Paraneoplastic pemphigus: the role of tumours and drugs

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.

[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.

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.

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.

Pemphigus: Current and Future Therapeutic Strategies

Pemphigus encompasses a heterogeneous group of autoimmune blistering diseases, which affect both mucous membranes and the skin. The disease usually runs a chronic-relapsing course, with a potentially devastating impact on the patients' quality of life. Pemphigus pathogenesis is related to IgG autoantibodies targeting various adhesion molecules in the epidermis, including desmoglein (Dsg) 1 and 3, major components of desmosomes. The pathogenic relevance of such autoantibodies has been largely demonstrated experimentally. IgG autoantibody binding to Dsg results in loss of epidermal keratinocyte adhesion, a phenomenon referred to as acantholysis. This in turn causes intra-epidermal blistering and the clinical appearance of flaccid blisters and erosions at involved sites. Since the advent of glucocorticoids, the overall prognosis of pemphigus has largely improved. However, mortality persists elevated, since long-term use of high dose corticosteroids and adjuvant steroid-sparing immunosuppressants portend a high risk of serious adverse events, especially infections. Recently, rituximab, a chimeric anti CD20 monoclonal antibody which induces B-cell depletion, has been shown to improve patients' survival, as early rituximab use results in higher disease remission rates, long term clinical response and faster prednisone tapering compared to conventional immunosuppressive therapies, leading to its approval as a first line therapy in pemphigus. Other anti B-cell therapies targeting B-cell receptor or downstream molecules are currently tried in clinical studies. More intriguingly, a preliminary study in a preclinical mouse model of pemphigus has shown promise regarding future therapeutic application of Chimeric Autoantibody Receptor T-cells engineered using Dsg domains to selectively target autoreactive B-cells. Conversely, previous studies from our group have demonstrated that B-cell depletion in pemphigus resulted in secondary impairment of T-cell function; this may account for the observed long-term remission following B-cell recovery in rituximab treated patients. Likewise, our data support the critical role of Dsg-specific T-cell clones in orchestrating the inflammatory response and B-cell activation in pemphigus. Monitoring autoreactive T-cells in patients may indeed provide further information on the role of these cells, and would be the starting point for designating therapies aimed at restoring the lost immune tolerance against Dsg. The present review focuses on current advances, unmet challenges and future perspectives of pemphigus management.

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.

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.

Pemphigus

Pemphigus vulgaris and paraneoplastic pemphigus are 2 subtypes of pemphigus that involve the oral mucosa. These autoimmune blistering disorders have antibodies targeted against proteins of keratinocyte adhesion, thereby causing acantholysis. Clinical findings include oral erosions and flaccid cutaneous bullae and erosions. Further malignancy workup in patients with suspected paraneoplastic pemphigus is warranted. Retrospective uncontrolled studies suggest that immunosuppressive agents reduce mortality in pemphigus vulgaris and cohort uncontrolled studies of rituximab, a monoclonal antibody against CD20, suggest it is an effective treatment for refractory patients. Ongoing studies will define its role in early disease.

Paraneoplastic pemphigus: a paraneoplastic autoimmune multiorgan syndrome or autoimmune multiorganopathy?

Paraneoplastic pemphigus (PNP), a clinically and immunopathologically distinct mucocutaneous blistering dermatosis, is a severe form of autoimmune multiorgan syndrome generally associated with poor therapeutic outcome and high mortality. This IgG-mediated disease is initiated by an obvious or occult lymphoproliferative disorder in most cases. Clinically severe mucositis, and polymorphic blistering skin eruptions, and histologically acantholysis, keratinocyte necrosis and interface dermatitis are its hallmark features. A 58-year-old female presented with recurrent, severe, recalcitrant stomatitis and widespread erosions/blistering lesions of one-year duration. Treatment with repeated courses of systemic corticosteroids at a peripheral center would provide temporary relief. She also had fever, productive cough, odynophagia and poor oral intake, herpes zoster ophthalmicus, pain in the abdomen, and watery diarrhea. An array of investigations revealed chronic lymphocytic leukemia (CLL), mediastinal and para-aortic lymphadenopathy, bronchiolitis obliterans, and vertebral osteoporosis/fractures. With the diagnosis of CLL-associated PNP she was managed with dexamethasone-cyclophosphamide pulse (DCP) therapy for 3 cycles initially, followed by COP regimen (cyclophosphamide, vincristine, and prednisolone) for 5 cycles. Remission is being maintained with chlorambucil and prednisolone pulse therapy once in 3 weeks with complete resolution of skin lesions and adequate control of CLL.

Cutaneous manifestations of internal malignancy

Background:

Many malignancies affecting the internal organs display cutaneous manifestations which may be either specific (tumor metastases) or nonspecific lesions.

Aims:

The study is aimed at determining the frequency and significance of cutaneous manifestations among patients with internal malignancy.

Materials and Methods:

750 cases of proven internal malignancy, who attended a cancer chemotherapy center in South India, were studied. Specific infiltrates were confirmed by histopathology, fine needle aspiration cytology (FNAC) and marker studies.

Results:

Out of the 750 patients with internal malignancy, skin changes were seen in a total of 52 (6.93%) patients.

Conclusion:

Cutaneous metastases (specific lesions) were seen in 20 patients (2.66%): contiguous in 6 (0.8%), and non-contiguous in 14 (1.86%). Nonspecific skin changes were seen in 32 patients (4.26%). None of our patients presented with more than one type of skin lesions. Herpes zoster was the most common nonspecific lesion noticed in our patients, followed by generalized pruritus, multiple eruptive seborrheic keratoses, bullous disorder, erythroderma, flushing, purpura, pyoderma gangrenosum, insect bite allergy and lichenoid dermatitis.

Autoimmune bullous diseases associations

The presence of one autoimmune disorder helps lead to the discovery of other autoimmune conditions. It is thought that diseases in which autoimmunity is a feature tend to be associated together more often than one can ascribe to chance. A variety of diseases have been implicated in the onset of intraepidermal and subepidermal autoimmune diseases. The presence of one autoimmune disease should alert the physician to watch for a second immunologic disorder. A list of autoimmune bullous diseases associations includes autoimmune bullous diseases, pemphigus, pemphigoid, epidermolysis bullosa acquisita, dermatitis herpetiformis (Duhring), linear immunoglobulin A disease, and multiple autoimmune syndrome.

Approach to the patient with autoimmune mucocutaneous blistering diseases

Autoimmune mucocutaneous blistering diseases (AMBD) are a rare group of dermatoses that can be potentially fatal. There are many subtypes and their clinical presentation can vary from being localized to general involvement. It is crucial that a diagnosis be made as early as possible and appropriate treatments are implemented. This article will discuss the diagnosis and available treatments of the major AMBDs. There are very few case-controlled studies regarding the treatments of these diseases. Most of the treatments used for these diseases are based on anecdotal reports. Hence, a synopsis of the conventional treatments and some brief recommendations will also be discussed. A brief discussion regarding "rescue" therapies that have been used for those patients with more recalcitrant cases of AMBD will also be presented.

Paraneoplastic autoimmune multiorgan syndrome: Review of the literature and support for a cytotoxic role in pathogenesis

Paraneoplastic autoimmune multiorgan syndrome (PAMS), first described as paraneoplastic pemphigus in 1990, is an autoimmune blistering disease associated with neoplasia. Patients with this rare disorder have severe blistering and painful erosions of the oral cavity and various other cutaneous findings ranging from classic pemphigus vulgaris-like erosions to targetoid lesions resembling erythema multiforme and papular to more confluent lichenoid eruptions. This syndrome involves multiple organ systems, and its high rate of mortality often stems from constrictive bronchiolitis obliterans. The histologic findings are as diverse as the clinical presentation, often making diagnosis difficult initially. Immunodermatologic and serologic laboratory findings typically establish the diagnosis. These results can be confirmed with immunoprecipitation profiling of specific molecular weight protein markers. The proposed pathogenesis of PAMS continues to evolve, and recent reports implicate the involvement of cell-mediated, cytotoxic immunity, in addition to humoral autoantibodies. This review characterizes and summarizes the clinical, pathologic, and immunohistologic features of PAMS and outlines the possible role of cytotoxic T lymphocytes in the pathogenesis of this syndrome.

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.

Autoantibody production from a thymoma and a follicular dendritic cell sarcoma associated with paraneoplastic pemphigus

BACKGROUND

Paraneoplastic pemphigus (PNP) is an autoimmune mucocutaneous disease. We previously reported that B cells in a Castleman tumour associated with PNP produced autoantibodies. However, it is uncertain whether the production of autoantibodies from the associated tumour is a common mechanism in PNP.

OBJECTIVES

To investigate autoantibody production in a thymoma and a follicular dendritic cell sarcoma that were excised from two patients with PNP.

METHODS

Tumour cells were cultured, and their surface markers were identified. Indirect immunofluorescence, immunoblotting and enzyme-linked immunosorbent assay (ELISA) using culture media from the tumours were used to detect PNP autoantibodies.

RESULTS

B cells with markers (CD22+, surface membrane IgG+ and surface membrane IgM+) of mature B lymphocytes constituted a proportion of cultured tumour cells in both tumours. Western blot showed that the medium from both the thymoma and the follicular dendritic cell sarcoma cells recognized 190-kDa periplakin and 210-kDa envoplakin bands of human epithelial proteins as well as recombinant linker regions of periplakin, envoplakin, desmoplakin and bullous pemphigoid antigen 1. ELISA was positive for antidesmoglein 3 antibody.

CONCLUSIONS

The presence and localization in tumours of B-lymphocyte clones against proteins of the plakin family and desmoglein 3 in skin may not be confined to PNP with Castleman disease, but is possibly a common mechanism in PNP associated with various tumours.

Life-threatening paraneoplastic cutaneous syndromes

Paraneoplastic syndromes are diseases or symptom complexes associated with malignancy, usually internal. In dermatology, we modify the definition to refer to dermatoses associated with internal malignancy. In this article, we discuss the link between malignancy and such dermatologic disorders as acanthosis nigricans, acrokeratosis paraneoplastica of Bazex, dermatomyositis, erythema gyratum repens, necrolytic migratory erythema (glucagonoma syndrome), and paraneoplastic pemphigus and discuss, where such information is known, the mechanism by which these paraneoplastic diseases occur.

Oral pemphigus vulgaris in children and adolescents: a review of the literature and a case report

This paper describes a case of oral pemphigus vulgaris (PV) in a child that was diagnosed in its early stages and managed successfully. The authors also report a literature review. Although oral PV in children and adolescents is extremely rare, it should be included in the differential diagnosis of oral ulcerative disease. It is of utmost importance to diagnose PV in children and adolescents in its initial stages in order to prevent the serious morbidity that may result from the disease, and to institute phamacotherapeutic measures so that they have the greatest effect. Furthermore, it is essential for dentists to be aware of the existence of PV in child and adolescent patients so that they may refer such cases for specialist management without undue delay.

Paraneoplastic pemphigus: A brief update

First described in 1990, paraneoplastic pemphigus is an autoimmune condition that causes considerable morbidity, is resistant to therapy and is frequently fatal. Clinical heterogeneity is being recognized as more cases are reported and the documented auto-antigen profile is also increasing. Target antigens are now known to be not restricted to the skin, suggesting that this condition is part of a paraneoplastic autoimmune multiorgan syndrome.

Pemphigus

Pemphigus is an umbrella term for more than 10 different epidermal disease types and subtypes currently classified under this name. Characteristic for pemphigus are the presence of autoantibodies against epidermal cell adhesion structures (desmosomes), leading to a breakdown of cutaneous and mucosal barriers. The two most important disease types for dentists are pemphigus vulgaris and paraneoplastic pemphigus because they almost invariably present with oral manifestations. This article highlights current knowledge on the pathophysiology, the clinical signs, and the practical clinical diagnostic approach to these two serious disorders and treatment.

PNP with Waldenstrom's macroglobulinaemia

We describe a 65-year-old Caucasian man with Waldenstrom's macroglobulinaemia who developed paraneoplastic pemphigus (PNP) 3 years after his haematological diagnosis. This is a very rare malignancy that is associated with PNP. The evolution of PNP in this patient appears to exhibit the postulated immunological phenomenon of epitope spreading.

Paraneoplastic pemphigus secondary to fludarabine evolving into unusual oral pemphigus vegetans

We report a patient with chronic lymphocytic leukaemia who developed paraneoplastic pemphigus (PNP) soon after the initiation of fludarabine therapy. He presented with severe oral and cutaneous erosions. Initially, he had high titres of circulating autoantibodies as detected by indirect immunofluorescence (IF) on multiple epithelial substrates (normal human skin, monkey oesophagus, and rat bladder) and by desmoglein 1 and 3 enzyme-linked immunosorbent assays (ELISAs). His oral erosions have subsequently progressed into unusual hyperplastic papillomatous lesions affecting the inner aspect of lips and buccal mucosae, histologically consistent with pemphigus vegetans. Desmoglein 1 antibodies and IF on rat bladder substrate have become negative after 18 months of therapy. Several agents had been initiated to bring the disease under control originally, but a partial remission was achieved and maintained with mycophenolate mofetil and low-dose prednisolone.

Exacerbation of paraneoplastic pemphigus by cyclophosphamide treatment: detection of novel autoantigens and bronchial autoantibodies

A 48-year-old woman with a follicular, grade III, B-cell non-Hodgkin lymphoma developed clinical, immunopathological and histological features of paraneoplastic pemphigus. The skin symptoms flared after repeated cyclophosphamide infusions, and were preceded and accompanied by a progressive dyspnoea. Although the skin and oral mucosal disease went into remission with high-dose steroid and intravenous immunoglobulin therapy, the severe alveolitis led to death. Immunoblotting of human epidermal extracts showed that the patient's serum IgG reacted with the 210-kDa envoplakin, 190-kDa periplakin, as well as the recombinant protein of BP180 NC16a domain. IgG and IgA enzyme-linked immunosorbent assays for desmoglein 3 were positive, too. Indirect immunofluorescence studies on COS-7 cells transiently transfected with desmocollin 1-3 cDNAs showed that the patient's serum contained IgG and IgA antibodies to desmocollin 3 as well as IgG antibodies to desmocollin 2. Serum IgG and IgA strongly stained rat bronchial epithelium, corresponding to autoantibodies possibly involved in the pathomechanism of the severe lung disease. In this case, which was characterized by a mixed IgA/IgG antibody panel displaying known and unique antigenicity, the serious episodes of paraneoplastic pemphigus flared after cyclophosphamide treatment.

Paraneoplastic pemphigus in association with Castleman's disease

BACKGROUND

Paraneoplastic pemphigus (PNP) is an autoimmune mucocutaneous disease associated with lymphoproliferative neoplasms, and frequently with a very rare tumour, Castleman's disease.

OBJECTIVES

To analyse the clinical history, immunopathological and histopathological findings in 28 patients with a confirmed diagnosis of PNP and Castleman's disease.

METHODS

Sera from all patients were assayed by indirect immunofluorescence (IF) and immunoprecipitation (IP) for plakin autoantibodies, immunoblotting for detection of plectin autoantibodies, and enzyme-linked immunosorbent assay for detection of desmoglein (Dsg)1 and Dsg3 autoantibodies.

RESULTS

Severe oral mucositis was observed in all patients, and lichenoid cutaneous lesions were seen in 19 of 28. Twenty cases of Castleman's disease were of the hyaline vascular type, four were of plasmacytoid type and four were of mixed type. Striking findings included pulmonary destruction leading to bronchiolitis obliterans in 26 patients and fatal outcome due to respiratory failure in 22 patients with pulmonary involvement. Histological findings included lichenoid and interface dermatitis with variable intraepithelial acantholysis. Direct IF showed deposition of IgG and C3 in the mouth and skin in 24 of 28 patients. However, indirect IF detected serum IgG autoantibodies in all patients. IP revealed IgG autoantibodies against desmoplakin I, envoplakin and periplakin in all cases, and against desmoplakin II and the 170-kDa antigen in 19 patients. Dsg3 and Dsg1 autoantibodies were present in 22 and 11 patients, respectively, and plectin autoantibodies in 23 patients.

CONCLUSIONS

PNP in association with Castleman's disease presents with severe oral mucositis and cutaneous lichenoid lesions. Serum autoantibodies against plakin proteins are the most diagnostic markers. Pulmonary injury with respiratory failure is the cause of death in most cases.

Conformational epitope mapping and IgG subclass distribution of desmoglein 3 in paraneoplastic pemphigus

BACKGROUND

Pemphigus vulgaris (PV) shows autoimmune reaction against desmoglein 3 (Dsg3), whereas paraneoplastic pemphigus (PNP) shows autoimmune reaction against Dsg3 as well as numerous members of the plakin family. It has been demonstrated that in PV, dominant epitopes reside in N-terminal adhesive regions of Dsg3 and that the dominant IgG subclass against Dsg3 is IgG4.

OBJECTIVE

We attempted to map conformational epitopes and analyze IgG subclass distribution against Dsg3 in PNP.

METHOD

Epitopes on Dsg3 for circulating IgG autoantibodies from PNP (n = 22) were studied with competition enzyme-linked immunosorbent assay (ELISA) using domain-swapped molecules between Dsg3 and Dsg1 and were compared with those for IgG autoantibodies from PV (n = 22). IgG subclass distribution was analyzed with PNP serum by Dsg3 ELISA (n = 17).

RESULTS

Epitopes on Dsg3 in PNP were distributed more broadly through the extracellular domain of Dsg3 than were those in PV, although the N-terminal extracellular domains of Dsg3 were more frequently recognized than the C-terminal extracellular domains. IgG subclass in PNP was IgG1 and IgG2 dominant.

CONCLUSION

Autoimmune response against Dsg3 in PNP is more diversified than that in PV, a finding that suggests PNP and PV have different pathophysiologic mechanisms for triggering production of anti-Dsg3 IgG.

Paraneoplastic pemphigus in children and adolescents

BACKGROUND

Paraneoplastic pemphigus (PNP) is an autoimmune mucocutaneous disease associated with specific B-cell lymphoproliferative neoplasms. There has been an increasing number of individual reports in the childhood and adolescent population.

OBJECTIVES

To examine the clinical and immunopathological features of PNP occurring in children and adolescents.

PATIENTS AND METHODS

We analysed the clinical and immunopathological findings of 14 patients under the age of 18 years with a confirmed diagnosis of PNP. Sera from all patients were analysed by indirect immunofluorescence (IF) and immunoprecipitation for plakin autoantibodies, immunoblotting for detection of plectin autoantibodies, and enzyme-linked immunosorbent assay (ELISA) for the detection of desmoglein (Dsg) 1 and Dsg3 autoantibodies.

RESULTS

Severe oral mucositis was observed in all patients, and lichenoid cutaneous lesions in eight of 14 patients. The average age at presentation was 13 years. Striking findings included: pulmonary destruction leading to bronchiolitis obliterans in 10 patients, association with Castleman's disease in 12 patients, and a fatal outcome in 10 patients. The underlying neoplasm was occult in 10 patients. Histological findings include lichenoid and interface dermatitis with variable intraepithelial acantholysis. Deposition of IgG and C3 in the mouth and skin by direct IF was not found in some cases, but indirect IF detected IgG autoantibodies in all cases. Immunoprecipitation revealed IgG autoantibodies against desmoplakin I, envoplakin and periplakin in all cases, and against desmoplakin II and the 170-kDa antigen in 13 and 10 patients, respectively. Dsg3 and Dsg1 autoantibodies were present in 10 and three patients, respectively, and plectin autoantibodies in 13 patients.

CONCLUSIONS

PNP in children and adolescents is most often a presenting sign of occult Castleman's disease. It presents with severe oral mucositis and cutaneous lichenoid lesions. Serum autoantibodies against plakin proteins were the most constant diagnostic markers. Pulmonary injury appears to account for the very high mortality rates observed.

Paraneoplastic dermatoses

Skin manifestations of systemic disease and malignancy are protean. The recognition of a potentially paraneoplastic dermatosis as such must prompt an investigation for occult malignancy. Lack of familiarity with cutaneous clues of internal malignancy may delay diagnosis and treatment of cancer. It is important to consider a paraneoplastic process in the differential diagnosis of a number of eruptive and treatment-resistant dermatoses. These dermatoses may be the first sign of an occult neoplasm. Their recognition may assist in cancer detection and the swift induction of appropriate therapy.