduction velocity of the fibular nerve and fiber density (p < 0.05) was also observed. Corneal confocal microscopy proved to be a fast, noninvasive and reproducible method for the diagnosis, staging, and monitoring of diabetic DSP.

Bronchoalveolar Lavage as a Diagnostic Tool in an Atypical Pulmonary Langerhans Cell Histiocytosis.

Pulmonary Langerhans cell histiocytosis (PLCH) is an uncommon diffuse cystic lung disease that occurs almost exclusively in young adult smokers. High-resolution computed tomography of the chest allows a confident diagnosis of PLCH in typical presentation, when nodules, cavitating nodules, and cysts coexist and show a predominance for the upper and middle lung. Atypical presentations require histology for diagnosis. Histologic diagnosis rests on the demonstration of increased numbers of Langerhans cells and/or specific histological changes. PLCH is one of the few diseases in which bronchoalveolar lavage (BAL) has a high diagnostic value and can in some circumstances replace lung biopsy. We present a case of PLCH in an elderly non-smoker. Chest imaging revealed the presence of advanced interstitial lung disease with a fibrocystic pattern. BAL cellular analyses disclosed a macrophage pattern with CD1a phenotype that strongly supports the PLCH diagnosis, even in the setting of atypical clinical presentation and a lack of smoking exposure. PLCH is extremely rare in non-smokers and could represent a distinct phenotype.

Melanocyte-secreted fibromodulin constrains skin inflammation in mice injected with lupus serum

Skin pigmentation has been linked to the development, prevalence, and severity of several immune-mediated diseases such as SLE. Here, we asked whether fibromodulin (FMOD), which is highly expressed in skin with light complexion, can explain the known differences in the magnitude of inflammation. C57 mice with different levels of pigmentation and FMOD were injected with human lupus serum to induce skin inflammation. Histopathologic studies revealed that black C57 FMOD+/+ that produce low levels of FMOD and white C57 FMOD −/− mice develop more severe inflammation compared with white FMOD +/+ mice. This study also revealed that dark pigmentation and FMOD deletion correlates with the increased numbers of Langerhans cells. Altogether, we identify low pigmentation and FMOD are linked to low severity of inflammation and approaches to promote FMOD expression should offer clinical benefit.

Immunolocalization of CD1a expressing dendritic cells in sinonasal polyposis

ABSTRACT Sinonasal polyps are benign projections of edematous nasal mucosa lined by respiratory epithelium. Langerhans cells (LCs) belonging to the dendritic cell family located in respiratory epithelium are involved in antigen presentation and maintenance of local immunological homeostasis. This study aims to elucidate the morphology and distribution of CD1a positive LCs in normal nasal mucosa and compare the same with polypoid nasal mucosa by immunohistochemistry. Normal nasal mucosa (n = 20) was obtained from patients who underwent septoplasty for deviated nasal septum. Polypoid nasal mucosa (n = 22) was obtained from patients with chronic rhinosinusitis (CRS) or allergic fungal rhinosinusitis who underwent excision of nasal polyps. The tissues obtained were processed for immunohistochemistry and stained with CD1a-EP80 Rabbit monoclonal antibody. In the tissues studied, CD1a positive LCs were observed in both the epithelium and lamina propria. Different morphological subtypes of LCs were noted in the epithelium. The cells were distributed adjacent to walls of subepithelial capillaries and cysts. The median number of CD1a positive LCs was significantly higher in polypoid category (13.5 per mm2) as compared with normal nasal mucosa (2.5per mm2) (p = .001). Presence of CD1a positive LCs in polypoid nasal mucosa hints at a critical immunological role in the etiopathogenesis of nasal polyps.

Isolation of tdTomato Expressing Inter-follicular Epidermal Melanocytes or Keratinocytes from Mouse Tail Skin.

The epidermis is the outermost layer of the skin. It is made up of mostly keratinocytes along with a small number of melanocytes and Langerhans cells. Melanocytes produce a pigment called melanin, which is transferred to the keratinocytes, and protects these cells from damage from UV radiation, as well as generating hair and skin colours. In this important relationship, keratinocytes exert control over melanocytes. Many questions regarding keratinocyte-melanocyte interactions have yet to be answered, and would benefit from study in model systems, to address diseases such as vitiligo and cutaneous melanoma. Most of the mouse is covered in fur and these areas lack the skin pigmenting inter-follicular epidermal (IFE) melanocytes. However, the mouse tail is pigmented analogously to human skin. Here, we present a method for isolating IFE melanocytes or keratinocytes expressing the tdTomato marker from the mouse tail, using fluorescence-activated cell sorting (FACS). The method involves firstly separating the tail skin epidermis from the dermis, and then digesting the epidermis to produce dissociated cells, which can then be sorted. These isolated cell populations can be studied using RNAseq or cultured in vitro. This protocol isolates IFE melanocytes or keratinocytes and immediately provides reasonable yields of cells, without the need to stain the cells for cell specific markers.

Origin of langerin (CD207)-expressing antigen presenting cells in the normal oral mucosa and in oral lichen planus lesions.

The number of langerin-expressing antigen-presenting cells is higher in oral lichen planus than in normal oral mucosa. However, langerin may be expressed by several functionally different lineages of antigen presenting cells (APCs), and this has important implications for our understanding of the pathogenesis of oral lichen planus. The aim of this study was to determine the origin of the langerin-expressing APCs. To this end, we examined oral mucosal biopsies from healthy persons and patients with oral lichen planus using multicolor immunofluorescence. In normal oral mucosa, a substantial fraction of Langerhans cells expressed Ki-67, indicating that steady-state oral mucosal Langerhans cells are at least partially maintained by self-renewal. In oral lichen planus, the numbers of Langerhans cells were higher but proliferation was not altered, indicating that the higher cell numbers appeared to depend on recruited dendritic cell (DC)-precursors. Moreover, we found a markedly higher number of langerin+ APCs within the lamina propria of oral lichen planus lesions. Such cells did not display monocyte- or macrophage markers, but rather showed a phenotype compatible with tissue-elicited IRF4+ cDC2. Detailed understanding of how the oral mucosal APC network is regulated and the functional capacities of the different ontogenies may identify novel treatment targets for oral lichen planus.

Change patterns in the corneal sub-basal nerve and corneal aberrations in patients with dry eye disease: An artificial intelligence analysis

We aimed to investigate the change patterns in corneal sub-basal nerve morphology and corneal intrinsic aberrations in dry eye disease (DED). Our study included 229 eyes of 155 patients with DED and 40 eyes of 20 healthy control. We used the Oculus keratograph and the ocular surface disease index questionnaire to assess their signs and symptoms. In vivo confocal microscopy was used to observe the corneal sub-basal nerves, corneal endothelial cells, and Langerhans cells (LCs). An artificial intelligence (AI) technique run by the deep learning model generated the sub-basal nerve fibre parameters. Furthermore, we used the Pentacam HR system to measure the corneal intrinsic aberrations and corneal surface regularity indices. DED patients more frequently had increased anterior and total corneal aberrations than controls (P < 0.05). In addition, DED had decreased average density and maximum length of corneal nerve. (Both P < 0.01) The LC number was significantly correlated with maximum length (CC = −0.19, P = 0.01) of the sub-basal nerve fibre. Furthermore, the corneal nerve average density was negatively correlated with IHD, and anterior, posterior, and total corneal aberrations (All P < 0.05) especially the higher-order aberrations. Significant correlations were seen between corneal nerve morphology changes, analysed by AI and corneal intrinsic aberrations, particularly higher-order aberrations.

Epicutaneous Administration of 17β-Estradiol Induces Langerhans Cells Depletion

ABSTRACT Background Langerhans cells (LC) number and function in mouse vaginal mucosa are affected by 17β-estradiol (E2) application; nonetheless, its effect on epidermal LC has not been studied. The purpose of this study was to evaluate the effect of topical administration of E2 on the number, phenotype, and migratory ability of LC in mouse skin. Methods Ears of adult CD1 male mice were topically treated once with several doses. Immunohistochemical staining for CD207 and TUNEL staining were performed. LC migration to lymph nodes and the effect on the expression of costimulatory molecules on cultured dendritic cells (DC) were also evaluated. Results E2 decreased the number of CD207+ LC in a dose-dependent manner. One hour after treatment, 1 and 10 µg/mL E2 significantly reduced the LC number by 21% and 26%, respectively, after two hours, the reduction was 23% and 41%, respectively. After 48 hours, LC recovered, and after 96 hours of treatment, the CD207+/MHCII+ DC numbers were increased in regional lymph nodes. However, CD86 and CD40 molecules were expressed at lower levels than in positive control. The TUNEL assay did not show apoptotic cells. Furthermore, in cultured DC, E2 promoted a decrease in CD40 and CD86 expression and an increase in CD273, CD274, MHCII, and CCR7. Conclusions The topical administration of E2 induced a transitory local diminution of LC population and a tolerogenic phenotype. This decrease in epidermal LC suggests that E2 may affect skin immune responses, inducing an inhibitory response, which should be considered when prescribing topical E2 medications.

Morphological Alterations and Increased S100B Expression in Epidermal Langerhans Cells Detected in Skin from Patients with Progressive Vitiligo.

The role of Langerhans cells (LCs) in vitiligo pathogenesis remains unclear, with published studies reporting contradictory results regarding the quantity of LCs and no data on the features of LCs in vitiligo. Here, we aimed to analyze the presence, density, and morphological features of LCs in the epidermis of patients with vitiligo. Skin biopsies were stained for LCs using anti-CD1a/anti-langerin antibodies and analyzed by immunocytochemistry with light and electron microscopy. Compared with healthy controls, we detected significantly increased numbers of epidermal LCs in lesional skin from vitiligo in the progressive state. These LCs exhibited striking morphological alterations, including an elevated number of dendrites, with increased length and more branches than dendrites from controls. Ultrastructure examination via immuno-electron microscopy revealed markedly reduced Birbeck granules (BGs) and shorter BG rods in LCs from progressive vitiligo, with higher expression of langerin. Additionally, expression of S100B, the activity biomarker of vitiligo, was increased in these LCs. This work provides new insight on the cellular composition of LCs in vitiliginous skin, revealing altered morphology and increased LC numbers, with elevated S100B expression. Our data suggest LCs might play a critical role in vitiligo pathogenesis and thus may represent a novel therapeutic target for this disease.

Skin-derived alternatively spliced IL-15 isoform-producing cells impair the generation of anti-viral effector CD8+ T cells in HSV-1 zosteriform mouse model

Abstract We previously reported a Pedigree 191 (P191) of N-ethyl-N-nitrosourea (ENU) mutagenized mice that highly expressed an alternatively spliced IL-15 isoform with deletion of the first 16 amino acids in exon 7 (IL-15ΔE7). Infection of P191 mice with herpes simplex virus-1 (HSV-1) via flank skin generated a prolonged and early re-emerged HSV-1 zosteriform rash compared to wild type (WT) C57BL/6 mice. Using Kb/gB498–505 MHC Class I tetramer provided by NIH Tetramer Core Facility, we found that the numbers of gB-specific CD8+ T cells generated in draining lymph nodes (dLN) of P191 mice were greatly reduced over 10-day course after HSV-1 flank infection compared with WT mice. As expressions of IFN-γ, granzyme B and perforin were induced in WT CD8+ T cells by in vitro restimulation with gB peptides, they were poorly expressed in P191 CD8+ T cells. While HSV-1 skin infection induced migration of Langerhans cells into dLNs accompanied with increased IL-15 expression in WT mice, the number of migrated Langerhans cells was less in P191 and they preferentially expressed IL-15ΔE7 rather than IL-15. The reverse relationship between the cell number of Langerhans cells and the increased expression of IL-15ΔE7 mRNA in dLN of P191 mice suggested that the influx of skin-derived IL-15ΔE7 expressing cells plays an important role in influencing the quantity and quality of anti-HSV-1 CD8+ T cells generated in P191 mice. More experiments will be carried out to understand how the alternatively cytokine splicing mechanism regulates a long term and effective CD8+ T cell immunity against virus infection.

Pathological and clinical relevance of selective recruitment of Langerhans cells in the respiratory bronchioles of smokers

Smoking causes an influx of inflammatory cells including Langerhans cells (LCs) into the airways and lung parenchyma, thus inducing histological changes, such as emphysema and fibrosis. We examined the distribution and quantity of Langerhans cells in relation to clinical and pathological findings and explored the association between smoking and accumulation of Langerhans cells in the respiratory bronchioles. Fifty-three patients who underwent lung resection for primary diseases, including lung cancer, were recruited. Histological and immunohistochemistry analyses were utilized to identify CD1a-positive Langerhans cells in peripheral lung specimens separated from primary lesions. Clinical characteristics, pathological changes, and distribution of CD1a-positive Langerhans cells distribution were assessed. Of the 53 patients, 35 were smokers and 18 were non-smokers. The number of Langerhans cells in the respiratory bronchioles was significantly increased in smokers as compared to that in non-smokers (p<0.001). The number of Langerhans cells in smokers was significantly higher in patients with mild emphysema than in those without emphysema (p<0.01). The high-LC group showed more frequent smoking-related histological changes, such as respiratory bronchiolitis, parenchymal fibrosis, accumulation of macrophages, and smoking-related interstitial fibrosis, than the low-LC group. However, there were no differences in the smoking indices and pulmonary functions of the groups. Selective accumulation of Langerhans cells in the respiratory bronchioles of smokers may lead to the development of smoking-related pathological changes.