Human autoantibodies against desmoplakins in paraneoplastic pemphigus

Lymphoma With a Skin Rash

A 62-year-old female had a generalized vesiculobullous rash on her face for 4 months. It started over the lips and gradually progressed to involve the oral mucosa and skin of the whole body. What is your diagnosis?

Focus on pemphigus treatment publications: A bibliometric and visual analysis (1992-2022)

Pemphigus is a chronic recurrent disease in dermatology. Although it is not very common, its treatment has been an increasing concern in recent years because it is difficult and long-lasting. At present, there are many papers on pemphigus treatment, and to better understand the research trends and research frontiers of pemphigus treatment, it is necessary to conduct a comprehensive systematic review and analysis. We combined bibliometric and visualization methods to analyze 1365 papers published in the Web of Science database from 1992 to 2022, including basic information about countries, institutions and authors, to gain a general understanding of the treatment of pemphigus. Among them, the United States is the country with the most output, Iran's Tehran University of Medical Sciences is the institution with the most published works, and Ahmed, A. Razzaque of Tufts University is the most influential scholar. In addition, we also learned about the research hotspots and frontiers of pemphigus treatment through a series of analyses on the frequency, clustering, keywords bursts and cited literature, and we briefly reviewed the highly cited literature. We found that the current research focuses in the study of pemphigus treatment are the types, pathogenesis, and treatment of pemphigus, including glucocorticoids, immunosuppressants and many other major treatment methods. Hailey-Hailey disease, genetic susceptibility, and traditional Chinese medicine are potential research hotspots. Rituximab is a research frontier. In conclusion, we hope to provide new research ideas for promoting the development of pemphigus treatment.

Recurrent Myocarditis in Patients With Desmosomal Pathogenic Variants: Is Self Antigen Presentation the Link?

Myocarditis is frequently associated with viral infections. Increasing evidence points to an association between myocarditis and inherited cardiomyopathies, though it is unclear whether myocarditis is a driver or an accessory. We present a primary vignette and case series highlighting recurrent myocarditis in patients later found to harbor pathogenic desmosomal variants and provide clinical and basic science context, exploring 2 potentially overlapping hypotheses: that stress induces cellular injury and death in structurally abnormal myocytes and that recurrent viral myocardial and truncated desomosomal protein byproducts as 2 hits could lead to loss of immune tolerance and subsequent autoreactivity.

S2k guidelines on the management of paraneoplastic pemphigus/paraneoplastic autoimmune multiorgan syndrome initiated by the European Academy of Dermatology and Venereology (EADV)

BACKGROUND

Paraneoplastic pemphigus (PNP), also called paraneoplastic autoimmune multiorgan syndrome (PAMS), is a rare autoimmune disease with mucocutaneous and multi-organ involvement. PNP/PAMS is typically associated with lymphoproliferative or haematological malignancies, and less frequently with solid malignancies. The mortality rate of PNP/PAMS is elevated owing to the increased risk of severe infections and disease-associated complications, such as bronchiolitis obliterans.

OBJECTIVES

These guidelines summarize evidence-based and expert-based recommendations (S2k level) for the clinical characterization, diagnosis and management of PNP/PAMS. They have been initiated by the Task Force Autoimmune Blistering Diseases of the European Academy of Dermatology and Venereology with the contribution of physicians from all relevant disciplines. The degree of consent among all task force members was included.

RESULTS

Chronic severe mucositis and polymorphic skin lesions are clue clinical characteristics of PNP/PAMS. A complete assessment of the patient with suspected PNP/PAMS, requiring histopathological study and immunopathological investigations, including direct and indirect immunofluorescence, ELISA and, where available, immunoblotting/immunoprecipitation, is recommended to achieve a diagnosis of PNP/PAMS. Detection of anti-envoplakin antibodies and/or circulating antibodies binding to the rat bladder epithelium at indirect immunofluorescence is the most specific tool for the diagnosis of PNP/PAMS in a patient with compatible clinical and anamnestic features. Treatment of PNP/PAMS is highly challenging. Systemic steroids up to 1.5 mg/kg/day are recommended as first-line option. Rituximab is also recommended in patients with PNP/PAMS secondary to lymphoproliferative conditions but might also be considered in cases of PNP/PAMS associated with solid tumours. A multidisciplinary approach involving pneumologists, ophthalmologists and onco-haematologists is recommended for optimal management of the patients.

CONCLUSIONS

These are the first European guidelines for the diagnosis and management of PNP/PAMS. Diagnostic criteria and therapeutic recommendations will require further validation by prospective studies.

Significance of anti-desmocollin autoantibodies in pemphigus

The major autoantigens for pemphigus are desmogleins (Dsgs), cell-cell adhesive structure proteins, one of the desmosomal cadherins. Recent progress in molecular biology has revealed that IgG autoantibodies of classical pemphigus react with Dsg1 or Dsg3. Desmocollins (Dscs) also belong to the cadherin supergene family that provides structure to the desmosomes and play an important role in cell-to-cell adhesion. In addition to the presence of four desmosomal Dsg isoforms, i.e. Dsg1-4, Dsc1, 2 and 3, all of which are derived from different genes, Dsc1 has been previously identified as the target antigen of IgA autoantibodies in the subcorneal pustular dermatosis (SPD)-type of intercellular IgA dermatosis. In addition to the IgA anti-Dsc1 autoantiboides, the presence of IgG anti-Dsc autoantibodies is described in patients of some autoimmune bullous diseases. In particular, the current pemphigus detecting autoantibodies to Dscs has shown a tendency in atypical variants of pemphigus. Therefore, autoantibodies against Dscs alone may cause detachment of cell-cell adhesion in the epidermis in some pemphigus. However, except for the findings of a few in vitro and in vivo studies, there is currently no clear evidence for the pathogenicity of anti-Dsc autoantibodies in pemphigus, whereas significance of anti-Dsg autoantibodies is well established. This article describes the structure and function of the Dscs, and explores the evidence regarding the pathogenic role of anti-Dsc autoantibodies in pemphigus.

Indirect immunofluorescence on rat bladder epithelium in patients with pemphigus vulgaris with an extended follow‐up

Background

Indirect immunofluorescence (IIF) on rat bladder epithelium (RBE) has been widely used to detect anti‐plakin antibodies present in paraneoplastic pemphigus (PNP). However, anti‐plakin antibodies have also been found in a group of patients with pemphigus vulgaris (PV).

Objectives

To assess the reactivity rate of PV sera in IIF using RBE as substrate and the diagnostic usefulness of the aforementioned test.

Methods

Patients diagnosed with PV presenting to Razi Hospital, Tehran, Iran, were recruited. The patients' demographics, disease severity, and response to the initial treatment were recorded. Sera were collected and tested by IIF on RBE and by desmoglein 3/1 (Dsg 3/1) enzyme‐linked immunosorbent assay. Patients were followed up closely for a mean of 53.9 months for any evidence of malignancy.

Results

Forty‐six patients were enroled (mean age of 42.9 years old, 31 females). Nine sera (19.6%) showed reactivity in IIF on RBE. Mean serum anti‐Dsg levels did not differ significantly among the two groups with positive and negative IIF results. Negative anti‐Dsg3 was related to a higher positive rate in IIF on RBE. There was no significant correlation between the reactivity of IIF on RBE and patients' demographic, clinical, or serological characteristics.

Conclusions

IIF on RBE is a sensitive test for detecting antibodies against plakins. However, it has a relatively high false‐positive rate in PV, probably due to the epitope spreading phenomenon. This test should be suggested when there is a clinical or immunohistopathological suspicion of PNP and should be interpreted with caution.

Paraneoplastic Pemphigus Autoantibodies Against C-terminus of Desmoplakin Induced Acantholysis In Vitro and In Vivo

Paraneoplastic pemphigus (PNP) is an autoimmune bullous disease associated with underlying neoplasms and characterized by antibodies against desmoglein 3 (Dsg 3) and plakins. Autoantibodies against desmoglein 3 in sera of patients with PNP have been proven to cause acantholysis in vivo in neonatal mice. As a member of the plakin family, autoantibodies against desmoplakin were detected frequently by immunoprecipitation in the sera of PNP. The recombinant C-terminus of desmoplakin was expressed and purified to adsorb the specific autoantibodies against the C-terminus of desmoplakin. In vitro dispase-dependent keratinocyte dissociation assay and in vivo IgG passive transfer into neonatal mice assay were performed, followed by the electronic microscopy examination and TUNEL assay. We found that anti-C terminus of desmoplakin autoantibodies caused blisters and acantholysis in mice skin at a dose-dependent manner. Moreover, dissociated fragments were observed after incubation with the purified IgG against desmoplakin, compared with normal human IgG (P-value =0.0207). The electronic microscopy examination showed the disconnection of keratin intermediate filaments from desmosomes. Lastly, apoptosis of keratinocytes in the TUNEL assay was all detected in the skins of neonatal mice after injection of the anti-C terminus of desmoplakin autoantibodies. Taken together, the study suggests that autoantibodies against the C-terminus of desmoplakin might be pathogenic in PNP.

Clinicians' pearls and myths in pemphigus

Pemphigus comprises a heterogeneous group of autoimmune blistering diseases, which can affect both skin and mucous membranes, especially oral mucosa. This group of diseases shows usually a chronic-relapsing course. Since pemphigus is a rare disease, the diagnosis is often delayed, because it is based upon the recognition of consistent clinical, histologic, and direct immunofluorescence findings, as well as indirect immunofluorescence, and/or enzyme-linked immunosorbent assay. Usually the patients are treated for multiple other conditions before starting the correct therapy, leading to a critical reduction of the patients' quality of life. This review is a succinct compilation of pearls gathered from clinical experience in pemphigus and the myths that may have influenced everyday practice but have been proven false. This review provided a selection of such dilemmas and controversies, focusing on myths and pearls that can help young dermatologist in the clinic, while also dispelling them.

Paraneoplastic Pemphigus: An Indication for Treatment in Chronic Lymphocytic Leukemia

Paraneoplastic disorders are rare multiorgan diseases associated with hematological malignancies such as chronic lymphocytic leukemia (CLL). Some of these paraneoplasms manifest as cutaneous lesions, appearing as a simple rash, ulcers or skin thickening. The pathogenesis for this process has been described as development of certain autoimmune reactions against cell wall antigens and proteins. An example is paraneoplastic pemphigus (PNP) which manifests as cutaneous bullae. Bullae may occur anytime during the course of the malignancy i.e. acute phase or remission. Diagnosis involves evaluation of clinical findings, serology and presence of characteristic histological findings. Its pathogenesis is described as development of auto-antibodies against cell junctional and basement membrane proteins. Presence of paraneoplasms has been associated with poorer prognosis and increased mortality in hematological malignancies including CLL. Currently, there are established indications for the treatment of CLL; however, presence of paraneoplasms as an indication for treatment is unclear. Patients with paraneoplasms who underwent expeditious treatment have exhibited better clinical outcomes. Herein we describe a case of a CLL patient in remission presenting with PNP and its response to treatment.

Detection of autoantibodies against alpha-2-macroglobulin-like 1 in paraneoplastic pemphigus sera utilizing novel green fluorescent protein-based immunoassays

BACKGROUND

Paraneoplastic pemphigus (PNP) is a devastating autoimmune multiorgan syndrome associated with autoantibodies against several autoantigens, including the alpha-2-macroglobulin-like-1 (A2ML1). A2ML1 is recognized by up to 70 % of PNP sera. The currently recommended techniques for serological diagnosis of PNP are inadequate to detect anti-A2ML1 antibodies.

OBJECTIVES

To develop novel assays which allow to easily and reliably detect anti-A2ML1 autoantibodies in PNP sera.

METHODS

We produced full-length A2ML1 in fusion with enhanced green fluorescent protein (EGFP-A2ML1) in transfected human embryonic kidney 293 T cells. The recombinant protein was used as fluorescent ligand for immunoprecipitation studies. We further developed an enzyme-linked immunosorbent assay (ELISA) by immobilizing EGFP-A2ML1 on 96-well plates.

RESULTS

A2ML1-positive PNP sera were able to immunoprecipitate EGFP-A2ML1. Direct measurement of fluorescence in immunoprecipitates correlates with the relative levels of anti-A2ML1 antibodies in the PNP sera. By the novel ELISA, based on the determined best cut-off value, 61 % of the tested 36 PNP sera were A2ML1 positive with a specificity of 88.9 % and a sensitivity of 95 %. The 20 tested normal sera (NHS) were negative, while 2 (10 %) of 20 pemphigus vulgaris and 3 (15 %) of 20 bullous pemphigoid sera showed borderline values.

CONCLUSIONS

Our novel immunoassays enable rapid stratification of PNP patients. The novel green fluorescent protein-based ELISA utilizing an active eukaryotic A2ML1 is highly sensitive and reliable and, hence, is useful for a better understanding of the immunological background of PNP. This approach may be easily applied for the rapid detection of antibodies to various other antigens.

Paraneoplastic Dermatoses: A Brief General Review and an Extensive Analysis of Paraneoplastic Pemphigus and Paraneoplastic Dermatomyositis

Skin manifestations of systemic disease and malignancy are extremely polymorphous. Clinicians should be familiarized with paraneoplastic dermatoses in order to perform an early diagnosis of the underlying neoplasm. Lack of familiarity with cutaneous clues of internal malignancy may delay diagnosis and treatment of cancer. In this review, we described several paraneoplastic dermatoses and discussed extensively two paradigmatic ones, namely paraneoplastic pemphigus and paraneoplastic dermatomyositis.

Modern diagnostic methods of paraneoplastic pemphigus

Paraneoplastic pemphigus (PNP) is one of the least investigated and rare forms of bullous dermatoses, which comes from underlying neoplasm. The article presents a literature review of dermatologist`s longstanding international experience about etiology, pathogenesis, diagnostics and treatment of this disease. According to the research results of native and foreign authors systematization of modern diagnostic methods of PNP and detectable antigens was performed.

Conflict of interest: the authors state that there is no potential conflict of interest requiring disclosure in this article.

Paraneoplastic Pemphigus Revealed by Anti-programmed Death-1 Pembrolizumab Therapy for Cutaneous Squamous Cell Carcinoma Complicating Hidradenitis Suppurativa

A 64-year-old patient developed a widespread autoimmune mucocutaneous blistering disease 3 weeks after the initiation of the anti-programmed death-1 (anti-PD-1) pembrolizumab therapy administered for a locally advanced cutaneous squamous cell carcinoma (SCC) of the buttocks arising from hidradenitis suppurativa. A diagnosis of paraneoplastic pemphigus (PNP) was made based on the presence of a suprabasal acantholysis associated with intercellular deposits of immunoglobulin G and C3 on basement membrane zone. Analysis of the patient's sera was positive on monkey bladder and detected circulating antibodies against desmoglein 3 and desmoplakin I prior to the initiation of pembrolizumab. At that time, the patient had few localized blisters limited to the peri-tumoral skin of the buttocks with acantholysis but without in vivo immune deposits. Pembrolizumab therapy was discontinued and a complete remission of PNP was obtained using oral steroids. Reintroduction of pembrolizumab resulted in flare of PNP. Given the close temporal relation between pembrolizumab initiation and the subsequent clinical expression of a widespread PNP, the patient was diagnosed with pre-existing subclinical PNP exacerbated by PD-1 inhibitor. The extreme rarity of PNP in the setting of cutaneous SCC and the effects of challenge, dechallenge, and rechallenge of pembrolizumab argue in favor of a checkpoint inhibitor related adverse effect. Our case is the first PNP associated with anti-PD-1 therapy and serological follow-up suggest that one infusion of pembrolizumab is sufficient to allow clinical expression of underlying pemphigus auto-immunity.

Paraneoplastic pemphigus: a clinical, laboratorial, and therapeutic overview

Paraneoplastic pemphigus is a rare and severe autoimmune blistering disease characterized by mucocutaneous lesions associated with benign and malignant neoplasms. Diagnostic criteria include the presence of chronic mucositis and polymorphic cutaneous lesions with occult or confirmed neoplasia; histopathological analysis exhibiting intraepidermal acantholysis, necrotic keratinocytes, and vacuolar interface dermatitis; direct immunofluorescence with intercellular deposits (IgG and C3) and at the basement membrane zone (IgG); indirect immunofluorescence with intercellular deposition of IgG (substrates: monkey esophagus and simple, columnar, and transitional epithelium); and, autoreactivity to desmogleins 1 and 3, desmocollins 1, 2, and 3, desmoplakins I and II, envoplakin, periplakin, epiplakin, plectin, BP230, and α-2-macroglobulin-like protein 1. Neoplasias frequently related to paraneoplastic pemphigus include chronic lymphocytic leukemia, non-Hodgkin lymphoma, carcinomas, Castleman disease, thymoma, and others. Currently, there is no standardized treatment for paraneoplastic pemphigus. Systemic corticosteroids, azathioprine, mycophenolate mofetil, cyclosporine, rituximab, cyclophosphamide, plasmapheresis, and intravenous immunoglobulin have been used, with variable outcomes. Reported survival rates in 1, 2, and 5 years are 49%, 41%, and 38%, respectively.

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.

Cutaneous paraneoplastic syndromes

A variety of cutaneous abnormalities can be seen in patients with malignant diseases, some of which are infectious, with others representing direct involvement of the skin by the underlying disorder. Yet another group of lesions can be regarded as associated markers of the malignant process, and, as such, are termed "paraneoplastic." This review considers the latter collection of conditions, grouping them by the generic type of malignancy that is usually linked to the paraneoplasia. Some of the processes show a predominant association with alimentary tract malignancies (acanthosis nigricans, acrodermatitis paraneoplastica, florid cutaneous papillomatosis, necrolytic migratory erythema, palmoplantar keratoderma, pancreatic fat necrosis, and pityriasis rotunda). Others are usually linked to a hematolymphoid malignancy (acquired ichthyosis, exfoliative erythroderma, necrobiotic xanthogranuloma, pemphigus paraneoplastica, plane xanthoma, pyoderma gangrenosum, scleromyxedema, Sweet syndrome, and leukocytoclastic vasculitis). Finally, yet another collection of paraneoplastic skin disorders can associate themselves with anatomically-diverse malignancies (Leser-Trelat syndrome, Trousseau syndrome, dermatomyositis, erythema gyratum repens, hypertrichosis lanuginosa acquisita, papuloerythroderma of Ofuji, tripe palms, and multicentric reticulohistiocytosis). Recognition of these processes by the pathologist can be a valuable step in the characterization of underlying malignant diseases.

Paraneoplastic Pemphigus: Insight into the Autoimmune Pathogenesis, Clinical Features and Therapy

Paraneoplastic pemphigus is a rare autoimmune skin disease that is always associated with a neoplasm. Usually, oral, skin, and mucosal lesions are the earliest manifestations shown by paraneoplastic pemphigus patients. The pathogenesis of paraneoplastic pemphigus is not yet completely understood, although some immunological aspects have been recently clarified. Because of its rarity, several diagnostic criteria have been proposed. Besides, several diagnostic procedures have been used for the diagnosis, including indirect immunofluorescence, direct immunofluorescence, and ELISA. We reviewed the most recent literature, searching on PubMed "paraneoplastic pemphigus". We included also papers in French, German, and Spanish. We found 613 papers for "paraneoplastic pemphigus". Among them, 169 were review papers. Because of its varying clinical features, paraneoplastic pemphigus still represents a challenge for clinicians. Furthermore, diagnosis and management of paraneoplastic pemphigus requires close collaboration between physicians, including dermatologist, oncologist, and otorhinolaryngologist.

Spectrum of orocutaneous disease associations: Immune-mediated conditions

There are a number of diseases that manifest both on the skin and the oral mucosa, and therefore the importance for dermatologists in clinical practice to be aware of these associations is paramount. In the following continuing medical education series, we outline orocutaneous disease associations with both immunologic and inflammatory etiologies.

Achievement of the longest survival of paraneoplastic pemphigus with bronchiolitis obliterans associated with follicular lymphoma using R-CHOP chemotherapy

Paraneoplastic pemphigus (PNP) is a rare, fatal, paraneoplastic autoimmune mucocutaneous blistering disease, commonly associated with lymphoproliferative disorders, including malignant lymphomas. Lymphoproliferative disorders associated with PNP are sometimes associated with a serious lung complication, bronchiolitis obliterans (BO). Due to its rarity, guidelines for the management of PNP have not been established. Furthermore, most patients die within 1 year. Here we report the successful treatment of lymphoma-associated PNP and BO using R-CHOP chemotherapy. A 53-year-old Japanese man was admitted to our hospital for severe erosive stomatitis. Computed tomography and positron emission tomography showed multiple lymphadenopathies. He was diagnosed with follicular lymphoma (Ann Arbor stage IVA) and PNP-related BO. The patient underwent six cycles of R-CHOP and an additional cycle of rituximab. Both the erosive stomatitis and the obstructive lung disease persisted, but complete response of the follicular lymphoma was achieved. The patient survived 27 months after diagnosis. Although he died from progressive respiratory failure due to BO, we note that this patient achieved the longest survival of any reported case of PNP-related BO associated with a lymphoproliferative disorder. The present case suggests that intensive immunochemotherapy for underlying lymphoma may improve the prognosis in patients with PNP-related BO associated with lymphoma.

Paraneoplastic Pemphigus and Autoimmune Blistering Diseases Associated with Neoplasm: Characteristics, Diagnosis, Associated Neoplasms, Proposed Pathogenesis, Treatment

Autoimmune paraneoplastic and neoplasm-associated skin syndromes are characterized by autoimmune-mediated cutaneous lesions in the presence of a neoplasm. The identification of these syndromes provides information about the underlying tumor, systemic symptoms, and debilitating complications. The recognition of these syndromes is particularly helpful in cases of skin lesions presenting as the first sign of the malignancy, and the underlying malignancy can be treated in a timely manner. Autoimmune paraneoplastic and neoplasm-associated bullous skin syndromes are characterized by blister formation due to an autoimmune response to components of the epidermis or basement membrane in the context of a neoplasm. The clinical manifestations, histopathology and immunopathology findings, target antigens, associated neoplasm, current diagnostic criteria, current understanding of pathogenesis, and treatment options for a selection of four diseases are reviewed. Paraneoplastic pemphigus manifests with clinically distinct painful mucosal erosions and polymorphic cutaneous lesions, and is often associated with lymphoproliferative neoplasm. In contrast, bullous pemphigoid associated with neoplasm presents with large tense subepidermal bullae of the skin, and mild mucosal involvement, but without unique clinical features. Mucous membrane pemphigoid associated with neoplasm is a disorder of chronic subepithelial blisters that evolve into erosions and ulcerations that heal with scarring, and involves stratified squamous mucosal surfaces. Linear IgA dermatosis associated with neoplasm is characterized by annularly grouped pruritic papules, vesicles, and bullae along the extensor surfaces of elbows, knees, and buttocks. Physicians should be aware that these autoimmune paraneoplastic and neoplasm-associated syndromes can manifest distinct or similar clinical features as compared with the non-neoplastic counterparts.

Paraneoplastic Pemphigus: A Refractory Autoimmune Mucocutaneous Disease

Background and Objective:

We report on a 42-year-old man with Stage IIA non-Hodgkin's lymphoma who developed a severe mucocutaneous blistering eruption. His diagnosis, paraneoplastic pemphigus, was based on clinical, histological, and immunofluorescence findings and confirmed by immunoprecipitation. Despite maximal therapy with plasmapheresis, corticosteroids, and mycophenolate mofetil and the subsequent addition of cyclophosphamide and cyclosporine, the condition was fatal.

Conclusion:

This case illustrates the refractory nature of this disease and the inadequacy of existing therapies.

Systemic lupus erythematosus and pemphigus vulgaris: association or coincidence

Few cases have been published relating systemic lupus erythematosus (SLE) and pemphigus vulgaris (PV). We describe a patient with this association. A 35-year old woman who started to develop persistent pain and morning stiffness of proximal inter and metacarpo-phalangeal joints. During the following year, the patient recalled the onset of blisters on both legs, face, arms and thorax, as well as erosions appearing on oral mucous membranes. We observed generalized multiple erosions on her trunk and legs, flaccid bullae located on her right thigh and multiple erosions on oral mucous membranes. A skin biopsy reported PV. Direct immunofluorescence on the perilesional skin specimen, showed beehive intercellular IgG deposits in the epidermis (+++), suggesting PV; granular discontinuous IgM and C3 deposits in the dermal-epidermal union (+++), suggesting SLE. Direct immunofluorescence of the healthy unexposed skin specimen, reported granular discontinuous IgG deposits in the dermal-epidermal union and beehive intercellular IgG deposits in the lower levels of the epidermis (+++); granular continuous IgM deposits in the dermal-epidermal union (+++). The results of rheumatic studies were obtained as follows: ANA: 3 +, Anti-DNA, Anti-Sm, Anti-Ro and Anti-La: 4 +. The definite diagnosis was PVand SLE. Treatment with 50 mg of prednisone daily with good evolution.

Anti-early endosome antigen 1 autoantibodies were detected in a pemphigus-like patient but not in the majority of pemphigus diseases

Although the major autoantigens in classic pemphigus are desmogleins, sera from various types of pemphigus react with a number of other molecules, including desmocollins and plakin proteins. However, other novel pemphigus-related autoantigens remain to be identified. In this study, immunoblotting for serum from an atypical autoimmune bullous disease patient identified an unknown 175 kDa protein. Subsequent studies using two-dimensional gel electrophoresis, immunoblotting and mass-spectrometry identified the 175 kDa protein as early endosome antigen 1 (EEA1). This finding was confirmed by subsequent immunological studies, including indirect immunofluorescence of skin and cultured keratinocytes, two-dimensional gel electrophoresis and immunoblotting with anti-EEA1 polyclonal antibody, and preabsorption with EEA1 recombinant protein. Finally, we developed a novel BIOCHIP assay using full-length EEA1 recombinant protein to detect anti-EEA1 antibodies. However, none of 35 sera from various types of pemphigus showed anti-EEA1 antibodies in the BIOCHIP assay, with the exception of the serum from the index case. In addition, various findings in the index case did not suggest pathogenic role of anti-EEA1 autoantibodies. Therefore, although we successfully identified the 175 kDa protein reacted by a serum of an atypical pemphigus-like patient as EEA1, novel BIOCHIP study for other pemphigus sera indicated that EEA1 is not a common and pathogenic autoantigen in pemphigus.

Laboratory diagnosis of paraneoplastic pemphigus

BACKGROUND

Paraneoplastic pemphigus (PNP) is a multiorgan disease characterized by antibodies against plakins, desmogleins and the α2-macroglobulin-like-1 (A2ML1) protein, in association with an underlying neoplasm. Accurate diagnosis relies on the demonstration of these autoantibodies in serum.

OBJECTIVES

To evaluate the value of different laboratory techniques in the serological diagnosis of PNP.

METHODS

We performed immunoblotting, envoplakin (EP) enzyme-linked immunosorbent assay (ELISA), indirect immunofluorescence (IIF) on rat bladder, radioactive immunoprecipitation and a nonradioactive combined immunoprecipitation-immunoblot assay. Additional assays included BP180 ELISA and BP230 ELISA. We included the sera of 19 patients with PNP and 40 control subjects.

RESULTS

The sensitivities were 63% for anti-EP ELISA, 74% for rat bladder IIF, 89% for immunoblotting, 95% for radioactive immunoprecipitation and 100% for nonradioactive immunoprecipitation. Specificities ranged from 86% to 100%. The BP180 and BP230 ELISAs had low sensitivity and specificity for PNP. The combination of rat bladder IIF and immunoblot showed 100% sensitivity and specificity. The analysis of sequential PNP sera showed that antibody titres may decrease over time, possibly resulting in negative outcomes for EP ELISA and rat bladder IIF studies.

CONCLUSIONS

The detection of autoantibodies against EP and periplakin, or A2ML1 by immunoprecipitation is most sensitive for PNP. The combination of rat bladder IIF and immunoblotting is equally sensitive and highly specific, and represents an alternative valuable and relatively easy approach for the serological diagnosis of PNP.

Anti-α-2-macroglobulin-like-1 autoantibodies are detected frequently and may be pathogenic in paraneoplastic pemphigus

Paraneoplastic pemphigus (PNP) shows autoantibodies mainly to plakin and desmosomal cadherin family proteins. We have recently identified alpha-2-macroglobulin-like-1 (A2ML1), a broad range protease inhibitor, as a unique PNP antigen. In this study, we tested a large number of PNP sera by various methods. Forty (69.0%) of 58 PNP sera recognized A2ML1 recombinant protein expressed in COS7 cells by immunofluorescence (IF) and/or immunoprecipitation (IP)/immunoblotting (IB). IP/IB showed higher sensitivity than IF. In addition, 22 (37.9%) PNP sera reacted with A2ML1 by IB of cultured normal human keratinocytes (NHKs) under non-reducing conditions. Statistical analyses using various clinical and immunological data showed that the presence of anti-A2ML1 autoantibodies was associated with early disease onset and absence of ocular lesions. Next, to investigate the pathogenic role of anti-A2ML1 antibody, we performed additional functional studies. Addition of anti-A2ML1 polyclonal antibody to culture media decreased NHK cell adhesion examined by dissociation assay, and increased plasmin activity detected by casein zymography, suggesting that anti-A2ML1 antibody may decrease NHK cell adhesion through plasmin activation by inhibition of A2ML1. This study demonstrates that autoantibodies to A2ML1 are frequently and specifically detected and may have a pathogenic role in PNP.

Paraneoplastic pemphigus

Paraneoplastic pemphigus (PNP) is a distinct autoimmune blistering disease that can affect multiple organs other than the skin. It occurs in association with certain neoplasms, among which lymphoproliferative diseases are most commonly associated. The clinical presentation of PNP consists typically of painful, severe oral erosions that may be accompanied by a generalised cutaneous eruption and systemic involvement. The eruption may be of different morphology, consisting of lesions that resemble pemphigus, pemphigoid, erythema multiforme or graft versus host disease, as well as lesions resembling lichen planus. Similarly, the histological findings also show considerable variability. PNP is characterised by the presence of autoantibodies against various antigens: desmoplakin I (250 kd), bullous pemphigoid antigen I (230 kd), desmoplakin II (210 kd), envoplakin (210 kd), periplakin (190 kd), plectin (500 kd) and a 170-kd protein. This 170-kd protein has recently been identified as alpha-2-macroglobulin-like-1, a broad range protease inhibitor expressed in stratified epithelia and other tissue damaged in PNP. The prognosis of PNP is poor and the disease is often fatal. Immunosuppressive agents are often required to decrease blistering, and treating the underlying malignancy with chemotherapy may control autoantibody production. The prognosis is better when PNP is associated with benign tumours and these should be surgically excised when possible.

Diagnosis and treatment of pemphigus

Pemphigus is an autoimmune bullous disease, in which autoantibodies react with the cell–cell adhesion structures, desmosomes, causing blisters and erosions on the oral mucosa and skin. Pemphigus is divided into two major subtypes: pemphigus vulgaris and pemphigus foliaceus. Oral corticosteroids are the primary treatment modality for pemphigus, while other therapeutic options, such as steroid pulse therapy, immunosuppressants, intravenous immunoglobulins, plasmapheresis and anti-CD20 monoclonal antibody therapy, are occasionally employed. Immunosuppressants used to treat pemphigus include azathioprine, cyclophosphamide, cyclosporine, mycophenolate mofetil and mizoribine. In this review, we summarize the current concepts of immunotherapy for the treatment of pemphigus in the Japanese population.

The protease inhibitor alpha-2-macroglobulin-like-1 is the p170 antigen recognized by paraneoplastic pemphigus autoantibodies in human

Background

Paraneoplastic pemphigus (PNP) is a devastating autoimmune blistering disease, involving mucocutaneous and internal organs, and associated with underlying neoplasms. PNP is characterized by the production of autoantibodies targeting proteins of the plakin and cadherin families involved in maintenance of cell architecture and tissue cohesion. Nevertheless, the identity of an antigen of Mr 170,000 (p170), thought to be critical in PNP pathogenesis, has remained unknown.

Methodology/Principal Findings

Using an immunoprecipitation and mass spectrometry based approach, we identified p170 as alpha-2-macroglobuline-like-1, a broad range protease inhibitor expressed in stratified epithelia and other tissues damaged in the PNP disease course. We demonstrate that 10 PNP sera recognize alpha-2-macroglobuline-like-1 (A2ML1), while none of the control sera obtained from patients with bullous pemphigoid, pemphigus vulgaris, pemphigus foliaceus and normal subjects does.

Conclusions/Significance

Our study unravels a broad range protease inhibitor as a new class of target antigens in a paraneoplastic autoimmune multiorgan syndrome and opens a new challenging investigation avenue for a better understanding of PNP pathogenesis.

Clinical and immunopathological spectrum of paraneoplastic pemphigus

BACKGROUND

Paraneoplastic pemphigus (PNP) is a rare life-threatening autoimmune bullous disorder. The clinical picture is often polymorphous and blisters may be absent. Autoantibodies are directed against several target antigens, including plakins and desmogleins. PNP has a high mortality rate that does not directly depend on the malignancy of the neoplasm. No generally accepted diagnostic criteria for PNP have been defined.

PATIENTS AND METHODS

On the basis of four selected PNP patients and the relevant literature, the spectrum of clinical and immunopathological findings as well as pathogenesis and treatment options of PNP are presented.

RESULTS

In addition to a neoplasm, severe stomatitis and the presence of autoantibodies against periplakin and envoplakin are characteristic for PNP. Based on the presented data, diagnostic criteria are proposed.

CONCLUSIONS

Knowledge of the polymorphous clinical picture and the complex autoantibody response is essential for an early diagnosis of PNP which has implications for both prognosis and rapid initiation of treatment.

Place of human amniotic membrane immunoblotting in the diagnosis of autoimmune bullous dermatoses

BACKGROUND

Fine analysis of antiskin autoantibodies can contribute to the differential diagnosis of autoimmune bullous dermatoses.

OBJECTIVES

To develop a high-performance immunoblotting method using human amniotic membrane as the antigen source, and to compare it with current laboratory methods.

METHODS

Sera from 113 patients were tested by immunoblotting (IB), rat and monkey oesophagus and salt-split skin indirect immunofluorescence (IIF), and enzyme-linked immunosorbent assay (ELISA) quantification of anti-BP180-NC16a and anti-BP230, or antidesmoglein (Dsg) 1 and 3 antibodies. There were 56 cases of bullous pemphigoid (BP), 22 cases of mucous membrane pemphigoid (MMP), eight cases of epidermolysis bullosa acquisita (EBA), two cases of bullous systemic lupus erythematosus (BSLE), 17 cases of pemphigus vulgaris (PV), and four cases each of pemphigus foliaceus (PF) and paraneoplastic pemphigus (PNP).

RESULTS

In BP, the three methods had similar sensitivity (84-89%) for both anti-BP180-NC16a and anti-BP230 antibody detection. In MMP, autoantibodies (mainly directed against BP180 or laminin 332 subunits) were detected in 77% of patients by IB, compared with only 9% by IIF on rat and monkey oesophagus and 36% on salt-split skin, and 14% by anti-BP180-NC16a and anti-BP230 ELISA. In patients with pemphigus, ELISA had 92% sensitivity for anti-Dsg1 and 3, but IB and rat bladder IIF were necessary to confirm PNP by revealing specific and rare patterns (antidesmoplakin I/II, antienvoplakin and antiperiplakin antibodies). IB also revealed anticollagen VII antibodies in 60% of patients with EBA and BSLE, and antibodies to BP180, BP230 and Dsg3 in a few patients who were negative using the other two techniques.

CONCLUSION

Amniotic membrane immunoblotting is an interesting diagnostic tool for bullous diseases, as the entire panel of autoantibodies can be detected with a single extract. This method improves the identification of complex and heterogeneous autoimmune processes in conjunction with IIF and ELISA, and is particularly useful for MMP characterization.

Immunoglobulin variable region gene analysis to the autoantibody-secreting B cells from tumors in association with paraneoplastic autoimmune multiorgan syndrome

OBJECTIVES

We have studied the role of lymphoproliferative tumors in the pathogenesis of autoimmune and the origin of the autoantibodies in PNP. Objectives of this study is to understand the characteristics of immunoglobulin genes of the B-cells isolated from the tumor which can produce auto-antibody.

METHODS

Total RNA of the tumor cells was then isolated and the mRNA was reversely transcribed into cDNA. V(H) and V(L) genes were amplified and cloned and their sequences were analyzed.

RESULTS

49 V(H) genes (527 to 577 bp) and 36 V(L) genes (445 to 454 bp) sequences were cloned from five tumors. All of the IgV(L) were mostly homologous to IGKV4-01 germ-line gene. The frequency of IgV(H) germ-line gene usage in a decreasing order was IGHV3-23 > IGHV3-9 > IGHV4-31 > IGHV4-59. There was more nucleotide changes occurred in complementary determining regions (CDR) than those in the framework regions (FR) in the V(H) and V(L) of B cell clones. In both V(H) and V(L), the probability (P) that the number of observed replacement mutations (R) in the CDRs would occur by random chance was low.

CONCLUSIONS

The clones of B-lymphocytes in the tumors carrying possibly functional rearranged immunoglobulin heavy and light chain genes were isolated and there were high incidences of somatic mutations in CDRs and relatively conserved sequences in framework region.

Genotyping of HLA-I and HLA-II alleles in Chinese patients with paraneoplastic pemphigus

BACKGROUND

Class I and class II HLA genes are thought to play a role in the immunopathogenesis of bullous dermatoses such as pemphigus vulgaris and pemphigus foliaceus, but we know little about the genetic background of paraneoplastic pemphigus (PNP) in Chinese patients.

OBJECTIVES

To identify class I and class II HLA alleles by genotyping in Chinese patients with PNP, and to find out the possible association between HLA alleles and disease susceptibility.

METHODS

Nineteen Chinese patients with PNP were enrolled in this study. HLA-A, B, C, DRB1 and DQB1 alleles were typed by polymerase chain reaction and a colour-coded sequence-specific oligonucleotide probes method.

RESULTS

The frequencies of HLA-B*4002/B*4004, B*51, B*52, Cw*14, DQB1*0301, DRB1*08 and DRB1*11 were relatively prevalent in Chinese Han patients with PNP in comparison with normal controls. After correction for multiple comparisons, Cw*14 remained statistically significant, and the other alleles were unremarkable in these patients.

CONCLUSIONS

The genetic background predisposing to PNP may be different in patients from various races and areas. HLA-Cw*14 may be the predisposing allele to PNP in Chinese patients, which is different from the predisposing allele in French patients with PNP and the alleles predisposing to pemphigus vulgaris and pemphigus foliaceus.

Paraneoplastic pemphigus

Paraneoplastic pemphigus (PNP) is a life-threatening autoimmune blistering skin disease. Clinically, it is characterized by severe mucosal erosions and various cutaneous lesions associated with lymphoproliferative neoplasmas. Suprabasal acantholysis and clefts with scattered necrotic keratinocytes are the unique histopathological features. PNP patient sera recognize multiple antigens, which have been identified as the plakin protein family that includes desmoplakin, bullous pemphigoid antigen I (BPAG1), envoplakin and periplakin, and desmogleins 1 and 3. Castleman's tumor, non-Hodgkin's lymphoma, thymoma, follicular dendritic cell sarcoma and chronic lymphocytic leukemia are the commonly associated neoplasmas in PNP. We have also demonstrated that the autoantibodies reacting to epidermal proteins are directly produced by the cells in the associated tumors. Bronchiolitis obliterans is frequently found in PNP and may cause respiratory failure and death. In our experience, the early detection and removal of the tumor and i.v. administration of immunoglobulin are critical for the treatment of PNP.

Paraneoplastic pemphigus

A paraneoplasticus pemphigus malignus vagy benignus tumorokhoz társuló autoimmun hólyagos megbetegedés diagnosztikus és immunológiai kritériumait 1990-ben fektette le Anhalt . Klinikailag súlyos, fájdalmas, mélyre terjedő bőr- és nyálkahártyatünetek jellemzik. A bőrtünetek polimorf jellegűek, általában dominál a hólyagképződés. Egyes esetekben, az ún. „graft-versus-host-disease” formákban előfordul, hogy kizárólag papulosus, lichenoid bőrtünetek észlelhetők, hólyagképződés nincs, vagy csak később jelenik meg. Elsősorban ezen alcsoport betegeiben a bőr- és nyálkahártyatünetek mellett súlyos dyspnoét okozó pulmonalis érintettség is kialakul, melynek hátterében bronchiolitis obliterans áll. A paraneoplasticus pemphigus diagnosztikájában alapvető fontosságú a bőr/nyálkahártyák direkt immunfluoreszcens, továbbá a szérum indirekt immunhisztológiai és immunoblot vizsgálata. Az eddig azonosított autoantigének döntő többsége a plakincsalád tagja: envoplakin (210 kDa), periplakin (190 kDa), plectin (~500 kDa), desmoplakin I (250 kDa), desmoplakin II (210 kDa), bullosus pemphigoid antigén 1 (230 kDa). A plakinok mellett a desmosomalis cadherinek közé sorolt desmoglein 1 és 3 a bullosus pemphigoid antigén 2 (180 kDa), a desmocollin 2 és 3, továbbá egy még nem azonosított, 170 kDa molekulatömegű transzmembrán fehérje szintén autoantigénje a kórképnek. A paraneoplasticus pemphigus nagy mortalitású kórkép, az esetek több mint 90%-ában halálos kimenetelű. A háttérben álló tumor eltávolítása mellett a bázisterápia továbbra is a nagy dózisú szisztémás szteroidkezelés, melyet citosztatikumok, immunmodulánsok adásával egészítenek ki. Szóba jön ezenkívül plasmapheresis, plazmacsere, photopheresis, nagy dózisú intravénás immunglobulin és anti-CD20 monoklonális antitest (rituximab) adása is.

Epitopes in the linker subdomain region of envoplakin recognized by autoantibodies in paraneoplastic pemphigus patients

Sera from paraneoplastic pemphigus (PNP) immunoprecipitate multiple antigens from human epidermal protein extract. In this study, we further characterized the autoantibodies in 12 PNP sera. Immunoblotting using recombinant linker subdomains of envoplakin, periplakin, desmoplakin, and bullous pemphigoid antigen I found that 11 of the 12 sera recognized linker subdomains of envoplakin and periplakin. We then synthesized 12 peptides covering the linker subdomain of envoplakin for ELISA. One of the peptides, peptide no. 8, was recognized by nine out of the 12 sera with a higher affinity. A method of ligand-receptor binding assay was designed and performed using this peptide labeled with fluorescence as the ligand. Peptide no. 8 bound to CD20+ cells in Castleman's tumors from the patients whose sera were positive to this peptide by ELISA. Our data suggest that the linker subdomain of plakin proteins may be one of the major areas recognized by PNP autoantibodies, and epitopes in the linker subdomain of envoplakin recognized by PNP autoantibodies with a high affinity are dispersed in several areas and are variable among PNP patients. We also demonstrate that B-lymphocyte clones specifically reacting to epidermal proteins exist in Castleman's tumors from PNP.

Antidesmoplakin antibodies in pemphigus vulgaris

BACKGROUND

Besides being present in paraneoplastic pemphigus (PNP), circulating antidesmoplakin (DP) antibodies have been found anecdotally in other bullous diseases, including pemphigus foliaceus and pemphigus vulgaris.

OBJECTIVES

To verify how frequent anti-DP antibodies are in pemphigus vulgaris.

METHODS

We studied 48 sera from patients with proven pemphigus vulgaris (29 mucosal dominant pemphigus and 19 mucocutaneous pemphigus) by indirect immunofluorescence (IIF) with rat bladder epithelium (RBE) as a substrate and by immunoblotting (IB) on human keratinocyte cultures enriched in DP.

RESULTS

Ten sera (21%) were positive in IIF on RBE. By IB, eight sera proved to have antibodies to both DP I (250 kDa) and DP II (210 kDa), one serum had antibodies directed to DP I only, and two sera to DP II only.

CONCLUSIONS

Our data confirm that RBE is not a specific IIF substrate for the serological diagnosis of PNP. It remains a sensitive and specific substrate for the detection of anti-DP antibodies, which, in patients with pemphigus vulgaris, are probably caused by an epitope-spreading phenomenon.