Anti-Desmocollin Autoantibodies in Autoimmune Blistering Diseases.

The presence of anti-desmocollin (Dsc) antibodies is rarely described in autoimmune blistering diseases patients. Moreover, several clinical phenotypes of pemphigus may be associated with these antibodies. In this review we analyze clinicopathological, immunologic and outcome features of anti-Dsc autoimmune blistering diseases patients, to improve their diagnosis and management. We conducted a systematic search of PubMed and Embase (1990-present) for studies reporting cases of autoimmune blistering diseases with anti-Dsc antibodies. We classified the selected patients as patients with exclusively anti-Dsc autoantibodies, and patients with anti-Dsc and other autoantibodies. Of 93 cases with anti-Dsc autoantibodies included, 38 (41%) had exclusively these antibodies. Only 18% of patients presented with the typical clinicopathological phenotype of pemphigus vulgaris or pemphigus foliaceous. Mucosal involvement was seen in approximately half of the patients. Up to 18% of cases were associated with neoplasms. Acantholysis was described in 54% of cases with histopathological information. Treatments and outcomes vary in the different clinical phenotypes. The presence of anti-Dsc antibodies must be suspected mainly in those patients with either atypical pemphigus, in special with clinical pustules, or in cases showing intraepithelial or dermal neutrophilic/eosinophilic infiltrate on histological examination and dual pattern by direct immunofluorescence examination.

Rituximab and Corticosteroid Effect on Desmoglein-Specific B Cells and Desmoglein-Specific T Follicular Helper Cells in Pemphigus.

Pemphigus is an autoimmune blistering disease mediated by autoantibodies directed against desmogleins (DSGs). We recently showed that first-line treatment with rituximab (RTX) enables more patients to achieve long-lasting remission off therapy than corticosteroids alone. To understand the immunological mechanisms that mediate long-lasting clinical remission after RTX treatment, we analyzed the phenotype of DSG-specific memory B cells and DSG-specific T follicular helper cells by flow cytometry and measured antibody-secreting cells by enzyme-linked immune absorbent spot in patients treated with corticosteroids alone or RTX. This post hoc analysis of the RITUX3 trial showed that RTX induced a significant decrease of IgG-switched DSG-specific memory B cells. Accordingly, anti-DSG antibody-secreting cells were no longer detected in patients in complete remission after RTX. In contrast, corticosteroids did not modify the frequency or the phenotype of DSG-specific memory B cells, and anti-DSG antibody-secreting cells were still detected after treatment, even in patients in remission. Using peptide-HLADRB1∗0402 tetramer staining, we identified DSG-3-specific T follicular helper cells, which dramatically decreased after RTX, while remaining stable after corticosteroid treatment. Our findings suggest that long-lasting response to RTX in pemphigus relies on the decrease of DSG-specific circulating T follicular helper cells, which correlates with a sustained depletion of IgG-switched memory autoreactive B cells, leading to the disappearance of anti-DSG antibody-secreting cells.

Fogo selvagem: endemic pemphigus foliaceus

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.

Diagnosis of autoimmune bullous diseases.

Autoimmune bullous disorders (AIBDs) are a heterogeneous group of rare diseases clinically characterized by erosions and/or blisters on the skin and mucous membranes. AIBDs can be categorized into two groups: pemphigus diseases, characterized by intraepidermal blistering and autoantibodies against desmosomal proteins such as desmoglein (Dsg) 1, Dsg3, members of the plakin family, and subepidermal AIBDs, comprised of pemphigoid diseases and dermatitis herpetiformis. Autoantibodies in dermatitis herpetiformis target transglutaminases 2 and 3, while in pemphigoid disease, autoantibodies are directed against structural proteins of the dermal-epidermal junction. Although analysis of a perilesional biopsy with direct immunofluorescence (IF) microscopy is still the diagnostic gold standard, several assays have become widely available that allow serological diagnosis in the majority of patients. Standard serological diagnosis includes indirect IF on monkey esophagus and salt-split human skin. Assays to further characterize autoantibody specificity include ELISA systems based on recombinant forms of the immunodominant regions of the target antigens as well as multivariant indirect IF microscopy tests with several miniature substrates. These serological assays are complemented by various in-house assays using immunoblotting and ELISA, which are only available in specialized laboratories. Here we review new developments in the diagnosis of AIBDs and describe state-of-the-art diagnostic procedures for this group of diseases.

Fogo selvagem: endemic pemphigus foliaceus.

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.

Soluble Fas Ligand Is Essential for Blister Formation in Pemphigus.

Pemphigus is a blistering disease characterized by pemphigus autoantibodies (PVIgG) directed mostly against desmogleins (Dsgs), resulting in the loss of keratinocyte adhesion (acantholysis). Yet, the mechanisms underlying blister formation remain to be clarified. We have shown previously that anti-Fas ligand (FasL) antibody (Ab) prevents PVIgG-induced caspase-8 activation and Dsg cleavage in human keratinocytes, and that sera from pemphigus patients contain abnormally increased levels of FasL. Here, we demonstrate that recombinant FasL induces the activation of caspases prior to Dsg degradation, and anti-FasL Ab prevents acantholysis in cultured keratinocytes. Moreover, the silencing of FasL reduces PVIgG-induced caspase-8 activation and Dsg3 cleavage. Following injection of PVIgG into mice, FasL is upregulated at 1-3 h and is followed by caspase-8-mediated keratinocyte apoptosis, before blister formation. The administration of anti-FasL Ab after PVIgG injection blocks blister formation in mice. Furthermore, we injected PVIgG into two different gene-targeted mutant mice that selectively lack either secreted soluble FasL (sFasL), FasLΔs/Δs mice, or the membrane-bound form of FasL (mFasL), FasLΔm/Δm mice. After PVIgG treatment, blisters are only visible in FasLΔm/Δm animals, lacking mFasL, but still producing sFasL, similar to wild-type (C57BL/6) animals. By contrast, a significant decrease in the relative acantholytic area is observed in the FasLΔs/Δs animals. These results demonstrate that soluble FasL plays a crucial role in the mechanisms of blister formation, and blockade of FasL could be an effective therapeutic approach for pemphigus.

Bullous pemphigoid associated with milia, increased serum IgE, autoantibodies against desmogleins, and refractory treatment in a young patient.

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.

Bullous pemphigoid associated with milia, increased serum IgE, autoantibodies against desmogleins, and refractory treatment in a young patient

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.

Prevalence of pemphigus and pemphigoid autoantibodies in the general population.

BACKGROUND: Mucocutaneous blistering is characteristic of autoimmune bullous dermatoses (AIBD). Blisters are caused by autoantibodies directed against structural components of the skin. Hence, detection of specific autoantibodies has become a hallmark for AIBD diagnosis. Studies on prevalence of AIBD autoantibodies in healthy individuals yielded contradictory results. METHODS: To clarify this, samples from 7063 blood donors were tested for presence of anti-BP180-NC16A, anti-BP230 and anti-Dsg1/3 IgG by indirect immunofluorescence (IF) microscopy using a biochip. RESULTS: Cumulative prevalence of these autoantibodies was 0.9 % (CI: 0.7-1.1 %), with anti-BP180-NC16A IgG being most prevalent. Validation of IF findings using ELISA confirmed presence of autoantibodies in 7/15 (anti-Dsg1), 6/7 (anti-Dsg3), 35/37 (anti-BP180-NC16A) and 2/3 (anti-BP230) cases. Moreover, in 16 samples, anti-BP180-NC16A autoantibody concentrations exceeded the cut-off for the diagnosis of bullous pemphigoid. Interestingly, these anti-BP180-NC16A autoantibodies from healthy individuals formed immune complexes with recombinant antigen and dose-dependently activated neutrophils in vitro. However, fine-epitope mapping within NC16A showed a different binding pattern of anti-BP180-NC16A autoantibodies from healthy individuals compared to bullous pemphigoid patients, while IgG subclasses were identical. CONCLUSIONS: Collectively, we here report a low prevalence of AIBD autoantibodies in a large cohort of healthy individuals. Furthermore, functional analysis shows differences between autoantibodies from healthy donors and AIBD patients.

Impaired function of CD19(+) CD24(hi) CD38(hi) regulatory B cells in patients with pemphigus.

BACKGROUND: Pemphigus is an organ-specific autoimmune bullous disease. OBJECTIVES: To determine the role of regulatory B cells (Bregs) in patients with pemphigus. METHODS: The frequency of the occurrence of CD19(+) CD24(hi) CD38(hi) Bregs was detected from 34 patients with pemphigus and 20 healthy controls. Interleukin (IL)-10 secretion was processed after stimulating B cells. Specific antidesmoglein antibody (Ab) titres and their subclasses were also measured. Ab response and cytokine production from peripheral blood mononuclear cells (PBMCs) with or without Bregs were analysed. RESULTS: The number of Bregs was significantly increased in patients with pemphigus compared with healthy controls (15 ± 7% vs. 9 ± 3%; P < 0·01) and the proportion of Bregs in the active groups (newly diagnosed and chronic active patients) was significantly higher than in remittent individuals (16 ± 7% vs. 13 ± 8%; P = 0·04). The IL-10-producing B cells were significantly increased upon stimulation both in patients and in healthy controls. However, the increase ratio of IL-10-producing B cells between short- and long-term stimulation was significantly lower in patients with pemphigus (1·0-fold vs. 2·6-fold increase in control group; P < 0·01). Strikingly, Bregs from the controls were able to suppress interferon (IFN)-γ expression and T helper cell 1 (Th1) immune response (26% inhibition rate), while the suppressive function of Bregs from patients with pemphigus was significantly decreased (9% inhibition rate). There was no difference in Ab levels from PBMCs with or without Bregs after stimulation. CONCLUSIONS: Bregs in patients with pemphigus are elevated but with defective regulatory function on Th1 cells.

Pemphigus herpetiformis: from first description until now.

Pemphigus herpetiformis is one of the less common forms of pemphigus, first introduced by Jablonska and colleagues in 1975. This autoimmune bullous disease combines the clinical features of dermatitis herpetiformis and the immunologic characteristics of pemphigus. The target autoantigen is usually desmoglein 1 (or less frequently desmoglein 3), although recently it has become increasingly obvious that patients with pemphigus herpetiformis also demonstrate autoantibodies against desmocollin. Here, we summarize reported cases of pemphigus herpetiformis and describe current knowledge considering epidemiology, clinical manifestations, histologic findings, immunopathology, pathophysiologic concepts, associated diseases, and treatment of this rare disorder.

Pemphigus: etiology, pathogenesis, and inducing or triggering factors: facts and controversies.

Pemphigus includes a group of autoimmune bullous diseases with intraepithelial lesions involving the skin and Malpighian mucous membranes. Pemphigus vulgaris (PV), the most frequent and representative form of the group, is a prototypical organ-specific human autoimmune disorder with a poor prognosis in the absence of medical treatment. The pathomechanism of PV hinges on autoantibodies damaging cell-cell cohesion and leading to cell-cell detachment (acantholysis) of the epidermis and Malpighian mucosae (mainly oral mucosa). A controversy exists about which subset of autoantibodies is primarily pathogenic: the desmoglein-reactive antibodies or those directed against the acetylcholine receptors of the keratinocyte membrane. The onset and course of PV depend on a variable interaction between predisposing and inducing factors. Genetic predisposition has a complex polygenic basis, involving multiple genetic loci; however, the genetic background alone ("the soil"), although essential, is not by itself sufficient to initiate the autoimmune mechanism, as proven by the reports of PV in only one of two monozygotic twins and in only two of three siblings with an identical PV-prone haplotype. The intervention of inducing or triggering environmental factors ("the seed") seems to be crucial to set off the disease. The precipitating factors are many and various, most of them directly originating from the environment (eg, drug intake, viral infections, physical agents, contact allergens, diet), others being endogenous (eg, emotional stress, hormonal disorders) but somehow linked with the subject's lifestyle. As to certain drugs, their potential of provoking acantholysis may be implemented by their interfering with the keratinocyte membrane biochemistry (biochemical acantholysis) and/or with the immune balance (immunologic acantholysis). Viral infections, especially the herpetic ones, may trigger the outbreak of PV or simply complicate its clinical course. The precipitating effect might be due to interferons and other cytokines released by the host as a consequence of the viral attack, which overactivate the immune response. Inductions of PV by physical agents (ultraviolet or ionizing radiation, thermal or electrical burns, surgery and cosmetic procedures), contact allergens (in particular, organophosphate pesticides), dietary factors (eg, garlic, leek, onion, black pepper, red chili pepper, red wine, tea), and emotional stress are rare, but well-documented events. The possible intervention of the environment in the outbreak of PV has been overlooked in the past, but nowadays clinicians perceive it more frequently. The assumption that genetic factors alone are not sufficient to cause the outbreak of the disease, inevitably instills the idea that PV may not occur spontaneously, but always results from an interaction between an individual predisposing genetic background and environmental precipitating factors, often concealed or apparently harmless.

[Antidesmoglein antibodies in a patient with Hailey-Hailey disease]. / Détection d'anticorps antidesmogléines circulants chez un patient atteint de maladie de Hailey-Hailey.

BACKGROUND: Hailey-Hailey disease (HHD) is a rare hereditary disease in which the genetic defect is characterized by mutation in the ATP2C1 gene coding for a transmembrane calcium pump. It is generally considered a non-immunologic acantholytic dermatosis in which direct and indirect immunofluorescence studies are negative, unlike in autoimmune pemphigus. PATIENTS AND METHODS: We describe a case of HHD associated with antidesmoglein antibodies in a 53-year-old woman. The clinical symptoms and histology were typical of HHD. Antidesmoglein antibody tests were positive on several occasions and a difference was found between the two types of Elisa test performed (positive with the MBL kit, negative with the Euroimmun kit). DISCUSSION: The positive result for desmoglein antibodies could be due to unmasking of antigens by the mechanism of acantholysis. The specificity of the main desmoglein Elisa tests also requires discussion.