Cicatricial pemphigoid with circulating autoantibodies to beta4 integrin, bullous pemphigoid 180 and bullous pemphigoid 230

Ocular involvement in oral vesiculobullous diseases: A review on reported cases in the literature

Introduction

Vesiculobullous disorders are a group of autoimmune diseases manifesting as chronic ulcers in the oral cavity. Ocular involvement may accompany oral ulcers and cause various problems for patients. This review summarizes the data regarding ocular involvement in patients with oral vesiculobullous.

Methods

Web of Science, Scopus, PubMed/MEDLINE, and Embase electronic databases were searched according to related keywords. Finally, 58 articles were included, all of which were case reports or series. Characteristics such as the age and sex of patients, location and type of oral lesion, type of ophthalmic injury, the interval between oral and ocular lesion, and treatment of oral and ocular disorders were summarized in tables.

Results

Eye involvement was 1.6 times more prevalent in women, and most patients were between 30 and 60 years old (67.4 %). Pemphigus vulgaris accounted for almost half of the cases (48.4 %), though lichen planus is more prevalent in the general population. The most frequently affected oral site was the buccal mucosa (17.5 %), and oral ulcers usually presented as erythema, erosion, or inflammation (22.7 %). Conjunctivitis was the most common type of eye involvement (18.4 %), and ophthalmic lesions regularly appeared 12-60 months after the development of oral lesions (30.1 %). Blindness was reported in only one case. Corticosteroids and immunosuppressives were the most frequent oral and ocular lesion therapies.

Conclusion

Considering the serious burdens of any ocular injury, monitoring the ocular health of patients with oral vesiculobullous diseases is highly recommended in high-risk cases, especially middle-aged women with oral pemphigus vulgaris.

Biologic treatment outcomes in mucous membrane pemphigoid: A systematic review

BACKGROUND

Mucous membrane pemphigoid (MMP) is an autoimmune disease that can lead to fibrosis of mucous membranes and functional impairment. Biologic agents should be explored as alternative treatment options to improve outcomes.

OBJECTIVE

To conduct a systematic review of biologic treatment outcomes in patients with MMP.

METHODS

A MEDLINE and Embase search was conducted on July 23, 2020, to include 63 studies using Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines.

RESULTS

Use of intravenous immunoglobulin (n = 154), rituximab (n = 112), tumor necrosis factor α inhibitors (n = 7), and combination treatments (n = 58) were reported in 331 patients with MMP. Intravenous immunoglobulin led to complete resolution in 61.7% (n = 95/154) of patients within 26.0 months, with a recurrence rate of 22.7% (n = 35/154) and headache as the most common adverse effect (8.4%, n = 13/154). Rituximab led to complete resolution in 70.5% (n = 79/112) of patients within 8.7 months, with a recurrence rate of 35.7% (n = 40/112). The most commonly reported adverse effects were urinary tract infections (4.5%, n = 5/112), leukocytopenia (2.7%, n = 3/112), and death due to severe infections (1.8%, n = 2/112). Tumor necrosis factor α inhibitors led to complete resolution in 71.4% (n = 5/7) of patients within 3.9 months of treatment without reported adverse events.

CONCLUSIONS

Randomized clinical trials with long-term follow-up are required to conclude the promising safety and efficacy of biologic agents in patients with MMP.

European guidelines (S3) on diagnosis and management of mucous membrane pemphigoid, initiated by the European Academy of Dermatology and Venereology - Part I

This guideline on mucous membrane pemphigoid (MMP) has been elaborated by the Task Force for Autoimmune Blistering Diseases of the European Academy of Dermatology and Venereology (EADV) with a contribution of physicians from all relevant disciplines and patient organizations. It is a S3 consensus-based guideline encompassing a systematic review of the literature until June 2019 in the MEDLINE and EMBASE databases. This first part covers methodology, the clinical definition of MMP, epidemiology, MMP subtypes, immunopathological characteristics, disease assessment and outcome scores. MMP describes a group of autoimmune skin and mucous membrane blistering diseases, characterized by a chronic course and by predominant involvement of the mucous membranes, such as the oral, ocular, nasal, nasopharyngeal, anogenital, laryngeal and oesophageal mucosa. MMP patients may present with mono- or multisite involvement. Patients' autoantibodies have been shown to be predominantly directed against BP180 (also called BPAG2, type XVII collagen), BP230, laminin 332 and type VII collagen, components of junctional adhesion complexes promoting epithelial stromal attachment in stratified epithelia. Various disease assessment scores are available, including the Mucous Membrane Pemphigoid Disease Area Index (MMPDAI), the Autoimmune Bullous Skin disorder Intensity Score (ABSIS), the 'Cicatrising Conjunctivitis Assessment Tool' and the Oral Disease Severity Score (ODSS). Patient-reported outcome measurements (PROMs), including DLQI, ABQOL and TABQOL, can be used for assessment of quality of life to evaluate the effectiveness of therapeutic interventions and monitor disease course.

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.

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.

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.

Ocular Manifestations and Management of Autoimmune Bullous Diseases

Autoimmune bullous diseases with ocular involvement consist of a group of systemic entities that are characterized by formation of autoantibodies against the proteins of the epithelial basement membrane zone of the conjunctiva. Mostly, the elderly are affected by these diseases. The characteristic patterns of mucocutaneous involvement and the specific tissue components targeted by these autoantibodies are differentiating features of these diseases. Ocular pemphigus vulgaris exhibits intraepithelial activity, whereas the autoimmune activity in linear immunoglobulin A disease, mucous membrane pemphigoid, and epidermolysis bullosa acquisita occurs at a subepithelial location. Given the increased risk for blindness with delays in diagnosis and management, early detection of ocular manifestations in these diseases is vital. The precise diagnosis of these autoimmune blistering diseases, which is essential for proper treatment, is based on clinical, histological, and immunological evaluation. Management usually includes anti-inflammatory and immunosuppressive medications. Inappropriate treatment results in high morbidity and even potential mortality.

Granzyme B is elevated in autoimmune blistering diseases and cleaves key anchoring proteins of the dermal-epidermal junction

In healthy skin, epidermis and dermis are anchored together at the dermal-epidermal junction (DEJ), a specialized basement membrane pivotal for skin integrity and function. However, increased inflammation in the DEJ is associated with the disruption and separation of this junction and sub-epidermal blistering. Granzyme B (GzmB) is a serine protease secreted by immune cells. Dysregulated inflammation may lead to increased GzmB accumulation and proteolysis in the extracellular milieu. Although elevated GzmB is observed at the level of the DEJ in inflammatory and blistering skin conditions, the present study is the first to explore GzmB in the context of DEJ degradation in autoimmune sub-epidermal blistering. In the present study, GzmB induced separation of the DEJ in healthy human skin. Subsequently, α6/β4 integrin, collagen VII, and collagen XVII were identified as extracellular substrates for GzmB through western blot, and specific cleavage sites were identified by mass spectrometry. In human bullous pemphigoid, dermatitis herpetiformis, and epidermolysis bullosa acquisita, GzmB was elevated at the DEJ when compared to healthy samples, while α6/β4 integrin, collagen VII, and collagen XVII were reduced or absent in the area of blistering. In summary, our results suggest that regardless of the initial causation of sub-epidermal blistering, GzmB activity is a common final pathway that could be amenable to a single targeted treatment approach.

Anti-BP180-type mucous membrane pemphigoid immunoglobulin G shows heterogeneity of internalization of BP180/collagen XVII into keratinocyte cytoplasm

Anti-BP180-type mucous membrane pemphigoid (BP180-MMP) is a rare autoimmune subepidermal blistering disease that targets the C terminus of BP180/collagen XVII. Currently, the pathomechanism of BP180-MMP is not well understood. We reported previously that immunoglobulin G (IgG) from patients with bullous pemphigoid (BP) can induce internalization of BP180 via a macropinocytic pathway, which depletes BP180 and weakens epidermal cell-matrix integrity. The purpose of the present study was to elucidate the pathomechanism of BP180-MMP. Immunohistochemistry of biopsy specimens from two patients with BP180-MMP revealed that one patient had BP180 internalization, but the other did not. In live-cell imaging using IgG from patients with BP180-MMP on several keratinocyte cell lines, IgG from only three out of the seven patients was associated with BP180 internalization into the cytoplasm. Our results suggest that IgG from patients with BP180-MMP shows heterogeneity of internalization of BP180. This variability in BP180 internalization in patients with BP or BP180-MMP may lead to differences in clinical presentation.

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.

Isolation of a hemidesmosome-rich fraction from a human squamous cell carcinoma cell line

Hemidesmosomes are cell-to-matrix adhesion complexes anchoring keratinocytes to basement membranes. For the first time, we present a method to prepare a fraction from human cultured cells that are highly enriched in hemidesmosomal proteins. Using DJM-1 cells derived from human squamous cell carcinoma, accumulation of hemidesmosomes was observed when these cells were cultured for more than 10 days in a commercial serum-free medium without supplemental calcium. Electron microscopy demonstrated that numerous electron-dense adhesion structures were present along the basal cell membranes of DJM-1 cells cultured under the aforementioned conditions. After removing cellular materials using an ammonia solution, hemidesmosomal proteins and deposited extracellular matrix were collected and separated by electrophoresis. There were eight major polypeptides, which were determined to be plectin, BP230, BP180, integrin α6 and β4 subunits, and laminin-332 by immunoblotting and mass spectrometry. Therefore, we designated this preparation as a hemidesmosome-rich fraction. This fraction contained laminin-332 exclusively in its unprocessed form, which may account for the promotion of laminin deposition, and minimal amounts of Lutheran blood group protein, a nonhemidesmosomal transmembrane protein. This hemidesmosome-rich fraction would be useful not only for biological research on hemidesmosomes but also for developing a serum test for patients with blistering skin diseases.

Mucous membranepemphigoid in two half-sisters. The potential roles of autoantibodies to β4 integrin subunits and HLA-DQβ1*0301

BACKGROUND

Mucous membrane pemphigoid (MMP) is a subepithelial autoimmune mucocutaneous disease. It most frequently affects the oral mucosa, followed by ocular and nasal mucosa, nasopharyngeal, anogenital, skin, laryngeal and esophageal mucosa.

MAIN OBSERVATION

Two half-sisters developed mucous membrane pemphigoid at approximately the same age. The older sister presented with primarily mucosal disease, while the younger had a more cutaneous disease. The histopathology demonstrated a subepithelial blister and direct immunofluorescence showed deposition of IgG and C3 at the basement membrane zone of perilesional tissues in both sisters. Antibodies to human β4 integrin were present in the sera of both patients and correlated with disease activity. Both sisters carried the same HLADQβ1* 0301 allele.

CONCLUSIONS

This is the first case of mucous membrane pemphigoid occurring in two half-sisters. Perhaps, it is the low incidence of mucous membrane pemphigoid that may account for the lack of reports on familial cases of the disease.

Molecular diagnosis in autoimmune skin blistering conditions

Blister formation in skin and mucous membranes results from a loss of cell-cell or cell-matrix adhesion and is a common outcome of pathological events in a variety of conditions, including autoimmune and genetic diseases, viral and bacterial infections, or injury by physical and chemical factors. Autoantibodies against structural components maintaining cell-cell and cell-matrix adhesion induce tissue damage in autoimmune blistering diseases. Detection of these autoantibodies either tissue-bound or circulating in serum is essential to diagnose the autoimmune nature of disease. Various immunofluorescence methods as well as molecular immunoassays, including enzyme-linked immunosorbent assay and immunoblotting, belong to the modern diagnostic algorithms for these disorders. There is still a considerable need to increase awareness of the rare autoimmune blistering diseases, which often show a severe, chronic-relapsing course, among physicians and the public. This review article describes the immunopathological features of autoimmune bullous diseases and the molecular immunoassays currently available for their diagnosis and monitoring.

Autoimmune blistering diseases in children

Autoimmune blistering disorders comprise a series of conditions in which autoantibodies target components of the skin and mucous membranes, leading to blister and bullae formation. Most conditions in the spectrum of autoimmune blistering disorders are uncommonly seen in the pediatric population, even the most common ones, such as chronic bullous disease of childhood and dermatitis herpetiformis; however, they often come into the differential diagnosis of other more common pediatric entities. In addition, prompt recognition and treatment avoids unnecessary morbidity and improves ultimate outcome.

Diagnosis and clinical severity markers of bullous pemphigoid

The use of a broad spectrum of novel detection systems for autoantibodies to the basement membrane proteins BP180 and BP230 has greatly facilitated the diagnosis of bullous pemphigoid, which most likely explains its increasing incidence in central Europe. Because the pathogenic relevance of antibodies to human BP180 has been convincingly shown both in vitro and in vivo, repeated testing for these antibodies appears to be helpful in guiding treatment decisions during the course of the disease.

Oral mucosal diseases: Mucous membrane pemphigoid

Subepithelial vesiculobullous conditions are chronic autoimmune disorders that arise from reactions directed against components of the hemidesmosomes or basement membrane zones (BMZ) of stratified squamous epithelium to which the term immune-mediated subepithelial blistering diseases (IMSEBD) has been given. Mucous membrane pemphigoid (MMP) is the most common, but variants do exist. Non-immune disorders that involve these epithelial components typically have a genetic basis--the main example being epidermolysis bullosa. All subepithelial vesiculobullous disorders present as blisters and erosions, and diagnosis must be confirmed by biopsy examination with immunostaining, sometimes supplemented by other investigations. No single treatment reliably controls all subepithelial vesiculobullous disorders; the immunological differences within IMSEBD may account for differences in responses to treatment. Currently, as well as improving oral hygiene, immunomodulatory treatment is used to control the oral lesions of MMP, but it is not known if its specific subsets reliably respond to different agents.

Ocular manifestations of blistering diseases

Ocular manifestations are a comorbidity of a group of chronic autoimmune blistering diseases that includes mucous membrane pemphigoid, linear immunoglobulin A disease, epidermolysis bullosa acquisita, and ocular pemphigus vulgaris. Various diagnostic measures differentiate between the diseases and allow for appropriate treatment including a specific selection of immunomodulatory medications. New treatment modalities offer alternatives that may minimize disease severity and residual tissue damage and may reduce treatment-related complications.

Metastatic ovarian carcinoma-associated subepidermal blistering disease with autoantibodies to both the p200 dermal antigen and the gamma 2 subunit of laminin 5 showing unusual clinical features

Anti-p200 pemphigoid is an autoimmune subepidermal blistering disease characterized by autoantibodies to an unknown 200-kDa acidic noncollagenous glycoprotein of the lower lamina lucida, whereas antilaminin 5 mucous membrane pemphigoid is characterized by autoantibodies to a major basement membrane extracellular matrix, laminin 5. We report a 64-year-old Japanese woman with a subepidermal blistering disease associated with lymph node metastasis of ovarian clear cell carcinoma 10 years after its surgical treatment. Clinical features showed severe blisters and erosions on multiple mucous membranes (i.e. lip, oral cavity, nose, eye, genitalia and anus) and on both the periungual and subungual regions. This is the first report in which an immunoblot analysis revealed the unusual combination of autoantibodies to both the p200 antigen and the gamma 2 subunit of laminin 5.

Relative risk for cancer in mucous membrane pemphigoid associated with antibodies to the beta4 integrin subunit

BACKGROUND

Mucous membrane pemphigoid (MMP) is a mucocutaneous vesiculobullous autoimmune disease characterized by autoantibodies to components of the basement membrane zone (BMZ). Recently, it has been reported that patients with MMP who have autoantibodies to laminin 5, known as anti-epiligrin cicatricial pemphigoid (AECP) have a high incidence of malignancy.

OBJECTIVE

The purpose of this study was to determine the association between malignancy and MMP in patients with antibodies to beta4 integrin.

METHODS

The incidence of cancer was studied in 79 patients with MMP and/or ocular cicatricial pemphigoid (OCP) who had antibodies to human beta4 integrin subunit. In each patient, the diagnosis was made by histology and confirmed by immunopathology of affected tissues. It was compared to the expected incidence, for age- and gender-matched individuals, in the National Cancer Institute's Surveillance, Epidemiology and End Results (NCISEER) database.

RESULTS

Of 79 patients, 3 had cancer. The relative risk (RR) for cancer in patients with MMP and/or OCP, with autoantibodies to human beta4 integrin subunit was 0.29 (95% CI 0.62-8.77). The expected number in the NCISEER database was 10.37. This difference was statistically significant (P < 0.01).

CONCLUSION

This incidence of cancer in MMP/OCP patients, with antibodies to human beta4 integrin subunit is considerably lower than expected. Preliminary observations in this and other studies suggest that serological subsets of MMP, based on antigen reactivity, have a different clinical course, prognosis and associations with cancer.

Expression of selected integrins and selectins in bullous pemphigoid

Blister development in bullous pemphigoid (BP) results from destruction of hemidesmosomes and basement membrane components within the dermoepidermal junction by autoantibodies. Adhesion molecules can take part in pathogenesis of this disease. The aim of the study was to determine the localization and expression of L- and E-selectins and β1, β3, and β4 integrins by immunohistochemistry in skin lesions of 21 patients with BP, compared with 10 healthy subjects. Expression of L and E selectins and β1, β3 integrins was detected mainly in basal keratinocytes and in inflammatory infiltrates in the dermis, expression of β4 integrin was irregular and was detected mainly in dermal part of the blister, while in the control group only weak and single expression of the examined molecules was detected in basal keratinocytes and endothelium cells. The obtained results reveal the important role of selected selectins and integrins in development of skin lesions in BP.

Scarring autoimmune bullous disease in a Ugandan patient with autoantibodies to BP180, BP230, and laminin 5

We report on a 24-year-old, male Ugandan patient with a 2-week history of itchy papules, vesicles, erosions, and crusts distributed on the entire body, accompanied by minor erosions on the palate, tongue, and lower lip. Conjunctivae and genital mucosa were not involved. Circulating IgG and IgA autoantibodies were found against recombinant full-length BP180, BP180 4575, and the C-terminus of BP230. In addition, IgG reactivity was observed against the 16th noncollagenous region of the BP180 ectodomain, the cell-derived soluble ectodomain of BP180 (linear IgA disease antigen 1), and the alpha3 and gamma2 chains of laminin 5. No reactivity was detected with type VII collagen, alpha6beta4 integrin, and the p200 protein. Oral prednisolone and dapsone led to clearance of lesions that mostly healed with scarring and milia formation. Here, we describe a scarring mucocutaneous variant of an autoimmune blistering skin disorder that extends the current clinical and immunopathologic spectrum of this group of diseases.

Bullous pemphigoid antigen II (BP180) and its soluble extracellular domains are major autoantigens in mucous membrane pemphigoid: the pathogenic relevance to HLA class II alleles and disease severity

BACKGROUND

Mucous membrane pemphigoid (MMP), a chronic autoimmune subepithelial blistering disease, is associated with circulating IgG and/or IgA autoantibodies against several basement membrane zone antigens. The heterogeneity of clinical presentation and diversity of target autoantigens have contributed to difficulties in characterizing this condition immunologically.

OBJECTIVES

To analyse serum autoantibody profile and HLA class II alleles in MMP patients and to correlate this with the clinical presentation of disease.

METHODS

Well-defined subgroups consisting of 124 patients with MMP were examined for IgG and IgA reactivity with immunoblotting using human epidermal, dermal and placental amnion proteins. The results were further analysed on the basis of detailed clinical (sites of involvement and disease severity) and immunopathological criteria (immunofluorescence study and HLA class II alleles).

RESULTS

Immunoblot assay revealed that the majority of MMP patients had IgG (93 of 124, 75%) and/or IgA autoantibodies (63 of 124, 51%) to BP180 (including its soluble ectodomains, 120-kDa LAD-1 and 97-kDa LABD97 antigens). Other antigens targeted predominantly by IgG autoantibodies included: BP230 in 34 (27%), beta4 integrin in 26 (21%), and laminin 5 in three (2%). All the BP230+ sera and 23 (88%) beta4 integrin+ sera also reacted with at least one of the BP180 antigens. Over 85% of patients with reactivity to beta4 integrin had ocular involvement. In most cases of MMP, more severe clinical features were associated with antibody reactivity to multiple basement membrane zone antigens, as well as reactivity to multiple BP180 component antigens. Dual BP180/LAD-1 reactivity with IgG and IgA was associated with a more severe phenotype. In addition, the subset-dependent autoantibody reactivity correlated well with specific HLA class II alleles, DQB1*0301, DRB1*04 and DRB1*11.

CONCLUSIONS

Our results confirmed that BP180 is a major autoantigen targeted by the sera of patients with MMP. The disease-prevalent HLA class II alleles and humoral autoimmune response against the particular subsets of antigenic epitope(s) within BP180 ectodomain may contribute to the clinicopathological significance and disease severity of MMP.

IgG autoantibodies to type VII collagen and an exclusive IgG3 reactivity to the laminin alpha3 chain in a patient with an autoimmune subepidermal blistering disease

We describe a patient with widespread skin lesions and circulating IgG autoantibodies to both type VII collagen and laminin 5. Although autoantibodies to type VII collagen belonged to IgG2, IgG3, and IgG4 subclasses, laminin 5 was targeted exclusively by IgG3 autoantibodies. Interestingly, despite the presence of IgG3 autoantibodies, the patient's serum failed to fix complement to the dermoepidermal junction. In addition, these autoantibodies did not recruit and activate leukocytes or induce dermoepidermal separation in skin sectioned by cryostat. We report a most unusual case of an autoimmune subepidermal blistering with an exclusive IgG3 reactivity to laminin 5.

Penfigoide de mucosas: manifestaciones clínicas y tratamiento con corticoides, dapsona y ciclofosfamida en cinco pacientes

INTRODUCTION

Cicatricial pemphigoid includes several processes which are characterized by the presence of subepidermal bullae, and which affect the mucous membranes and, more rarely, the skin. At present, the term mucous membrane pemphigoid (MMP) is more accepted than other names used in the past, as they do not clearly define the broad spectrum presented by this disease. MMP can cause significant dysfunctions, primarily in the mucous membranes. Therefore, it is necessary to diagnose the disease as soon as possible, in order to quickly initiate systemic immunosuppressive treatment.

MATERIAL AND METHODS

We present our experience with 5 patients with MMP. We analyze the clinical manifestations and the response to immunosuppressive treatment during the evolution of the disease.

RESULTS

The patients were aged 41 to 69 years. The most frequent location of the lesions was the oral mucosa (80 %) and the ocular mucosa (80 %), followed by the pharyngeal mucosa (60 %), laryngeal mucosa (40 %), skin, anal mucosa (20 %) and genital mucosa (20 %). Three patients received systemic corticosteroids, dapsone and cyclophosphamide, and several sessions of plasmapheresis were also associated in one patient. One patient was controlled with topical corticosteroids and dapsone.

CONCLUSIONS

Many patients with MMP can present with severe secondary complications. For this reason, the diagnosis must be confirmed quickly and the appropriate treatment started as soon as possible. The association of corticosteroids, dapsone and cyclophosphamide is a combination that gives very good results.

[Mucous membrane pemphigoid: IgG and IgA antibodies against the BP180 antigen]

INTRODUCTION

Mucous membrane pemphigoid is a group of autoimmune bullous diseases, mediated by autoantibodies directed against different proteins in the dermoepidermal junction, including the BP180 antigen.

PATIENTS, MATERIAL AND METHODS

We included five patients with MMP in this study. We studied the presence of circulating autoantibodies against the BP180 antigen and against recombinant extracellular fragments of this protein.

RESULTS

We detected the presence of circulating antibodies against BP180 in all of the patients. Indirect immunofluorescence (IIF) studies were positive in 2 patients (20 %), as well as in 2 patients via salt-split studies. We found reactivity to the extracellular fragment of BP180 (LAD-1) in 3 patients, 2 of them via IgA and 1 with IgG. The serum of only 2 patients recognized the NC16A fragment, and 4 of the 5 patients had antibodies against the carboxy-terminal domain BP180 4575.

CONCLUSIONS

Molecular biology techniques are very important to complement the diagnosis of MMP, especially when the results of hematoxylin-eosin or IF studies are not satisfactory for a diagnosis of MMP.

Number III Mucous membrane pemphigoid

Mucous membrane pemphigoid (MMP) is a sub-epithelial vesiculobullous disorder. It is now quite evident that a number of sub-epithelial vesiculobullous disorders may produce similar clinical pictures, and also that a range of variants of MMP exist, with antibodies directed against various hemidesmosomal components or components of the epithelial basement membrane. The term immune-mediated sub-epithelial blistering diseases (IMSEBD) has therefore been used. Immunological differences may account for the significant differences in their clinical presentation and responses to therapy, but unfortunately data on this are few. The diagnosis and management of IMSEBD on clinical grounds alone is impossible and a full history, general, and oral examination, and biopsy with immunostaining are now invariably required, sometimes supplemented with other investigations. No single treatment regimen reliably controls all these disorders, and it is not known if the specific subsets of MMP will respond to different drugs. Currently, apart from improving oral hygiene, immunomodulatory-especially immunosuppressive-therapy is typically used to control oral lesions. The present paper reviews pemphigoid, describing the present understanding of this fascinating clinical phenotype, summarising the increasing number of subsets with sometimes-different natural histories and immunological features, and outlining current clinical practice.

Subepidermal blistering disease with autoantibodies to both the p200 autoantigen and the α3 chain of laminin 5

Anti-p200 pemphigoid and anti-laminin 5 mucous membrane pemphigoid are two distinct autoimmune blistering skin diseases. Patients with anti-p200 pemphigoid demonstrate circulating autoantibodies to an unknown 200-kd acidic noncollagenous glycoprotein of the lower lamina lucida, whereas anti-laminin 5 mucous membrane pemphigoid is characterized by an autoimmune response against the major basement membrane adhesion molecule laminin 5. In this report, we describe a patient who developed a recurrent nonscarring blistering eruption, affecting both skin and mucous membranes. Immunoblotting of dermal extracts and extracellular matrix of cultured keratinocytes revealed circulating autoantibodies directed to the p200 antigen and the alpha3 chain of laminin 5, respectively. The unusual clinical and immunologic profile of this case suggests that molecular specificity of circulating autoantibodies affects the clinical presentation of autoimmune subepidermal blistering skin diseases.

Granulocyte-derived elastase and gelatinase B are required for dermal-epidermal separation induced by autoantibodies from patients with epidermolysis bullosa acquisita and bullous pemphigoid

Epidermolysis bullosa acquisita (EBA) and bullous pemphigoid (BP) are two clinically and immunologically distinct autoimmune subepidermal blistering skin diseases associated with IgG autoantibodies against the dermal-epidermal junction. BP antibodies are directed against the hemidesmosomal antigens BP180 and BP230, and those in patients with EBA target type VII collagen, a major component of anchoring fibrils. While the pathogenetic mechanisms of subepidermal blistering in BP have been previously studied using a passive transfer mouse model, the effector pathways of blister formation in EBA are largely unknown. Autoantibodies to type VII collagen and BP180 have recently been shown to induce leucocyte-mediated subepidermal cleavage in cryosections of human skin. The aim of the present study was to identify human leucocyte protease(s) instrumental in dermal-epidermal separation induced by autoantibodies to type VII collagen and BP180. When incubated with cryosections of human skin pretreated with IgG from patients with EBA or BP but not from patients with anti-laminin 5 mucous membrane pemphigoid or healthy controls, granulocytes were recruited to the dermal-epidermal junction and induced subepidermal splits. A combination of broad-range protease inhibitors as well as inhibitors of serine and matrix metalloproteases completely abolished dermal-epidermal separation induced by EBA or BP autoantibodies. When characterizing the proteases involved more specifically, selective inhibition of human leucocyte elastase or gelatinase B/MMP-9 was also found to result in suppression of blistering. These findings strongly suggest that elastase and gelatinase B are essential for granulocyte-mediated proteolysis resulting in dermal-epidermal separation in EBA and BP patients' skin.

Desquamative Gingivitis Associated With IgG/IgA Pemphigoid Presents a Challenging Diagnosis and Treatment: A Case Report

BACKGROUND

Mucous membrane pemphigoid (MMP) is a heterogeneous group of autoimmune blistering disorders characterized by subepithelial separation and the deposition of immunoglobulins and complement along the basement membrane zone (BMZ). This disease is diagnosed with direct immunofluorescence testing showing a linear deposition of immunoglobulins and/or complement along the BMZ and indirect immunofluorescence testing showing circulating IgG (and sometimes IgA) autoantibodies along the BMZ. In this case report we describe desquamative gingivitis secondary to IgG/IgA pemphigoid and the management of this challenging variant of MMP.

METHODS

Routine histology, direct immunofluorescence testing, and indirect immunofluorescence testing were utilized and correlated to the clinical findings to diagnose this unusual immunobullous disease.

RESULTS

Direct and indirect immunofluorescence testing confirmed the clinical diagnosis of IgG/IgA pemphigoid as the cause of desquamative gingivitis and the other mucosal findings in this patient. A treatment program including dapsone and other drugs completely resolved the oral lesions after 14 months of therapy.

CONCLUSIONS

Desquamative gingivitis associated with IgG/IgA pemphigoid can be challenging to diagnose and treat. After 14 months of treatment, a combination therapy consisting of dapsone with cimetidine and vitamin E to enhance drug efficacy and frequent intramuscular administrations of triamcinolone achieved control of both the oral and genital elements of IgG/IgA pemphigoid in this patient.

Comparative analysis of methods for detection of anti-laminin 5 autoantibodies in patients with anti-epiligrin cicatricial pemphigoid

BACKGROUND

Anti-epiligrin cicatricial pemphigoid (AECP) is a subepidermal blistering disease characterized by circulating anti-basement membrane autoantibodies to laminin 5.

OBJECTIVE

To evaluate the relative sensitivity of immunoblotting and immunoprecipitation techniques for the detection of anti-laminin 5 antibodies, comparative studies using reference laminin 5 antiserum as well as sera from patients with AECP, other immunobullous diseases, and normal volunteers were performed.

METHODS

Equivalent amounts of protein from five different substrates were studied by immunoblotting; immunoprecipitation experiments examined biosynthetically radiolabeled human keratinocyte (HK) extracts. Results HK extracellular matrix (ECM) was the most sensitive substrate for detection of antibodies to laminin 5; extracts of HKs, A-431 cells and HaCat cells represented alternative test substrates (though the later required higher amounts of protein input). Sera from patients with AECP immunoblotted laminin 5 in HK ECM at end titers exceeding those identified in indirect immunofluorescence microscopy studies of 1 M NaCl split skin. Immunoprecipitation studies found that a 10,000-fold dilution of reference laminin 5 antiserum retained the ability to identify laminin 5. Maximal dilutions of sera from AECP patients retaining the ability to immunoprecipitate laminin 5 ranged from 500 to 5,000.

CONCLUSION

Immunoprecipitation was the most sensitive technique for detection of anti-laminin 5 antibodies, while immunoblotting of HK ECM or HK extracts represented practical alternatives.

Analysis of antigens targeted by circulating IgG and IgA antibodies in patients with mucous membrane pemphigoid predominantly affecting the oral cavity

BACKGROUND

Mucous membrane pemphigoid (MMP) includes a range of variants frequently having oral, particularly gingival, lesions. It has been suggested that MMP exclusively involving the oral cavity could be a distinct subset, but the immunological status of patients with predominantly oral lesions has received little attention.

METHODS

Indirect immunofluorescence (IIF) on normal human skin and normal human salt-split skin (SSS) as a substrate and immunoblotting on extracts of human keratinocyte cultures and normal human skin were carried out in 28 consecutive patients with MMP predominantly affecting the gingiva.

RESULTS

There was no significant difference between frequency of positive SSS-IIF among patients with exclusive oral lesions (42%) and with MMP not restricted to the oral cavity (78%) (P = 0.114). By immunoblotting, IgG of 13 sera (46%) reacted with the 180 kD bullous pemphigoid antigen (BPAg2), six (21%) reacted with the 230 kD bullous pemphigoid antigen (BPAg1), and two (7%) reacted with an antigen of 200 kD. IgA of three sera (11%) reacted with BPAg2 and three (11%) reacted with BPAg1. There was no significant difference between frequency of positive immunoblotting among patients with exclusive oral lesions (68%) and with MMP not restricted to the oral cavity (67%) (P = 1.00).

CONCLUSIONS

Most of the MMP sera contain IgG and IgA antibodies to the two major bullous pemphigoid antigens, independent of clinical presentation. Thus, in the majority of cases, patients with exclusively gingival pemphigoid lesions do not appear to have a distinct variety of mucous membrane pemphigoid.

Profile of autoantibody to basement membrane zone proteins in patients with mucous membrane pemphigoid: long-term follow up and influence of therapy

Mucous membrane pemphigoid (MMP) is an autoimmune mucocutaneous blistering disease characterized by autoantibodies to components within the basement membrane zone. In this study, we report the titers of autoantibodies to antigens in the BMZ, in the sera of 13 patients, treated with intravenous immunoglobulin as monotherapy over a consecutive 18-month period. Using bovine gingiva lysate as substrate in an immunoblot assay, autoantibodies to human bullous pemphigoid antigens (BPAg1 and BPAg2), human beta4 integrin, and laminin 5 were measured. A statistically significant (P < 0.05) decline in the autoantibody titers to beta4-integrin was observed after 3.42 months of initiating the IVIg therapy. These titers were undetectable after 13 months of therapy. The titers of antibodies to BPAg1 and BPAg2 did not correlate with disease activity or response to therapy. Antibodies to laminins were not detected. In patients with MMP, autoantibody titers to beta4-integrin correlate with disease activity and response to therapy.

Anti-p200-Pemphigoid - Eine neue blasenbildende Autoimmundermatose. Anti-p200 pemphigoid - a new bullous autoimmune dermatosis

Anti-p200 pemphigoid is an autoimmune skin disease characterized by tense blisters, subepidermal split formation, and mainly neutrophilic inflammatory infiltration of the dermal-epidermal junction (DEJ). Direct immunofluorescence microscopy of perilesional skin biopsies demonstrates linear deposits of IgG and C3 along the DEJ, while by indirect immunofluorescence microscopy on NaCI-split human skin, patients' IgG labels the dermal side. The antigenic target of the autoantibodies is a 200 kD protein (p200) of the lower lamina lucida that can be detected in human dermal extracts by immunoblotting. While p200 is thought to be important for cell-matrix adhesion, its exact identity is unknown. To date, the p200 autoantigen has been demonstrated to be distinct from bullous pemphigoid antigens 180 und 230, laminin 1, 5, and 6, alpha6beta4 integrin, and type VII collagen. Biochemical characterization of the p200 molecule revealed a noncollagenous N-glycosylated acidic protein with an isoelectric point of approximately 5.5. We provide an overview on pathogenesis, clinical features, diagnosis, and treatment of this unique autoimmune dermatosis.

Ultrastructural orientation of laminin 5 in the epidermal basement membrane: an updated model for basement membrane organization

Laminin 5 is a trimeric glycoprotein involved in cell adhesion in the epidermal basement membrane. To determine the precise orientation of laminin 5 in adult human skin, we used plural epitope-specific monoclonal antibodies, a polyclonal antiserum, and postembedding immunogold electron microscopy (IEM). Immunogold labeling distances from the basal keratinocyte plasma membrane (PM) were measured for each gold particle (>200 particles) and the mean distance (nm) calculated. Antibodies included BM165 (recognizing the alpha 3-chain first globular domain) that was measured at 35.40 +/- 2.20 nm from the keratinocyte PM, K140 (recognizing a region adjacent to the beta 3-chain globular domain IV) that measured 45.20 +/- 3.60 nm from the PM, and an anti-laminin 5 polyclonal antiserum that was 43.43 +/- 6.28 nm from the PM. The laminin 5 gamma 2-chain short arm hinge domain was previously localized to the lower lamina densa (LD) at approximately 56.30 +/- 1.65 nm from the keratinocyte PM. Taken together with previous gamma 2-chain data and the distribution of the polyclonal antisera, we estimate that the long axis of laminin 5 is oriented at an angle of approximately 27 degrees from the horizontal lamina lucida (LL)/LD border and propose that the gamma 2-chain lies farthest from the PM. This novel orientation, with the majority of the laminin 5 molecule lying obliquely along the LL/LD border and not perpendicularly, as was first thought, sheds new light on the organization of the basement membrane and likely molecular interactions.