Dermal Langerhans Research Articles

Clinicodermoscopic and immunopathological profile of non-infectious non-eczematous inflammatory tattoo reactions: A retrospective study from a tertiary care centre of East India.

Introduction Tattoo-associated complications are on the rise due to the popularity of decorative tattoos in recent years. The exact pathogeneses of various tattoo reaction patterns are still unclear, and their dermoscopic details are sparsely reported. Aim We aimed to retrospectively study the clinical, dermoscopic and immunopathological details of patients with non-infectious, non-eczematous inflammatory tattoo reaction patterns in a tertiary care centre of East India. Method The clinical, dermoscopic and pathological details of all the patients who had non-infectious, non-eczematous inflammatory tattoo reactions were collected. In all the cases, immunohistochemistry was done for CD1a, CD3, CD4, CD8, FoxP3, CD20 and CD56. Results A total of five patients of skin phototypes IV and V and six tattoo reactions were analysed. Five lesions had reactions at the site of a black tattoo, and one at the site of red tattoo. Clinically, the patients presented with erythematous or blue-grey flat-topped to verrucous papules and plaques. Dermoscopic features were dominated by a central white to pink-white structureless area, a peripheral grey-white to bluish-white structureless area, white scales, comedo-like opening with keratotic plugging, milia-like cysts and shiny white structures. Pathologically, except for one lesion that only showed a lichenoid reaction pattern in the red tattoo, all had a combination of reaction patterns. Immunohistochemistry showed increased epidermal and dermal Langerhans cells, predominantly CD8 positive T cells in the epidermis and dermis, sparse dermal B cells and CD4 positive T cells, reduced T regulatory cells and a complete absence of CD56 positive NK cells. Limitations Small sample size was the limitation of the study. Conclusion The clinical morphology and dermoscopy may not differentiate between various types of non-infectious non-eczematous inflammatory tattoo reactions. The immunological profile supports a delayed hypersensitivity reaction due to contact sensitisation to tattoo pigment, and CD8 positive T cells play a central role in executing various pathological reaction patterns, both in the epidermis and dermis.

Expanding landscape of CDKN1A (p21) functions: CDKN1A-mediated radioresistance of dermal Langerhans cells and its impact on the immune system

The CDKN1A (p21 WAF1/CIP1 ) protein is the founding member of the CIP/KIP family of cyclin-dependent kinase (CDK) inhibitors. It is a p53 transcriptional target that plays a pivotal role in the DNA damage surveillance network through activating cell cycle checkpoints, promoting DNA repair, downregulating apoptosis, and triggering a senescence-like growth arrested response (premature senescence). The anti-apoptotic property of CDKN1A is not only associated with its ability to halt cell-cycle progression and facilitate DNA repair, but also relies on its ability to inhibit the activity of proteins directly involved in the induction of apoptosis (e.g., the caspase cascade) and to control transcription, resulting in downregulation of pro-apoptotic genes and upregulation of genes with anti-apoptotic activities. In addition, we recently provided evidence suggesting that CDKN1A can positively regulate wild-type p53-induced phosphatase 1 (WIP1), an anti-apoptotic phosphatase that inhibits p53 and its upstream kinases (e.g., ATM; CHK2). Consistent with these properties of CDKN1A, treatment of p53 wildtype solid tumor-derived cells with ionizing radiation or chemotherapeutic agents results in sustained upregulation of CDKN1A, protection against apoptotic cell death, and growth arrest through premature senescence.

E-Cadherin Is Expressed by Mono- and Multinucleated Histiocytes in Cutaneous Sarcoidal and Foreign Body Granulomas

E-cadherin, a member of the cadherin family of transmembrane adhesion receptors, is critical for cutaneous barrier function, as it promotes keratinocyte and Langerhans cell adhesion in the epidermis. Recent murine models of chronic inflammation identified new E-cadherin expressing subsets of mononuclear phagocytes, including alternatively activated macrophages and selected inflammatory dendritic cells. It has been shown in vitro that expression of E-cadherin by murine macrophages promotes their homotypic aggregation and fusion to multinucleated giant cells (MNGCs), a signature cell type of granulomatous inflammation. The purpose of this study was to assess E-cadherin expression on histiocytes and giant cells in cutaneous granulomas in humans. E-cadherin expression was evaluated by immunohistochemistry of formalin-fixed paraffin-embedded skin biopsies of foreign body granulomas (n = 21) and sarcoidosis (n = 21). The results showed consistent membranous E-cadherin staining pattern on mononucleated histiocytes and MNGCs in both granuloma types. These E-cadherin expressing histiocytes are distinct from dermal Langerhans cells because they lacked CD1a expression. Our findings suggest that E-cadherin expressing mononuclear histiocytes are likely precursors for MNGCs in cutaneous granulomas and may play a critical role in disease pathogenesis.

Expression of the Niacin Receptor GPR109A in Retina: More than Meets the Eye?

GPR109A was discovered recently as the G-protein coupled receptor for niacin (nicotinic acid), a drug used widely in the treatment of hyperlipidemia. Upon its initial discovery, expression of the receptor was thought to be restricted primarily to adipocytes and immune cells (monocytes/macrophages), a pattern of localization consistent with the known actions of niacin – anti-lipolytic and anti-atherogenic. Of late however, several new reports have arisen detailing expression of the receptor in other cell and tissue types. Interestingly, with the exception of dermal Langerhans cells, the cells responsible for skin flushing, an unwanted side effect of high-dose niacin therapy, the function of the receptor in the additional cell types described is largely anti-inflammatory in nature. The receptor might also have a role in cancer; silencing of the receptor has been reported in colon and breast cancers, and forced expression of the receptor in tumor cells induces apoptosis, thereby suggesting a tumor-suppressive role for the receptor. This supports strongly not only the critical importance of GPR109A expression and activity under normal, basal conditions, but also the strength in impact that therapies capable of augmenting or optimizing its expression and activation may have in thwarting the development and progression of inflammation and cancer. Given the key causative role of inflammation in diabetic retinopathy, and the critical lack of viable strategies for intervening early in this pathology, new therapies, particularly those targeting inflammation, are sorely needed. Herein, we describe preclinical and clinical studies documenting the expression of GPR109A, the pleiotropic effects elicited in response to its activation and the underlying mechanisms to explain these actions. This information we discuss in the context of its relevance to diabetic retina, ultimately providing insight into strategy for future targeting of the receptor and development of new therapies for prevention and treatment of retinopathy in diabetes.

Abstract P5-16-04: A phase I study of a DNA plasmid based vaccine encoding the HER-2/neu intracellular domain in subjects with HER2+ breast cancer.

Abstract HER2+ breast cancer (BC) is associated with early disease relapse, usually to distant sites. This would suggest relapse is due to residual microscopic disease. Generation of vaccine-induced HER2-specific CD4+ T helper immunity (Th1) may result in immunologic eradication of residual HER2+ tumor cells and subsequent development of immunologic memory and epitope spreading (ES), which has been associated with a survival benefit in vaccinated BC patients. We have shown HER2 peptide-based vaccines can generate immunity in BC however, more recently we developed a plasmid DNA based vaccine (pNGVL3-hICD) which may have additional advantages over synthetic peptides. DNA vaccines offer a strategy to immunize against multiple tumor antigens and are able to elicit both CTL and Th1 immunity. Plasmid DNA can also remain at the vaccine site, providing a constant source of antigen. Intradermal (i.d.) delivery of DNA vaccines with GM-CSF as adjuvant may enhance immunogenicity due to local influx of dermal Langerhans cells. We have recently completed a phase I trial utilizing pNGVL3-hICD in optimally treated stage III and IV HER2+ BC patients and have defined vaccine safety profile, optimal dose and schedule; and demonstrated vaccine biologic activity. Methods: A total of 66 subjects with stage III and IV HER2+ BC in complete remission were enrolled sequentially into 1 of 3 pNGVL3-hICD dose arms (22 subjects/arm): Arm 1=10µg, Arm 2=100 µg, and Arm 3 = 500µg. All vaccines were admixed with 100µg GM-CSF and given i.d. monthly for a total of 3 vaccines. Toxicity was assessed at baseline, during vaccination and at follow-up. Immune responses to HER ICD and ECD were assessed with IFN-γ ELISPOT at baseline and serially through week 60 post-vaccination. Linear regression analysis was used to compare differences in immune responses from baseline over the whole study period between dose arms. Vaccine site skin biopsies and peripheral lymphocytes were serially analyzed for plasmid persistence via RT-PCR. Results: 64 subjects (20 in Arm 1; 22 in Arm 2; 22 in Arm 3) completed 3 vaccines. Age, stage/status, number of previous chemotherapy regimens, and use of bisphosphonate and trastuzumab therapies was similar across dose arms. Vaccine-related toxicity was primarily Grade 1/2 injection site reactions, myalgias, arthralgias and not significantly different between arms; no cardiac or grade IV toxicity was observed. Immune responses to HER2 ICD were significantly better in Arms 2 and 3 vs Arm 1 (p = 0.001 and 0.002, respectively) but not statistically different between Arms 2 and 3. 38 patients had DNA plasmid persistence at the vaccination site with no difference between arms. There has been no detection of DNA plasmid in lymphocytes from patients in all arms. Analyses of survival and ES (HER ECD immune responses) are on-going and will be presented. Conclusions: pNGVL3-hICD was safe and effectively induced persistent HER2 ICD specific Th1 immunity without increased cardiac toxicity. Moreover, immunity was present more than 1 year after end of vaccination, indicative of vaccine-induced immunologic memory. Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P5-16-04.

UV immunosuppression and cutaneous malignancies

Skin cancer is the most common cancer in the USA with ultraviolet radiation (UVR) exposure being the major environmental risk factor. The mechanism by which UVR causes cancer is not yet clear but involves direct and indirect DNA damage, as well as local and systemic immunosuppression leading to a tumorigenic environment. At the cellular level, dermal dendritic cells, Langerhans cells, skin-infiltrating monocyte/macrophages, T lymphocytes, chemokines and cytokines participate. Dermal dendritic cells are recognized as the main antigen presenting cell of the skin. UV-induced skin-infiltrating monocytes/macrophages may be a source for these dermal dendritic cells. Langerhans cells serve an immunosuppressive role and activate regulatory T cells upon UVR damage. CD4+CD25+ regulatory T lymphocytes, upon activation by UV damage, suppress effector T lymphocyte proliferation, maturation and function, leading to decreased contact hypersensitivity responses. IL-12, a cytokine suppressed by UVR, is involved in DNA rep...

Chemokine Receptor CCR5 Mediates AlloImmune Responses in Graft-versus-Host Disease

Allogeneic bone marrow transplantation (BMT) is an effective therapy for hematologic malignancies. However graft-versus-host disease (GVHD) is a major limiting factor for a successful patient outcome. GVHD is a result of alloimmune responses of donor T lymphocytes attacking the recipient's cells and tissues. Chemokine receptor CCR5 plays a role in solid organ allograft rejection and mediates murine GVHD pathogenesis. Herein, we report that infiltrating lymphocytes in the skin of human acute GVHD (aGVHD) samples are predominantly CCR5(+) T cells. In addition, we characterized the features of the CCR5 expression on alloreactive T lymphocytes. We found that the CCR5(+) population exhibits the characteristics of the activated effector T cell phenotype. CCR5 expression is upregulated upon allogenic stimulation, and CCR5(+) cells are proliferating with coexpression of T cell activation markers. Furthermore, the activated T cells producing inflammatory cytokine tumor necrosis factor (TNF)alpha, interleukin (IL)-2, or interferon (IFN)-gamma, are positive for CCR5. Thus, CCR5 is a marker for GVHD effector cells and CCR5(+) T cells are active participants in the pathogenesis of human aGVHD.

The mechanism and mitigation of niacin-induced flushing

Aims:To summarise the metabolic responses to niacin that can lead to flushing and to critically evaluate flushing mitigation research.Methods and results:This comprehensive review of the mechanism of action of niacin-induced flushing critically evaluates research regarding flushing mitigating formulations and agents. Niacin induces flushing through dermal Langerhans cells where the activation of G protein-coupled receptor 109A (GPR109A) increases arachidonic acid and prostaglandins, such as prostaglandin D2 (PGD2) and prostaglandin E2 (PGE2), subsequently activating prostaglandin D2 receptor (DP1), prostaglandin E2 receptor (EP2) and prostaglandin E receptor 4 (EP4) in capillaries and causing cutaneous vasodilatation. Controlling niacin absorption rates, inhibiting prostaglandin production, or blocking DP1, EP2 and EP4 receptors can inhibit flushing. Niacin extended-release (NER) formulations have reduced flushing incidence, duration and severity relative to crystalline immediate-release niacin with similar lipid efficacy. Non-steroidal anti-inflammatory drugs (NSAIDs), notably aspirin given 30 min before NER at bedtime, further reduce flushing. An antagonist to the DP1 receptor (laropiprant) combined with an ER niacin formulation can reduce flushing; however, significant residual flushing occurs with clinically-relevant dosages.Conclusions:Niacin is an attractive option for treating dyslipidemic patients, and tolerance to niacin-induced flushing develops rapidly. Healthcare professionals should particularly address flushing during niacin dose titration.

A phase I study of a DNA plasmid based vaccine encoding the HER2/neu (HER2) intracellular domain (ICD) in subjects with HER2+ breast cancer

3054 Background: HER2 is overexpressed in 25% of breast cancers and plays a role in the malignant transformation of cells. Vaccine-induced immunity against the HER2 ICD correlates with antitumor responses in animal models. DNA-based vaccines offer a strategy to immunize against multiple tumor antigens and are able to elicit both CTL and T helper immune responses. Plasmid DNA can also remain at the vaccine site, providing a constant source of antigen. However, DNA vaccines have been poorly immunogenic due in part to inefficient APC transfection. Intradermal (i.d.) delivery of DNA vaccines with GM-CSF as adjuvant may enhance immunogenicity due to local influx of dermal Langerhans cells. A phase I study was conducted to evaluate the safety and immunogenicity of a DNA-based vaccine encoding the HER2 ICD. Methods: 44 subjects with stage III and IV HER2+ breast cancer in complete remission were enrolled sequentially into 2 vaccine arms (22 subjects/arm) and received 10μg pNGVL3-hICD (Arm 1) or 100μg pNGVL3-hICD (Arm 2). All vaccines were admixed with 100μg GM-CSF and given i.d. monthly for a total of 3 vaccines. Toxicity was assessed at baseline, during vaccination, and at follow-up. Immune responses were assessed with IFN-γ ELISPOT at baseline and post-vaccination. Vaccine site biopsies were analyzed for plasmid persistence via RT-PCR, 1 and 6 months after vaccination. Results: 43 subjects (21 in Arm 1; 22 in Arm 2) completed 3 vaccines. Vaccine-related toxicity in both arms was primarily grade I/II; no cardiac or grade IV toxicity was observed. 13/21 (62%) subjects in Arm 1 developed T-cell immunity, defined as HER2-specific T cell precursors:PBMC, to the HER2 protein (median 1:5,972, range 1:717–1:3,000,000) and to p776, a HER2 pan DR binding epitope (median 1:3,150, range 1:543–1:108,696). 13/19 (68%) subjects in Arm 1 had persistent plasmid DNA at the vaccine site. ELISPOT and RT-PCR analysis for Arm 2 are on-going. Conclusions: Immunization with a DNA plasmid-based HER2 vaccine is safe and immunogenic. Moreover, plasmid DNA persists at the vaccine site post-immunization and HER2+ cancer patients are able to develop immunity to the HER2 ICD. No significant financial relationships to disclose.

Tacrolimus ointment 0.1% in the treatment of allergic contact eyelid dermatitis

Tacrolimus inhibits T-lymphocyte activation and dermal Langerhans' cells, without the side-effects of corticosteroids. The safety profile of tacrolimus makes it a promising therapeutic option for dermatitis affecting the delicate periorbital skin. To access the efficacy and tolerability of tacrolimus ointment 0.1% in the treatment of allergic contact eyelid dermatitis. Twenty adults (16 women, 4 men) with eyelid dermatitis and with at least one positive patch test reaction to relevant contact allergens were treated with topical tacrolimus in a prospective, open-label, non-comparative clinical study. Dermatitis was graded at baseline, at day 30 and day 60, using a 4-point grading system for the following parameters: erythema, oedema, scaling, lichenification, fissuring (investigator assessment) and burning/stinging and pruritus (patient assessment). All patients completed the study. Erythema, oedema, scaling and lichenification showed improvement from baseline to 30 days of treatment ( P < 0.001), but fissuring was not significantly affected. At 60 days, no further improvement of these investigator parameters was observed. Patient parameters improved significantly by day 30 ( P < 0.004) and there was a trend for further improvement at the end of 60 days (for burning, P = 0.046; for pruritus, P = 0.059). Ten per cent of patients mentioned burning and itching, at the application site, during the first days of treatment. No other adverse events were observed. Topical tacrolimus is a promising alternative in patients with allergic contact eyelid dermatitis. Therapy was effective by 1 month and was well tolerated. These preliminary results merit a larger, controlled, study.

Evaluation of Langerhans’ cells in normal and eczematous dermatitis skin by CD1a protein immunohistochemistry: preliminary findings

Langerhans' cells (CD1a positive, bone marrow-derived cells), are the antigen presenting cells of the skin. Our knowledge about the status of these cells in eczematous dermatitis is incomplete. This study tests the hypothesis that 'the development of eczematous dermatitis is associated with alterations of Langerhans' cells'. Biopsy specimens from patients with eczematous dermatitis and normal skin (20 cases, each) were studied. Langerhans' cells were stained for CD1a using imunoperoxidase-staining methods and mouse monoclonal antibodies. In normal skin, CD1a+ Langerhans' cells were seen in suprabasal position. In eczematous dermatitis skin, CD1a positive cells were seen scattered in the acanthotic epidermis. Compared with normal skin, the mean values of the Langerhans' cells were statistically significantly higher in eczematous dermatitis [epidermal Langerhans' cells: 1.20 (standard error of mean, SEM, 0.13) vs. 2.50 (SEM, 0.16); and dermal Langerhans' cells: 1.30 (SEM, 0.15) vs. 2.7 (SEM, 0.15); for normal and eczematous skin, respectively; p < 0.05]. The higher Langerhans' cell counts in eczematous dermatitis suggest a possible link between antigen presenting capabilities of these cells, and development of these lesions.

CD14+ antigen-presenting cells in human dermis are less mature than their CD1a+ counterparts

We recently demonstrated that three antigen-presenting cell (APC) subsets exist in the healthy human dermis, CD14(+) and CD1a(+) dermal APCs and migratory dermal Langerhans cells. Here, we extend these findings by defining CD208 as an exclusive marker of migratory dermal Langerhans cells, confirming that migratory dermal Langerhans cells (CD1a(high) CD207(+) CD208(+)) and CD1a(+) dermal APCs (CD1a(mid) CD207(-) CD208(-)) are two distinct APC populations. Using flow cytometry and multicolor fluorescence immunohistochemistry, we demonstrated that there were striking differences between CD1a(+) and CD14(+) dermal APCs in their expression of pattern recognition receptors and maturation markers. Expression of Toll-like receptor (TLR) 2, CD206 and CD209 was largely restricted to CD14(+) dermal APCs. Consistent with these observations, most CD14(+) dermal APCs expressed an immature phenotype when compared with CD1a(+) dermal APCs, which expressed high levels of the maturation marker CD83 on their cell surface. However, a subset of CD14(+) dermal APCs also expressed cell-surface CD83, associated with a loss of cell-surface TLR2, suggesting that they have the capacity to mature. CD14(+) dermal APCs are therefore the dominant cutaneous APC population capable of sensing ligands recognized by CD206, CD209 and TLR2 and subsequently may have the potential to mature. CD68 expression was largely restricted to a subset of CD14(+) dermal APCs, while both CD14(+) and CD1a(+) dermal APCs expressed CD11b and CD11c. These findings have important implications for understanding cutaneous immune responses in humans and for the optimization of vaccine delivery via the skin.

Comprehensive analysis of MHC‐II expression in healthy human skin

A number of antigen-presenting cells (APCs) expressing major histocompatibility complex class II (MHC-II) have been identified in healthy human skin including the Langerhans cells of the epidermis and the three recently defined dermal APC subsets. It is well documented that in other tissues HLA-DR expression is not exclusive to APCs. Following a comprehensive analysis of the cells in human skin using flow cytometry and fluorescence immunohistochemistry, we have identified additional cell subsets that express HLA-DR. Using markers exclusive for blood and lymphatic endothelium, we demonstrated that both of these cell populations have the capacity to express HLA-DR. In addition, a small subset of dermal T lymphocytes was found to express low-level HLA-DR suggesting an activated phenotype. Dermal T lymphocytes were often in intimate contact with either CD1a(+) CD207(-) dermal APCs or CD1a(+) CD207(+) dermal Langerhans cells, possibly explaining the activated phenotype of a subset of dermal T lymphocytes.

Tackling Inner-City Asthma Vechicles for Success

Sarcoidosis, a chronic granulomatous disease of unknown etiology, is treated with immune suppressive drugs such as corticosteroids. Sarcoidosis patients have been reported to benefit clinically from treatment with thalidomide. We administered thalidomide for 16 weeks to eight patients with chronic skin sarcoidosis and evaluated the drug's effects before and with treatment. After thalidomide treatment, all skin biopsies showed decreases in granuloma size and reduction in epidermal thickness. We also observed extensive T cell recruitment into the granulomas, the appearance of multinucleated giant cells, and increased numbers of dermal Langerhans cells (CD1a+) and mature dendritic cells (CD83+ or DC-LAMP+). Plasma IL-12 levels increased and remained elevated during the treatment period. We noted increased HLA-DR expression on peripheral blood lymphocytes and a corresponding drop in the naive T cell marker CD45RA. Our data suggest that thalidomide treatment of sarcoidosis results in granuloma differentiation to a Th1-type cellular immune response usually associated with protective immunity to tuberculosis and tuberculoid leprosy.

Thalidomide Induces Granuloma Differentiation in Sarcoid Skin Lesions Associated with Disease Improvement

Sarcoidosis, a chronic granulomatous disease of unknown etiology, is treated with immune suppressive drugs such as corticosteroids. Sarcoidosis patients have been reported to benefit clinically from treatment with thalidomide. We administered thalidomide for 16 weeks to eight patients with chronic skin sarcoidosis and evaluated the drug's effects before and with treatment. After thalidomide treatment, all skin biopsies showed decreases in granuloma size and reduction in epidermal thickness. We also observed extensive T cell recruitment into the granulomas, the appearance of multinucleated giant cells, and increased numbers of dermal Langerhans cells (CD1a+) and mature dendritic cells (CD83+ or DC-LAMP+). Plasma IL-12 levels increased and remained elevated during the treatment period. We noted increased HLA-DR expression on peripheral blood lymphocytes and a corresponding drop in the naive T cell marker CD45RA. Our data suggest that thalidomide treatment of sarcoidosis results in granuloma differentiation to a Th1-type cellular immune response usually associated with protective immunity to tuberculosis and tuberculoid leprosy.

Neuroimmune interactions in the skin

Neuroimmunologic aspects of skin inflammation involve several interacting systems. The modulating influence of autonomic and sensory nerves has been known for a long time. Neurokinines derived from these nerves have recently been shown to interact with antigen presentation in dermal Langerhans cells and other key functions of allergic skin disease. While some mechanisms of afferent function and local reflex are known, the nature of efferent effects (from brain to periphery) remains to be elucidated. New aspects include involvement of the brain-derived neurotrophic factor in addition to the autonomic nervous system in mental stress response and insight in the immunomodulation by proopiomelanocortins. Novel strategies for therapy and prevention of chronicity may also result from understanding the role of increased secretion of nerve growth factor in atopic eczema and psoriasis.

Neuroimmune interactions in the skin.

Neuroimmunologic aspects of skin inflammation involve several interacting systems. The modulating influence of autonomic and sensory nerves has been known for a long time. Neurokinines derived from these nerves have recently been shown to interact with antigen presentation in dermal Langerhans cells and other key functions of allergic skin disease. While some mechanisms of afferent function and local reflex are known, the nature of efferent effects (from brain to periphery) remains to be elucidated. New aspects include involvement of the brain-derived neurotrophic factor in addition to the autonomic nervous system in mental stress response and insight in the immunomodulation by proopiomelanocortins. Novel strategies for therapy and prevention of chronicity may also result from understanding the role of increased secretion of nerve growth factor in atopic eczema and psoriasis.

Immunological Activation of Dermal Langerhans Cells in Contact with Lymphocytes in a Model of Human Inflamed Skin

Langerhans cells play an important role in the skin's immune system. Little is known, however, about the antigen-presenting capacity of Langerhans cells in the context of skin inflammation. By immunohistochemistry we investigated the phenotypic characteristics of epidermal and dermal Langerhans cells and their spatial relationship with infiltrating lymphocytes. We studied skin flaps autotransplanted to the oral cavity to fill a defect after maxillofacial cancer surgery. In 15 of 21 cases sampled for the present study, the skin flaps were severely inflamed by Candida albicans infection. In contrast to the normal skin, such inflamed skin showed a marked increase in CD1a(+) dermal Langerhans cells. Double immunohistochemistry revealed that dermal Langerhans cells abundantly expressed B7-2 (CD86), a representative costimulatory molecule, and CD83, a marker of mature dendritic cells. Furthermore, these dermal Langerhans cells were in close contact with CD4(+)/CD45RO(+) lymphocytes. This cell-to-cell contact was further visualized by immunoelectron microscopy. Langerhans cells were also observed within lymphatic vessels that were identified by the expression of vascular endothelial growth factor receptor-3. Ki-67 labeling indices were 4.2% in CD4(+) T cells and 0.8% in CD8(+) T cells within the dermis. Factor XIIIa(+) dermal dendrocytes were distributed outside the clusters of lymphocytes and were not in contact with them. Our observations indicate that dermal Langerhans cells in the inflamed skin are activated to express common phenotypes to mature dendritic cells so that they could stimulate neighboring memory CD4(+) T cells.

Langerhans cells in prurigo nodularis investigated by HLA-DR and S-100 immunofluorescence double staining

The Langerhans cell is one of the antigen-presenting cells in the immune system. To study the presence of cutaneous Langerhans cells in prurigo nodularis, age- and sex-matched prurigo nodularis patient and healthy volunteer skin biopsies were investigated by an HLA-DR and S-100 immunohistochemical double staining method. The results showed that the HLA-DR- and S-100-immunoreactive (IR) Langerhans cells were altered in prurigo nodularis epidermis and dermis. The number of epidermal Langerhans cells in the prurigo nodularis patients was decreased in five and increased in two cases. In the dermis, the HLA-DR- and S-100-IR cells were apparently more numerous than in the controls. In the involved skin there were also more S-100-IR coarse nerve fibres in the dermis as compared to controls. The results indicate that dermal Langerhans cells (HLA-DR and S-100 double-labeled) as well as other dermal HLA-DR- and S-100-IR dendritic cells, but most likely not epidermal Langerhans cells, may be critically involved in the development or persistence of prurigo nodularis.

Expression, but lack of calcium mobilization by high-affinity IgE Fc epsilon receptor I on human epidermal and dermal Langerhans cells.

In atopic dermatitis (AD) patients, IgE molecules are demonstrated on the surface of Langerhans cells (LC). Fc epsilon RI molecules, which are present on the surface of LC in AD patients as well as normal individuals, are responsible for this binding. In this study, we have investigated phenotypic and functional characteristics of Fc epsilon RI on epidermal and dermal cell populations. Epidermal and dermal cell suspensions were prepared enzymatically with dispase followed by either trypsin or collagenase treatment, respectively. Peripheral blood basophils were negatively selected by excluding other leukocytes with surface marker staining. Consistent with previous reports, both peripheral blood basophils and epidermal LC were positively stained with anti Fc epsilon RI monoclonal antibody. In addition, an Fc epsilon RI positive population was demonstrated among dermal HLA-DR positive cells. These cells express significant amounts of HLA-DR molecules (DRHi) and co-express CD 1 a molecules, which identifies them as LC-like dendritic APC of the dermis. No other Fc epsilon RI positive population was found in the other dermal DRMid or DR- populations, except for a minor DRLo population, presumably mast cells. To analyze whether these Fc epsilon RI molecules are signal transducing for LC, intracellular calcium mobilization after crosslinking of Fc epsilon RI was measured with flow cytometry. Following crosslinking, peripheral blood basophils clearly increased intracellular calcium. On the other hand, neither normal epidermal LC nor dermal DRHiCD1a + cells changed their intracellular calcium level after Fc epsilon RI crosslinking. These data indicate that normal epidermal and dermal LC, but not basophils, are resistant to calcium flux following Fc epsilon RI engagement.