IgA autoantibodies against the NC16a domain of BP180 but not 120-kDa LAD-1 detected in a patient with linear IgA disease

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.

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.

Anti-human serum albumin autoantibody may be involved in the pathogenesis of autoimmune bullous skin diseases

Although effective immunological diagnostic systems for autoimmune bullous skin diseases (AIBD) have been established, there are still unidentified cutaneous autoantigens. The purpose of this study is to investigative whether anti-human serum albumin (HSA) autoantibodies exist in AIBD sera and their potential pathogenesis. By immunoprecipitation-immunoblotting, immunofluorescence assay, anti-HSA autoantibodies could be detected in AIBD sera; by ELISAs, positive rates of AIBD sera for IgG and IgA anti-HSA autoantibodies were 29% and 34%, respectively. The IgG anti-HSA autoantibodies in ABID sera recognized a number of HSA antigen epitopes and therefore a polyclonal antibody against HSA were next employed to study its pathogenesis. In vitro cell and tissue culture models, anti-HSA antibody could influence DNA damage-related signaling proteins, via activation of phospho-p38 signaling pathway. This is the first report that an autoantibody may influence DNA damage-related signaling proteins. Statistical analyses also proved that anti-HSA autoantibodies were positively correlated with various known autoantibodies and clinical features of ABID patients. In summary, IgG and IgA autoantibodies to HSA may have diagnosis values for AIBD. DNA damage-related signaling proteins might be involved in the pathogenic role of anti-HSA autoantibodies in AIBD. Phospho-p38 signaling pathway is a potential target for treatment of AIBD positive for serum anti-HSA autoantibodies.

Radiation-Associated Pemphigus Vulgaris in a Patient With Preceding Malignancy: Treatment With Rituximab as a Valuable Option

Pemphigus is a chronic autoimmune blistering disorder, characterized by (muco-)cutaneous erosions due to autoantibodies against desmoglein 3 and/or 1. Pemphigus induction might be associated with drugs, malignancy or radiation therapy (RT); the latter being only rarely described. A rigorous literature review revealed around 30 cases of RT-associated pemphigus, which had been primarily treated with topical and/or systemic steroids, in some cases also dapsone or few other immunosuppressive agents were given. The most common underlying cancer type was breast cancer. We here present a 63-year-old male patient, who was pre-treated with adjuvant RT for larynx carcinoma 3 months before admission. He developed extensive cutaneous, ocular, and oral erosions. Despite the clinical picture comparable to a paraneoplastic pemphigus, the diagnosis of pemphigus vulgaris of mucocutaneous type was established based on the direct immunofluorescence, showing positive cell surface IgG and discrete C3 deposits, with matching cell surface IgG pattern on monkey esophagus. Serum autoantibodies to desmoglein 1 and 3 were highly positive. No further autoantibodies were found, thus paraneoplastic pemphigus was excluded. The patient was treated with high dose prednisolone, partially given intravenously up to 2 mg/kg per day, as well as topical disinfectants and class IV steroid cream. To stabilize the disease rituximab 2 × 1,000 mg was given, leading to clinical and serological remission for up to 2 years now. We show that rituximab represents a good treatment option for the frequently treatment-refractory RT-associated pemphigus, a clinically and immunologically specific RT-induced skin disorder, resulting in long-term clinical, and serological remission.

["Decoratively figured blisters" on the whole integument in initially diagnosed ulcerative colitis]

The rare case of a 61-year-old patient suffering from linear IgA dermatosis is presented. The patient was previously hospitalized with chronic inflammatory bowel disease. The correct diagnosis of the disease was based on clinical and histological findings. Serological methods, such as indirect immunofluorescence, ELISA and immunoblotting are suitable for identification of the autoantibodies. In this case the detection of IgA antibodies along the basal membrane was achieved by direct immunofluorescence. Other bullous dermatoses with similar symptoms, such as an IgG-mediated bullous pemphigoid have to be excluded. The therapy of linear IgA dermatosis is ensured by steroid-containing topical agents, alongside antiseptic measures as well as systemic dapsone p.o.

Bullous pemphigoid induced by dipeptidyl peptidase-4 inhibitors. Eight cases with clinical and immunological characterization

BACKGROUND

Dipeptidyl peptidase-4 (DPP-4) inhibitors have increasingly been identified as causative agents of bullous pemphigoid. The clinical and immunological characteristics of this pemphigoid variant are still unclear. The objective of our study was to analyze the clinical and immunological features of patients with pemphigoid induced by DPP-4 inhibitors.

METHODS

All patients diagnosed with DPP-4 inhibitor-associated bullous pemphigoid at dermatology departments in three Spanish centers during the period 2013 to 2015 were included. ELISA assays for the NC16A domain of BP180 and BP230 were performed. Immunoblot studies using epidermal/dermal extracts and the C-terminal, NC16A and LAD-1 regions of BP180 were also carried out.

RESULTS

A total of eight patients were identified (5 treated with vildagliptin, 2 with linagliptin, and one with sitagliptin). Of these, four presented the classical inflammatory phenotype of bullous pemphigoid and four a noninflammatory phenotype. The ELISA for BP180 (NC16A domain) was positive in six patients at diagnosis. Most patients reacted to more than one BP180 antigenic site (LAD-1 and/or C-terminal domain) on the immunoblot. Two patients showed no reaction against the NC16A domain of BP180 on either the ELISA or immunoblot but recognized either LAD-1 or both LAD-1 and the C-terminal domain. Only one of the NC16A-negative patients had a noninflammatory subtype of bullous pemphigoid.

CONCLUSIONS

Patients with DPP-4 inhibitor-induced BP may present either an inflammatory or a noninflammatory phenotype of BP. IgG response against other BP180 regions different from the NC16A domain, such as LAD-1 and the C-terminal domain, could be pathogenically relevant to the onset of DPP-4 inhibitor-induced BP.

Clinical and Immunological Study of 30 Cases With Both IgG and IgA Anti-Keratinocyte Cell Surface Autoantibodies Toward the Definition of Intercellular IgG/IgA Dermatosis

Several sporadic cases, in which direct and indirect immunofluorescence studies simultaneously detected IgG and IgA autoantibodies to keratinocyte cell surfaces, have been reported mainly under the name of IgG/IgA pemphigus. However, there have been no systematic studies for this condition. In this study, we collected 30 cases of this condition from our cohort of more than 5,000 autoimmune bullous disease cases, which were consulted for our diagnostic methods from other institutes, and summarized their clinical and immunological findings. Clinically, there was no male-female prevalence, mean age of disease onset was 55.6 years, and mean duration before this condition was suspected was 18 months. The patients showed clinically bullous and pustular skin lesions preferentially on the trunk and extremities, and histopathologically intraepidermal pustules and blisters with infiltration of neutrophils and eosinophils. Immunologically, ELISAs frequently detected IgG and IgA autoantibodies to both desmogleins and desmocollins. From the characteristic clinical, histopathological, and immunological features, which are considerably different from those in classical IgG types of pemphigus, we propose this disease as a new disease entity with preferential name of intercellular IgG/IgA dermatosis (IGAD). This was the largest study of IGAD to date.

Clinical and immunological studies of 49 cases of various types of intercellular IgA dermatosis and 13 cases of classical subcorneal pustular dermatosis examined at Kurume University

BACKGROUND

Intercellular IgA dermatosis (IAD) is a subset of autoimmune bullous disease exclusively with IgA antikeratinocyte cell-surface antibodies. The classification and pathogenesis of this condition are still obscure.

OBJECTIVES

To classify IAD and study its pathogenesis.

METHODS

From our cohort of 5402 cases of autoimmune bullous disease, we selected 49 cases of various types of intercellular IgA dermatosis (IAD) and 13 cases of classical subcorneal pustular dermatosis (SPD), for which sera and information were available. We studied these cases clinically and immunologically.

RESULTS

There were 17 SPD-type IAD, 12 intraepidermal neutrophilic IgA dermatosis (IEN)-type IAD, two IgA-pemphigus vegetans, four IgA-pemphigus foliaceus, six IgA-pemphigus vulgaris and eight unclassified IAD cases. There was no sex predominance, and the average age at disease onset was 45·9 years. Clinically, bullous and pustular skin lesions developed on various sites, particularly intertriginous areas. Histopathology showed intraepidermal blisters or pustules at the upper epidermis in the SPD-type and at the midepidermis in the IEN-type. Immunological studies revealed that direct immunofluorescence, indirect immunofluorescence of normal human skin and enzyme-linked immunosorbent assays (ELISAs) of recombinant proteins of desmogleins and desmocollins frequently showed positive results, although no antigens were detected in many cases. All cases of classical SPD, which showed no positive immunological results, were indistinguishable clinically and histopathologically from SPD-type IAD.

CONCLUSIONS

The present study of the largest cohort of cases of IAD showed that the major subtypes are SPD and IEN, and that the combination of indirect immunofluorescence and ELISAs of desmogleins and desmocollins, in addition to direct immunofluorescence, was useful for the diagnosis of IAD and its subtypes.

Clinical and immunological studies for 105 Japanese seropositive patients of epidermolysis bullosa acquisita examined at Kurume University

OBJECTIVES

Using our serological diagnostic criteria, we selected 105 Japanese patients with epidermolysis bullosa acquisita (EBA), an autoimmune bullous disease (AIBD) reacting with type VII collagen, from our cohort of 5063 AIBD patients.

METHODS

We examined the patients clinically and immunologically.

RESULTS

We found diversity of clinical manifestations in both cutaneous and oral mucosal lesions and a high rate of inflammatory-type EBA patients in Japan. Common treatments were systemic steroids, followed by immunosuppressives, DDS, tetracycline/minocycline and colchicine. Immunological studies revealed that indirect immunofluorescence of 1M-NaCl-split skin, immunoblotting of dermal extract, and type VII collagen ELISA were sensitive methods, with possible multiplicity of circulating autoantibodies against other basement membrane autoantigens.

CONCLUSION

The present study analyzed the largest cohort of EBA patients, confirming the scarcity of EBA (only 105 of the 5063 AIBD patients), and showed that the three serological tests are useful for the diagnosis of EBA.

Four cases of mucous membrane pemphigoid with clinical features of oral lichen planus

BACKGROUND

Mucous membrane pemphigoid (MMP) and oral lichen planus (OLP) show similar clinical features on the oral mucosa. As clinical manifestations of oral mucosal lesions, MMP shows blisters and erosions, whereas OLP shows lace-like whitish lesions in an annular arrangement with erythema and erosions. Histopathologically, MMP shows subepithelial bullae with infiltrates of lymphocytes and neutrophils, whereas OLP shows band-like interface infiltration of lymphocytes with damage in basal cells. However, these two diseases are frequently difficult to distinguish both clinically and histopathologically.

OBJECTIVES

We report four patients with oral MMP who showed OLP-like clinical and histopathological lesions.

METHODS

We performed direct immunofluorescence, indirect immunofluorescence of normal human skin and 1 m NaCl-split skin, enzyme-linked immunosorbent assays for BP180, BP230, and desmogleins 1 and 3, and immunoblotting of normal human epidermal and dermal extracts, recombinant proteins of BP180-NC16a and -C-terminal domains, concentrated culture supernatant of HaCaT cells, and purified laminin-332.

RESULTS

The results of various immunological studies suggested the diagnoses of various types of MMP for all four patients.

CONCLUSIONS

Because MMP and OLP require different treatments, all dentists and dermatologists should have knowledge about the disease entity and the serological diagnostic methods for various types of MMP.

Diaminodiphenyl Sulfone-Induced Hemolytic Anemia and Alopecia in a Case of Linear IgA Bullous Dermatosis

Linear immunoglobulin A (IgA) bullous dermatosis (LABD) is an autoimmune mucocutaneous disease characterized by subepidermal blistering induced by IgA autoantibodies against several autoantigens in the basal membranous zone of the skin and mucosal tissue. Although diaminodiphenyl sulfone (DDS), also known as dapsone, is generally recognized as the first-line therapy for LABD, DDS can induce several severe side effects. We present a Japanese case of LABD with DDS-induced hemolytic anemia and alopecia. In the present case, the DDS-induced hemolytic anemia and hair loss made the DDS monotherapy difficult. When DDS is used in LABD patients with iron deficiency anemia (IDA), hemolytic anemia is concealed by IDA. It is thus necessary to carefully and frequently examine the laboratory data to find the signs of DDS-induced hemolytic anemia. Even though there is no literature on DDS-induced alopecia, alopecia was reported as one of the side effects of DDS in an FDA report, and, in our case, hair loss was improved after reducing its dosage. We have to recognize that alopecia is one of the side effects of DDS and that careful management is needed in order not to overlook the adverse side effects of DDS when treating LABD patients.

A Case of Chronic Bullous Disease of Childhood That Was Reactive to the Antigen of 120 kDa (LAD-1)

Chronic bullous disease of childhood (CBDC) is an autoimmune blistering disease that is characterized by Immunoglobulin A (IgA) deposits at the basement membrane zone. IgA autoantibodies (aAbs) from the serum of patients with CBDC react with antigens of 97 kDa (LABD97) and 120 kDa (LAD-1), and both of which are fragments of the extracellular domain of bullous pemphigoid 180 (BP180, type XVII collagen). The CBDC sera reacts with the immunodominant NC16a domain of BP180, which is the major region recognized by IgG aAbs in patients with bullous pemphigoid. A five-year-old boy presented with multiple pruritic tense blisters on the umbilical and inguinal areas for six weeks. The direct immunofluorescence of the perilesional area demonstrated linear deposits of IgA at the basement membrane zone. Using immunoblotting and an enzyme linked immunosorbent assay (ELISA), we identified the IgA aAbs reactive to antigens with a molecular weight of 120 kDa (LAD-1), which is a fragment of the extracellular domain of BP180.

Role of dermal-epidermal basement membrane zone in skin, cancer, and developmental disorders

The dermal-epidermal basement membrane zone is an important epithelial and stromal interface, consisting of an intricately organized collection of intracellular, transmembrane, and extracellular matrix proteins. The basement membrane zone has several main functions including acting as a permeability barrier, forming an adhesive interface between epithelial cells and the underlying matrix, and controlling cellular organization and differentiation. This article identifies key molecular players of the dermal-epidermal membrane zone, and highlights recent research studies that have identified structural and functional roles of these components in the context of various blistering, neoplastic, and developmental syndromes.