A clinical and serological study of linear IgA bullous dermatosis without linear immunoglobulin deposition other than IgA at the basement membrane zone using direct immunofluorescence

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.

Drug-Induced Linear IgA Bullous Dermatosis in an Oncologic Patient

Blister formation in the skin can result from various conditions, such as autoimmune disorders, drug reactions, infections, etc. A comprehensive patient assessment may offer clues for diagnosis. Linear IgA bullous dermatosis (LABD) is a rare subepidermal blistering disorder characterized by the deposition of IgA at the basement membrane zone of the skin and mucous membranes. Here, we describe a case of a patient with a new onset of painless blisters located in the skin and oral mucosa after initiating antibiotic treatment.

Case Report: Prurigo nodularis-like linear IgA/IgG bullous dermatosis: a case report and literature review

Linear IgA/IgG bullous dermatosis (LAGBD) is a rare autoimmune subepidermal bullous disorder characterized by linear deposition of concurrent IgA and IgG autoantibodies along the basement membrane zone (BMZ). The clinical features of LAGBD can be diverse, including tense blisters, erosions, erythema, crusting and mucosa involvement, while papules or nodules are generally absent. In this study, we present a unique case of LAGBD, which showed prurigo nodularis-like clinical appearance on physical examination, linear deposition of IgG and C3 along the basement membrane zone (BMZ) in direct immunofluorescence (DIF), IgA autoantibodies against the 97-kDa and 120-kDa of BP180 and IgG autoantibodies against the 97-kDa of BP180 by immunoblotting (IB), while BP180 NC16a domain, BP230, and laminin 332 were negative by enzyme-linked immunosorbent assay (ELISA). After administration of minocycline, the skin lesions improved. We performed a literature review of LAGBD cases with heterogeneous autoantibodies and found clinical presentations of most cases resemble bullous pemphigoid (BP) and linear IgA bullous disease (LABD), which is consistent with previous reported findings. We aim to increase our understanding of this disorder and to enhance the importance of applying immunoblot analyses and other serological detection tools in clinic for precise diagnosis as well as accurate treatment strategy of various autoimmune bullous dermatoses.

Eosinophil-rich linear IgA bullous dermatosis induced by mRNA COVID-19 booster vaccine

We present a case of eosinophil-rich linear IgA bullous disease (LABD) following the administration of a messenger RNA COVID-19 booster vaccine. A 66-year-old man presented to the emergency department with a 3-week history of a pruritic blistering rash characterized by fluid-filled bullae and multiple annular and polycyclic plaques. He was initially diagnosed with bullous pemphigoid based on a biopsy showing a subepidermal blister with numerous eosinophils. However, direct immunofluorescence studies showed linear IgA and IgM deposition along the basement membrane zone with no immunoreactivity for C3 or IgG. Additionally, indirect immunofluorescence was positive for IgA basement membrane zone antibody. The patient was subsequently diagnosed with LABD and initiated on dapsone therapy with resolution of his lesions at 3-month follow-up. This case illustrates the growing number of autoimmune blistering adverse cutaneous reactions from vaccination. Dermatopathologists should be aware that features of autoimmune blistering diseases can overlap and may not be distinguishable based on these histopathological findings alone. Confirmation with direct immunofluorescence and/or serological studies may be necessary for accurate diagnosis.

Type XVII collagen: Relevance of distinct epitopes, complement-independent effects, and association with neurological disorders in pemphigoid disorders

Pemphigoid diseases (PD) are autoimmune skin blistering diseases characterized by autoantibodies directed against proteins of the cutaneous basement membrane zone (BMZ). One of the major antigens is type XVII collagen (BP180), a transmembrane glycoprotein, which is targeted in four PDs: bullous pemphigoid, mucous membrane pemphigoid, linear IgA dermatosis, and pemphigoid gestationis. To date, different epitopes on BP180 have been described to be recognized by PD disease patients’ autoantibodies. Different BP180 epitopes were associated with distinct clinical phenotypes while the underlying mechanisms are not yet fully understood. So far, the main effects of anti-BP180 reactivity are mediated by Fcγ-receptors on immune cells. More precisely, the autoantibody–antigen interaction leads to activation of complement at the BMZ and infiltration of immune cells into the upper dermis and, by the release of specific enzymes and reactive oxygen species, to the degradation of BP180 and other BMZ components, finally manifesting as blisters and erosions. On the other hand, inflammatory responses independent of Fcγ-receptors have also been reported, including the release of proinflammatory cytokines and internalization and depletion of BP180. Autoantibodies against BP180 can also be found in patients with neurological diseases. The assumption that the clinical expression of PD depends on epitope specificity in addition to target antigens, autoantibody isotypes, and antibody glycosylation is supported by the observation that epitopes of PD patients differ from those of PD patients. The aim of the present review is to describe the fine specificities of anti-BP180 autoantibodies in different PDs and highlight the associated clinical differences. Furthermore, the direct effects after binding of the autoantibodies to their target are summarized.

Updates in the Diagnosis and Management of Linear IgA Disease: A Systematic Review

Background and Objectives: Linear IgA disease (LAD) is a rare autoimmune blistering disease with linear IgA deposits along the basement membrane zone. Direct immunofluorescence remains the gold standard for diagnosis, but other diagnostic measures reported in recent literature have proven useful in the setting of inconclusive preliminary results. Dapsone is a commonly used treatment, but many therapeutic agents have emerged in recent years. The objective of this study is to provide a comprehensive overview of updates on the diagnosis and management of LAD. Materials and Methods: A literature search was conducted from May to June of 2021 for articles published in the last 5 years that were related to the diagnosis and management of LAD. Results: False-negative results in cases of drug-induced LAD and the presence of IgG and IgM antibodies on immunofluorescence studies were reported. Serration pattern analysis has been reported to be useful in distinguishing LAD from sublamina densa-type LAD. Rituximab, omalizumab, etanercept, IVIg, sulfonamides, topical corticosteroids, and others have been used successfully in adult and pediatric patients with varying disease severity. Topical corticosteroids were preferred for pediatric patients while rituximab and IVIg were used in adults with recalcitrant LAD. Sulfonamides were utilized in places without access to dapsone. Conclusion: In cases where preliminary biopsy results are negative and clinical suspicion is high, repeat biopsy and additional diagnostic studies should be used. Patient factors such as age, medical comorbidities, and disease severity play a role in therapeutic selection.

Subepithelial autoimmune blistering dermatoses: Clinical features and diagnosis

Subepithelial autoimmune blistering dermatoses are a group of rare skin disorders that are characterized by the disruption of the dermal-epidermal junction through the action of autoantibodies. The third article in this continuing medical education series explores the background, epidemiology, clinical features, and diagnostic criteria of each of the major subepithelial autoimmune blistering dermatoses, including bullous pemphigoid, pemphigoid gestationis, lichen planus pemphigoides, mucous membrane pemphigoid, linear IgA bullous dermatosis, and dermatitis herpetiformis.

Practical Direct Immunofluorescence

Direct immunofluorescence (DIF) remains a valuable tool that may be underused because of perceived challenges in the interpretation, limitations, and processing of DIF specimens. The aim of this review is to provide a practical guide for appropriately incorporating DIF in a variety of clinical diseases, such as autoimmune blistering disorders. In vasculitis, the role of DIF continues to evolve, particularly in the setting of IgA vasculitis. Although typically not indicated for the workup of connective tissue disease, DIF may be helpful in cases with negative serologies, nondiagnostic histologic findings, or scarring alopecia. Practical pearls for biopsy technique, specimen handling, and storage are also discussed.

Successful treatment of a case of idiopathic linear IgA bullous dermatosis with oral sulfasalazine

Linear IgA bullous dermatosis (LABD) is a rare acquired autoimmune chronic vesiculobullous dermatosis affecting primarily young children and older adults. We report a 17-year-old Chinese boy with a 2-month history of intense itching erythema or tense vesicles on healthy skin or on an erythematous base, with parts of lesions arising a characteristic "cluster of jewels" pattern. With the characteristics of vesicles or blisters on the skin, subepidermal blisters with neutrophilic infiltrate on histology, and linear IgA deposits on the basement membrane zone and absence of other immunoglobulins on direct immunofluorescence, LABD was dignosized. Sulfapyridine has also been reported as one of the best options of systemic therapy for LABD. Our patient successfully treated with only oral sulfasalazine (alternative medicine of sulfasalazine), which is safe and effective.

Advances in the diagnosis of autoimmune bullous dermatoses

Autoimmune bullous dermatoses are defined by autoantibodies directed against adhesion proteins in the epidermis or basement membrane zone, resulting in blister formation on the skin and mucosa. Diagnosis depends on lesional biopsy for histopathology and perilesional biopsy for direct immunofluorescence. Additional diagnostic methods include indirect immunofluorescence, enzyme-linked immunosorbent assay, and immunoblot (Western blot), which may be selected in specific clinical scenarios due to improved sensitivity and/or specificity. This contribution reviews the available evidence supporting the use of each method to provide a practical reference for clinicians when diagnosing autoimmune bullous disorders. Techniques and cost are reviewed, and newer diagnostic techniques with potential for clinical application are.

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.

Immunological methods for the diagnosis of oral mucosal diseases

Immunological methods, which have been widely used in autoimmune blistering diseases (AIBDs) of the oral mucosa, can also be adopted as auxiliary diagnostic tools in oral lichen planus (OLP) and discoid lupus erythematosus (DLE). AIBDs, characterized by autoantibodies against structural proteins of keratinocytes or the basement membrane zone, clinically present as blisters and erosions of the oral mucosa. When atypical lesions occur, OLP or DLE may be confused with AIBDs. The improvement of diagnostic accuracy is necessary due to the significant differences in treatment and prognosis among these diseases. A variety of immunological methods are used for qualitative and quantitative detection of target antigens and autoantibodies. These methods can evaluate efficacy of treatment, monitor diseases and guide treatment decisions. In this review, we discuss the application of immunofluorescence, biochemical tests, and protein microarrays for AIBDs, OLP and DLE, as well as the differential diagnostic methods using immunological tests.

Analysis of the relationship between Oxford classification, IgM deposition and multiple indexes and the adverse prognosis of patients with primary IgA nephropathy and related risk factors

The risk and influencing factors of prognosis in patients with primary IgA nephropathy (IgAN) were explored. One hundred and twenty-four patients who were diagnosed with IgA nephropathy in West China Hospital of Sichuan University were selected as the study subjects. The baseline data were recorded. All patients were followed up for 3 years. Patients with poor prognosis were defined as poor prognosis group, and the patient with no adverse prognosis was defined as a good prognosis group during the follow-up period. The risk factors that may affect the prognosis of patients with IgAN were analyzed by single factor analysis. The influence of all factors that were statistically significant on the prognosis of the patients was further evaluated by multifactor Cox regression. The single factor analysis and multivariate Cox proportional hazard model showed that patients with 24 h urinary protein, pathological type, Oxford classification (T1+T2), Lee (grade IV) and mesangial IgM deposition were independent factors of patients, and the difference was statistically significant, their P-values were 0.041, 0.046, 0.037, 0.043, and 0.028, respectively. Patients with 24 h urinary protein, pathological type, Oxford classification (T1+T2), Lee (grade IV) and mesangial IgM deposition can be used as independent factors affecting poor prognosis in primary IgAN patients. It provides evidence for early detection of high-risk IgA nephropathy.

Antigen recognition in the pathogenesis of immunoglobulin A-related autoimmune bullous diseases

Immunoglobulin A (IgA) is the most common subtype of antibodies in mucosal surfaces. In most of autoimmune bullous diseases, however, immunoglobulin G (IgG) is the main pathogenic antibody that plays a role through complementation. The IgA antibody for epidermal connection protein can be found in the sera of some patients with blistering skin disease. Of these patients, some have the IgA antibody in their sera, while others have IgG and IgA antibodies. IgA-related autoimmune bullous diseases are less common in clinical practice. In the past, these diseases were not fully understood and their classifications were confusing. Recently, some progress has been made in the study of these diseases.