Meta-analysis of the clinical and immunopathological characteristics and treatment outcomes in epidermolysis bullosa acquisita patients

Rituximab in the Treatment of Epidermolysis Bullosa Acquisita: A Systematic Review

Objective

Epidermolysis bullosa acquisita (EBA) is a rare dermatosis of the mucous membrane and/or skin. Employing biologic treatment modalities, specifically rituximab (RTX), have become pivotal measure in treating patients with blistering diseases. This study aims to summarize the current evidence on the safety and efficacy of RTX in EBA.

Methods

An extensive search was performed in MEDLINE/PubMed, Embase, Scopus, and Web of Science databases until the end of August 19th, 2023. Two independent reviewers screened the papers, and collected data. Two hundred thirty-three studies were screened using Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines.

Results

Thirty-one studies were enrolled. The most common reason of RTX administration in patients with EBA was recalcitrant diseases. Clinical response and disease remission was recorded as 92.7 percent (63 patients) and 73.8 percent (45 patients) of the patients, respectively. A relapse rate of 39.5 percent (15 patients) in the mean follow-up of 23.0 months was reported in the studies. Of the patients, 28.2 percent (11 patients) experienced RTX-related side events, mostly mild and transient infusion reactions.

Conclusion

The results of this systematic review demonstrated that RTX is safe and effective in patients with EBA. This biological treatment modality can be routinely used in managing EBA.

Rituximab in the Management of Autoimmune Bullous Diseases: A Treatment-Resistant Case Series from a Single Central European Referral Center

Background and Objectives: Rituximab (RTX) has been the predominant treatment for autoimmune bullous diseases (AIBDs). The objective of this research was to assess the advantages and safety characteristics of RTX treatment in individuals with AIBD. This assessment focused on clinical remission and a reduction in glucocorticosteroid usage, its effect on the titers of autoantibodies targeting desmoglein-1 (DSG-1) and desmoglein-3 (DSG-3), and adverse occurrences during a 12-month follow-up period in a dermatology department within a Central European university context. Materials and Methods: Our case series involved eleven patients, including eight patients with pemphigus vulgaris, two with pemphigus foliaceus, and one with epidermolysis bullosa acquisita. They received a 1 g dose of rituximab, repeated over a two-week interval. Results: The reduction in a prednisone-equivalent dosage after 2, 6, and 12 months following the second RTX infusion was 65.05%, 73.99%, and 76.93%, in that order. The titers of antibodies against DSG-1 exhibited reductions of 43.29%, 75.86%, and 54.02% at 2, 6, and 12 months, respectively. By contrast, the antibody concentrations targeting DSG-3 displayed a decrease of 27.88%, 14.48%, and 5.09% at the corresponding time points. Over the course of the 12-month monitoring period, 18.18% of patients experienced disease relapse, while the remaining individuals achieved either complete or partial remission with minimal or no therapy. Adverse effects were noted in 36.36% of the patient population; they were mild, and no serious adverse effects were reported. Conclusions: RTX represents an efficacious and well-tolerated therapeutic option for the management of AIBD and merits consideration in cases of refractory AIBD. However, further research is imperative to delineate the most optimal dosage, dosing frequency, and total quantity of maintenance infusions required. Additionally, there is a compelling need for studies that explore the impact of RTX on individuals with AIBD who do not exhibit a significant reduction in anti-desmoglein autoantibody levels.

Clinical Features of Paediatric Inflammatory Epidermolysis Bullosa Acquisita: A Case Series Study

Epidermolysis bullosa acquisita (EBA) rarely develops in childhood. This study retrospectively recruited paediatric patients with EBA (age ≤ 16 years), diagnosed by clinical and histopathological features and results of immunofluorescence, immunoblotting and enzyme-linked immunosorbent assay (ELISA), and reviews their clinical manifestations, histopathology, immunological features, and responses to various treatments. All 7 included patients presented with inflammatory EBA. Among them, 3 had a bullous pemphigoid-like phenotype. Pathologically, in addition to dermal-epidermal blistering, in all patients, the distribution of neutrophils was superficial perivascular or interstitial, or in the dermal papilla. Mixed neutrophils and eosinophils were detected in 2 of the 3 patients with bullous pemphigoid-like phenotypes. In addition to treatment with glucocorticoids, dapsone was administered in 4 patients, while thalidomide and sulfasalazine were administered in 1 patient. All patients responded to the these therapies. Relapse was mainly due to reduction and cessation of glucocorticoids. In conclusion, EBA in childhood may be unique, and thus distinct from its adult counterpart. Specific treatment and follow-up protocols are required for therapy of this rare autoimmune skin disease in children.

Pemphigus and pemphigoids: Clinical presentation, diagnosis and therapy

Pemphigus and pemphigoid are two potentially life-threatening groups of autoimmune diseases, characterized by autoantibodies targeting structural components of desmosomes or hemidesmosomes, respectively. Affected patients typically show itchy/painful plaques or blistering skin lesions and/or impairing mucosal blistering and erosions, which may strongly impact their quality of life. Since the milestone work of Walter Lever in 1953, who differentiated these two groups of diseases by histopathological analysis of the level of antibody-mediated skin cleavage, enormous progresses occurred. Achievements made in laboratory diagnostics now allow to identify antigen specific structural proteins of the skin that are targeted by pathogenic autoantibodies. These progresses were accompanied by an increased understanding of the pathogenesis of these diseases thanks to the establishment of animal models reproducing disease and on studies on skin and blood of affected individuals, which have been leading to novel and disease-specific treatments. Yet, given their phenotypical overlap with more common dermatological diseases, correct diagnosis and appropriate treatment are often delayed, in some cases leading to irreversible sequelae, including organ dysfunction (i.e., loss of vision in mucous membrane pemphigoid). Here, we provide a concise overview of the clinical appearance, diagnosis and therapeutic management of pemphigus and pemphigoid diseases.

Pemphigus- und Pemphigoid-Erkrankungen: Klinik, Diagnostik und Therapie: Pemphigus and pemphigoids: Clinical presentation, diagnosis and therapy

Pemphigus und Pemphigoid sind seltene Autoimmunkrankheiten der Haut mit potenziell lebensbedrohlichem Verlauf. Autoantikörper gegen epidermale und junktionale Strukturproteine (Desmosomen sowie Hemidesmosomen) führen bei Betroffenen typischerweise zu juckenden, schmerzhaften Plaques oder Blasen an der Haut und/oder Blasenbildung und Erosionen der Schleimhäute mit möglicher Einschränkung der Lebensqualität. Seit der bahnbrechenden Arbeit von Walter Lever im Jahr 1953, dem es gelang, mittels histopathologischer Untersuchung diese beiden Krankheitsgruppen anhand des Musters der Antikörper‐vermittelten Blasenbildung zu differenzieren, wurden enorme Fortschritte im Verständnis der Erkrankungen erzielt. Die Errungenschaften in der Labordiagnostik ermöglichten die Identifikation von Zielstrukturen zur präzisen Unterscheidung verschiedener Varianten der bullösen Autoimmunerkrankungen. Diese Fortschritte gingen dank der Entwicklung von Tiermodellen mit einem besseren Verständnis der Pathogenese einher. Außerdem haben Studien an Haut und Blut betroffener Patienten zu neuen und krankheitsspezifischen Behandlungen geführt. Aufgrund ihrer Seltenheit und der klinischen Ähnlichkeit mit anderen dermatologischen Erkrankungen verzögern sich die korrekte Diagnosestellung und die Einleitung einer entsprechenden Therapie häufig, was in einigen Fällen zu irreversiblen Folgeerscheinungen, einschließlich Funktionsstörungen von Organen (zum Beispiel Verlust des Sehvermögens beim Schleimhautpemphigoid) führt. Wir geben hier einen Überblick über das klinische Erscheinungsbild, den Diagnosealgorithmus und das therapeutische Management von Pemphigus‐ und Pemphigoid‐Erkrankungen.

Case Report: Biological treatment of epidermolysis bullosa acquisita: report on four cases and literature review

Epidermolysis bullosa acquisita (EBA) is a chronic, recurrent autoimmune subepidermal bullous disease characterized by the presence of autoantibodies targeting type VII collagen -- basement membrane zone antigen. Standard therapy for EBA includes a combination of systemic corticosteroids and dapsone; however, severe cases may require advanced treatment. The current article reports on four EBA cases in which biologics: infliximab, rituximab (Rtx), and intravenous immunoglobulin (IVIG) were applied. All patients fulfilled the clinical and immunological criteria of EBA: they presented tense blisters healing with atrophic scars on the skin on traumatized areas and in mucous membranes. The diagnosis of EBA was established using numerous techniques: direct and indirect immunofluorescence, salt split skin, ELISA, Fluorescence Overlay Antigen Mapping using Laser Scanning Confocal Microscopy. Since all the patients did not achieve long-term remission on standard treatment (prednisone, dapsone) due to ineffectiveness or side effects of drugs, they eventually were treated with biologics leading to extraordinary skin improvement and stopping the disease for 1-3 years. Biologics in all patients were tolerated very well. No side effects were observed during application as well as multi-month follow-up. The presented cases provide a premise that biological drugs can be a valuable component of EBA therapy.

Intravenous Immunoglobulin for Autoimmune Bullous Diseases: A Case Series from a Central European Referral Center

Background and Objectives: Autoimmune bullous diseases (AIBDs) may be treated with intravenous immunoglobulin (IVIG) infusions. This study aimed to evaluate the benefits and safety profiles of high-dose IVIG therapy in AIBD patients, as determined by clinical remission, the glucocorticosteroid-sparing effect, and adverse events at 12 months follow-up in a Central European university dermatology department setting. Materials and Methods: Our case series included 10 patients: five patients with pemphigus vulgaris, one with pemphigus herpetiformis, one with pemphigus foliaceus, one with bullous pemphigoid, two with epidermolysis bullosa acquisita. They underwent 4-12 monthly cycles of IVIG therapy at a dose of 2 g/kg per cycle. Results: The prednisone dosage reduction after 2, 6, and 12 months following the final IVIG course was 65.45%, 70.91%, and 76.37%, respectively. During the 12-month observation period, disease relapse was observed in 20% of patients, while others achieved complete or partial remission without or with minimal therapy. Side effects were seen in 80% of patients; they were transient and did not necessitate discontinuation of IVIG. Conclusions: IVIG demonstrates effectiveness as a treatment with a favorable safety profile. Nevertheless, its high cost remains a significant drawback, particularly in low-income countries. IVIG should be considered, especially in patients opposed to standard therapies or with contraindications to their use.

A systematic review on efficacy, safety and treatment durability of intravenous immunoglobulin in autoimmune bullous dermatoses: Special focus on indication and combination therapy

Autoimmune bullous diseases (AIBDs) are a group of rare blistering dermatoses of the mucous membrane and/or skin. The efficacy, safety and treatment durability of intravenous immunoglobulin (IVIg) as an alternative treatment should be explored to systematically review the available literature regarding treatment outcomes with IVIg in AIBD patients. The predefined search strategy was incorporated into the following database, MEDLINE/PubMed, Embase, Scopus and Web of Science on 18 July 2022. Sixty studies were enrolled using Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. The use of IVIg alone or combined with rituximab was reported in 500 patients with pemphigus, 82 patients with bullous pemphigoid, 146 patients with mucous membranes pemphigoid and 19 patients with epidermolysis bullosa acquisita. Disease remission with IVIg therapy and RTX + IVIg combination therapy were recorded as 82.8% and 86.7% in pemphigus, 88.0% and 100% in bullous pemphigoid and 91.3% and 75.0% in mucous membrane pemphigoid, respectively. In epidermolysis bullosa acquisita, treatment with IVIg led to 78.6% disease remission; no data were available regarding the treatment with RTX + IVIg in this group of patients. Among all the included patients, 37.5% experienced at least one IVIg-related side effect; the most common ones were headaches, fever/chills and nausea/vomiting. The use of IVIg with or without rituximab had a favourable clinical response in patients with AIBDs. IVIg has no major influence on the normal immune system, which makes its utilization for patients with AIBDs reasonable.

Vesiculobullous Lesions of the Oral Cavity

Several dermatological conditions may manifest in the oral cavity, particularly those that are immune-mediated, and they must be distinguished from the various other types of oral ulcerations. This chapter discusses the clinical features, pathogenesis, differential diagnosis, and diagnostic features, including histology and immunofluorescence findings, as well as management of vesiculobullous diseases. These diseases include pemphigus Vulgaris, benign mucous membrane pemphigoid, bullous pemphigoid, and epidermolysis bullosa acquisita. These diseases have a significant impact on the quality of life, as they can lead to serious complications, depending on the extent of the disease. Therefore, early recognition is crucial, helping to reduce disease-related morbidity, mortality and prevent life-threatening complications.

Epidermolysis Bullosa Acquisita-Current and Emerging Treatments

Epidermolysis bullosa acquisita (EBA) is a rare chronic autoimmune subepidermal blistering disease of the skin and mucous membranes, usually beginning in adulthood. EBA is induced by autoantibodies to type VII collagen, a major component of anchoring fibrils in the dermal-epidermal junction (DEJ). The binding of autoantibodies to type-VII collagen subsequently leads to the detachment of the epidermis and the formation of mucocutaneous blisters. EBA has two major clinical subtypes: the mechanobullous and inflammatory variants. The classic mechanobullous variant presentation consists of skin fragility, bullae with minimal clinical or histological inflammation, erosions in acral distribution that heal with scarring, and milia formation. The inflammatory variant is challenging to differentiate from other autoimmune bullous diseases, most commonly bullous pemphigoid (BP) but also mucous membrane pemphigoid (MMP), Brunsting-Perry pemphigoid, and linear IgA dermatosis. Due to its recalcitrance conventional treatment of epidermolysis bullosa acquisita is shown to be demanding. Here we discuss novel therapeutic strategies that have emerged and which could potentially improve the quality of life in patients with EBA.

Risk factors and sequelae of epidermolysis bullosa acquisita: A propensity-matched global study in 1,344 patients

Identification of risk factors and sequelae of any given disease is of key importance. For common diseases, primary prevention and disease management are based on this knowledge. For orphan diseases, identification of risk factors and sequelae has been challenging. With the advent of large databases, e.g., TriNetX, this can now be addressed. We used TriNetX to identify risk factors and sequelae of epidermolysis bullosa acquisita (EBA), a severe and orphan autoimmune disease. To date, there is only enigmatic information on EBA comorbidity. We recruited 1,344 EBA patients in the Global Collaborative Network of TriNetX. Using the "explore outcomes" function we identified 55 diagnoses with a different prevalence between EBA and no-EBA patients. We next performed propensity-matched, retrospective cohort studies in which we determined the risk of EBA development following any of the identified 55 diseases. Here, 31/55 diseases were identified as risk factors for subsequent EBA. Importantly, the highest risk for EBA were other chronic inflammatory diseases (CID), especially lupus erythematosus and lichen planus. Lastly, we determined the risk to develop any of the identified diseases after EBA diagnosis. Here, 38/55 diseases were identified as sequelae. Notably, EBA patients showed an increased risk for metabolic and cardiovascular disease, and thrombosis. Furthermore, the risk for CIDs, especially lupus erythematosus and lichen planus, was elevated. These insights into risk factors and sequelae of EBA are not only of clinical relevance, e.g., optimizing cardiovascular disease risk, but in addition, point to shared pathogenetic pathways between EBA and other inflammatory diseases.

Review of an Anti-CD20 Monoclonal Antibody for the Treatment of Autoimmune Diseases of the Skin

Biologic therapies targeting B-cells are emerging as an effective strategy to treat a variety of immune-mediated diseases. One of the most studied B-cell-targeted therapies is rituximab, an anti-CD20 monoclonal antibody that exemplifies B-cell depletion therapy and has served as the prototype for other anti-CD20 monoclonal antibodies and the development of biosimilars. While there are multiple studies on the use of rituximab in dermatology, a comprehensive review of rituximab therapy in autoimmune skin conditions is lacking. In this literature review, we summarize indications, treatment efficacy, and safety of rituximab among common autoimmune diseases of the skin: pemphigus vulgaris, cutaneous lupus erythematous, dermatomyositis, systemic sclerosis, thyroid dermopathy, autoimmune pemphigoid diseases, and cutaneous vasculitis diseases. Existing data on rituximab support the approach of rituximab, biosimilars, and newer B-cell-targeting therapies in immune-mediated cutaneous diseases. Overall, rituximab, which targets CD20, provides an effective alternative or concomitant option to traditional immunosuppressants in the management of various autoimmune diseases of the skin. Further studies are necessary to expand the understanding and possible utility of B-cell-targeted therapies among autoimmune skin diseases.

[Rare variants of pemphigoid diseases]

Pemphigoid diseases comprise a heterogeneous group of subepidermal autoimmune blistering dermatoses characterized by autoantibodies against structural proteins of the dermal-epidermal junction. Recent decades have witnessed a significant surge in the incidence of these diseases, which, in addition to general aging of the population, can be attributed to the availability of precise diagnostic methods and improved knowledge of the clinical and immunopathological spectrum. While bullous pemphigoid, mucous membrane pemphigoid, and linear IgA disease account for most pemphigoid disorders, less frequent, presumably underdiagnosed variants are increasingly becoming relevant for clinicians. These include epidermolysis bullosa acquisita, anti-p200 pemphigoid, pemphigoid gestationis, lichen planus pemphigoides, and recently defined entities such as IgM pemphigoid and Orf-induced pemphigoid. Accurate characterization and differentiation of these subtypes are not only of diagnostic relevance but may also be associated with therapeutic and prognostic implications for affected individuals. Due to the rarity of these diseases, no controlled prospective clinical trials currently exist, making their diagnosis and therapy challenging.

Off-Label Uses of Rituximab in Dermatology

Purpose of Review

Rituximab has transformed the treatment of B-cell malignancies and rheumatoid arthritis in the past 2 decades. More recently, this anti-CD20 monoclonal antibody has seen increasing usage in the field of dermatology. This review highlights the evidence supporting its use in several important dermatologic conditions.

Recent Findings

Key recent findings include the 2018 FDA approval of rituximab for the treatment of moderate-to-severe pemphigus.

Summary

Data from randomized controlled trials have demonstrated the efficacy of rituximab in pemphigus, ANCA-associated vasculitis, and cryoglobulinemic vasculitis. More limited data suggests its use in recalcitrant cases of diseases such as pemphigoid, epidermolysis bullosa acquisita, and dermatomyositis. There is scarce evidence and mixed results for rituximab when studied in cutaneous polyarteritis nodosa and cutaneous lupus erythematosus.

Systems biology and artificial intelligence analysis highlights the pleiotropic effect of IVIg therapy in autoimmune diseases with a predominant role on B cells and complement system

Intravenous immunoglobulin (IVIg) is used as treatment for several autoimmune and inflammatory conditions, but its specific mechanisms are not fully understood. Herein, we aimed to evaluate, using systems biology and artificial intelligence techniques, the differences in the pathophysiological pathways of autoimmune and inflammatory conditions that show diverse responses to IVIg treatment. We also intended to determine the targets of IVIg involved in the best treatment response of the evaluated diseases. Our selection and classification of diseases was based on a previously published systematic review, and we performed the disease characterization through manual curation of the literature. Furthermore, we undertook the mechanistic evaluation with artificial neural networks and pathway enrichment analyses. A set of 26 diseases was selected, classified, and compared. Our results indicated that diseases clearly benefiting from IVIg treatment were mainly characterized by deregulated processes in B cells and the complement system. Indeed, our results show that proteins related to B-cell and complement system pathways, which are targeted by IVIg, are involved in the clinical response. In addition, targets related to other immune processes may also play an important role in the IVIg response, supporting its wide range of actions through several mechanisms. Although B-cell responses and complement system have a key role in diseases benefiting from IVIg, protein targets involved in such processes are not necessarily the same in those diseases. Therefore, IVIg appeared to have a pleiotropic effect that may involve the collaborative participation of several proteins. This broad spectrum of targets and 'non-specificity' of IVIg could be key to its efficacy in very different diseases.

Cutaneous kinase activity correlates with treatment outcomes following PI3K delta inhibition in mice with experimental pemphigoid diseases

Chronic blistering at the skin and/or mucous membranes, accompanied by a varying degree of inflammation, is the clinical hallmark of pemphigoid diseases that impose a major medical burden. Pemphigoid diseases are caused by autoantibodies targeting structural proteins of the epithelial basement membrane. One major pathogenic pathway of skin blistering and inflammation is activation of myeloid cells following Fc gamma receptor-dependent binding to the skin-bound immune complexes. This process requires activation of specific kinases, such as PI3Kδ, which have emerged as potential targets for the treatment of pemphigoid diseases. Yet, it is unknown if global cutaneous kinase activity present in lesional pemphigoid disease correlates with therapeutic effects following treatment with a given target-selective kinase inhibitor. To address this, we here first determined the kinase activity in three different mouse models of pemphigoid diseases: Antibody transfer-induced mucous membrane pemphigoid (MMP), antibody transfer-induced epidermolysis bullosa acquisita (EBA) and immunization-induced EBA. Interestingly, the kinome signatures were different among the three models. More specifically, PI3Kδ was within the kinome activation network of antibody transfer-induced MMP and immunization-induced EBA, but not in antibody transfer-induced EBA. Next, the therapeutic impact of the PI3Kδ-selective inhibitor parsaclisib was evaluated in the three model systems. In line with the kinome signatures, parsaclisib had therapeutic effects in antibody transfer-induced MMP and immunization-induced EBA, but not in autoantibody-induced EBA. In conclusion, kinase activation signatures of inflamed skin, herein exemplified by pemphigoid diseases, correlate with the therapeutic outcomes following kinase inhibition, demonstrated here by the PI3Kδ inhibitor parsaclisib.

Epidermolysis bullosa acquisita

Epidermolysis bullosa acquisita is a rare autoimmune disease, characterized by the synthesis of anti-collagen VII autoantibodies, the main component of hemidesmosome anchoring fibrils. The antigen-antibody binding elicits a complex inflammatory response, which culminates in the loss of dermo-epidermal adhesion of the skin and/or mucous membranes. Skin fragility with bullae, erosions, and milia in areas of trauma characterizes the mechanobullous form of the disease. In the inflammatory form of epidermolysis bullosa acquisita, urticarial inflammatory plaques with tense bullae, similar to bullous pemphigoid, or mucosal lesions can determine permanent scars and loss of functionality in the ocular, oral, esophageal, and urogenital regions. Due to the similarity of the clinical findings of epidermolysis bullosa acquisita with other diseases of the pemphigoid group and with porphyria cutanea tarda, the diagnosis is currently confirmed mainly based on the clinical correlation with histopathological findings (pauci-inflammatory subepidermal cleavage or with a neutrophilic infiltrate) and the demonstration of the presence of anti-collagen VII IgG in situ by direct immunofluorescence, or circulating anti-collagen VII IgG through indirect immunofluorescence and/or ELISA. There is no specific therapy for epidermolysis bullosa acquisita and the response to treatment is variable, usually with complete remission in children and a worse prognosis in adults with mucosal involvement. Systemic corticosteroids and immunomodulators (colchicine and dapsone) are alternatives for the treatment of mild forms of the disease, while severe forms require the use of corticosteroid therapy associated with immunosuppressants, intravenous immunoglobulin, and rituximab.

Unmet Medical Needs in Chronic, Non-communicable Inflammatory Skin Diseases

An estimated 20-25% of the population is affected by chronic, non-communicable inflammatory skin diseases. Chronic skin inflammation has many causes. Among the most frequent chronic inflammatory skin diseases are atopic dermatitis, psoriasis, urticaria, lichen planus, and hidradenitis suppurativa, driven by a complex interplay of genetics and environmental factors. Autoimmunity is another important cause of chronic skin inflammation. The autoimmune response may be mainly T cell driven, such as in alopecia areata or vitiligo, or B cell driven in chronic spontaneous urticaria, pemphigus and pemphigoid diseases. Rare causes of chronic skin inflammation are autoinflammatory diseases, or rheumatic diseases, such as cutaneous lupus erythematosus or dermatomyositis. Whilst we have seen a significant improvement in diagnosis and treatment, several challenges remain. Especially for rarer causes of chronic skin inflammation, early diagnosis is often missed because of low awareness and lack of diagnostics. Systemic immunosuppression is the treatment of choice for almost all of these diseases. Adverse events due to immunosuppression, insufficient therapeutic responses and relapses remain a challenge. For atopic dermatitis and psoriasis, a broad spectrum of innovative treatments has been developed. However, treatment responses cannot be predicted so far. Hence, development of (bio)markers allowing selection of specific medications for individual patients is needed. Given the encouraging developments during the past years, we envision that many of these challenges in the diagnosis and treatment of chronic inflammatory skin diseases will be thoroughly addressed in the future.

The association of six autoimmune bullous diseases with thyroid disorders: A population-based study

BACKGROUND

The association of autoimmune bullous diseases (AIBDs) with thyroid disorders remains to be profoundly investigated.

OBJECTIVE

To evaluate the epidemiological association between six AIBDs and thyroid disorders.

METHODS

A population-based cross-sectional study enrolled patients with bullous pemphigoid (BP), mucous membrane pemphigoid (MMP), epidermolysis bullosa acquisita (EBA), pemphigoid gestationis (PG), pemphigus vulgaris (PV), and pemphigus foliaceus (PF). Patients with these six AIBDs were compared with six age- and sex-matched control groups regarding the prevalence of thyroiditis and hyperthyroidism. Logistic regression was used to calculate the odds ratio (OR) and 95% confidence interval (CI) for thyroid disorders.

RESULTS

The study population included 1,743, 251, 106, 126, 860, and 103 patients with BP, MMP, EBA, PG, PV, and PF, respectively. The corresponding control groups consisted of 10,141, 1,386, 606, 933, 5,142, and 588 matched controls, respectively. A significant association was found between thyroiditis and BP (OR, 1.98; 95% CI, 1.18-3.35; P=0.010), MMP (OR, 7.02; 95% CI, 1.87-26.33; P=0.004), and PV (OR, 2.73; 95% CI, 1.45-5.15; P=0.002). With regard to hyperthyroidism, PF was the only AIBD to demonstrate significant comorbidity (OR, 2.42; 95% CI, 1.13-5.21; P=0.024). EBA and PG were not found to cluster with any of the investigated thyroid conditions.

CONCLUSION

Patients with BP, MMP, PV, and PF experience an elevated burden of thyroid disorders. Patients with these AIBDs presenting with suggestive symptoms may be carefully screened for comorbid thyroid disorders.

Cutaneous Manifestations of Inflammatory Bowel Disease: A Basic Overview

Inflammatory bowel disease (IBD) is a chronic inflammatory condition of the gastrointestinal (GI) tract that is subdivided into Crohn's disease (CD) and ulcerative colitis (UC). CD is characterized by involvement of the entire GI tract, while UC mainly affects the distal GI tract. Moreover, both CD and UC can present with extraintestinal manifestations (EIMs) of the disease affecting multiple organ systems including the hepatobiliary tract, kidney, bones, eyes, joints, and skin. These complications can cause significant morbidity and negatively impact the quality of life for IBD patients. Although the pathogenesis of EIMs is not clearly elucidated, it is postulated that the diseased GI mucosa similarly stimulates excess immune responses at the extraintestinal sites. Cutaneous EIMs occur in up to 15% of patients with IBD, often predating their IBD diagnosis. They are categorized into (1) specific, (2) reactive, (3) associated, and (4) treatment-induced. Here, we review the epidemiological, clinical, diagnostic, and histologic features of the most commonly described cutaneous EIMs of IBD along with their respective treatment options.

The pathogeneses of pemphigus and pemphigoid diseases

Autoimmune bullous diseases (AIBDs) are skin disorders which are mainly induced by autoantibodies against desmosomal or hemidesmosomal structural proteins. Previous studies using patients' samples and animal disease models identified target antigens and elucidated the mechanisms of blister formation. Pemphigus has been the subject of more active clinical and basic research than any other AIBD. These efforts have revealed the pathogenesis of pemphigus, which in turn has led to optimal diagnostic methods and novel therapies, such as rituximab. In bullous pemphigoid (BP), studies with passive-transfer mouse models using rabbit anti-mouse BP180 antibodies and studies with passive-transfer or active mouse models using autoantigen-humanized mice elucidated the immune reactions to BP180 in vivo. Recently, dipeptidyl peptidase-4 inhibitors have attracted attention as a trigger for BP. For epidermolysis bullosa acquisita (EBA), investigations using mouse models are actively under way and several molecules have been identified as targets for novel therapies. In this review, we give an overview and discussion of the recent progress in our understanding of the pathogenesis of pemphigus, BP, and EBA. Further studies on the breakdown of self-tolerance and on the identification of key molecules that are relevant to blister formation may expand our understanding of the etiology of AIBDs and lead to the development of novel therapeutic strategies.

NUTRITION AND BULLOUS DISEASES

Although relatively uncommon, autoimmune bullous diseases carry the risk of increased mortality and can significantly impact quality of life. This group of diseases is broad and encompasses subepidermal conditions like bullous pemphigoid, cicatricial pemphigoid, epidermolysis bullosa acquisita, dermatitis herpetiformis, and linear IgA bullous dermatosis, as well as intraepidermal conditions like pemphigus and its variants. The pathophysiology of each condition is incompletely understood but broadly involves the formation of autoantibodies targeting skin adhesion proteins, a process which relies on a complex interplay between a dysregulated immune system, genetic predisposition, and environmental factors. We review the impact of nutrition on pathogenesis, clinical course, and treatment of various autoimmune bullous diseases.

Multiple modes of action mediate the therapeutic effect of IVIg in experimental epidermolysis bullosa acquisita

Substitution of IgG in antibody deficiency or application of high-dose intravenous IgG (IVIg) in patients with autoimmunity are well-established treatments. Data on the mode of action of IVIg are, however, controversial and may differ for distinct diseases. In this study, we investigated the impact and molecular mechanism of high-dose IgG treatment in murine autoantibody-induced skin inflammation, namely, epidermolysis bullosa acquisita (EBA). EBA is caused by antibodies directed against type VII collagen (COL7) and is mediated by complement activation, release of reactive oxygen species, and proteases by myeloid cells. In murine experimental EBA the disease can be induced by injection of anti-COL7 IgG. Here, we substantiate that treatment with high-dose IgG improves clinical disease manifestation. Mechanistically, high-dose IgG reduced the amount of anti-COL7 in skin and sera, which is indicative for an FcRn-dependent mode-of-action. Furthermore, in a non-receptor-mediated fashion, high-dose IgG showed antioxidative properties by scavenging extracellular reactive oxygen species. High-dose IgG also impaired complement activation and served as substrate for proteases, both key events during EBA pathogenesis. Collectively, the non-receptor-mediated anti-inflammatory properties of high-dose IgG may explain the therapeutic benefit of IVIg treatment in skin autoimmunity.

Bullous Pemphigoid and Other Pemphigoid Dermatoses

The pemphigoid family of dermatoses is characterized by autoimmune subepidermal blistering. The classic paradigm for pemphigoid, and the most common member, is bullous pemphigoid. Its variable clinical presentation, with or without frank bullae, is linked by significant pruritus afflicting the elderly. Mucous membrane pemphigoid is an umbrella term for a group of subepidermal blistering dermatoses that favor the mucosal membranes and can scar. Epidermolysis bullosa acquisita is a chronic blistering disorder characterized by skin fragility, sensitivity to trauma, and its treatment-refractory nature. Clinicians that encounter these pemphigoid disorders may benefit from an overview of their clinical presentation, diagnostic work-up, and therapeutic management, with an emphasis on the most frequently encountered pemphigoid disease, bullous pemphigoid.

Topical Application of the PI3Kβ-Selective Small Molecule Inhibitor TGX-221 Is an Effective Treatment Option for Experimental Epidermolysis Bullosa Acquisita

Class I phosphoinositide 3-kinases (PI3K) have been implemented in pathogenesis of experimental epidermolysis bullosa acquisita (EBA), an autoimmune skin disease caused by type VII collagen (COL7) autoantibodies. Mechanistically, inhibition of specific PI3K isoforms, namely PI3Kβ or PI3Kδ, impaired immune complex (IC)-induced neutrophil activation, a key prerequisite for EBA pathogenesis. Data unrelated to EBA showed that neutrophil activation is also modulated by PI3Kα and γ, but their impact on the EBA has, so far, remained elusive. To address this and to identify potential therapeutic targets, we evaluated the impact of a panel of PI3K isoform-selective inhibitors (PI3Ki) on neutrophil function in vitro, and in pre-clinical EBA mouse models. We document that distinctive, and EBA pathogenesis-related activation-induced neutrophil in vitro functions depend on distinctive PI3K isoforms. When mice were treated with the different PI3Ki, selective blockade of PI3Kα (alpelisib), PI3Kγ (AS-604850), or PI3Kβ (TGX-221) impaired clinical disease manifestation. When applied topically, only TGX-221 impaired induction of experimental EBA. Ultimately, multiplex kinase activity profiling in the presence of disease-modifying PI3Ki identified unique signatures of different PI3K isoform-selective inhibitors on the kinome of IC-activated human neutrophils. Collectively, we here identify topical PI3Kβ inhibition as a potential therapeutic target for the treatment of EBA.

Pediatric epidermolysis bullosa acquisita: A review

Epidermolysis bullosa acquisita (EBA) is an acquired autoimmune blistering skin disorder that is rare in adults and even rarer in childhood. This review aims to identify cases of pediatric EBA and report their clinical features and course. Our literature review was conducted in MEDLINE^® using the search terms related to juvenile epidermolysis bullosa acquisita. We identified 40 cases of pediatric EBA. Mucosal tissues were affected in 29 out of 40 cases. Treatment mostly consisted of a systemic corticosteroid combined with dapsone. Prognosis is favorable with 17 of 40 cases achieving complete remission, 9 of 40 with complete control with therapy, 12 of 40 with partial control with therapy, 1 of 40 with no response to therapy, and 1 of 40 terminating treatment early. Though it is a rare condition, childhood EBA should still be included in the differential diagnosis of pediatric blistering diseases.

Evaluation and Comparison of Clinical and iLaboratory Characteristics of Patients With IgA Epidermolysis Bullosa Acquisita, Linear IgA Bullous Dermatosis, and IgG Epidermolysis Bullosa Acquisita

Importance

Immunoglobulin A (IgA) epidermolysis bullosa acquisita (EBA) is an autoimmune skin blistering disease with IgA autoantibodies directed against type VII collagen. There is debate whether it should be considered part of the clinical spectrum of linear IgA bullous dermatosis (LABD) or a separate disease entity.

Objective

This cohort study aimed to define the clinical features and treatment responses of IgA EBA and anti-BP180-driven LABD, and to compare the prevalences of IgA EBA anti-BP180 LABD and classic IgG-mediated EBA in an autoimmune diagnostic laboratory database.

Design, Setting, and Participants

This retrospective cohort study and case series study included demographic, immunopathologic, and serologic data from 300 patients diagnosed with IgA EBA, IgG EBA, or LABD. Furthermore, clinical features and treatment responses of IgA EBA were analyzed in a case series including 4 patients with IgA EBA. All patients from the database of the autoimmune diagnostic laboratory at the Department of Dermatology, University of Lübeck, Germany, who were diagnosed with IgA EBA, LABD, or IgG EBA between October 2010 and July 2019 were included. Four patients diagnosed with IgA EBA between October 2015 and January 2018 are described in detail.

Main Outcomes and Measures

The clinical course of IgA EBA was observed before and during different treatments.

Results

The database search yielded 21 cases of IgA EBA (12 females [57%]/9 males [43%]), 222 cases of LABD (111 females [51%]/106 males [49]), and 57 cases of IgG EBA (29 females [50%]/28 males [48%]). The median (range) age of each cohort was 64 (4-81) years for IgA EBA, 56 (3-92) years for IgG EBA, and significantly older compared with IgG EBA (P = .002) for those with LAPD (median [range], 70 [1-94] years). The patients with IgA EBA exhibited heterogeneous clinical presentations that significantly differed from those of anti-BP180 LABD. All 4 patients with IgA EBA described in detail were first treated with dapsone, but only 1 responded to this treatment. The others required treatment with high-dose dexamethasone, rituximab, and/or intravenous immunoglobulins to achieve partial clinical remission.

Conclusions and Relevance

Overall, the findings of this cohort study and small case series suggest that IgA EBA may be more common than expected and may require more intensive systemic treatment than LABD, suggesting it should be considered a separate disease entity.

The burden of neurological comorbidities in six autoimmune bullous diseases: a population-based study

BACKGROUND

Apart from bullous pemphigoid (BP), the association of other autoimmune bullous diseases (AIBDs) with neurological conditions is poorly understood.

OBJECTIVE

To estimate the association between a wide array of AIBDs and neurological conditions.

METHODS

A retrospective cross-sectional study recruited patients with BP, mucous membrane pemphigoid (MMP), epidermolysis bullosa acquisita (EBA), pemphigoid gestationis (PG), pemphigus vulgaris (PV) and pemphigus foliaceus (PF). These patients were compared with their age- and sex-matched control subjects with regard to the lifetime prevalence of Parkinson's disease (PD), Alzheimer's disease (AD), stroke, epilepsy and multiple sclerosis (MS). Logistic regression was used to calculate OR for specified neurological disorders.

RESULTS

The current study included 1743, 251, 106, 126, 860 and 103 patients diagnosed with BP, MMP, EBA, PG, PV and PF, respectively. These patients were compared with 10 141, 1386, 606, 933, 5142 and 588 matched controls, respectively. Out of the investigated neurological conditions, PD associated with BP (OR, 2.71; 95% CI, 2.19-3.35); AD with BP (OR, 2.11; 95% CI, 1.73-2.57), MMP (OR, 2.37; 95% CI, 1.03-5.47), EBA (OR, 6.00; 95% CI, 1.90-18.97) and PV (OR, 2.24; 95% CI, 1.40-3.60); stroke with BP (OR, 1.84; 95% CI, 1.55-2.19) and EBA (OR, 2.79; 95% CI, 1.11-7.01); and epilepsy with BP (OR, 2.18; 95% CI, 1.72-2.77) and PV (OR, 1.80; 95% CI, 1.19-2.73). MS did not significantly cluster with any of the six AIBDs.

CONCLUSION

In addition to BP, EBA and PV were found to cluster with neurological comorbidities. Patients with these AIBDs with compatible symptoms may be carefully assessed for comorbid neurological disorders.

Bullous Autoimmune Dermatoses–Clinical Features, Diagnostic Evaluation, and Treatment Options

BACKGROUND

Bullous autoimmune dermatoses are a clinically and immunopatho - logically heterogeneous group of diseases, characterized clinically by blisters or erosions of the skin and/or mucous membranes. In Germany, their prevalence is approximately 40 000 cases nationwide, and their incidence approximately 20 new cases per million people per year.

METHODS

This review is based on publications that were retrieved by a selective search of the literature focusing on the current German and European guidelines.

RESULTS

Recent years have seen the publication of guidelines, controlled prospective clinical trials, and multicenter diagnostic studies improving both diagnosis and therapy. Specific monovalent and multivariate serological test systems and pattern analysis of tissue-bound autoantibodies allow identification of the target antigens in 80-90% of patients. This enables the precise classification of disease entities, with implications for treatment selection and disease outcome. In 2019, the anti-CD20 antibody rituximab was approved by the European Medicines Agency for the treatment of moderate and severe pemphigus vulgaris, with an ensuing marked improvement in the care of the affected patients. To treat mild and moderate bullous pemphigoid, topical clobetasol proprionate is recommended, in severe disease, combined with systemic treatment, i.e. usually (a) prednisolone p.o. at an initial dose of 0.5mg/kg/d , (b) an immunomodulant, e.g. dapsone or doxycycline, or (c) prednisolone plus an immunomodulant.

CONCLUSION

The early recognition and precise diagnostic evaluation of bullous autoimmune dermatoses now enables improved, often interdisciplinary treatment, in accordance with the available guidelines. Current research projects are focused on new treatment approaches, an improved understanding of the underlying pathophysiology, and further refinements of diagnostic techniques.

Propranolol Is an Effective Topical and Systemic Treatment Option for Experimental Epidermolysis Bullosa Acquisita

Propranolol is an ADRB2 blocker that regulates heart muscle contractions, smooth muscle relaxation, and glycogenolysis. In addition, an increasing number of applications in dermatology have been described, most prominently, the use as a first-line treatment for infantile hemangiomas. We here show that propranolol enhances IL-8-induced neutrophil chemotaxis and reduces the release of ROS after immune complex stimulation. To obtain further molecular insights into the modulatory effects of propranolol in activated neutrophils, we performed RNA sequencing of immune complex-stimulated neutrophils in the absence and presence of the drug. We identified the transcriptomic signature of propranolol and demonstrated an ADR2-independent immunomodulatory effect. To determine if the anti-inflammatory transcriptomic signature of propranolol also translates into clinical effects, we next evaluated the impact of propranolol in a prototypical neutrophil-dependent skin disease, specifically, antibody transfer-induced epidermolysis bullosa acquisita in mice. To validate the identified propranolol gene signature obtained in human neutrophils, we analyzed a selection of genes by RT-PCR in mouse epidermolysis bullosa acquisita skin and confirmed TNF, among others, to be differentially regulated by propranolol treatment. Our data clearly indicate that, based on its molecular impact on immune complex-activated neutrophils, propranolol is a potential treatment option for neutrophil-mediated inflammatory skin diseases.

[European Guidelines (S1) on the use of high-dose intravenous immunoglobulin in dermatology]

BACKGROUND AND OBJECTIVES

Treatment of severe dermatological autoimmune diseases and toxic epidermal necrolysis (TEN) with high-dose intravenous immunoglobulin (IVIg) is a well-established procedure in dermatology. As treatment with IVIg is usually considered for rare clinical entities or severe cases, the use of immunoglobulin is not generally based on data from randomized controlled trials usually required for evidence-based medicine. Since the indications for the use of IVIg are rare, it is unlikely that such studies will be available in the foreseeable future. Because first-line use is limited by the high costs of IVIg, the first clinical guidelines on the use of IVIg in dermatological conditions were established in 2008 and renewed in 2011.

METHODS

The European guidelines presented here were prepared by a panel of experts nominated by the European Dermatology Forum (EDF) and European Academy of Dermatology and Venereology (EADV). The guidelines were developed to update the indications for treatment currently considered effective and to summarize the evidence for the use of IVIg in dermatological autoimmune diseases and TEN.

RESULTS AND CONCLUSION

The current guidelines represent consensual expert opinions and definitions on the use of IVIg reflecting current published evidence and are intended to serve as a decision-making tool for the use of IVIg in dermatological diseases.

Treatment with anti-neonatal Fc receptor (FcRn) antibody ameliorates experimental epidermolysis bullosa acquisita in mice

Background and Purpose

Pemphigus and pemphigoid diseases are characterized and caused predominantly by IgG autoantibodies targeting structural proteins of the skin. Their current treatment relies on general and prolonged immunosuppression that causes severe adverse events, including death. Hence, novel safe and more effective treatments are urgently needed. Due to its' physiological functions, the neonatal Fc receptor (FcRn) has emerged as a potential therapeutic target for pemphigus and pemphigoid, primarily because IgG is protected from proteolysis after uptake into endothelial cells. Thus, blockade of FcRn would reduce circulating autoantibody concentrations. However, long‐term effects of pharmacological FcRn inhibition in therapeutic settings of autoimmune diseases are unknown.

Experimental Approach

Therapeutic effects of FcRn blockade were investigated in a murine model of the prototypical autoantibody‐mediated pemphigoid disease, epidermolysis bullosa acquisita (EBA). B6.SJL‐H2s C3c/1CyJ mice with clinically active disease were randomized to receive either an anti‐FcRn monoclonal antibody (4470) or an isotype control over 4 weeks.

Key Results

While clinical disease continued to worsen in isotype control‐treated mice, overall disease severity continuously decreased in mice injected with 4470, leading to almost complete remission in over 25% of treated mice. These clinical findings were paralleled by a reduction of autoantibody concentrations. Reduction of autoantibody concentrations, rather than modulating neutrophil activation, was responsible for the observed therapeutic effects.

Conclusion and Implications

The clinical efficacy of anti‐FcRn treatment in this prototypical autoantibody‐mediated disease encourages further development of anti‐FcRn antibodies for clinical use in pemphigoid diseases and potentially in other autoantibody mediated diseases.

Genetics and Omics Analysis of Autoimmune Skin Blistering Diseases

Autoimmune blistering diseases (AIBDs) of the skin are characterized by autoantibodies against different intra-/extracellular structures within the epidermis and at the basement membrane zone (BMZ). Binding of the antibodies to their target antigen leads to inflammation at the respective binding site and degradation of these structures, resulting in the separation of the affected skin layers. Clinically, blistering, erythema and lesions of the skin and/or mucous membranes can be observed. Based on the localization of the autoantigen, AIBDs can be divided into pemphigus (intra-epidermal blistering diseases) and pemphigoid diseases (sub-epidermal blistering diseases), respectively. Although autoantigens have been extensively characterized, the underlying causes that trigger the diseases are still poorly understood. Besides the environment, genetic factors seem to play an important role in a predisposition to AIBDs. Here, we review currently known genetic and immunological mechanisms that contribute to the pathogenesis of AIBDs. Among the most commonly encountered genetic predispositions for AIBDs are the HLA gene region, and deleterious mutations of key genes for the immune system. Particularly, HLA class II genes such as the HLA-DR and HLA-DQ alleles have been shown to be prevalent in patients. This has prompted further epidemiological studies as well as unbiased Omics approaches on the transcriptome, microbiome, and proteome level to elucidate common and individual genetic risk factors as well as the molecular pathways that lead to the pathogenesis of AIBDs.

From bench to bedside: evolving therapeutic targets in autoimmune blistering disease

Autoimmune blistering diseases comprise a group of heterogenous conditions characterized by the loss of tolerance and subsequent development of autoantibodies targeting epidermal and subepidermal adhesion proteins. Blisters and erosions form on the skin and mucous membranes leading to significant morbidity and mortality. Traditional therapies rely on systemic immunosuppression. Advancements in our understanding of the pathophysiology of pemphigus and pemphigoid have led to the development of molecules which target specific pathways involved in induction and perpetuation of disease. In this review, we outline the novel therapeutic strategies including B-cell depletion, T-regulatory cell repletion, cell signalling inhibitors and small molecular inhibitors, inhibitory monoclonal antibodies, as well as complement inhibition. We additionally review their current level of clinical evidence. We lastly review therapeutics targets gleaned from the experimental epidermolysis bullosa acquisita mouse model. These emerging treatments offer an exciting progression from basic science discoveries that have the potential to transform the treatment paradigm in autoimmune blistering diseases.

Learning From Success and Failure: Biologics for Non-approved Skin Diseases

The impressive potential of biologics has been demonstrated in psoriasis, hidradenitis suppurativa, and urticaria. Numerous biologicals are entering the field for a restricted number of skin disorders. Off-label use of biologics in other recalcitrant skin diseases has increased. Mounting data point to the potential of already existing biologics acting on the IL-17/IL-23 pathway in skin disorders with epidermal hyperkeratosis (e.g., pityriasis rubra pilaris), acneiform inflammation (e.g., hidradenitis suppurativa), and loss of mucosal integrity (e.g., aphthosis). TNF-α blockers are also effective in the latter conditions but seem of particular value in granulomatous (e.g., granuloma annulare) and neutrophilic disorders (e.g., pyoderma gangrenosum). Failure of IL-17 blockade in skin diseases resulting from immune-mediated cell destruction (e.g., alopecia areata and vitiligo) illustrates its limited involvement in Th1-dependent skin immunology. Overall, disappointing results of TNF-α blockers in alopecia areata and vitiligo point to the same conclusion although promising results in toxic epidermal necrolysis suggest TNF-α exerts at least some in vivo Th1-related activities. Acting on both the Th1 and Th17 pathway, ustekinumab has a rather broad potential with interesting results in lupus and alopecia areata. The efficacy of omalizumab in bullous pemphigoid has revealed an IgE-mediated recruitment of eosinophils leading to bullae formation. Reconsidering reimbursement criteria for less common but severe diseases seems appropriate if substantial evidence is available (e.g., pityriasis rubra pilaris). For other disorders, investigator- and industry-initiated randomized clinical trials should be stimulated. They are likely to improve patient outcome and advance our understanding of challenging skin disorders.

Pemphigoid variants affecting the skin

Pemphigoid diseases are autoimmune subepidermal blistering diseases affecting the skin and mucous membranes, which are caused by autoantibodies targeting structural hemidesmosomal proteins or hemidesmosome-associated proteins. Variants of pemphigoid can be differentiated based on targeted antigens and clinical aspects. In this review, we will discuss pemphigoid variants that predominantly affect the skin, and provide clinicians with clues to diagnosis.

Current Clinical Trials in Pemphigus and Pemphigoid

Autoimmune bullous dermatoses (AIBDs) are a group of rare chronic inflammatory skin diseases, which clinically manifest as blisters and erosions of the skin and/or mucosa. Immunologically, AIBDs are characterized and caused by autoantibodies targeting adhesion molecules in the skin and mucosa. According to the histological location of the blistering, AIBDs are classified into the following two main subtypes: pemphigus (intraepidermal blistering) and pemphigoid (subepidermal blistering). Most AIBDs were potentially life-threatening diseases before the advent of immunosuppressive drugs, especially systemic steroid therapies, which suppress pathogenic immunological activity. Although there have been recent advancements in the understanding of the pathogenesis of AIBDs, glucocorticosteroids and/or adjuvant immunosuppressive drugs are still needed to control disease activity. However, the long-term use of systemic immunosuppression is associated with major adverse events, including death. Based on the growing understanding of AIBD pathogenesis, novel treatment targets have emerged, some of which are currently being evaluated in clinical trials. Within this article, we review the current clinical trials involving pemphigus and pemphigoid and discuss the rationale that lead to these trials. Overall, we aim to foster insights into translational research in AIBDs to improve patient care.

[Epidermolysis bullosa acquisita]

Epidermolysis bullosa acquisita (EBA) is a rare acquired subepidermal bullous autoimmune dermatosis, associated with autoantibodies against collagen type VII, the most important component of dermal anchoring fibrils. Blister induction occurs after binding of autoantibodies to collagen type VII, leading to complement activation, recruitment of neutrophils and secretion of proteases. Clinically, the disease is mostly characterized by tense blisters on trauma-exposed body areas which heal with scarring (mechanobullous form of EBA). The second most frequent subtype of EBA is inflammatory EBA, a bullous pemphigoid-like disease associated with pruritus. Involvement of mucous membranes and/or lesions in the head and neck area additionally point to the diagnosis of EBA. The mechanobullous type of EBA and EBA with intensive mucous membrane lesions display a chronic course and are often extremely resistant to therapy. Topical and systemic glucocorticoids, dapsone, colchicine, classical immunosuppressants, anti-CD20 antibodies, immunoadsorption or intravenous immunoglobulins have been reported as treatments.

Drug Discovery for Pemphigoid Diseases

Pemphigoid diseases (PDs) are a group of autoimmune bullous diseases characterized and caused by autoantibodies targeting structural proteins of the skin and mucous membranes. Chronic inflammation, subepidermal blistering, and often scaring are the clinical characteristics of PDs. Itching and, in severe cases, disabilities resulting from scaring (i.e., blindness, esophageal strictures) are the leading subjective symptoms. Treatment of PDs, which is based on nonspecific immunosuppression, is challenging because of frequent relapses, lack of efficacy, and numerous adverse events. In addition, the incidence of PDs is increasing. Given the high morbidity, limited therapeutic options, and increasing incidence, there is a growing urgency for drug discovery to help treat this condition. The recent development of PD model systems has added to the understanding of PD pathogenesis and, based on these insights, new clinical trials will soon be launched. The (auto-)antibody transfer PD models allow for investigations into autoantibody-mediated tissue pathology, while immunization-induced PD models more closely resemble the clinical situation. The latter duplicate all aspects of the human disease and are useful for investigating PD pathogenesis and testing therapeutic interventions. This article describes antibody transfer and immunization-induced PD mouse models currently employed for translational PD research. © 2019 by John Wiley & Sons, Inc.

Epidermolysis Bullosa Acquisita: The 2019 Update

Epidermolysis bullosa acquisita (EBA) is an orphan autoimmune disease. Patients with EBA suffer from chronic inflammation as well as blistering and scarring of the skin and mucous membranes. Current treatment options rely on non-specific immunosuppression, which in many cases, does not lead to a remission of treatment. Hence, novel treatment options are urgently needed for the care of EBA patients. During the past decade, decisive clinical observations, and frequent use of pre-clinical model systems have tremendously increased our understanding of EBA pathogenesis. Herein, we review all of the aspects of EBA, starting with a detailed description of epidemiology, clinical presentation, diagnosis, and current treatment options. Of note, pattern analysis via direct immunofluorescence microscopy of a perilesional skin lesion and novel serological test systems have significantly facilitated diagnosis of the disease. Next, a state-of the art review of the current understanding of EBA pathogenesis, emerging treatments and future perspectives is provided. Based on pre-clinical model systems, cytokines and kinases are among the most promising therapeutic targets, whereas high doses of IgG (IVIG) and the anti-CD20 antibody rituximab are among the most promising "established" EBA therapeutics. We also aim to raise awareness of EBA, as well as initiate basic and clinical research in this field, to further improve the already improved but still unsatisfactory conditions for those diagnosed with this condition.