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Abstract Background Anti-desmoglein (Dsg)1 is produced in pemphigus foliaceus (PF), affecting exclusively the skin. Pemphigus vulgaris (PV) shows the production of anti-Dsg3 in the mucosal form, and anti-Dsg1 and 3 in the mucocutaneous form. Anti-Dsg3 autoantibodies have been rarely reported in PF. Objectives To determine the factors associated with the production and pathogenicity of anti-Dsg3 in PF. Methods Comparative analytical study of three patients groups: 16 PF-anti-Dsg3+, and 42 PF-anti-Dsg3(-) and 22 PV treatment-naïve cases. Serum was used in the anti-Dsg1 and 3 ELISA, and in immunoblotting (IB) with human epidermis extract. The expression of Dsg1 and 3 in paraffin sections was analyzed by immunohistochemistry (IHC). HLA-DRB1 alleles were compiled from a database. Results In the PF-anti-Dsg3+ group: age range similar to that of the PV group (p > 0.9999); predominance of the generalized form of PF (p = 0.002); anti-Dsg3 titers lower than those of PV (p < 0.0001); IB confirmed Dsg3 identification in one (8.33%) of 12 patients; IHC showed exclusive cytoplasmic internalization of Dsg1; HLA-DRB1 alleles of susceptibility to PF, with the absence of alleles associated with PV, in the five typed patients. Study limitations Most of the patients in the PF-anti-Dsg3+ group were undergoing treatment. Conclusion The presence of anti-Dsg3 antibodies in PF was related to older age (comparable to that of PV) and the generalized form of PF. The non-pathogenicity of anti-Dsg3 antibodies in PF can be attributed to the low serum anti-Dsg3 titers, the lack of Dsg3 internalization as detected by IHC, and the absence of PV-associated HLA-DRB1 alleles.

Pemphigus vegetans and pemphigus foliaceus are rare autoimmune blistering diseases characterized by the disruption of desmosomal adhesion proteins, particularly desmoglein 3 and desmoglein 1. We report the case of a 62-year-old male who presented initially with scaly red plaques posing several diagnostic challenges. A histopathological examination revealed subcorneal acantholysis, matching the suspected clinical diagnosis of pemphigus foliaceus. The patient progressed, developing vegetating plaques, and a new biopsy was performed. The new histopathological and direct immunofluorescence exams were consistent with pemphigus vegetans. This case highlights the diagnostic challenges posed by the transition of pemphigus foliaceus to its vegetating form. We discuss the role of desmogleins in the pathogenesis of pemphigus and explore potential therapeutic strategies targeting these specific autoantigens.

Background: Carcinogenesis is a complex multistep process involving alterations at the cellular level. Alteration in cell-to-cell adhesion of oral epithelium plays an important role in carcinogenesis and metastasis. The alterations in the role of desmosomal components due to autoantibodies to desmoglein 1 (DSG 1) and desmoglein 3 (DSG 3) may cause the detachment of the cells due to altered adhesiveness leading to initiation and metastasis. The exact role of autoantibodies in DSG 1 and 3 and their role in oral carcinogenesis remains unclear. Objectives: A pilot study was undertaken to evaluate autoantibodies to DSG 1 and 3 oral cancer (OC), Oral potentially malignant disorder (OPMDs) patients, and healthy controls. Materials and Methods: A total of 25 cases (15 OC, 5 OPMDs, and 5 healthy controls) were selected. Serum and tissue biopsies were taken and evaluated for autoantibodies to DSG 1 and 3 by enzyme-linked immunosorbent assay (ELISA) and was confirmed with direct immunofluorescence (DIF). Results: The DSG 1 and 3 values obtained were way below the positive value of 20 RU/ml for autoantibody levels for either DSG 1 or DSG 3 in serum. Direct immunofluorescence (DIF) of tissues also failed to demonstrate the presence of antibodies in all three groups. Conclusion: Though the results were not encouraging, they suggest a possible role of desmosomal components, DSG 1 and 3, in oral carcinogenesis and metastasis.

IgG4 is the least potent human IgG subclass for the FcγR-mediated antibody effector function. Paradoxically, IgG4 is also the dominant IgG subclass of pathogenic autoantibodies in IgG4-mediated diseases. Here, we show that the IgG subclass and Fc-FcγR interaction have a distinct impact on the pathogenic function of autoantibodies in different IgG4-mediated diseases in mouse models. While IgG4 and its weak Fc-FcγR interaction have an ameliorative role in the pathogenicity of anti-ADAMTS13 autoantibodies isolated from thrombotic thrombocytopenic purpura (TTP) patients, they have an unexpected exacerbating effect on anti-Dsg1 autoantibody pathogenicity in pemphigus foliaceus (PF) models. Strikingly, a non-pathogenic anti-Dsg1 antibody variant optimized for FcγR-mediated effector function can attenuate the skin lesions induced by pathogenic anti-Dsg1 antibodies by promoting the clearance of dead keratinocytes. These studies suggest that IgG effector function contributes to the clearance of autoantibody-Ag complexes, which is harmful in TTP, but beneficial in PF and may provide new therapeutic opportunity.

In the endemic variants of pemphigus foliaceus (PF), in Brazil and Tunisia, patients generate pathogenic IgG4 anti-desmoglein 1 autoantibodies. Additionally, these patients possess antibodies against salivary proteins from sand flies that react with Dsg1, which may lead to skin disease in susceptible individuals living in endemic areas. This minireview focuses on recent studies highlighting the possible role of salivary proteins from Lutzomyia longipalpis (L. longipalpis) in EPF from Brazil and Phlebotomus papatasi (P. papatasi) in EPF from Tunisia. We will briefly discuss the potential mechanisms of molecular mimicry and epitope spreading in the initiation and development of endemic PF (EPF) in Brazil and Tunisia.

Epidermolysis bullosa simplex (EBS) is a blistering dermatosis that is mostly caused by dominant mutations in KRT5 and KRT14. In this study, we investigated one patient with localized recessive EBS caused by novel homozygous c.1474T > C mutations in KRT5. Biochemical experiments showed a mutation-induced alteration in the keratin 5 structure, intraepidermal blisters, and collapsed keratin intermediate filaments, but no quantitative change at the protein levels and interaction between keratin 5 and keratin 14. Moreover, we found that MAPK signaling was inhibited, while desmosomal protein desmoglein 1 (DSG1) was upregulated upon KRT5 mutation. Inhibition of EGFR phosphorylation upregulated DSG1 levels in an in vitro model. Collectively, our findings suggest that this mutation leads to localized recessive EBS and that keratin 5 is involved in maintaining DSG1 via activating MAPK signaling.

Abstract: Fogo selvagem or endemic pemphigus foliaceus is an autoimmune acantholytic anti-cadherin bullous disease that primarily affects seborrheic areas, which might disseminate. Brazil has the world's largest number of patients, mainly in the Central-West region, but the disease has also been reported in other South American countries. It affects young people and adults who have been exposed to rural areas, with occurrence of familial cases. Anti-desmoglein-1 autoantibodies are directed against desmosomal structures, with loss of adhesion of the upper layers of the epidermis, causing superficial blisters. The etiology is multifactorial and includes genetic, immune, and environmental factors, highlighting hematophagous insect bites; drug-related factors are occasionally involved. Flaccid blisters readily rupture to yield erosive-crusty lesions that sometimes resemble seborrheic dermatitis, actinic keratosis, and chronic cutaneous lupus erythematosus. The clinical presentation varies from localized to disseminated lesions. Clinical suspicion should be confirmed with histopathological and immunofluorescence tests, among others. The progression is usually chronic, and therapy varies according to clinical presentation, but generally requires systemic corticosteroid therapy associated with adjuvant immunosuppressive treatment to decrease the adverse effects of corticosteroids. Once the disease is under control, many patients remain stable on low-dose medication, and a significant proportion achieve remission.

Pemphigus foliaceus (PF) is one of the two main forms of pemphigus and is characterized by circulating IgG to the desmosomal cadherin desmoglein 1 (DSG1) and by subcorneal blistering of the skin. The pathomechanism of blister formation in PF is unknown. Previously we have shown that PF IgG induces aggregation of DSG1, plakoglobin (PG), and IgG outside of desmosomes, what in immunofluorescence of PF patient skin visualizes as a granular IgG deposition pattern with a limited number of coarse IgG aggregates between cells. Here we have investigated the fate of these aggregates in skin and found that these are cleared by endocytosis. We performed double immunofluorescence staining on snap-frozen skin biopsies of six PF patients for the following molecules: IgG, the desmosomal proteins DSG1 and DSG3, desmocollins 1 and 3, PG, desmoplakin and plakophilin 3, and for the endosomal marker early endosomal antigen 1 and the lysosomal markers cathepsin D and lysosomal-associated membrane protein 1. Endosomes were present in all cells but did not make contact with the aggregates in the basal and suprabasal layers. In the higher layers they moored to the aggregates, often symmetrically from two adjacent cells, and IgG, DSG1, and PG were taken up. Finally these endosomes became localized perinuclear. Endocytosis was only observed in perilesional or lesional skin but not in non-lesional skin. Older immunoelectron microscopic studies have suggested that in PF skin endocytosis of detached desmosomes takes place but we found no other desmosomal proteins to be present in these endosomes. Double staining with cathepsin D and LAMP-1 revealed no overlap with IgG, DSG1, or PG suggesting that lysosomes have no role in the clearing process. Collectively, our results show that endocytosis is part of the pathogenic process in PF but that no detached desmosomes are taken up but instead the deposited IgG is taken up together with DSG1 and PG.

Abstract: Bullous pemphigoid is a blistering autoimmune disease characterized by two hemidesmosomal proteins (anti-BP180 and 230). Pemphigus, by contrast, is characterized by two autoantibodies (anti-desmoglein 1 and 3). Coexistence of autoantibodies of bullous pemphigoid and pemphigus in a patient is rare. A 25-year-old male patient was admitted to our hospital, reporting a 3-month history of multiple papules, vesicles, and erosions over an extensive erythema on the entire body. Laboratory tests showed high levels of serum IgE, anti-BP180 antibodies, and anti-desmoglein 1 and 3. Histopathologic and immunopathologic features were characterized by bullous pemphigoid. No improvement was seen with systemic corticosteroid therapy, however, pulse corticosteriod therapy combined with methylprednisolone, immunosuppressants, immunomodulators, and plasmapheresis led to the recovery of his condition with numerous milia.

Pemphigus vulgaris lesions have a tendency to localize around natural body orifices. The aim here was to analyze the involvement of nail apparatus in pemphigus vulgaris. Sixty seven ethnic Poles suffering from pemphigus vulgaris on photographic files archiving initial presentation were retrospectively evaluated. Pemphigus vulgaris was diagnosed using combination of clinical data, H+E histology, direct immunofluorescence of plucked scalp hair and/or perilesional tissue also for IgG1 and IgG4 deposits evaluation, indirect immunofluorescence on mosaic substrate and/or monkey esophagus, mono-analyte ELISA with desmoglein 1/3 or multi-analyte ELISA. The nail apparatus involvement was found in 9 of 67 patients (13.4%; 3 females and 6 males). Periungual fingernail lesions were found in 6 patients (2 females, 4 males), whereas periungual toenail lesions in just 3 patients (1 female, 2 males). Our patients nail apparatus changes included, by order of frequency, paronychia, nail discoloration, onychorrhexis, Beau lines, periungual hemorrhages, onychomadesis, cross-ridging, onycholysis, and trachyonychia. The average time between the onset, as recalled by patients, and the diagnosis of pemphigus vulgaris with direct immunofluorescence was not statistically different in PV patients with and without nail apparatus lesions. In this article the molecular and immunological rationale for of periungual involvement is discussed. Our single-center study suggests that nail apparatus involvement is infrequent in pemphigus vulgaris in ethnic Poles. Due to the fact that nail apparatus lesions in pemphigus vulgaris may clinically resemble onychomycosis, giving the proper diagnosis can be difficult particularly when other lesions are overlooked or misinterpreted.

Desmosomes and corneodesmosomes are the most important adhering junctions, providing strength for the epidermal sheet structure made of living keratinocytes and enucleated stratum corneum corneocytes, respectively. These junctions are connected directly with transmembrane desmosomal cadherins, desmogleins (Dsgs), and desmocollins (Dscs); mainly Dsg1/Dsc1 and Dsg3/Dsc3 in desmosomes, and Dsg1/Dsc1 with corneodesmosin in corneodesmosomes. Dsgs and Dscs are associated with several proteins at their inner cytoplasmic domains to anchor keratin intermediate filaments. Desmosomes are not static, but dynamic units that undergo regular remodeling to allow for keratinocyte outward-migration in the epidermis. In corneodesmosomes, this dynamic nature of desmosomes is lost by fixing desmosomal cadherins with corneodesmosin at the intercellular domain of desmosomes and possibly with the formation of peptide bonds by activation of transglutaminase-1 at the intracellular face of desmosomes. Immediately after formation, corneodesmosomes normally commit to degradation, which is complicatedly regulated by proteolytic cleavage of their respective extracellular portions, via kallikrein-regulated peptidases and cathepsins. This proteolytic activity is in turn controlled by a variety of inhibitory agents, including protease inhibitors, cholesterol sulfate, and an acidic gradient. The impairment of protease control causes keratinization disorders. This review focuses on the regulation of corneodesmosome remodeling in relation to disorders of the stratum corneum.

BACKGROUND: Trichoscopy is becoming increasingly popular in diagnosing hair and scalp diseases. Scalp involvement in pemphigus is common. The scalp may be the first or only site of clinical manifestation of the disease. OBJECTIVE: The aim of this study was to analyze whether trichoscopy may be useful in aiding differential diagnosis of scalp lesions in patients with pemphigus vulgaris and pemphigus foliaceus. METHODS: Trichoscopy was performed in 19 patients with scalp lesions in the course of pemphigus (9 patients with pemphigus vulgaris and 10 with pemphigus foliaceus). In all patients, the diagnosis of scalp pemphigus was confirmed by histopathology. The working magnification was 20-fold and 70-fold. RESULTS: The most frequently observed trichoscopy features of pemphigus lesions were: extravasations (18/19; 94.7%) and yellow hemorrhagic crusts (11/19; 57.9%). Yellow dots with whitish halo were observed in 6/19 (31.6%) patients with pemphigus. White polygonal structures were observed in pemphigus foliaceus (6/10; 60%), but not in pemphigus vulgaris. Vascular abnormalities were more frequent in pemphigus vulgaris, when compared to pemphigus foliaceus, and were associated with a severe course of disease. Linear serpentine vessels were the most frequent vascular abnormality in patients with pemphigus vulgaris and pemphigus foliaceus (77.8% and 30%, respectively). CONCLUSION: Trichoscopy may serve as a useful supplementary method in the differential diagnosis of pemphigus, especially in cases of desquamative or exudative lesions limited to the scalp. Extravasations, yellow hemorrhagic crusts, yellow dots with whitish halo, white polygonal structures and linear serpentine vessels are trichoscopy features which may suggest the diagnosis of pemphigus.

Although the role that Autoimmune Regulator (Aire) plays in the induction of central tolerance is well known, the precise cellular and molecular mechanisms are still unclear and debated. In the prevailing view, Aire serves mainly as a direct inducer of tissue-specific antigens (TSAs). However, there is a growing amount of evidence suggesting that Aire modulates the differentiation program of medullary thymic epithelial cells (mTECs), which may directly contribute to the negative selection of self-reactive thymocytes. In addition, Aire has been shown to regulate the expression of many intrathymic chemokines that are required for the proper localization of thymocytes and dendritic cells (DCs), and thus are potentially important for direct and indirect self-antigen presentation in the thymic medulla. Further, recent evidence suggests that the induction of certain antigen-specific Tregs that translocate to tumors and peripheral tissues can be Aire dependent and may contribute to tissue-specific tolerance. This review summarizes the current understanding of the effects of Aire on these alternative mechanisms for the induction of Aire-induced central tolerance.

مقدمه: پمفیگوس فولیاسه، یکی از بیماریهای پوستی اتوایمیون است که بوسیله حضور آنتی بادیهای آنتیمیگردد. تصور میشود تشکیل این آنتی بادیها، از طریق وکتورهای بیماریهای انگلی مانند لیشمانیازیس که در مناطق آندمیک پمفیگوس فولیاسه شیوع فراوانتری دارند واسطه گری میشود. از آنجا که انواع غیر پاتولوژیک این آنتی بادی در بیماران مبتلا به اینگونه بیماریهای انگلی در مناطق آندمیک پمفیگوس فولیاسه یافت شده است، این نظریه می‌تواند توسط یافتن این آنتی بادی در بیماران مبتلابه بیماریهای انگلی در مناطق غیر آندمیک پمفیگوس فولیاسه تایید گردد. بنابر این مطالعهجهت ارزیابی وجود این آنتی بادی در بیماران مبتلا به لیشمانیوز جلدی در شهر اصفهانبه عنوان منطقه اندمیک لیشمانیوز پوستی و منطقه غیر آندمیک پمفیگوس فولیاسه طراحی گردید. روش‌ها: :سرم خون بیماران مبتلا به لیشمانیوز پوستی که توسط علائم بالینی و اسمیر مستقیم تایید شده بود، جدا شده و وجود آنتی بادی توسط تکنیک تشخیصی الایزا مورد ارزیابی قرار گرفت. یافته‌ها: 56 بیمار از 58 بیمار مورد مطالعه ما از نظر وجود این آنتی بادی منفی بودند. یک بیمار از نظر وجود این آنتی بادی به میزان حدواسط و یک بیمار در حد مثبت ارزیابی شد. نتیجه‌گیری: نتایج این مطالعه، نظریه نقش ناقل بیماری انگلی لیشمانیوز پوستی را در تشکیل این آنتی بادی Anti-DSG1 را تایید نمی کند.احتمال دخالت سایر عوامل مانند حضور پشه‌های سیمولیوم نیگریمانوم را در تشکیل این آنتی بادیقابل طرح می‌باشد.