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.

A propósito de un caso: enfermedad IgA lineal de la infancia / Apropos of a case: Linear IgA bullous dermatosis of childhood

La enfermedad IgA lineal se trata de un trastorno autoinmune poco frecuente. En la infancia aparece sobre todo en edad preescolar, y en adultos es necesario realizar un buen diagnóstico diferencial con otras enfermedades ampollosas como la dermatitis herpetiforme o el penfigoide ampollar. Hasta un cuarto de los casos se relacionan con infecciones o con la toma de medicamentos entre los que destacan antibióticos y antiinflamatorios no esteroideos. El diagnóstico se basa en la clínica, biopsia cutánea e inmunofluorescencia. Típicamente se presenta como ampollas anulares tensas de morfología anular con imagen característica en collar de perlas. Al realizar el estudio de inmunofluorescencia directa se evidencia una banda lineal de IgA en la unión dermoepidérmica. Suele responder de forma completa a la retirada del fármaco causante y al tratamiento con Dapsona oral y glucocorticoides tópicos. (AU)

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.

Linear IgA bullous dermatosis associated with immunotherapy.

Linear IgA bullous dermatosis (LABD) is a rare mucocutaneus blistering autoimmune disease caused by IgA autoantibodies. Its clinical manifestation can be indistinguishable from bullous pemphigoid (BP), a similar autoimmune bullous disease caused by IgG and IgE autoantibodies. Although BP has been reported as an adverse cutaneous effect of immunotherapy, LABD has rarely been associated with immunotherapy in the literature. We present the case of a 67-year-old woman with metastatic ovarian cancer receiving anti-PD1 and anti-CTLA4 with new onset pruritic tense bullae to the trunk, hands, elbows (in annular distribution) that occurred after immunotherapy. Skin biopsy showed subepidermal blister with abundant neutrophils on H&E histology, and linear IgA staining at the basement membrane on direct immunofluorescence consistent with the diagnosis of LABD. The condition did not improve on initial prednisone taper, but blisters rapidly resolved a few days after initiation of dapsone therapy. We favor that our patient's LABD is secondary to her immunotherapy. Our case highlights the importance of both H&E histology and direct immunofluorescence in diagnosis of blistering disorders in patients on immunotherapy to help in choosing the most effective treatment option in an attempt to avoid discontinuation of immunotherapy.

Disseminated Tuberculosis in a Nigerian Adolescent with Linear IgA Bullous Dermatosis: A Case Report and Review of Literature.

Linear IgA bullous dermatosis (LABD) is an auto-immune disease affecting young children and adults, characterized by the linear deposition of IgA at the basement membrane zone with resultant complement activation and a cascade of immune reactions. There is a loss of adhesion at the dermo-epidermal junction and subsequent blister formation. It is a rare disease that has a good prognosis with adequate therapy. However, the underlying depressed immunity associated with the disease may expose them to such infections as tuberculosis. We report the case of an 11-years-old Nigerian female adolescent with LABD, diagnosed at the age of four years but defaulted on follow-up, who developed disseminated tuberculosis (pulmonary, lymph nodes, abdominal and pericardial effusion) seven years after the appearance of the initial blistering skin lesions. She commenced anti-tuberculosis drugs, steroids, and a tube pericardiostomy for the pericardial effusion. Dapsone was initiated for the LABD during the continuation phase of anti-tuberculosis therapy, with subsequent disappearance of the skin rash within two weeks.

La dermatose bulleuse linéaire à IgA (DBL) est une maladie auto-immune affectant les jeunes enfants et les adultes, caractérisée par le dépôt linéaire d'IgA dans la zone de la membrane basale, avec l'activation du complément qui en résulte et une cascade de réactions immunitaires. Il y a une perte d'adhérence à la jonction dermo-épidermique et une formation ultérieure de vésicules. C'est une maladie rare qui a un bon pronostic avec un traitement adéquat. Cependant, l'immunité déprimée sous-jacente associée à la maladie peut les exposer à des infections telles que la tuberculose. Nous rapportons le cas d'une adolescente nigériane de 11 ans atteinte de la LABD, diagnostiquée à l'âge de quatre ans mais en défaut de suivi, qui a développé une tuberculose disséminée (pulmonaire, ganglions lymphatiques, épanchement abdominal et péricardique) sept ans après l'apparition des lésions cutanées vésiculeuses initiales. Elle a commencé à recevoir des médicaments antituberculeux, des stéroïdes et une péricardiostomie par sonde pour l'épanchement péricardique. La dapsone a été initiée pour la DLB pendant la phase de continuation du traitement antituberculeux, avec une disparition de l'éruption cutanée en deux semaines. Mots clés: IgA linéaire, dermatose bulleuse, tuberculose disséminée, adolescent.

Linear IgA bullous dermatosis of childhood.

A 4-year-old boy presented with blistering on his face and distal upper and lower extremities. Subepidermal blisters containing neutrophils and eosinophils visualized on histology supported the diagnosis of linear IgA bullous dermatosis of childhood (LABDC). The dermatosis presents with vesicles and tense blisters in an annular distribution, erythematous papules, and/or excoriated plaques. Histopathology shows subepidermal blisters with a neutrophilic infiltrate in the dermis, mainly concentrated at the tips of dermal papillae in the early stage of the disease, which can be mistaken for the pattern of neutrophilic infiltration as seen in dermatitis herpetiformis. Dapsone is the treatment of choice, which is started at a dosage of 0.5mg/kg/day. Linear IgA bullous dermatosis of childhood is a rare autoimmune disease that can be mistaken for other conditions with similar presentations but should always be considered in the differential diagnosis of children with blistering.

Assessment of Clinical and Laboratory Use of the Cutaneous Direct Immunofluorescence Assay.

IMPORTANCE: Dermatologists submit direct immunofluorescence (DIF) biopsies on a daily basis, using an assay detecting immunoreactant deposition with a panel that has traditionally comprised immunoglobulin (Ig) G, IgA, IgM, C3, and fibrin, with or without albumin antibodies. OBJECTIVES: To evaluate and compare the frequency of immunoreactants in DIF biopsies submitted over an 8-year period and assess use by dermatologists based on clinical impression. DESIGN, SETTING, AND PARTICIPANTS: A quality improvement study was conducted in a community outreach reference laboratory associated with a large academic medical center. Results of 2050 consecutive DIF skin biopsies submitted to the laboratory between April 1, 2012, and June 12, 2020, were analyzed by final pathologic diagnosis and antibody subtype positivity, in comparison with clinical impression. Biopsies in which the submitting physician had not performed the biopsy were excluded. MAIN OUTCOMES AND MEASURES: Histopathologic findings and the results of DIF biopsies using the standard 6-antibody panel were evaluated in correlation with the submitted clinical diagnosis to assess immunoreactivity of the assay. RESULTS: Of 2050 DIF biopsies submitted, 367 (17.9%) were positive; IgG, IgA, and C3 alone identified all primary immunobullous disease cases (pemphigoid, pemphigus, linear IgA, and dermatitis herpetiformis), and IgA, C3, and fibrin antibodies alone identified all vasculitis cases. A panel of IgG, IgA, IgM, and fibrin identified all cases of lupus erythematosus. DIF results were positive in less than half of cases of hematoxylin and eosin biopsy-confirmed lupus erythematosus (23 of 47 [49%]). A total of 247 biopsies were submitted for clinical diagnoses not optimally supported on DIF: lichen planus, porphyria, and connective tissue disease. CONCLUSIONS AND RELEVANCE: The findings of this study suggest that there is a knowledge gap among dermatologists relating to the opportunity for high-value, cost-conscious use of DIF. The practice of reflexive antibody testing using a 6-antibody panel for all DIF biopsies is likely unnecessary. DIF protocols tailored to the clinical diagnosis may enhance cost-effectiveness without loss of test sensitivity or specificity.

Neonatal Linear IgA Bullous Dermatosis Mediated by Breast Milk-Borne Maternal IgA.

IMPORTANCE: Neonatal linear immunoglobulin A (IgA) bullous dermatosis (LABD) is a rare disease that can be fatal when associated with respiratory failure. All previously reported cases of neonatal LABD have been in newborns with healthy asymptomatic mothers, and the pathogenic IgA was of unknown origin. OBJECTIVE: To clarify the origin of IgA associated with LABD in neonates born of healthy asymptomatic mothers. DESIGN, SETTING, AND PARTICIPANTS: This case study analyzed the laboratory findings of a single breast-fed newborn male with neonatal LABD admitted to the Keio University Hospital in Tokyo and his healthy asymptomatic mother. The healthy newborn developed life-threatening blisters and erosions of the skin and mucous membranes on day 4 after birth. Blood serum, skin, and maternal breast milk were examined for IgA autoantibodies. MAIN OUTCOMES AND MEASURES: Histopathologic and immunofluorescence analyses of specimens (serum, skin, and breast milk) from the patient and his mother. RESULTS: Histopathologic evaluation of the newborn's skin revealed subepidermal blisters with neutrophil infiltrates, and immunofluorescence testing showed linear IgA deposition along the basement membrane zone (BMZ), which lead to the diagnosis of neonatal LABD. Indirect immunofluorescence using normal human skin after treatment with 1-mol/L sodium chloride showed the patient to have circulating IgA binding to the dermal side of BMZ. Immunohistochemical staining proved the deposition of secretory IgA in the neonatal skin by demonstrating the presence of J chain-not been seen in other LABD cases-indicating that the autoantibodies producing the blisters were derived from the maternal breast milk. Although no circulating IgA against the skin was detected in mother's sera, the breast milk contained IgA that reacted with the dermal side of the BMZ. No new blister formation was observed after cessation of breastfeeding. CONCLUSIONS AND RELEVANCE: The results of this case study suggest a passive transfer of pathogenic IgA to a newborn from an asymptomatic mother via breast milk. In prior reports, no serum from asymptomatic mothers of newborns with LABD had IgA autoantibodies binding to skin components; however, in this case, we found that the maternal breast milk contained IgA autoantibodies associated with neonatal LABD. In neonatal LABD, maternal breast milk should be examined for IgA autoantibodies and breast milk feeding should be discontinued as soon as neonatal LABD is suspected.

Flame Figures in Linear Immunoglobulin A Bullous Dermatosis Secondary to Parvovirus B19 Infection.

ABSTRACT: Flame figures represent a characteristic but nondiagnostic histological finding in eosinophilic dermatoses. Some bullous autoimmune diseases with a predominant eosinophilic infiltrate, such as bullous pemphigoid, pemphigoid gestationis, and pemphigus vegetans, may show them. However, it is rare to find them in predominant neutrophilic bullous dermatoses such as linear immunoglobulin A. We present a 60-year-old man with a history of chronic urticaria, which presented a bullous disease after an acute parvovirus B19 infection. The histological findings showed an exceptional linear immunoglobulin A bullous dermatosis with an eosinophilic infiltrate in the dermis forming "flame figures." The clinical and histopathological findings for this entity may be identical to those of other dermatoses. For this reason, combining these findings with direct immunofluorescence analysis is essential for correct diagnosis of this bullous disease.

Linear IgA bullous dermatosis associated with ulcerative colitis: A case report and literature review.

We report the case of a 59-year-old Japanese woman who developed linear IgA bullous dermatosis during treatment for ulcerative colitis that manifested as pruritic vesicles with erythema on the trunk and scalp. Histopathological examination revealed subepidermal bulla with neutrophil and eosinophil infiltration in the upper dermis. Direct immunofluorescence revealed linear IgA deposits at the basement membrane zone, and indirect immunofluorescence using split skin revealed IgA reaction to the epidermal side (lamina lucida type). We reviewed 33 reported cases of linear IgA bullous dermatosis associated with ulcerative colitis and found that ulcerative colitis preceded the onset of linear IgA bullous dermatosis in 94% of the patients and that IgA-positive patients in split skin indirect immunofluorescence all showed the lamina lucida type, indicating that target antigens for serum IgA antibodies may reside in the lamina lucida. Regarding the pathogenetic association of ulcerative colitis and linear IgA bullous dermatosis, intestinal inflammation may induce the exposure and presentation of intestinal antigens that are cross-reactive to cutaneous antigens, stimulating autoimmune response to antigens of cutaneous basement membrane zones.