Production of numerous autoantibodies in paraneoplastic pemphigus

[Paraneoplastic autoimmune dermatoses]

Paraneoplastic skin manifestations associated with malignancies are extremely polymorphous. Clinicians should be familiar with paraneoplastic dermatoses to establish an early diagnosis of the underlying neoplasm. Lack of familiarity with cutaneous clues for internal malignancies may delay diagnosis and treatment of cancer. In this review, we describe several paraneoplastic autoimmune dermatoses, including paraneoplastic autoimmune multiorgan syndrome, paraneoplastic bullous pemphigoid, and paraneoplastic dermatomyositis.

Immune serological diagnosis of pemphigus

Pemphigus is a rare autoimmune blistering disease which manifests with painful erosions and blisters of the skin and mucosa. This disorder is caused by autoantibodies attacking desmosomal proteins, necessary for cell-cell contact stability and epidermal integrity. Desmoglein (Dsg) 1 and Dsg3 are the two major target antigens in pemphigus. Yet, many other target proteins, which have been described over the years, seem to be involved in the loss of epidermal integrity. Clinical examination, combined to serological advances and detection of targeted antigens, permitted to differentiate among several pemphigus subtypes, in which pemphigus vulgaris and pemphigus foliaceus are the most common. Nowadays, serological analysis in pemphigus is a fundamental step of the diagnostic algorithm. This is based on analysis of clinical symptoms, histopathological examination of lesional skin, detection of tissue bound and circulating antibodies by direct and indirect immunofluorescence, and determination of target antigens either by enzyme-linked immunosorbent essay (ELISA) or by western blot analysis. A correct and exhaustive diagnostic algorithm is fundamental to characterize pemphigus subtypes, which lastly permits to adopt a correct treatment approach. Moreover, quality and quantity of circulating antibodies in patient's sera deliver important information regarding clinical course, disease severity and treatment response; thus, relevantly affecting physician's decision. To facilitate this process, "easy-to-perform" diagnostic kits with high sensitivity and specificity are being commercialized. In this review, we focus on available methods and established assays to correctly detect circulating autoantibodies in pemphigus. Moreover, we discuss subtype specific serological peculiarities in the five most relevant subtypes (pemphigus vulgaris, pemphigus foliaceus, pemphigus vegetans, paraneoplastic pemphigus and intercellular IgA dermatosis (also called as IgA pemphigus).

Paraneoplastic autoimmune multiorgan syndrome

Originally described by Anhalt as paraneoplastic pemphigus in 1990, paraneoplastic autoimmune multiorgan syndrome (PAMS) is a potentially lethal blistering disease, characterized by polymorphous clinical features, including mucocutaneous erosions, blisters, lichenoid papules, and erythemas. Several autoantibodies have been detected in serum of PAMS patients, including antiplakins, anti-alpha-2-macroglobulin like 1, and antidesmogleins autoantibodies. The mortality rate of PAMS is up to 90%. This is due on the one hand to the poor response to treatments and on the other hand to the delay in the diagnosis and to the prognosis of the underlying neoplasia.

Thymoma-Associated Paraneoplastic Autoimmune Multiorgan Syndrome-From Pemphigus to Lichenoid Dermatitis

Introduction: Paraneoplastic autoimmune multi-organ syndrome (PAMS) is a rare clinical condition characterized by variable and heterogeneous clinical phenotypes in the presence of neoplasias which largely depend on the activation of humoral and cellular immune responses. Clinically, these patients present with a spectrum of antibody-driven pemphigus-like lesions to graft-vs.-host-disease-like exanthemas with a lichenoid inflammatory infiltrate in the skin. PAMS is occasionally associated with thymoma, in which altered immune surveillance eventually leads to multiorgan autoimmunity which often includes variable cutaneous symptoms. This disorder is associated with a profound disturbance of peripheral immune tolerance against human autoantigens. Objectives: We here present a patient with relapsing thymoma who developed PAMS with several cutaneous and extracutaneous autoimmune disorders. Materials: Peripheral blood mononuclear cells (PBMC), sera, and lesional skin biopsies were obtained at different clinical disease stages. Peripheral T cell subsets were characterized phenotypically and the cytokine profile of the peripheral blood T cellular response against distinct epidermal and dermal autoantigens of the skin was analyzed by ELISpot assay. Serological screening was performed by ELISA and immunoblot analysis. Skin biopsies were subjected to immunohistochemical analysis of distinct T cell subsets. Thymoma tissue was analyzed for the presence of T regulatory cells and compared with adult thymus and indolent thymoma. Results and Conclusions: In the present case, thymoma was the cause of the observed multi-organ autoimmune syndromes as its recurrence and surgical removal was associated with the relapse and regression of the cutaneous symptoms, respectively. Initially, the patient presented with two autoimmune disorders with Th2/Th1 imbalance, myasthenia gravis (MG) and pemphigus foliaceus (PF), which regressed upon immunosuppressive treatment. Months later, the patient developed a lichenoid exanthema with a Th1-dominated skin infiltrate. Further clinical evaluation revealed the recurrence of the thymoma and the lichenoid exanthema gradually regressed upon thymectomy. Our contention that T cell recognition against distinct cutaneous autoantigens, such as desmoglein 1 (Dsg1), shifted from a Th2 to a Th1-dominated immune response could not be fully substantiated as the patient was on a stringent immunosuppressive treatment regimen. We could only observe a decrease of the initially present serum IgG autoantibodies against Dsg1. Phenotypic analysis of the associated thymoma showed a lower number of T regulatory cells compared to adult thymus and indolent thymoma, suggesting that impaired thymus-derived immune surveillance had a direct impact on the outcome of the observed cutaneous autoimmune disorders.

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 short review

Paraneoplastic pemphigus (PNP) is a fatal autoimmune blistering disease associated with an underlying malignancy. It is a newly recognized blistering disease, which was first recognized in 1990 by Dr Anhalt who described an atypical pemphigus with associated neoplasia. In 2001, Nguyen proposed the term paraneoplastic autoimmune multiorgan syndrome because of the recognition that the condition affects multiple organ systems. PNP presents most frequently between 45 and 70 years old, but it also occurs in children and adolescents. A wide variety of lesions (florid oral mucosal lesions, a generalized polymorphous cutaneous eruption, and pulmonary involvement) may occur in patients with PNP. The earliest and most consistent finding is severe stomatitis. There is a spectrum of at least five clinical variants with different morphology. Similarly, the histological findings are very variable. Investigations to diagnose PNP should include checking for systemic complications (to identify tumor), skin biopsies (for histopathological and immunofluorescence studies), and serum immunological studies. PNP is characterized by the presence of autoantibodies against antigens such as desmoplakin I (250 kD), bullous pemphigoid aniygen I (230 kD), desmoplakin II (210 kD), envoplakin (210 kD), periplakin (190 kD), plectin (500 kD), and a 170 kD protein. Unlike other forms of pemphigus, PNP can affect other types of epithelia, such as gastrointestinal and respiratory tract. Treatment of PNP is difficult, and the best outcomes have been reported with benign neoplasms that have been surgically excised. The first-line treatment is high-dose corticosteroids with the addition of steroid-sparing agents. Treatment failures are often managed with rituximab with or without concomitant intravenous immunoglobulin. In general, the prognosis is poor, not only because of eventual progression of malignant tumors but also because treatment with aggressive immunosuppression therapy often results in infectious complications, which is unfortunately at this time the most common cause of death in PNP.