Epidermolysis Bullosa Acquisita: The 2019 Update

Evidence for a role of extracellular heat shock protein 70 in epidermolysis bullosa acquisita

Heat shock protein 90 (Hsp90) and Hsp70 are chaperones implicated in different inflammatory disorders, given their property to impact innate and adaptive immune responses. Here, we determined the so far unknown role of extracellular Hsp70 in epidermolysis bullosa acquisita (EBA), an anti-type VII collagen autoantibody-mediated blistering dermatosis. The in vivo pathophysiological relevance of extracellular Hsp70 was demonstrated in an anti-type VII collagen antibody transfer-induced EBA mouse model in which elevated blood levels of this chaperone were recorded. We found that Hsp70-treated mice had a more intense clinical disease severity compared to controls that were paralleled by increased levels of cutaneous matrix metalloproteinase 9 and plasma hydrogen peroxide. The latter finding was confirmed in an independent reactive oxygen species release assay using EBA-specific immune complexes combined with recombinant Hsp70. Finally, cell culture experiments using human naive peripheral blood mononuclear cells (PBMC) revealed that extracellular Hsp70 stimulated the secretion of the T cell-derived pro-inflammatory cytokines IL-6 and IL-8. This work extends knowledge about the role of Hsps in autoimmune bullous diseases, suggesting that extracellular Hsp70 represents a pathophysiological factor and potential treatment target in EBA.

Preventive but Not Therapeutic Topical Application of Local Anesthetics Can Inhibit Experimental Epidermolysis Bullosa Acquisita in Mice

Epidermolysis bullosa acquisita (EBA) is an autoimmune blistering disorder characterized and caused by autoantibodies against type VII collagen (COL7). Although it has been noticed that EBA in both patients and mice is associated with an increased scratching, it is not clear whether and how the scratching contributes to disease manifestation. Hence, we here aimed to validate this clinical observation and also to investigate the potential contribution of increased scratching in EBA pathogenesis in mice. Longitudinal assessment of scratching behavior revealed an increased frequency of scratching as early as 12 hours after injection of anti-COL7 IgG into the skin of mice. Subsequently, scratching events became even more frequent in mice. In contrast, mice injected with a control antibody showed an unaltered scratching behavior throughout the observation period. Based on these observations, we hypothesized that mechanical irritation may promote the induction of inflammation in experimental EBA. To challenge this assumption, the local anesthetic dyclonine hydrochloride was topically applied before injection of anti-COL7 IgG. Dyclonine hydrochloride reduced the scratching events and impaired clinical disease manifestation. In therapeutic experimental settings, i.e. administration of the local anesthetic 24 hours after injection of anti-COL7 IgG, dyclonine hydrochloride only inhibited the scratching behavior, but had no significant effect on clinical disease development. In addition, eosinophils were detected in the skin before the injection of anti-COL7 IgG and significantly increased 48 hours after the antibody injection. Collectively, our results suggest that scratching behavior contributes to the initiation phase of disease manifestation in experimental EBA.

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.

Management of Cutaneous Manifestations of Genetic Epidermolysis Bullosa: A Multiple Case Series

BACKGROUND

Epidermolysis bullosa (EB) is a rare disease characterized by blistering and erosion of the skin and mucus membranes in response to minor external forces. Research focusing on daily skin care in EB patients is sparse. Two international clinical practice guidelines (CPGs) have been published in English, but they have not yet been translated into other languages such as Japanese. Therefore, their recommendations have not been adapted to multiple geographic regions in the world. This multiple case series describes our approach to the skin care of 3 Japanese patients with EB.

RESULTS

All 3 patients were diagnosed with genetic EB. A 13-year-old male patient had dominant dystrophic EB and suffered skin breakdown covering nearly 1% to 6% of his total body surface area (TBSA) during a 21-week data collection period. A 3-year-old male patient had EB simplex; he suffered skin breakdown covering 2% to 40% of his TBSA during a 36-week data collection period. The third case was a 5-year-old male patient with recessive dystrophic EB who experienced skin breakdown covering 2% to 40% of his TBSA during a 35-week data collection period. Blisters were punctured daily and treated with a soft silicone dressing. Daily application of moisturizers was undertaken to prevent the skin from drying out and itching.

CONCLUSION

Our experience suggests that application of published CPGs promoted wound healing. Nevertheless, given the nature of the disease, a complete resolution to an individual's vulnerability to skin lesions even with relatively minor trauma remains elusive. Additional research is needed to explore interventions for skin and ulcer care, along with symptom management, including pain and pruritus.

Serration pattern analysis as a practical adjunct tool for categorization of subepidermal autoimmune blistering diseases

BACKGROUND

Serration pattern analysis helps in the classification of subepidermal autoimmune blistering disorders; more precisely, it helps to differentiate epidermolysis bullosa acquisita from other subepidermal autoimmune blistering disorders. Most of the published reports of this tool have come from a single center.

OBJECTIVES

The objectives of the study were to study the utility of serration pattern analysis in classifying subepidermal autoimmune blistering disorders.

METHODS

Seventy five cases of subepidermal autoimmune blistering disorders were enrolled in this prospective study. A three millimeter punch biopsy was taken from the perilesional skin or mucosa for direct immunofluorescence; indirect immunofluorescence was carried out using salt-split skin. Subclassification of subepidermal autoimmune blistering disorders was done based on direct immunofluorescence, indirect immunofluorescence on salt-split skin, indirect immunofluorescence using knockout skin and serration pattern analysis findings.

RESULTS

Indirect immunofluorescence was positive in 68 cases; 14 cases showed a dermal staining pattern while the rest showed either an epidermal or a combined pattern. All patients with epidermal or combined staining patterns showed "n" serrated pattern on direct immunofluorescence. Nine patients with dermal staining on indirect immunofluorescence also revealed an "n" serration pattern on direct immunofluorescence indicating the diagnosis of anti-p200 pemphigoid, and the rest showed a "u" serrated pattern. Three patients with negative indirect immunofluorescence showed "u" serration on direct immunofluorescence while the rest showed "n" serration.

LIMITATIONS

ELISA and immunoblotting could not be performed due to resource constraints.

CONCLUSION

Based on indirect immunofluorescence and serration pattern analysis, classification of the majority of patients with subepidermal autoimmune blistering disorders was possible in our study. Pattern recognition is a cost-effective tool and can be easily learnt. It is recommended to be practiced in all laboratories where facilities for advanced immunological diagnosis are unavailable.

Epidermolysis Bullosa Registry Data in Iran

BACKGROUND

In many countries, there is no registry system to record data for Epidermolysis Bullosa patients. However, the first steps for establishing a registry system have been taken in Iran. Therefore, we decided to publish it for the first time.

METHODS

This was a prospective cross-sectional study. Data was obtained from 538 patients consecutively enrolled in the Iranian Epidermolysis Bullosa Registry, using a detailed instrument created by burn research center of Iran University of Medical Sciences, Tehran, Iran from Jan 2017 to Sep 2017. Patients' information such as age, gender, address, educational status, parents' family relationship and pathology result were recorded. Then a physician examined patients focusing on gastrointestinal system, teeth, ophthalmologic disorders, psychological problems and contracture of the upper and lower limbs and any other complaint. Data entered SPSS ver.19 and analyzed using ANOVA and LSD tests.

RESULTS

Overall, 538 EB patients were registered in Iran (6.72 patient in 100.000 person) with an approximately equal ratio between males and females. Among 103 patients whose disease type was determined by a pathologist, 78 patients (75.7%) had dystrophic type, 13 (12.6%) junctional, 9 (8.7%) simplex and 3 (2.9%) kindler type. The most common complaint of patients was dysphagia followed by tooth damage.

CONCLUSION

We stablished a data registry for EB patients for the first time in Iran. The frequency of EB in Iran is less than many other countries. However, data completion is to be done to include all patients as possible.

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.

Pathogenetic Therapy of Epidermolysis Bullosa: Current State and Prospects

Epidermolysis bullosa is a severe hereditary disease caused by mutations in genes encoding cutaneous basement membrane proteins. These mutations lead to dermal-epidermal junction failure and, as a result, to disturbances in the morphological integrity of the skin. Clinically, it manifests in the formation of blisters on the skin or mucosa that in some cases can turn into non-healing chronic wounds, which not only impairs patient's quality of life, but also is a live-threatening condition. Now, the main approaches in the treatment of epidermolysis bullosa are symptomatic therapy and palliative care, though they are little effective and are aimed at reducing the pain, but not to complete recovery. In light of this, the development of new treatment approaches aimed at correction of genetic defects is in progress. Various methods based on genetic engineering technologies, transplantation of autologous skin cells, progenitor skin cells, as well as hematopoietic and mesenchymal stem cells are studied. This review analyzes the pathogenetic methods developed for epidermolysis bullosa treatment based on the latest achievements of molecular genetics and cellular technologies, and discusses the prospects for the use of these technologies for the therapy of epidermolysis bullosa.

Prevalence and presumptive triggers of localized bullous pemphigoid

Bullous pemphigoid (BP) is an autoimmune skin disease, caused by autoantibodies to BP180 and/or BP230. While both these autoantigens are expressed in the entire skin, only some parts of the body become affected. Rare clinical observations indicate that BP may also manifest locally, usually following exposure to triggers. Here, we evaluated the occurrence and potential triggers of localized BP (LBP) in a cohort of 285 BP patients. Medical records of all BP patients hospitalized between 2009 and 2019 were reviewed. In 7/285 BP patients, a localized variant was identified. In 5/7 LBP patients, the disease remained local, while in 2/7 patients, an initial LBP subsequently spread. All cases were preceded by presumptive triggers, including previously described triggers and bacterial infections. Overall, LBP is rare. LBP, however, might be underdiagnosed and should thus be considered in the differential diagnosis, particularly when trigger factors preceded.

Epidermolysis bullosa acquisita: an uncommon cause of esophageal stricture

Epidermolysis bullosa acquisita (EBA) encompasses a wide spectrum of rare diseases with a common genetic origin transmitted in an autosomal recessive fashion. Mild forms of non-inflammatory EBA are characterized by skin lesions and have gained great relevance in the literature. However, resistant inflammatory EBA with widespread mucosal involvement remains a rare entity given its low prevalence. It commonly represents a great burden for the patient's quality of life with most cases being resistant to different therapeutic modalities. We present a case of resistant inflammatory EBA with esophageal strictures that improved after therapy with intravenous immunoglobulin and rituximab.

Current approaches to the diagnosis of autoimmune bullous dermatoses

A modern review of highly effective methods for the diagnosis of autoimmune bullous dermatoses are presented. The specificity of the production of autoantibodies underlying bullous dermatoses are described. Considering the severity of the disease and a significant deterioration in the quality of life of patients suffering from bullous dermatoses; the systematization of diagnostic criteria will help improve the prognosis and management of patients; and it will also help optimize work on the development of targeted drugs for the treatment of patients with this pathology.

Propranolol Off-Target: A New Therapeutic Option in Neutrophil-Dependent Dermatoses?

Epidermolysis bullosa acquisita (EBA) is a rare subepidermal blistering dermatosis characterized by autoantibodies targeting collagen VII (COL7), an essential component of the anchoring fibrils, located in the sublamina densa of the dermal‒epidermal junction. In EBA, tissue-bound autoantibodies cause the recruitment and subsequent activation of neutrophils, which eventually lead to subepidermal blistering through the release of proteases and ROS. Thus, targeting either pathogenic IgG autoantibodies or neutrophil recruitment or activation has shown efficacy in experimental murine EBA models and patients with EBA. In this issue, Stüssel et al. demonstrate that propranolol, a nonselective β-adrenoreceptor blocker, markedly inhibits the neutrophil release of ROS induced by complexes of COL7 and/or anti-COL7 IgG in vitro and ameliorates the formation of blisters and erosions in an antibody passive-transfer model of murine EBA. These findings warrant further investigations aimed at characterizing the therapeutic efficacy of propranolol in EBA and possibly beyond.

Therapy of autoimmune mouth bullous disease: 2020 review

Most diseases of oral mucosa are either autoimmune in nature or are the results of immunologically mediated events. The diseases with autoimmune pathogenesis are namely pemphigus and pemphigoid; the oral involvement is frequent or regularly observed in these diseases. The treatments with traditional drugs or biologic agents or combinations of these molecules are employed in clinical practice. New therapeutic targets aim to provide new treatment strategies that may go beyond nonspecific immunosuppression.

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.

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.

Epidermal Damage Induces Th1 Polarization and Defines the Site of Inflammation in Murine Epidermolysis Bullosa Acquisita

Epidermolysis bullosa acquisita is an autoimmune skin disease characterized by subepidermal blisters. The pathogenesis is mediated by deposits of autoantibodies directed against type VII collagen in the skin, but the sequence of events regulating the localization of skin blisters is not fully understood. In this study, using the immunization-induced mouse model of epidermolysis bullosa acquisita, we demonstrate that epidermal disruption induces not only an infiltration of CD4⁺ T cells but also a T helper type 1 phenotype as it has been described for delayed-type hypersensitivity reactions. This T helper type 1 reaction was not found when different antigens were applied. Deep T-cell receptor β profiling revealed shifts in the V/J gene usage only in epidermolysis bullosa acquisita, suggesting an infiltration of autoantigen-specific T cells. To target these autoantigen-specific T cells, we established an approach with which skin inflammation could be prevented without impairing the functionality of autoantibodies. We conclude that T-cell involvement in skin blistering diseases such as epidermolysis bullosa acquisita relates not only to T-cell help for B cells that produce pathogenic autoantibodies but also to autoreactive T helper type 1 effector cells that migrate into injured skin sites, exacerbate inflammation through production of inflammatory cytokines such as IFNγ, and prevent wound healing.

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.

Serological Diagnosis of Autoimmune Bullous Skin Diseases

Autoimmune bullous dermatoses (AIBD) encompass a variety of organ-specific autoimmune diseases that manifest with cutaneous and/or mucosal blisters and erosions. They are characterized by autoantibodies targeting structural proteins of the skin, which are responsible for the intercellular contact between epidermal keratinocytes and for adhesion of the basal keratinocytes to the dermis. The autoantibodies disrupt the adhesive functions, leading to splitting and blister formation. In pemphigus diseases, blisters form intraepidermally, whereas in all other disease types they occur subepidermally. Early identification of autoimmune bullous dermatoses is crucial for both treatment and prognosis, particularly as regards tumor-associated disease entities. The diagnosis is based on clinical symptoms, histopathology, direct immunofluorescence to detect antibody/complement deposits, and the determination of circulating autoantibodies. The identification of various target antigens has paved the way for the recent development of numerous specific autoantibody tests. In particular, optimized designer antigens and multiplex test formats for indirect immunofluorescence and ELISA have enhanced and refined the laboratory analysis, enabling highly efficient serodiagnosis and follow-up. This review elaborates on the current standards in the serological diagnostics for autoimmune bullous dermatoses.

Proteases in Pemphigoid Diseases

Pemphigoid diseases are a subgroup of autoimmune skin diseases characterized by widespread tense blisters. Standard of care typically involves immunosuppressive treatments, which may be insufficient and are often associated with significant adverse events. As such, a deeper understanding of the pathomechanism(s) of pemphigoid diseases is necessary in order to identify improved therapeutic approaches. A major initiator of pemphigoid diseases is the accumulation of autoantibodies against proteins at the dermal-epidermal junction (DEJ), followed by protease activation at the lesion. The contribution of proteases to pemphigoid disease pathogenesis has been investigated using a combination of in vitro and in vivo models. These studies suggest proteolytic degradation of anchoring proteins proximal to the DEJ is crucial for dermal-epidermal separation and blister formation. In addition, proteases can also augment inflammation, expose autoantigenic cryptic epitopes, and/or provoke autoantigen spreading, which are all important in pemphigoid disease pathology. The present review summarizes and critically evaluates the current understanding with respect to the role of proteases in pemphigoid diseases.

Linear IgA bullous dermatosis in adults and children: a clinical and immunopathological study of 38 patients

BACKGROUND

Linear IgA bullous dermatosis (LABD) is a rare autoimmune subepithelial vesiculobullous disease due to IgA autoantibodies directed against different antigens of the basement membrane zone (BMZ) of the skin and/or mucosae. It affects mainly preschool-aged children and adults, with only few studies on large series. The aim of this study was to assess possible differences between adults and children regarding clinical presentation, immunopathologic features, management and course of the disease.

METHODS

A retrospective review of 38 LABD patients, followed-up from November 2006 to September 2018, was performed.

RESULTS

Of 38 patients, 27 were adults and 11 children. Mean age at diagnosis was 5.4 years and 60.6 years in the pediatric and adult group, respectively. Considering both groups, limbs were the most commonly involved site (73.7%), followed by trunk (55.3%), head (36.8%) and buttocks (13.2%). Interestingly, head (p = 0.008), particularly perioral (p = 0.001), involvement, as well as "string of pearls" arrangement (p = 0.03), were more prevalent in children. Mucosal involvement was seen in 9 (23.7%) patients and was more frequent in children than adults (45.5% vs 14.8%, respectively, p = 0.09). Linear IgA deposits along the BMZ were observed in 30 patients (78.9%), while linear/granular IgA deposits in 8 patients (21.1%). Dapsone was the most commonly used drug (78.9%) and complete remission was achieved in most cases (81.6%).

CONCLUSIONS

Our epidemiological and clinicopathological findings relative to a large cohort of LABD patients are mostly consistent with the literature data. Interestingly, head, notably perioral, involvement and "string of pearls" arrangement occurred more frequently in the paediatric than adult group. The above clinical parameters may be regarded as diagnostic tools for LABD in children.

Ocular involvement in epidermolysis bullosa acquisita with long-term follow-up

Background/aims

To describe the ocular manifestations associated with epidermolysis bullosa acquisita (EBA).

Methods

This retrospective study was conducted at a tertiary bullous disease clinic. Consecutive patients were enrolled with biopsy proven diagnosis of EBA, with ocular involvement and a follow-up of at least 36 months. A multidisciplinary team of dermatologists, ENT specialists and ophthalmologists evaluated all patients. Immunological workup included direct (including immune-electron microscopy) and indirect immunofluorescence. Ophthalmological examination included best-corrected visual acuity (BCVA) and slit-lamp examination with grading of conjunctival fibrosis using the Tauber classification.

Results

Nine patients (five females, four males) were included. The mean age at diagnosis was 32 years (range 1–52 years). Follow-up ranged from 3 to 18 years (mean 10.7 years). Conjunctival fibrosis was present in all affected eyes and was stage III or greater in 60% of patients. Eight patients (14 eyes) had corneal involvement most frequently associated with trichiasis-associated mechanical irritation or extensive cicatrising conjunctivitis. Corneal lesions developed on three eyes of three patients without eyelid disease or severe fibrosis or any identifiable triggering factor. Eyelids were affected in six patients, with trichiasis being the most common feature (affecting three patients, four eyes). Corneal-related blindness occurred in at least one eye in 44% of the patients.

Conclusion

EBA may be associated with devastating ocular manifestations. Most patients develop severe cicatrising conjunctivitis. A subset of patients may present with isolated corneal lesions. Further studies are warranted to assess the effects of systemic treatments on the evolution of ocular manifestations.

Skin Barrier and Autoimmunity-Mechanisms and Novel Therapeutic Approaches for Autoimmune Blistering Diseases of the Skin

One of the most important functions of the skin besides regulating internal body temperature includes formation of the barrier between the organism and the external environment, hence protecting against pathogen invasion, chemical and physical assaults and unregulated loss of water and solutes. Disruption of the protective barrier is observed clinically in blisters and erosions of the skin that form in autoimmune blistering diseases where the body produces autoantibodies against structural proteins of the epidermis or the epidermal-dermal junction. Although there is no cure for autoimmune skin blistering diseases, immune suppressive therapies currently available offer opportunities for disease management. In cases where no treatment is sought, these disorders can lead to life threatening complications and current research efforts have focused on developing therapies that target autoantibodies which contribute to disease symptoms. This review will outline the involvement of the skin barrier in main skin-specific autoimmune blistering diseases by describing the mechanisms underpinning skin autoimmunity and review current progress in development of novel therapeutic approaches targeting the underlying causes of autoimmune skin blistering diseases.

[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.