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

Pemphigus Vulgaris and Bullous Pemphigoid of the Upper Aerodigestive Tract: A Review Article and Novel Approaches to Management

BACKGROUND

Autoimmune bullous diseases are rare conditions characterized by blistering of the skin and mucous membranes. The 2 commonest forms are pemphigus vulgaris and bullous pemphigoid. The oral cavity or oropharynx may be the initial site of presentation or often the only site involved.

SUMMARY

These conditions are often misdiagnosed or overlooked leading to poorer patient outcomes. Due to the chronic nature of these conditions and the systemic effects of treatment, there is a significant associated morbidity and mortality. As such, an understanding of the fundamentals of autoimmune bullous diseases is vital to those working in otolaryngology. The mainstay of management in both conditions is topical and systemic corticosteroids. There is also a role for immunomodulating and non-steroidal anti-inflammatory drugs as adjunct or alternative therapies. Surgical intervention may be required to protect the airway. Often multimodality treatment is required involving multidisciplinary input from otolaryngologists, oral surgeons, dermatologists, and rheumatologists. This review article will highlight the aetiology, pathology, clinical features, investigations, and management of both pemphigus vulgaris and bullous pemphigoid including recent advances in management.

A Case of Severe Refractory Pemphigus Vulgaris in a Patient With Stable Esophageal Malignancy

Pemphigus is a broad term that is used to describe a group of bullous autoimmune diseases affecting the skin and mucous membranes; the pathogenesis involves autoantibodies directed against various cell junction desmosomal proteins. In patients with a history of malignancy who present with bullous lesions, the differential diagnosis may include, but is not limited to, paraneoplastic pemphigus (PNP) and pemphigus vulgaris (PV) secondary to a primary autoimmune process, or induced by chemotherapy or radiation therapy. In this report, we present a case of refractory PV in a patient with stable esophageal cancer, five years after undergoing radiation therapy. He was poorly responsive to corticosteroids and intravenous immunoglobulin (IVIG). PNP or PV in a patient with stable esophageal malignancy has not been previously reported. PNP and PV can have overlapping autoantigens [desmoglein types 1 and 3 (DSG1 and DSG3)] as well as similar presentations. Thus, distinguishing between the two may be challenging in a patient with a history of cancer. More research must be done to determine if PNP can be seen in a patient with stable esophageal malignancy and, similarly, if PV can be precipitated by stable esophageal malignancy. Such research would aid in determining whether or not similar presentations are more severe or refractory to standard treatment regimens, thereby contributing to improve treatment strategies.

Paraneoplastic pemphigus: Revised diagnostic criteria based on literature analysis

BACKGROUND

Paraneoplastic pemphigus (PNP) is a rare autoimmune bullous disease classically associated with an underlying neoplasm. The heterogeneous clinical and histopathologic features of the disease make diagnosis challenging for clinicians. There are no formally accepted diagnostic criteria, and newer techniques for identifying antibodies directed against plakin proteins have largely replaced immunoprecipitation, the historic gold standard.

METHODS

An analysis of 265 published cases of PNP was performed. The clinical, histopathologic, and immunologic features of PNP were assessed.

RESULTS

Based on this review, we modified previous diagnostic criteria to capture 89.4% of PNP cases compared to 71.2% of cases captured by the most commonly referenced criteria devised by Camisa and Helm (p-value < 0.01, z-test; 95% CI [10.2, 33.6]).

CONCLUSION

These revised diagnostic criteria address the variable clinical, histopathologic, and biochemical features of PNP, allowing physicians to have greater confidence in diagnosis of this rare and often fatal disease. The revised criteria include three major criteria and two minor criteria, whereby meeting either all three major criteria or two major and both minor criteria would fulfill a diagnosis of paraneoplastic pemphigus. The major criteria include (a) mucous membrane lesions with or without cutaneous involvement, (b) concomitant internal neoplasm, and (b) serologic evidence of anti-plakin antibodies. The minor criteria include (a) acantholysis and/or lichenoid interface dermatitis on histopathology and (b) direct immunofluorescence staining showing intercellular and/or basement membrane staining.

Intraepithelial autoimmune blistering dermatoses: Clinical features and diagnosis

Intraepithelial autoimmune blistering dermatoses are a rare group of skin disorders characterized by the intraepithelial disruption of intercellular connections through the action of autoantibodies. The first article in this continuing medical education series explores the background, epidemiology, clinical features, and diagnostic criteria of each of the major intraepithelial autoimmune blistering dermatoses, including pemphigus foliaceus, pemphigus erythematosus, pemphigus herpetiformis, fogo selvagem, pemphigus vulgaris, pemphigus vegetans, drug-induced pemphigus, IgA pemphigus, IgG/IgA pemphigus, and paraneoplastic pemphigus/paraneoplastic autoimmune multiorgan syndrome.

[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 pemphigus associated with small lymphocytic lymphoma: A case report

INTRODUCTION

Paraneoplastic pemphigus (PNP) is a life-threatening autoimmune blistering disease associated with underlying neoplasms. Currently, this disease is very difficult to treat.

PATIENT CONCERNS

We reported a rare case of paraneoplastic pemphigus associated with small lymphocytic lymphoma responsive to desmoglein 3 (Dsg3) and bullous pemphigoid (BP) antigen 180.

DIAGNOSES

The initial diagnosis was hypothesized to be Stevens-Johnson syndrome based on the severe mucosal erosion and polymorphous skin lesions. However, the histopathological examination of the skin biopsy and immunology revealed PNP.

INTERVENTIONS

Anti-tumor therapy, immunosuppression and anti-infective therapy were administered.

OUTCOMES

After a series of treatments, the skin lesions had been alleviated remarkably. Enzyme-linked immunoassays indices for Dsg3 and bullous pemphigoid antigen 180 decreased (Dsg3, 32; bullous pemphigoid antigen 180, 70.44). Unfortunately, 2 months later, the patient suffered respiratory failure due to the lung impairment of small lymphocytic lymphoma and infection. Eventually, the patient chose to be discharged from the hospital and lost the opportunity for follow-up treatment as he could not afford the expensive treatment costs.

LESSONS

It is highly susceptible to misdiagnosis due to polymorphous skin lesions. In this case, it was also initially misdiagnosed as Stevens-Johnson syndrome. Therefore, we should pay great attention to differential diagnosis. When refractory stomatitis and mucosal erosions occur, the possibility of PNP should be considered first. At the same time, pathology, immunology and other related tests as well as the examination of primary tumors should be carried out as soon as possible.

Multidisciplinary diagnosis and treatment of recurrent follicular dendritic cell sarcoma in abdomen: A case report

RATIONALE

Follicular dendritic cell sarcoma (FDCS) is a rare malignant tumor derived from follicular dendritic cells, and is often associated with Castleman disease. Here we present a rare case of paraneoplastic pemphigus (PNP) with FDCS which required multidisciplinary approach for the diagnosis and treatment.

PATIENT CONCERNS

A 28-year-old Chinese female had FDCS recurrence, and primary clinical manifestation was PNP.

DIAGNOSES

PNP with FDCS.

INTERVENTIONS

The patient received gamma globulin infusion, took anlotinib, and underwent plasma exchange therapy.

OUTCOMES

The skin lesions recovered and there was no evidence of tumor recurrence.

LESSONS

The diagnosis and management of PNP with FDCS require close cooperation among surgeons, dermatologists, hematologists, otolaryngologists, oncologists, radiologists, pathologists, and respiratory doctors. The interesting clinical manifestations of this patient provide a multifaceted approach to the investigation of the interactions among FDCS, Castleman disease, and PNP.

Deep pemphigus (pemphigus vulgaris, pemphigus vegetans and paraneoplastic pemphigus) in dogs, cats and horses: a comprehensive review

Pemphigus is the term used to describe a group of rare mucocutaneous autoimmune bullous diseases characterized by flaccid blisters and erosions of the mucous membranes and/or skin. When the autoantibodies target desmosomes in the deep layers of the epidermis, deep pemphigus variants such as pemphigus vulgaris, pemphigus vegetans and paraneoplastic pemphigus develop. In this article, we will review the signalment, clinical signs, histopathology and treatment outcome of pemphigus vulgaris, pemphigus vegetans and paraneoplastic pemphigus in dogs, cats and horses; where pertinent, we compare the animal diseases to their human homologue. Canine, feline and equine pemphigus vulgaris, pemphigus vegetans and paraneoplastic pemphigus have many features similar to the human counterpart. These chronic and often relapsing autoimmune dermatoses require aggressive immunosuppressive therapy. In animals, the partial-to-complete remission of pemphigus vulgaris and pemphigus vegetans has been achieved with high dose glucocorticoid therapy, with or without adjunct immunosuppressants; the prognosis is grave for paraneoplastic pemphigus.

Radiotherapy-Associated Paraneoplastic Pemphigus and Its Complications in a Patient with Nasopharyngeal Carcinoma

Paraneoplastic pemphigus arising in association with non-haematological cancers is extremely rare, and there are no reported cases of a patient developing this in the setting of nasopharyngeal carcinoma and only 2 reported cases of patients developing this in response to radiotherapy. Here, we present the case of a patient who developed radiotherapy-associated paraneoplastic pemphigus in the setting of nasopharyngeal carcinoma and who then developed multiple complications.

LEARNING POINTS

Paraneoplastic pemphigus has a remarkably similar clinical picture to other dermatologic diseases (for example, pemphigus vulgaris), and therefore, it is easy to miss the diagnosis.Patients with oral and mucocutaneous lesions refractory to conventional therapy should be worked up for underlying occult malignancy.Our case highlights that prompt diagnosis and initiation of immunosuppressive therapy alongside effective management of complications can ensure recovery and survival.

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.

Chronic lymphocytic leukemia-associated paraneoplastic pemphigus: potential cause and therapeutic strategies

Paraneoplastic pemphigus (PNP) is a severe autoimmune syndrome commonly triggered by neoplasms. The prognosis of CLL-associated PNP is dismal due to its refractory course and secondary infection and no standard treatment was recommended. We retrospectively reported six CLL with PNP cases from 842 cases of CLL including diagnosis, treatment and prognosis. The median time between the initial of CLL to PNP was 36 months while the median overall survival from the diagnosis of PNP was 26 months. And three cases died of lung infection while 5 developed pulmonary symptoms. And 5 cases received fludarabine-based chemotherapy before developing PNP, which suggesting fludarabine was one of potential causes of PNP. For the treatment, five patients were rescued by combined regimens including rituximab, methylprednisolone, immunoglobulin, fresh frozen plasma and the last received ibrutinib combined with short-term prednisone. Fludarabine-based regimen may be one of the potential causes of PNP. The combined regimen might shed a new light, while ibrutinib is a promising drug for CLL with PNP, but needs much more evidence. PNP should be carefully treated to guide early diagnosis and intervention for a better prognosis.

Thalidomide as a potential adjuvant treatment for paraneoplastic pemphigus: A single-center experience

Paraneoplastic pemphigus (PNP) is a rare autoimmune bullous disease associated with an underlying malignancy. The survival rate at 5 years is reported to be as low as 38%. Thalidomide is a medication with strong anti‐inflammatory, immunomodulatory, antiangiogenic, and sedative properties. Recently, the successful application of thalidomide in several dermatological and hematological disorders inspired us to investigate its potential as an adjuvant treatment for PNP. Here, we report our experience of trial thalidomide therapy in 14 PNP patients. After treatment of their associated tumors, the patients were administered thalidomide (75‐100 mg/d) combined with or without low‐ to mid‐dose oral prednisone. Twelve patients completed the therapy. Seven patients (58%) achieved complete remission with no relapse, including two patients who received thalidomide monotherapy. Five patients (42%) died within 1 to 3 months. The 1‐year and 2‐year survival rates in our case series were 58% and 55%, respectively. The regimen was well tolerated. Although the treatment experience presented has a limited sample size and no control, our results imply that thalidomide may be an effective, safe, and economical treatment option for PNP patients. Further research is needed to better understand the mechanisms of action of thalidomide in PNP.

Paraneoplastic Pemphigus Involving the Respiratory and Gastrointestinal Mucosae

Paraneoplastic pemphigus (PNP), an autoimmune mucocutaneous disorder involving the oral and bronchial mucosae, is a rare complication of hematologic malignancy. Serologically, serum autoantibodies against varied desmosome-related proteins are of notice. PNP is often lethal due to bronchiolitis obliterans and opportunistic infection. A 70-year-old Japanese male complained of dry cough, stomatitis, and sore throat. The lips and oral mucosa were severely eroded, and skin eruptions were seen on the chest and abdomen. The biopsy features were consistent with PNP, and the deposition of IgG and IgM was shown on the plasma membrane of the involved keratinocytes. Serological studies demonstrated autoantibodies to desmoglein-3, desmocollins-2 and -3, bullous pemphigoid antigen-1, envoplakin and periplakin. Systemic evaluation disclosed mantle cell lymphoma, stage 4B. After chemotherapy, partial remission was reached. PNP was treated with methylprednisolone and intravenous immunoglobulins, and the oral lesion only temporarily responded. He died of respiratory failure two months after onset. Autopsy revealed residual indolent lymphoma and systemic opportunistic infections. Aspergillus colonized the eroded bronchial/bronchiolar mucosa, associated with extensive vascular invasion. Coinfection of cytomegalovirus (CMV) and Pneumocystis jirovecii caused interstitial pneumonia. The oropharyngeal, respiratory, esophageal, and gastrointestinal mucosae were diffusely infected by CMV. Bronchiolitis obliterans was observed in the peripheral lung. PNP-related acantholysis-like lesions were microscopically identified in the bronchial and gastrointestinal mucosa. IgG deposition and cleaved caspase-3-immunoreactive apoptotic cell death were proven in the involved mucosal columnar cells. Pathogenesis of the mucosal involvement is discussed.

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.

The Risk of Depression in Patients with Pemphigus: A Nationwide Cohort Study in Taiwan

Pemphigus is a chronic dermatological disorder caused by an autoimmune response and is associated with a high proportion of comorbidities and fatalities. The aim of this study was to investigate the risk of depression in patients with pemphigus. Data were derived from the National Health Insurance Research Database recorded during the period 2000–2010 in Taiwan. Multivariate Cox proportional hazards regression models were used to analyze the data and assess the effects of pemphigus on the risk of depression after adjusting for demographic characteristics and comorbidities. Patients with pemphigus were 1.98 times more likely to suffer from depression than the control group (pemphigus, adjusted HR: 1.99, 95% CI = 1.37–2.86). People aged ≥65 years were 1.69 times more likely to suffer from depression than those aged 20–49 years (≥65 years, adjusted HR: 1.42, 95% CI = 0.92–2.21). Female and male patients with pemphigus were respectively 2.02 and 1.91 times more likely to suffer from depression than the control group (female, adjusted HR: 2.09, 95% CI = 1.24–3.54; male, adjusted HR: 1.87, 95% CI = 0.97–3.60). People with HTN, hyperlipidemia, asthma/COPD, and chronic liver disease were respectively 1.73, 2.3, 2.2, and 1.69 times more likely to suffer from depression than those without these comorbidities (HTN, adjusted HR: 0.75, 95% CI = 0.41–1.42; hyperlipidemia, adjusted HR: 1.48, 95% CI = 0.78–2.82; asthma/COPD, adjusted HR: 1.4, 95% CI = 0.72–2.69; and chronic liver disease, adjusted HR: 1.61, 95% CI = 1.07–2.43). There was a significant association between pemphigus and increased risk of depression. Female patients had a higher incidence of depression.

Cutaneous paraneoplastic pemphigus syndrome associated with undifferentiated uterine sarcoma

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This case report identifies a non-classical paraneoplastic pemphigus foliaceous cause by an undifferentiated uterine sarcoma.

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This patient’s paraneoplastic pemphigus (PNP) was resistant to treatment with azathioprine, dapsone, mupirocin cream, or betamethasone ointment, but stabilized with prednisone and rituximab per lymphoma protocol at 375 mg/m² weekly for one month.

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Dermatological symptom resolution was noted by the patient after surgical resection, with a corresponding drop in anti-Dsg1 IgG from 230u to 32u.

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No PNP cases exist that expressed only anti-Dsg1 IgG like this patient.

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This patient lacked mucosal involvement and anti-Dsg3 IgG, agreeing with literature suggesting their correlation.

Pemphigus is a group of autoimmune intraepidermal blistering diseases caused by immunoglobulins directed against keratinocyte cell surface components. In this case report, we identify a non-classical paraneoplastic pemphigus (PNP) foliaceous related to an undifferentiated uterine sarcoma.

The patient is a 54-year-old Chinese female with a past medical history of arthritis who presented with worsening fatigue in November 2017 and an itchy, blistering, erythematous annular plaque that first appeared on her chest in February 2018. Given high suspicion for primary immunobullous disease despite negative immunofluorescence and lack of subepidermal split on initial biopsy, a repeat biopsy was performed from the right thigh showing positive intraepidermal “net-like” staining for C3 and IgG, but was negative for IgA, IgM, and fibrinogen. IgG antibodies against desmoglein 1 were elevated at 280u (reference range <18), but none resulted against desmoglein 3, consistent with pemphigus foliaceus. This patient’s PNP was resistant to treatment with azathioprine, dapsone, mupirocin cream, or betamethasone ointment, but responded to prednisone and rituximab per lymphoma protocol at 375 mg/m² weekly for one month in December 2018.

In February 2019, the patient had 2–3 episodes of postmenopausal vaginal bleeding and subsequent hysteroscopy with dilation and curettage revealed an undifferentiated uterine sarcoma. The patient underwent an exploratory laparotomy, total abdominal hysterectomy, bilateral salpingo-oophorectomy, and bilateral pelvic lymph node sampling. After surgical staging, she noted significant improvement in her baseline skin lesions and has had no new lesions since surgery. Repeat desmoglein antibodies showed anti-Dsg1 antibodies of 32u (reference range <18) and anti-Dsg3 antibodies of 1u (reference range <19), as compared to the anti-Dsg1 antibodies of 280u in June 2018. She has since completed 4 cycles of adjuvant gemcitabine and docetaxel for her stage IIB undifferentiated uterine sarcoma with no recurrence of the pemphigus lesions.

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.

Bullous autoimmune dermatoses

Pathophysiologically, bullous autoimmune dermatoses are caused by autoantibodies directed against adhesion molecules or structural proteins of the skin and mucous membranes, clinically resulting in blister formation. Depending on the respective target proteins of the autoimmune response and their location in the skin, a distinction is made between intraepidermal (pemphigus disorders), junctional (pemphigoid disorders), and subepidermal (epidermolysis bullosa acquisita, dermatitis herpetiformis) autoimmune blistering diseases. The most common bullous autoimmune dermatosis, bullous pemphigoid is characterized by marked clinical variability and intense pruritus. Predominantly affecting elderly individuals, there has been a significant increase in its incidence in recent years. While mucosal lesions occur in less than 30 % of bullous pemphigoid patients, the second most common bullous autoimmune dermatosis, pemphigus vulgaris, typically presents with oral erosions as the predominant and - frequently - initial symptom. Its onset is usually in the 4^th to 6^th decade of life. Scarring is typically found in subepidermal blistering disorders such as epidermolysis bullosa acquisita or mucous membrane pemphigoid. Diagnosis is based on clinical and histological findings as well as direct and indirect immunofluorescence and detection of circulating autoantibodies. Although a number of controlled clinical trials have been conducted in recent years, treatment of bullous autoimmune disorders is still primarily based on clinical experience. Therapeutic options include topical and systemic corticosteroids as well as adjuvant immunosuppressants. Recalcitrant cases may require treatment with immunoadsorption, intravenous immunoglobulins, or the monoclonal anti-CD20 antibody rituximab.

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: Paraneoplastic Autoimmune Disease of the Skin and Mucosa

Paraneoplastic pemphigus (PNP) is a rare but life-threatening mucocutaneous disease mediated by paraneoplastic autoimmunity. Various neoplasms are associated with PNP. Intractable stomatitis and polymorphous cutaneous eruptions, including blisters and lichenoid dermatitis, are characteristic clinical features caused by humoral and cell-mediated autoimmune reactions. Autoreactive T cells and IgG autoantibodies against heterogeneous antigens, including plakin family proteins and desmosomal cadherins, contribute to the pathogenesis of PNP. Several mechanisms of autoimmunity may be at play in this disease on the type of neoplasm present. Diagnosis can be made based on clinical and histopathological features, the presence of anti-plakin autoantibodies, and underlying neoplasms. Immunosuppressive agents and biologics including rituximab have been used for the treatment of PNP; however, the prognosis is poor due to underlying malignancies, severe infections during immunosuppressive treatment, and bronchiolitis obliterans mediated by autoimmunity. In this review, we overview the characteristics of PNP and focus on the immunopathology and the potential pathomechanisms of this disease.

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.

The rash that presents as target lesions

We have explored the rash that appears as target lesions, with the central and dominant diseases belonging to the Stevens-Johnson syndrome/toxic epidermal necrolysis group. After presenting the clinical patterns of an individual target lesion and classifying them into different types of lesions, the contribution has been organized with groups characterized by such specific findings according to the type of lesion: flat or raised, typical or atypical, presence or absence of fever, presence or absence of mucosal ulcerations, presence or absence of arthralgias, and/or internal organ involvement. Other specific features, such as histologic appearance, immunofluorescence findings, and laboratory changes, are considered. We provide clinicians with an algorithmic, systematic, and logical approach to diagnose the condition of the patients who present with targetoid lesions, and enable them to differentiate between those with serious systemic and life-threatening diseases from others with ordinary skin ailments.

The potential roles of herpesvirus and cytomegalovirus in the exacerbation of pemphigus vulgaris

Background

Among exogenous etiologies, the critical role of microbial agents such as herpesviruses (HSV1/2) and cytomegalovirus (CMV) in triggering and flaring autoimmune conditions such as pemphigus vulgaris (PV) has been recently discovered.

Objectives

The present study aimed to investigate the plausible role of these viruses in the exacerbation of PV using serological and molecular methods.

Patients/Methods

Sixty patients with PV (30 with relapse type and 30 with remission type) were recruited for the purpose of this case-control study. Skin, mucosal, and throat specimens were obtained and examined for viruses by reverse transcriptase polymerase chain reaction. To determine the immunoglobulin G (IgG) titer, enzyme-linked immunosorbent assay was used.

Results

Desmoglein1-specific IgG was positive in 56.7% of patients with the relapse form and in 20.0% of those with the remission form indicating a significant difference across the 2 groups (P = 0.003), but the rate of positivity for desmoglein3-specific IgG in the relapse and remission types was 76.7% and 63.3%, respectively, with no significant difference (P = 0.260). There was no difference in the mean levels of HSV-IgG and CMV-IgG in the relapse and remission groups. HSV and CMV positivity in PV patients was independent of the site of the samples. Using the multivariable linear regression model, the level of CMV-IgG in PV patients was directly affected by female sex and advanced ages.

Conclusions

Our study could not demonstrate the role of HSV1/2 and CMV as triggering factors for PV exacerbation. Further studies are needed to evaluate the potential role of these viruses in PV exacerbation especially considering demographic variables.

Facilitated subcutaneous immunoglobulin treatment in pemphigus vulgaris

A novel administration strategy of immunoglobulin treatment is represented by injection of recombinant human hyaluronidase (rHUPH20) with subcutaneous immunoglobulins. The use of facilitated subcutaneous immunoglobulin treatment (fSCIG) for the treatment of autoimmune conditions is yet to be investigated. We present the case of a 56-year-old female patient with pemphigus vulgaris predominantly of the oral mucous membranes, previously treated for 24 months with azathioprine and medium doses of steroids, with only partial remission. When she came to our attention, a concomitant newly diagnosed infiltrating ductal breast cancer limited the use of immunosuppressive agents. She was started with fSCIG (25 g/monthly). After 18 months of follow-up, her breast cancer has been successfully treated and a substantial decrease of the rate of bullous mucous lesions and improvement of time to lesion healing and resolution was observed. fSCIG might represent a steroid-sparing tool for the treatment of selected cases of pemphigus vulgaris.

Humoral Epitope Spreading in Autoimmune Bullous Diseases

Autoimmune blistering diseases are characterized by autoantibodies against structural adhesion proteins of the skin and mucous membranes. Extensive characterization of their autoantibody targets has improved understanding of pathogenesis and laid the basis for the study of antigens/epitopes diversification, a process termed epitope spreading (ES). In this review, we have reported and discussed ES phenomena in autoimmune bullous diseases and underlined their functional role in disease pathogenesis. A functional ES has been proposed: (1) in bullous pemphigoid patients and correlates with the initial phase of the disease, (2) in pemphigus vulgaris patients with mucosal involvement during the clinical transition to a mucocutaneous form, (3) in endemic pemphigus foliaceus, underlining its role in disease pathogenesis, and (4) in numerous cases of disease transition associated with an intermolecular diversification of immune response. All these findings could give useful information to better understand autoimmune disease pathogenesis and to design antigen/epitope specific therapeutic approaches.