Tissue Remodeling in Ocular Mucous Membrane Pemphigoid.

Purpose: Ocular mucous membrane pemphigoid (OcMMP) is a rare eye disease characterized by relapsing-remitting or persisting long-lasting inflammatory events associated with progressive scarring. Despite long-term immunomodulating therapy, abnormal fibrosis keeps worsening in patients with OcMMP. This study investigates the fibrotic process in patients with OcMMP, as well as the critical role of the epithelium in modulating the local fibrosis. Methods: In this prospective, observational pilot study, patients affected by long-lasting OcMMP were compared with age- and gender-matched healthy controls. Clinical grading was assessed, and conjunctival biopsy and impression cytology were performed. Conjunctival samples were used for quantifying the expression of transcripts regulating the inflammatory and fibrogenic processes. Results: Ocular surface clinical and functional markers worsened in patients with OcMMP with fibrotic disease progression. In more advanced disease stages, both impression cytologies and conjunctival biopsies revealed increased tissue remodeling and profibrotic markers (α-SMA and TGF-ß), and decreased levels of inflammatory markers (I-CAM1, IL-10, and IL-17). Increased epithelial expression of profibrotic markers and histological changes were detected. Conclusions: Chronic OcMMP is characterized by a progressive, aberrant self-sustaining fibrotic process that worsens clinical signs and symptoms. Conjunctival epithelial cells may transdifferentiate into myofibroblast-like phenotypes when chronically exposed to high levels of inflammation, as in the case of OcMMP. Tissue remodeling markers in OcMMP could be used as early diagnostic, prognostic, and therapeutic biomarkers, harvested in a non-invasive and painless procedure such as impression cytologies.

Neutrophil-predominant bullous pemphigoid induced by checkpoint inhibitors: A case series.

Checkpoint inhibitors have been revolutionary in the treatment of metastatic melanoma, non-small-cell lung cancer, and renal cell carcinoma. By restricting negative feedback of T-cells, checkpoint inhibitors allow the immune system to identify and destroy malignant cells. This enhanced immune response is efficacious in the treatment of the aforementioned malignancies; however, it may lead to immune-related adverse events. Bullous pemphigoid (BP) is a well-documented cutaneous adverse reaction of checkpoint inhibitors, with a majority of cases reporting an eosinophil-predominant or mixed inflammatory infiltrate. We report two cases of neutrophil-predominant BP presenting in patients on checkpoint inhibitors.

Interleukin 2 regulates the activation of human basophils.

Basophils are important effector cells in allergic disorders and anti-parasitic immune response. A number of activators including interleukin 3 (IL-3) and IgE have been identified in the regulation of human basophils expressing mediators such as histamine and leukotriene C4 (LTC4) and cytokines, including IL-4 and IL-13. Human basophils express high levels of IL-2 receptors. However, the function of the IL-2 pathway in basophils remains unknown. Here, we identified that IL-2 induced the activation of human basophils in vitro to express a variety of inflammatory cytokines and chemokines including IL-5, IL-13, GM-CSF and CCL-17. This effect by IL-2 is confirmed by an upstream regulator analysis using Ingenuity pathway analysis. Of note, one of the top regulated cytokines, IL-5, was for the first time identified to be induced by IL-2 in human basophils rather than IL-3 or anti-IgE. Immunofluorescence analysis of skin specimens from bullous pemphigoid and eczema revealed that infiltrating basophils in skin lesions widely expressed IL-5 and GM-CSF. Together, our findings reveal IL-2 as a novel regulator of human basophils. This adds a new layer to support the importance of basophils in allergic disorders.

IL-23/IL-17 Axis Activates IL-1ß-Associated Inflammasome in Macrophages and Generates an Auto-Inflammatory Response in a Subgroup of Patients With Bullous Pemphigoid.

Bullous Pemphigoid (BP) is a skin autoimmune blistering disease characterized by immune-mediated degradation of the dermo-epidermal junction and release of a large number of inflammatory cytokines. Interleukin-1ß (IL-1ß) is a pleiotropic pro-inflammatory cytokine associated with inflammasome activation and known to be pivotal in several auto-immune and auto-inflammatory diseases. We sought to clarify the presence of inflammasome-dependent IL-1ß and to investigate its role in BP. Skin biopsy specimens (n = 13), serum (n = 60), blister fluid (n = 26), and primary inflammatory cells from patients with BP were used to investigate inflammasome activation and function. We here highlighted a differential occurrence of a functional in situ inflammasome in patients with BP, biologically distinguished by IL-1ß and NLRP3 expression. Clinically, elevated IL-1ß levels were associated with the presence of erythema and urticarial plaques reflecting the inflammatory phase preceding blister formation. We further identified IL-17 and IL-23 as important molecules favoring IL-1ß expression in monocyte-derived macrophages from BP patients. Finally, we demonstrated the ability of IL-1ß to stimulate the release of the matrix metalloproteinase-9 in those macrophages, reinforcing the role of IL-1ß in the auto-amplification loop of the inflammatory response associated to BP. However, whether this inflammasome is an epiphenomenon associated with BP disease or constitutes an amplification inflammatory step in certain patients still need to be determined. In the context of a precision medicine approach, our findings allowed us to delineate a subgroup of patients with BP that showed similarities with auto-inflammatory diseases. Subsequently, this opens up alternative therapeutic strategies targeting IL-1ß pathway in the aim to control the early, pre-blistering inflammatory phase. Ultimately, this could also help in reducing the detrimental effects associated with high doses of corticosteroids treatment.

Dipeptidyl Peptidase-4 Inhibitor-Associated Bullous Pemphigoid.

Bullous pemphigoid (BP) is an organ-specific autoantibody-mediated blistering skin disease that mainly affects the elderly. Typical clinical features include the widespread blisters, often preceded by and/or associated with itchy urticarial or eczema-like lesions. BP patients have circulating autoantibodies against BP180 and/or the plakin family protein BP230 both of which are components of hemidesmosomes in basal keratinocytes. Most BP autoantibodies particularly target the epitopes within the non-collagenous NC16A domain of BP180. Clinical findings and murine models of BP have provided evidence of a pathogenic role of anti-NC16A autoantibodies. However, it is largely unknown what triggers the breakage of immunotolerance against BP180 in elderly individuals. The incidence of BP has been increased over the past two decades in several countries. Aside from aging populations, the factors behind this phenomenon are still not fully understood. Neurodegenerative diseases such as multiple sclerosis, Parkinson's disease, and certain dementias are independent risk factors for BP. Recently several case reports have described BP in patients with diabetes mellitus (DM) patients who have been treated with dipeptidyl peptidase-4 inhibitors (DPP-4i or gliptins), which are a widely used class of anti-DM drugs. The association between the use of DPP-4is, particularly vildagliptin, and BP risk has been confirmed by several epidemiological studies. Evidence suggests that cases of gliptin-associated BP in Japan display certain features that set them apart from cases of "regular" BP. These include a "non-inflammatory" phenotype, targeting by antibodies of different immunodominant BP180 epitopes, and a specific association with the human leukocyte antigen (HLA) types. However, recent studies in European populations have found no major differences between the clinical and immunological characteristics of gliptin-associated BP and "regular" BP. The DPP-4 protein (also known as CD26) is ubiquitously expressed and has multiple functions in various cell types. The different effects of the inhibition of DPP-4/CD26 activity include, for example, tissue modeling and regulation of inflammatory cells such as T lymphocytes. Although the pathomechanism of gliptin-associated BP is currently largely unknown, investigation of the unique effect of gliptins in the induction of BP may provide a novel route to better understanding of how immunotolerance against BP180 breaks down in BP.

Immune Reaction to Type XVII Collagen Induces Intramolecular and Intermolecular Epitope Spreading in Experimental Bullous Pemphigoid Models.

Bullous pemphigoid (BP), the most common autoimmune blistering disease, is induced by autoantibodies to type XVII collagen (COL17). Previous studies demonstrated that COL17 harbors several epitopes targeted by autoreactive T and B cells and that the target epitopes change sequentially during the disease course. To elucidate the details of the humoral immune response to COL17, we used an active BP mouse model in which BP is induced by the adoptive transfer of spleen cells from wild-type mice immunized with human COL17-expressing skin grafting to immunodeficient COL17-humanized (Rag-2-/-, mouse Col17-/-, human COL17+) mice. By immunoblot analysis, antibodies to the NC16A domain and other extracellular domains (ECDs) of COL17 were detected earlier than antibodies to intracellular domains (ICDs) in the active BP model. Time course analysis by enzyme-linked immunosorbent assay demonstrated a delayed peak of antibodies to ICD epitopes in active BP model. The blockade of CD40-CD40 ligand interaction soon after the adoptive transfer suppressed the production of antibodies to the non-collagenous 16A (NC16A) domain but not to an ICD epitope, suggesting the sequential activation from T and B cells against the ECD epitopes including the NC16A domain to those against ICD epitopes in vivo. Both wild-type mice immunized with a fragment of the NC16A domain and the recipients of those spleen cells produced IgG antibodies to ICD and ECD epitopes, showing intramolecular epitope spreading from the NC16A domain to other epitopes of COL17. Furthermore, we found that a portion of the active BP model mice show intermolecular epitope spreading from human COL17 to murine BP230. The appearance of antibodies to ICD epitopes of COL17 or of antibodies to murine BP230 did not correlate with the skin changes in the mice, suggesting that those antibodies have low pathogenicity. These results suggest that the immune response to the ECD epitopes of COL17, especially to the NC16A domain, triggers intramolecular, and intermolecular epitope spreading to ICD epitopes of COL17 and to murine BP230. These novel findings provide insight into the mechanism of epitope spreading in organ-specific, antibody-mediated autoimmune disorders.

A comparative study of Michel's medium versus honey as a transport medium for skin specimens prior to direct immunofluorescence microscopy and antigen mapping.

BACKGROUND: Michel's medium (MM) is currently the recommended transport medium for skin biopsy specimens prior to direct immunofluorescence (DIF) microscopy. OBJECTIVE: To compare the utility of honey with that of MM as a transport medium for skin biopsy specimens used for DIF and antigen mapping. METHODS: Group I consisted of 45 freshly-taken skin specimens earmarked for DIF testing. It was divided into three groups (A, B and C), each containing 15 specimens. Biopsy specimens were sliced into two, one each for MM and honey. Samples in group A were processed at the end of week 1 while those in group B and C were processed at the end of weeks 2 and 4, respectively. Group II consisted of five specimens of epidermolysis bullosa (EB) which was further divided into three groups; two specimens were processed for antigen mapping at the end of week 1, while others were processed at the end of week 2 (two specimens) and 4 (one specimen). RESULTS: Sensitivity of honey as a transport medium for skin biopsy specimens was 100%, 92.6% and 53.8% at weeks 1, 2 and 4, respectively. The antigen mapping was positive in all specimens. CONCLUSION: Utility of honey was comparable to MM for DIF samples tested at weeks 1 and 2 but was lower at week 4.

Integrin α6ß4 Recognition of a Linear Motif of Bullous Pemphigoid Antigen BP230 Controls Its Recruitment to Hemidesmosomes.

Mechanical stability of epithelia requires firm attachment to the basement membrane via hemidesmosomes. Dysfunction of hemidesmosomal proteins causes severe skin-blistering diseases. Two plakins, plectin and BP230 (BPAG1e), link the integrin α6ß4 to intermediate filaments in epidermal hemidesmosomes. Here, we show that a linear sequence within the isoform-specific N-terminal region of BP230 binds to the third and fourth FnIII domains of ß4. The crystal structure of the complex and mutagenesis analysis revealed that BP230 binds between the two domains of ß4. BP230 induces closing of the two FnIII domains that are locked in place by an interdomain ionic clasp required for binding. Disruption of BP230-ß4 binding prevents recruitment of BP230 to hemidesmosomes in human keratinocytes, revealing a key role of this interaction for hemidesmosome assembly. Phosphomimetic substitutions in ß4 and BP230 destabilize the complex. Thus, our study provides insights into the architecture of hemidesmosomes and potential mechanisms of regulation.

Gliptin-associated Bullous Pemphigoid and the Expression of Dipeptidyl Peptidase-4/CD26 in Bullous Pemphigoid.

Dipeptidyl peptidase-4 inhibitors (DPP-4i or gliptins) increase the risk of developing bullous pemphigoid (BP). To clarify, whether gliptin-associated BP has special features, we analyzed the clinical, histopathological and immunological features of 27 BP patients, 10 of which previously used gliptin medication. Compared to those who had not previously received gliptins, subjects who had, showed higher BP180-NC16A ELISA (enzyme-linked immunosorbent assay) values, fewer neurological co-morbidities and shorter time to remission, but differences were not statistically significant. The HLA-DQB1*03:01 allele was more commonly present among the BP patients than the control population, but was not more common in those with gliptin history. To determine the effect of gliptins on the expression of the DPP-4/CD-26 protein we performed immunohistochemistry, which showed that the skin expression of DPP-4/CD-26 was increased in BP patients, but not affected by prior gliptin treatment. We conclude that DPP-4i medication is common among BP patients and prior gliptin treatment may be associated with some specific features.

Exosomes in chronic inflammatory skin diseases and skin tumors.

Exosomes are membrane vesicles of endocytic origin that can mediate communication between cells and the transport of cellular components such as microRNAs, mRNAs, proteins and DNA. Recently, exosomes have been under investigation for their significant roles in both healthy physiology and disease states. Herein, we review the role of exosomes in chronic inflammatory skin diseases and skin tumors, especially focusing on systemic lupus erythematosus, psoriasis, atopic dermatitis, bullous pemphigoid and melanoma. Moreover, we emphasize the involvement of changes in exosome cargo in the regulation of these diseases.

Downregulation of aquaporin 3 in bullous pemphigoid patients.

Bullous pemphigoid (BP) is a chronic autoimmune skin disease. Aquaporin 3 (AQP 3) has a possible role in the pathogenesis of many dermatological diseases. In this work, we aimed to evaluate the expression of AQP 3 in BP. Perilesional skin biopsies were taken from 24 BP patients and 13 controls. The biopsies were stained by direct immunofluorescence using rabbit anti-human AQP 3 FITC antibody. The expression of AQP 3 was weak in 5 patients (20.8%), moderate in 18 patients (75%), strong in 1 patient (4.2%) in the suprabasal layers. It was negative in 4 patients (16.7%), weak in 18 patients (75%), moderate in 2 patients (8.3%) and no strong fluorescence was seen in the basal layers. In the controls, the expression was strong in ten controls (76.9%), moderate in three controls (23.1%) and no controls showed weak fluorescence in the suprabasal layer. The basal layer showed strong fluorescence in 11 controls (84.6%), moderate in 2 controls (15.4%) and no controls showed mild or no fluorescence. There was a statistically significant difference in the expression of AQP 3 between basal and suprabasal layers of BP patients but not of the controls. There was statistically significant difference in the expression of AQP 3 between patients and controls in both the basal (P value < 0.001) and the suprabasal layers (P value < 0.001). In conclusion, AQP 3 was downregulated in BP patients especially in the basal cell layer. This suggests that AQP 3 plays a role in the pathogenesis of BP.

Minocycline decreases Th2 chemokines from M2 macrophages: Possible mechanisms for the suppression of bullous pemphigoid by traditional bullous disease drugs.

Minocycline/tetracycline is clinically used for the treatment of bullous pemphigoid (BP), and its clinical benefits are superior to those of prednisolone when considering adverse events. Although the clinical benefits of minocycline/tetracycline are well known, its immunosuppressive mechanisms are still unclear. In this study, we investigated the immunomodulatory effects of traditional anti-BP drugs (minocycline, nicotinic acid amide, dexamethasone and cyclosporine) on CD163+ M2 macrophages in vitro, with special focus on the production of CCL18 and CCL22, both of which are produced by CD163+ M2 macrophages in the lesional skin of BP and are increased in the serum of BP patients. Minocycline decreased the production of CCL22, CCL24 and CCL26 as well as CCL2 from M2 macrophages. CCL18 from M2 macrophages was decreased by dexamethasone and cyclosporine, but not decreased by minocycline. These data suggest that the clinical benefit of minocycline is partially explained by its suppressive effects against the production of specific Th2 chemokines from M2 macrophages, which should contribute to the recruitment of Th2 cells and eosinophils in the lesional skin of BP patients.

Variation of the epidermal expression of glucocorticoid receptor-beta as potential predictive marker of bullous pemphigoid outcome.

Bullous pemphigoid (BP) is the most common autoimmune subepidermal blistering disease in Western countries. Although topical and/or systemic glucocorticoids treatment efficacy is widely recognized, up to 30% of patients with BP may undergo a relapse during the first year of treatment. We investigated the protein expression of the total glucocorticoid receptor and GRß isoform in the skin biopsy specimens from patients with BP and wondered whether such investigation at baseline provided a tool to predict disease outcome. Total GR and GRß protein expressions were detected by immunohistochemistry at baseline on 12 patients who later relapse and 11 patients who remained on remission in comparison with 14 control patients. The expression of GRß in the epidermis of patients with BP who later relapse was significantly higher than that in the epidermis of patients with BP controlled upon corticosteroid treatment, which was also higher than control patients. Thus, our results suggest that increased protein expression of GRß in skin epithelial cells is predictive of reduced steroid treatment efficacy, and therefore of increased risk of disease relapse in patients with BP.

TWEAK/Fn14 Activation Contributes to the Pathogenesis of Bullous Pemphigoid.

TWEAK participates in various cellular effects by engaging its receptor of Fn14. Increased levels of soluble TWEAK are associated with systemic autoimmunity in patients with lupus erythematosus, rheumatoid arthritis, or dermatomyositis. However, the role of TWEAK in bullous pemphigoid (BP) remains unknown. In this study, we found an elevated serum level of TWEAK and a positive correlation between serum TWEAK and anti-BP180 antibodies. Immunohistochemistry showed strong TWEAK and Fn14 expression and implied an opposite relationship between the TWEAK and BP180 expression in skin samples from BP patients. In vitro TWEAK stimuli reduced BP180 expression in HaCaT cells and inhibited the adhesion of cells to the culture dish. Consistently, the transfection of Fn14 small interfering RNA preserved BP180 and protected cells from losing adherence. Moreover, such effect of TWEAK correlated with activation of the extracellular signal-regulated kinase and NF-κB pathways and downstream ADAMs. By silencing ADAM17 with small interfering RNA, we showed that ADAM17 participated in TWEAK-induced BP180 loss. Therefore, TWEAK may contribute to the pathogenesis of BP by reducing BP180 expression and cellular adherence, involving the activation of ERK and NF-κB pathways. TWEAK may serve as a biomarker or therapeutic target of BP.

Macropinocytosis of type XVII collagen induced by bullous pemphigoid IgG is regulated via protein kinase C.

Macropinocytosis is an endocytic pathway that is involved in the nonselective fluid uptake of extracellular fluid. Bullous pemphigoid (BP) is an autoimmune subepidermal blistering disease associated with autoantibodies to type XVII collagen (COL17), which is a component of hemidesmosome. When keratinocytes are treated with BP-IgG, COL17 internalizes into cells by way of the macropinocytosis. We investigated the mechanism of COL17 macropinocytosis using DJM-1 cells, a cutaneous squamous cell carcinoma cell line. First, non-hemidesmosomal COL17 was preferentially depleted by stimulation with the BP-IgG in the DJM-1 cells. To investigate the signaling involved in COL17-macropinocytosis, the inhibition of small GTPase family members Rac1 and Cdc42 was found to strongly repress COL17 internalization; in addition, the Rho inhibitor also partially blocked that internalization, suggesting these small GTPases are involved in signaling to mediate COL17-macropinocytosis. Western blotting using Phostag-SDS-PAGE demonstrated high levels of COL17 phosphorylation in DJM-1 cells under steady-state condition. Treatment with BP-IgG increased the intracellular calcium level within a minute, and induced the overabundant phosphorylation of COL17. The overabundant phosphorylation of COL17 was suppressed by a protein kinase C (PKC) inhibitor. In addition, PKC inhibitor repressed COL17 endocytosis using cell culture and organ culture systems. Finally, the depletion of COL17 was not observed in the HEK293 cells transfected COL17 without intracellular domain. These results suggest that COL17 internalization induced by BP-IgG may be mediated by a PKC pathway. In summary, BP-IgG initially binds to COL17 distributed on the plasma membrane, and COL17 may be internalized by means of a macropinocytic pathway related to the phosphorylation of the intracellular domain by PKC.

Immunohistochemical study of toll-like receptors 2, 4, and 9 expressions in pemphigus and bullous pemphigoid lesions.

Pemphigus and bullous pemphigoid (BP) are severe autoimmune skin diseases. Whether innate immunity could be a trigger or a part of the pathogeneses is unknown. Toll-like receptors (TLRs) are important components of the innate immune system, with no previous evaluation of TLRs in autoimmune bullous diseases. This work aims to investigate TLRs 2, 4, and 9 expressions in pemphigus and bullous pemphigoid. Thirty-six patients with pemphigus vulgaris (PV), pemphigus foliaceus (PF), bullous pemphigoid (BP), and six healthy controls were studied. Skin biopsies from the patients and the controls were examined immunohistochemically for TLR2, 4, and 9 expressions. The TLR4 expressed mainly at the basal layer of epidermis in controls, but in the cases with autoimmune bullous diseases, TLR4 staining located at basal layer and suprabasal layer, even superficial layer of epidermis. The immunostaining-intensity-distribution (IID) index of TLR4 in patients with PF (13.83, P = 0.001), PV (13.08, P = 0.003), and BP (11.42, P = 0.042) were significantly higher than that of the controls (6.17). TLR2 and TLR9 showed no significantly changes at epidermal expression (P > 0.05) compared with controls. There was no correlation found between the expressions of these TLRs. This work, thus, shows a re-localization of TLR4 expression sites with increased expression in pemphigus and bullous pemphigoid lesions. Targeting TLR4 signaling is expected to be a novel treatment strategy for autoimmune bullous diseases.

Expression of Glucocorticoid Receptors GRα and GRß in Bullous Pemphigoid.

First-line treatments of bullous pemphigoid (BP) are topical and systemic glucocorticoids (GC). The actions of GC are mediated by glucocorticoid receptors (GR), which exist in several isoforms, of which GRα and GRß are the most important. In many inflammatory diseases, up-regulation of GRß is associated with GC insensitivity. The aims of this study were to determine the expression of GRα and GRß in patients with BP and to investigate the effect of prednisolone treatment on the expression of GR isoforms in BP. Quantitative real-time PCR (qPCR) analysis demonstrated that GR isoform mRNAs are expressed in peripheral blood mononuclear cells (PBMC) from patients with BP. Expression of GRα and GRß protein was confirmed by immunohistochemical staining of BP skin biopsies and by Western blot analysis and flow cytometric analysis of PBMCs. During prednisolone treatment, GRα and GRß expression varied markedly, but changes were not suitable as a clinical marker of GC sensitivity in patients with BP.

Myeloid-related proteins-8 and -14 are expressed but dispensable in the pathogenesis of experimental epidermolysis bullosa acquisita and bullous pemphigoid.

BACKGROUND: Myeloid-related protein-8 (MRP-8) and its heterodimeric partner, MRP-14 belong to the group of danger-associated molecular patterns (DAMPs) and are associated with numerous chronic human disorders. However, their functional role in autoimmunity remains largely unclear. OBJECTIVE: Here, we examined the involvement of MRP-8/-14 in two difficult-to-treat autoimmune blistering diseases, epidermolysis bullosa acquisita (EBA) and bullous pemphigoid (BP). METHODS: MRP-8/-14 concentrations in the sera of EBA and BP patients were quantified by ELISA. Experimental EBA and BP in mice were induced by transfer of antibodies directed against type VII or XVII collagen, respectively. Expression of MRP-8/-14 was analyzed in skin samples of these experimental mouse models. The functional role of MRP-8/-14 proteins was evaluated by the induction of experimental EBA and BP in MRP-14-deficient mice. RESULTS: We found serum levels of MRP-8/-14 to be elevated in both, EBA and BP patients. Furthermore, in the lesional skin of mice with experimental diseases expression of MRP-8/-14 was increased as compared to healthy controls. However, MRP-14-deficient mice were fully susceptible to experimental disease with a phenotype comparable to that of wild type controls. CONCLUSION: Although MRP-8/-14 expression is highly increased in experimental as well as human disease, these proteins do not contribute to the pathogenesis in the effector phase of EBA and BP.

Regulatory T cells as well as IL-10 are reduced in the skin of patients with dermatitis herpetiformis.

BACKGROUND: Dermatitis herpetiformis (DH) and celiac disease (CD) are considered as autoimmune diseases that share a defined trigger (gluten) and a common genetic background (HLA-DQ2/DQ8). However, the pathogenesis of DH is not fully understood and no data are available about the immune regulation in such a disease. OBJECTIVE: The aim of this study was to assess if alterations in the pattern of the immune response and, in particular, impairments of regulatory T (Tregs) cells may contribute to the phenotypic differences between DH and CD. METHODS: We investigated the presence of Tregs cell markers, in the skin, the duodenum and the blood of patients with DH by immunohistochemistry, confocal microscopy and flow cytometry. As controls, we included patients with bullous pemphigoid, patients with CD without skin lesions, as well as healthy subjects (HS). RESULTS: In the skin of DH patient, we found a significantly lower proportion of FOXP3(+) Tregs and IL-10(+) cells than in HS (p < 0.001 for both cell populations). In duodenal samples, no differences where found in the proportion of Tregs between patients with DH and patients with CD without skin manifestations. Finally, the frequency of CD25(bright)FOXP3(+) cells within the CD4(+) subset was significantly reduced in CD patients either with or without DH with respect to HS (p = 0.029 and p = 0.017, respectively). CONCLUSIONS: Our findings suggested that a reduction of Tregs may play a major role in the skin, leading to a defective suppressive function and thus to the development of the lesions. By contrast, no differences could be detected about Tregs between patients with DH and patients with CD in the duodenum, suggesting that the mechanisms of the intestinal damage are similar in both diseases.

Comparison of CD163+ CD206+ M2 macrophages in the lesional skin of bullous pemphigoid and pemphigus vulgaris: the possible pathogenesis of bullous pemphigoid.

BACKGROUND: M2 macrophages play a critical role in the induction of T helper 2 (Th2) polarization. METHODS: To investigate the contribution of M2 macrophages to the pathogenesis of bullous pemphigoid (BP) and pemphigus vulgaris (PV), we employed immunohistochemical staining for CD163 and CD206, as well as pSTAT1, pSTAT6, interleukin (IL)-4, IL-13, CCL17, CCL18 and Foxp3 in the lesional skin of 10 cases of BP and PV. RESULTS: The numbers of CD163+ CD206+ M2 macrophages were higher in BP than in PV. Moreover, pSTAT6+ cells, CCL17+ cells, CCL18+ cells and Foxp3+ regulatory T cells were prominent only in the lesional skin of BP. To further investigate the function of M2 macrophages, we examined the mRNA expression and production of Th2-related chemokines from M2 macrophages in vitro, which showed a significant increase in the mRNA expression and production of CCL18 when stimulated by IL-4 or IL-13. CONCLUSION: Our study sheds light onto one of the possible immunological mechanisms of BP and PV.