The role of lymphocytes, granulocytes, mast cells and their related cytokines in lesional skin of linear IgA bullous dermatosis

S2k guidelines on diagnosis and treatment of linear IgA dermatosis initiated by the European Academy of Dermatology and Venereology

INTRODUCTION

Linear IgA dermatosis (LAD) is a rare subepidermal autoimmune bullous disease (AIBD) defined by predominant or exclusive immune deposits of immunoglobulin A at the basement membrane zone of skin or mucous membranes. This disorder is a rare, clinically and immunologically heterogeneous disease occurring both in children and in adults. The aim of this project is to present the main clinical features of LAD, to propose a diagnostic algorithm and provide management guidelines based primarily on experts' opinion because of the lack of large methodologically sound clinical studies.

METHODS

These guidelines were initiated by the European Academy of Dermatology and Venereology (EADV) Task Force Autoimmune Bullous Diseases (AIBD). To achieve a broad consensus for these S2k consensus-based guidelines, a total of 29 experts from different countries, both European and non-European, including dermatologists, paediatric dermatologists and paediatricians were invited. All members of the guidelines committee agreed to develop consensus-based (S2k) guidelines. Prior to a first virtual consensus meeting, each of the invited authors elaborated a section of the present guidelines focusing on a selected topic, based on the relevant literature. All drafts were circulated among members of the writing group, and recommendations were discussed and voted during two hybrid consensus meetings.

RESULTS

The guidelines summarizes evidence-based and expert opinion-based recommendations (S2 level) on the diagnosis and treatment of LAD.

CONCLUSION

These guidelines will support dermatologists to improve their knowledge on the diagnosis and management of LAD.

Anti-NC16A IgA from Patients with Linear IgA Bullous Dermatosis Induce Neutrophil-Dependent Subepidermal Blistering in Mice

Linear IgA bullous dermatosis (LABD) is an acquired autoimmune subepidermal blistering skin disease characterized by circulating and tissue-bound IgA autoantibodies that recognize epitopes within the hemidesmosomal protein BP180, including its NC16A domain. Histologically, LABD has long been defined by neutrophil infiltration and dermal-epidermal separation. However, the pathogenic roles of anti-NC16A IgA and neutrophils in LABD, as well as their interactions, have not been thoroughly studied. We show that passive transfer of patient-derived anti-NC16A IgA induce clinical and histologic LABD pathology in humanized NC16A mice that are reconstituted locally or systemically with human neutrophils. The lesional skin of mice exhibits significantly elevated levels of the neutrophil chemoattractants CXCL-1 and CXCL-2. Furthermore, we show significantly increased levels of the neutrophil chemoattractant IL-8 in blister fluids of patients with LABD. This study provides direct evidence that anti-NC16A IgA in patients with LABD are pathogenic and interact with neutrophils to mediate tissue injury and subepidermal blister formation. This study further corroborates the importance of neutrophil-mediated tissue injury in LABD disease physiology and establishes a clinically relevant in vivo model system that can be used to systematically dissect the immunopathogenesis of LABD.

Pruritogens in pemphigoid diseases: Possible therapeutic targets for a burdensome symptom

Pruritus is a hallmark feature in pemphigoid diseases, where it can be severe and greatly impact the quality of life of affected patients. Despite being a key symptom, the exact pathophysiological mechanisms involved in pruritus in pemphigoid are yet to be fully elucidated and effective therapies addressing them are limited. This review summarizes the present understanding of pruritus specific to pemphigoid diseases, especially the pruritogens that induce it, and the therapeutic options that have been explored so far. The majority of the available evidence is on bullous pemphigoid and epidermolysis bullosa acquisita. Histamine derived from basophils correlates with pruritus severity, with omalizumab demonstrating promising efficacy in pruritus for bullous pemphigoid. IL-4/-13 contribute to itch in bullous pemphigoid with dupilumab being evaluated in clinical trials. Other pruritogens of interest include substance P, tryptase, and thymic stromal lymphopoetin, with therapies targeting them requiring further investigation. Scratching behaviors contribute directly to blister formation through various mechanisms, such as pathological autoantibody recruitment, T helper cell type 1 polarization, and exposure of intracellular autoantigens. Treatments addressing these pathways may contribute to decreasing disease severity. Additional studies are needed to fully characterize how pruritus is regulated in pemphigoid diseases, to help pave the way to develop novel and effective therapeutics that will not only address pruritic symptoms but also decrease disease severity.

Autoimmune blistering diseases provoked during the treatment of chronic inflammatory disease with biologic agents: a systematic review

BACKGROUND

To investigate the clinical course of autoimmune blistering diseases (AIBDs) following treatment with biologic agents (BAs) for chronic inflammatory diseases.

METHODS

A comprehensive review of available, published literature was performed using PubMed and CINAHL search engines. Diagnostic criteria of AIBD included positive direct immunofluorescence studies and/or positive serology with clinically suggestive features.

RESULTS

A total of 22 cases of AIBDs provoked by the use of BAs were found. The most commonly implicated agents were tumor necrosis factor-alpha inhibitors (n = 14). The mean age of onset of AIBD was 59.4 years (median 61.5 years, range 31-82). Average time to onset of AIBD following initiation of the suspected BA was 33.7 ± 43.8 weeks (range 3 days to 152 weeks). Psoriasis was the most common associated condition for which the BA was prescribed (n = 11), followed by rheumatoid arthritis (n = 6) and ulcerative colitis (n = 5). Of the 21 cases reporting AIBD outcome, 17 reported remission or complete resolution upon stopping treatment with the involved BA. Four cases reported continued bullae formation without worsening of disease following cessation of the BA or systemic corticosteroids used to treat the AIBD. Five cases rechallenged the patient with the involved BA and four of the five reported recurrence, often with quicker onset and more severe symptoms.

CONCLUSIONS

BAs may be suspected in patients developing AIBD while being treated for chronic inflammatory diseases. A majority of cases resolve upon cessation of the offending agent.

Consensus on the treatment of autoimmune bullous dermatoses: dermatitis herpetiformis and linear IgA bullous dermatosis - Brazilian Society of Dermatology

Dermatitis herpetiformis and linear IgA bullous dermatosis are autoimmune diseases that present with pruritic urticarial papules and plaques, with formation of vesicles and blisters of subepidermal location, mediated by IgA antibodies. Mucosal lesions are present only in linear IgA bullous dermatosis. The elaboration of this consensus consisted of a brief presentation of the different aspects of these dermatoses and, above all, of an updated literature review on the various therapeutic options that were discussed and compared with the authors' experience, aiming at the treatment orientation of these diseases in Brazil. Dermatitis herpetiformis is a cutaneous manifestation of celiac disease, and can be controlled with a gluten-free diet and dapsone. On the other hand, linear IgA bullous dermatosis arises spontaneously or is triggered by drugs, and can be controlled with dapsone, but often requires the association of systemic corticosteroids and eventually immunosuppressants.

The Role of Mast Cells in Autoimmune Bullous Dermatoses

Skin mast cells (MCs), a resident immune cell type with broad regulatory capacity, play an important role in sensing danger signals as well as in the control of the local immune response. It is conceivable to expect that skin MCs regulate autoimmune response and are thus involved in autoimmune diseases in the skin, e.g., autoimmune bullous dermatoses (AIBD). Therefore, exploring the role of MCs in AIBD will improve our understanding of the disease pathogenesis and the search for novel therapeutic targets. Previously, in clinical studies with AIBD, particularly bullous pemphigoid, patients' samples have demonstrated that MCs are likely involved in the development of the diseases. However, using MC-deficient mice, studies with mouse models of AIBD have obtained inconclusive or even discrepant results. Therefore, it is necessary to clarify the observed discrepancies and to elucidate the role of MCs in AIBD. Here, in this review, we aim to clarify discrepant findings and finally elucidate the role of MCs in AIBD by summarizing and discussing the findings in both clinical and experimental studies.

Linear immunoglobulin A dermatosis mimicking toxic epidermal necrolysis: a case report of etanercept treatment

A 65-year-old pluripathological woman attended our hospital with a cutaneous eruption of sudden appearance after vancomycin treatment. She presented targetoid lesions affecting approximately 25-30% of her body surface, large erosions with mucosal lesions and positive Nikolsky sign. Under the initial clinical suspicion of toxic epidermal necrolysis (TEN), and considering the recent literature of successful use of etanercept in these cases, she was treated with a single dose of this antitumour necrosis factor (anti-TNF) agent. Subsequently, the exanthema progression stopped and resolution of the lesions happened in a few days. Later on, histopathology revealed a subepidermal blister with dense neutrophilic infiltrate and linear deposits of immunoglobulin A (IgA) on the dermoepidermal junction, allowing us to establish the diagnosis of drug-induced linear IgA dermatosis mimicking TEN. Linear IgA dermatosis can have severe clinical manifestations, even mimicking TEN, and can have high mortality, especially in drug-induced cases. We have not found any other report of linear IgA dermatosis treated with etanercept in the English literature. Anti-TNF medications could represent useful therapeutic alternatives in this dermatosis.

Linear immunoglobulin A dermatosis: A case report

We present the case of a sixty five year old woman with two months history of pruritus and hyperpigmented annular lesions on the trunk, buttocks and upper extremities. In addition, she presents vesicles with healthy skin on the basis, in the flexor aspect of wrists. No evidence of mucosal involvement. Histological study showed subepidermal vesicular dermatitis with inflammatory infiltrate of neutrophils and eosinophils. Direct immunofluorescence evidenced linear and continuous deposition of immunoglobulin A in basement membrane zone, compatible with linear immunoglobulin A disease.

Blistering disease: insight from the hemidesmosome and other components of the dermal-epidermal junction

The hemidesmosome is a specialized transmembrane complex that mediates the binding of epithelial cells to the underlying basement membrane. In the skin, this multiprotein structure can be regarded as the chief adhesion unit at the site of the dermal-epidermal junction. Focal adhesions are additional specialized attachment structures located between hemidesmosomes. The integrity of the skin relies on well-assembled and functional hemidesmosomes and focal adhesions (also known as integrin adhesomes). However, if these adhesion structures are impaired, e.g., as a result of circulating autoantibodies or inherited genetic mutations, the mechanical strength of the skin is compromised, leading to blistering and/or tissue inflammation. A particular clinical presentation emerges subject to the molecule that is targeted. None of these junctional complexes are simply compounds of adhesion molecules; they also play a significant role in signalling pathways involved in the differentiation and migration of epithelial cells such as during wound healing and in tumour invasion. We summarize current knowledge about hereditary and acquired blistering diseases emerging from pathologies of the hemidesmosome and its neighbouring proteins as components of the dermal-epidermal junction.

Linear immunoglobulin A bullous dermatosis

Linear immunoglobulin A (IgA) bullous dermatosis, also known as linear IgA disease, is an autoimmune mucocutaneous disorder characterized by subepithelial bullae, with IgA autoantibodies directed against several different antigens in the basement membrane zone. Its immunopathologic characteristic resides in the presence of a continuous linear IgA deposit along the basement membrane zone, which is clearly visible on direct immunofluorescence. This disorder shows different clinical features and distribution when adult-onset of linear IgA disease is compared with childhood-onset. Diagnosis is achieved via clinical, histopathologic, and immunopathologic examinations. Two common therapies are dapsone and sulfapyridine, which reduce the inflammatory response and achieve disease remission in a variable period of time.

The lesional skin of linear IgA bullous dermatosis expresses growth-regulated peptide (GRO)-alpha

The patient was a 62-year-old man with erythema with tense vesiculobullae and erosions on the bilateral elbows, right knee, and one buttock. A skin biopsy specimen revealed subepidermal blister formation with a predominant infiltration of neutrophils and papillary neutrophilic microabscesses. Direct immunofluorescence study showed linear deposition of IgA and weak deposition of IgG at the basement membrane zone of the lesional skin, and indirect immunofluorescence study showed linear deposition of IgA at the epidermal side of the 1M NaCl-separated normal skin. He was diagnosed with linear IgA bullous dermatosis. Immunohistochemical study revealed that the lesional and perilesional keratinocytes expressed growth-regulated peptide (GRO) -alpha, a potent chemoattractant for neutrophils. This suggests that GRO-alpha plays a role in the infiltration of neutrophils into the lesional skin and in bulla formation in linear IgA bullous dermatosis.

Association of cord blood cytokines with prematurity and cerebral palsy

BACKGROUND

Many studies have shown that certain cytokines in amniotic fluids are correlated to premature labor and neonatal brain insults.

AIMS

We investigated whether different fetal phagocyte and vascular mediators including IL-8, myeloperoxidase (MPO), PGE(2) and soluble vascular cell adhesion molecule-1 (sVCAM-1) levels were correlated to prematurity and cerebral palsy (CP) of premature infants.

SUBJECTS

Umbilical cord blood samples from 96 preterm babies from 2250 cord blood collections were studied.

METHOD

The enzyme-linked immunoassay (ELISA) technique was used to determine concentrations of cord blood IL-8, MPO, PGE(2) and sVCAM-1.

RESULTS

Preterm babies with gestational age (GA) < or =32 weeks had significant higher cord blood IL-8, MPO and PGE(2) levels than full-term babies. These mediators, however, were not correlated to gestational age, suggesting that increases of these mediators are more related to preterm delivery but not fetal maturation. Further analysis showed that IL-8, a mediator mainly from monocytes, but not MPO, another mediator mostly from granulocytes, was correlated to cerebral palsy.

CONCLUSIONS

Taken together, these results suggest that both premature monocytes and granulocytes activation are involved in preterm delivery, but maybe only monocytes activation is correlated to premature infants' cerebral palsy. Selective manipulation of monocytes activation may be useful to prevent premature-related cerebral palsy.

Two cases of linear IgA disease with clinical manifestations limited to the gingiva

Linear IgA disease (LAD) is a chronic, subepithelial blistering disease that is associated with the presence of linear deposits of IgA along the basement membrane zone. Etiopathogenic aspects of LAD are only partially known. LAD is clinically characterized by vesiculobullous skin and mucous lesions. Although more than half of LAD patients present oral mucosal lesions, there are only a few cases reported of oral lesions as the only manifestation of LAD. This study presents 2 of these uncommon cases.