Development of pemphigus vulgaris in a patient with pemphigus foliaceus: antidesmoglein antibody profile shift confirmed by enzyme-linked immunosorbent assay

Clinical and immunological features of pemphigus relapse

BACKGROUND

More than half of patients with pemphigus experience relapse during the disease course. The risk factors and clinical and immunological characteristics of relapse remain largely unclear.

OBJECTIVES

To elucidate the risk factors and clinical features of pemphigus relapse.

METHODS

We carried out a retrospective review of the clinical records of 42 cases of pemphigus at a single centre.

RESULTS

Sixty-two per cent of patients experienced relapse, usually when oral prednisolone was tapered to around 0·1 mg kg^-1 . In mucocutaneous pemphigus vulgaris (mcPV), the initial doses (mean ± SD) of prednisolone were significantly lower in patients with relapse (0·78 ± 0·24 mg kg^-1 ) than in those without relapse (1·01 ± 0·01 mg kg^-1 ). At relapse, mcPV shifted to mucosal dominant PV (mPV; 40%), pemphigus foliaceus (PF) (20%) or 'other' (20%). In contrast, relapsing mPV and PF had the same clinical phenotypes as the initial phenotypes. Patients with both anti-desmoglein (Dsg)1 and anti-Dsg3 antibodies at onset had recurrence with anti-Dsg3 antibodies alone (40%), with both anti-Dsg1 and anti-Dsg3 antibodies (30%), with anti-Dsg1 antibody alone (20%) or were subthreshold (10%).

CONCLUSIONS

mcPV shows transitions in clinical phenotype and autoantibody profile at relapse. At least 1 mg kg^-1 daily of prednisolone, especially for patients with mcPV, and prudent tapering around 0·1 mg kg^-1 may lead to better outcomes.

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.

A Case of Concomitant Pemphigus Foliaceus and Oral Pemphigus Vulgaris

Pemphigus is a chronic autoimmune condition that can affect multiple areas of the body. The two main subtypes of pemphigus are pemphigus vulgaris (PV) and pemphigus foliaceus (PF) which can rarely occur concurrently or even transition from one to the other. The process of transition may be explained by qualitative changes in desmoglein autoantibody profile. We present a rare case of concomitant PF and oral PV and explore the literature on transitions between pemphigus subtypes and whether this case could represent a transition from PF to PV. Furthermore, the realities of multidisciplinary patient management are discussed.

[Transition from pemphigus vulgaris to pemphigus foliaceus: a case report]

BACKGROUND

Pemphigus vulgaris (PV) and pemphigus foliaceus (PF) are the two main subtypes of auto-immune pemphigus, each having different clinical, histological and immunopathological features. We report the case of a patient initially with typical PV who relapsed within 2years, presenting clinically, histologically and immunologically typical PF.

PATIENTS AND METHODS

A 47-year old man presented in March 2008 with clinically, histologically and serologically typical PV and treated with systemic corticosteroids alone (prednisone: 1mg/kg per day) then combined with a cycle of rituximab, which resulted in complete remission. After discontinuation of therapy (duration: 26months), he relapsed 6 months later with PF presenting clinical, histological and serological characteristics typical of this condition.

DISCUSSION

This is a rare case of complete transition from PV to PF in clinical, histological and serological terms, and the first case occurring after initial treatment with rituximab.

Incidence of pemphigus vulgaris exceeds that of pemphigus foliaceus in a region where pemphigus foliaceus is endemic: analysis of a 21-year historical series

BACKGROUND

There are two main clinical subsets of pemphigus: pemphigus vulgaris and pemphigus foliaceus. Clinical and epidemiological changes related to both types of pemphigus have been observed in the last years.

OBJECTIVES

To analyze a 21-year historical case series of pemphigus vulgaris and pemphigus foliaceus in the northeast region of the state of Sao Paulo, where pemphigus foliaceus is endemic.

METHODS

In this descriptive study, data related to annual incidence and age of onset of symptoms compatible with pemphigus vulgaris or pemphigus foliaceus were analyzed, comparing both forms, in the period from 1988 to 2008.

RESULTS

The overall results cover a period of 21 years, with 103 cases of pemphigus vulgaris and 163 cases of pemphigus foliaceus. An evaluation of the trend lines regarding incidence has shown that pemphigus foliaceus is decreasing while pemphigus vulgaris is increasing. There was great variation in the age ranges, with persistence of the minimum range, from 10 to 20 years old, for pemphigus foliaceus (mean age = 32.1 years old), and clear downward in the minimum age for pemphigus vulgaris (mean age = 41.5 years old), especially from the middle of the first decade of the total period studied.

CONCLUSION

The incidence of pemphigus vulgaris has been exceeding that of pemphigus foliaceus since 1998. The results of this case series comprehending 21 years corroborate the change in the epidemiology of both clinical forms of pemphigus in Brazil, raising new hypotheses for their etiology and pathogenesis.

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.

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.

Diagnosis and clinical features of pemphigus foliaceus

Pemphigus foliaceus is an acquired autoimmune blistering disease in which the body's immune system produces IgG autoantibodies that target the intercellular adhesion glycoprotein desmoglein-1, which is principally expressed in the granular layer of the epidermis, resulting in the loss of intercellular connections between keratinocytes (acantholysis) and the formation of subcorneal blisters within the epidermis. This article summarizes the epidemiology, clinical features, techniques for diagnosis, and drugs associated with treatment of this rare disease.

Autoimmune bullous diseases the spectrum of infectious agent antibodies and review of the literature

Pemphigus and bullous pemphigoid are two autoimmune diseases that have a similar pathogenesis. Both have a genetic predisposition which promotes the production of auto-antibodies targeted against different components of the epidermal desmosome and hemidesmosome. Environmental factors play an important role in the pathogenesis of this autoimmune disease. Among these, the role of infectious agents was debated as a causative factor. We sought to determine a possible connection between various infectious agents and autoimmune bullous disease (ABD). A cohort of 148 serum samples of patients with pemphigus, bullous pemphigoid and controls was screened for evidence of a prior infection with HBV, HCV, EBV, CMV, Helicobacter pylori, Toxoplasma gondii and Treponema pallidum, utilizing the Bio-Rad BioPlex 2200 system as well as ELISA assays to complete the panel. HBV, HCV, H. pylori, T. gondii and CMV were demonstrated to have significantly higher prevalence of antibodies in patients with pemphigus and bullous pemphigoid in comparison to controls. Among them, we found a novel association between H. pylori and ABD. Our study suggests a contributing role for HBV, HCV, H. pylori, T. gondii and CMV in inducing ABD in the genetically susceptible host.

A single helper T cell clone is sufficient to commit polyclonal naive B cells to produce pathogenic IgG in experimental pemphigus vulgaris

The development of naive B cells into IgG-producing memory B cells requires cognate T cell-B cell interaction in Ag-specific immune responses. It is unknown whether a single T cell clone is sufficient or whether multiple clones are necessary to induce polyclonal IgG production in vivo. We addressed this issue using a mouse model of pemphigus vulgaris, a fatal autoimmune blistering skin disease caused by IgG autoantibodies against desmoglein (Dsg) 3. We previously isolated several Dsg3-reactive T cell clones from Dsg3(-/-) mice. Among these, two pathogenic T cell clones induced anti-Dsg3 IgG production and the development of a pemphigus phenotype when adoptively transferred with unprimed B cells from Dsg3(-/-) mice. IgG Abs harvested from recipient mice reacted with at least three parts of the extracellular domain of Dsg3, as determined using domain-swapped Dsg3/Dsg1 molecules. The anti-Dsg3 IgGs included at least two subclasses among IgG1, IgG2a, IgG2b, and IgG3 in each mouse. The anti-Dsg3 IgG induced by Dsg3-reactive T cell clones with primed B cells from Dsg3(-/-) mice also showed reactivity against different parts of the molecule, with a similar epitope distribution. Together, these results indicate that a single potent Dsg3-reactive T cell is sufficient to commit polyclonal naive B cells to produce pathogenic anti-Dsg3 IgG Abs and induce the PV phenotype. These findings provide an important framework for examining immunological mechanisms in Ab-mediated autoimmune diseases.

Anti-desmoglein IgG autoantibodies in patients with pemphigus in remission

BACKGROUND

Desmoglein (Dsg) enzyme-linked immunosorbent assay (ELISA) is a highly sensitive and specific method to detect anti-Dsg3 and anti-Dsg1 IgG autoantibodies in pemphigus vulgaris (PV) and pemphigus foliaceus (PF), respectively. Whereas ELISA index values fluctuate in parallel with disease activity, ELISA positivity during clinical remission has been observed.

OBJECTIVE

To determine the prevalence of positive Dsg ELISA index values during clinical remission. To ascertain how positive Dsg ELISA scores during remission compare with those during active disease.

METHODS

Dsg ELISA was performed on serum samples of PV and PF patients taken during remission (lesion-free >or= 3 months on <or= 15 mg or <or= 5 mg/day prednisolone) and active disease. We used a modified ELISA protocol with optimal serum dilutions in sera with very high initial index values, as we previously described.

RESULTS

When remission was defined as no eruption >or= 3 months with <or= 15 mg/day prednisolone, 20 of 43 PV patients (46.5%) and 4 of 12 PF patients (33.3%) showed Dsg3 and Dsg1 ELISA positivity, respectively. With <or= 5 mg/day, 6 of 17 PV (35.3%) and 1 of 6 PF patients (16.7%) showed Dsg3 and Dsg1 ELISA positivity, respectively. The index value of each ELISA-positive remission serum was consistently lower than that of its corresponding active disease serum. We observed consistent correlation between ELISA index values and indirect immunofluorescence titres.

CONCLUSIONS

Circulating anti-Dsg IgG autoantibodies are found in a considerable percentage of pemphigus patients in remission, who have high levels of antibody production during active stages.

Significado do epitope spreading na patogênese dos pênfigos vulgar e foliáceo

Os pênfigos são dermatoses bolhosas auto-imunes, em que há a produção de auto-anticorpos direcionados contra moléculas de adesão dos epitélios, levando à perda da coesão celular. A produção de auto-anticorpos ocorre quando os pacientes desenvolvem um desequilíbrio da resposta imune (quebra da tolerância imunológica), passando a reconhecer antígenos próprios. A resposta é geralmente direcionada contra um único epítopo alvo; entretanto, como conseqüência da resposta inflamatória do processo primário e do extenso dano tecidual ocasionado, pode haver exposição de componentes protéicos ocultos, levando à produção de diferentes auto-anticorpos. Assim, é possível que surja uma nova doença cutânea auto-imune, em decorrência do fenômeno intra ou intermolecular de epitope spreading. São revistos os principais conceitos desse fenômeno e sua ocorrência nas dermatoses bolhosas auto-imunes, com ênfase nos pênfigos, grupo de dermatoses bolhosas autoimunes mais prevalente no Brasil.

Case of pemphigus foliaceus that shifted into pemphigus vulgaris after adrenal tumor resection

A 79-year-old Japanese woman visited our hospital on 6 May 2003, who had suffered from erythema and crusted vesicles located on the head, face and trunk. The eruptions first appeared in February 2003. Histopathological findings included blister formation spreading from just below the horny layers to the upper squamous layers, where acantholytic cells were observed. Direct immunofluorescence disclosed immunoglobulin G depositions in the epidermal intercellular spaces. Enzyme-linked immunosorbent assay showed an elevated titer of anti-desmoglein (Dsg)1 autoantibodies (154 index value), but almost normal levels of anti-Dsg3 autoantibodies (8 index value in serum). The diagnosis at first was made as pemphigus foliaceus (PF). Topical use of corticosteroids alone could control the eruptions well. Systemic examinations on admission revealed a right adrenal tumor that had caused Cushing's syndrome. Its resection was performed on 24 July 2003. Histopathological diagnosis of the removed tumor was a functional adrenal adenoma. The symptoms had worsened after the resection. Topical use of corticosteroids alone could no longer control the symptoms. Additional p.o. medications of minocycline hydrochloride and nicotinic acid amides improved the symptoms to some extent. However, oral cavity erosions appeared in December 2004, and the titer of anti-Dsg3 autoantibodies in serum elevated, suggesting a transition from PF to pemphigus vulgaris (PV). p.o. administration of corticosteroids started, which improved the symptoms significantly. To date, there have been no reports of pemphigus complicated with an adrenal tumor that caused Cushing's syndrome in Japan. The present case is particularly interesting in that the symptoms became worse after the tumor resection and that the first diagnosis of PF shifted into PV after the operation.

Dissecting the anti-desmoglein autoreactive B cell repertoire in pemphigus vulgaris patients

Pemphigus vulgaris (PV) encompasses two clinical phenotypes, one producing mucosal blisters and the other mucosal and skin lesions (mcPV). The mucosal blister-producing PV variant is characterized by autoantibodies against desmoglein (Dsg)3, whereas mucosal and skin lesion-producing PV is characterized by autoantibodies to Dsg3 and Dsg1. The present study was aimed at disclosing the diversity and clonality of the anti-Dsg3 response, as well as whether anti-Dsg3 B cells are Ag selected. Human-mouse heterohybridomas were generated by fusion of EBV-transformed or freshly isolated PBLs from six PV patients with mouse myeloma cells. A total of 73 anti-Dsg hybridomas (47 IgM and 26 IgG) were isolated. Over 90% are specific for both Dsg1 and Dsg3 indicating extensive cross-reactivity between these responses. V(H) gene segment use by IgM hybridomas is diverse, but is restricted among IgG hybridomas, where the majority uses one of two V(H) genes. V(L) gene segment use was diverse even among IgG hybridomas suggesting that the V(L) is less critical to defining desmoglein specificity. Additionally, the IgG hybridomas were extensively mutated and the distribution and nature of the mutations suggested that they had been Ag selected. We conclude that the potentially pathogenic IgG anti-Dsg response is restricted in V(H) use, is somatically mutated, and is Ag selected.

Desmoglein autoimmunity in the pathogenesis of pemphigus

The most characteristic feature of pemphigus is a loss of cohesion between keratinocytes, resulting in formation of blisters and erosions on the mucosal membranes and the skin. Identification of circulating antibodies which bind to desmogleins (Dsg), transmembrane proteins involved in assembly of the desmosomes, led to the immediate realization that these antibodies may be pathogenic by interfering with desmosomal function. Despite extensive experimental evidence documenting the presence of the anti-Dsg response, its pathogenic relevance is still debated. At the current stage of the knowledge it seems likely that anti-Dsg imunoglobulins may play a role in pemphigus via interference with cellular Dsg trafficking and by activation of specific signalling pathways rather than by simple interference with desmosomal adhesion.

Detection of pemphigus desmoglein 1 and desmoglein 3 autoantibodies and pemphigoid BP180 autoantibodies in saliva and comparison with serum values

Although there is much literature on the detection of pemphigus and pemphigoid autoantibodies by enzyme-linked immunosorbent assay (ELISA) in serum, nothing is known about their presence in saliva. The aim of this study was to evaluate the salivary levels of these autoantibodies in pemphigus and pemphigoid patients. Autoantibodies against desmoglein3, desmoglein1, and BP180 were assayed, by ELISA, in serum and saliva samples of patients and healthy controls. The titres of autoantibodies against Dsg1/3 found in both serum and saliva of pemphigus patients showed a statistically significant correlation, suggesting that saliva may be a useful biological material for diagnostic purposes, in monitoring disease activity, as well as for the early detection of relapses. By contrast, the titres of autoantibodies against BP180 in the serum and saliva of bullous pemphigoid patients were not statistically related, and further study of the usefulness of the BP180 ELISA for saliva in this disease is needed. In addition, based on our results, the BP180 ELISA with a recombinant NC16a epitope failed to detect the autoantibodies against BP180 in the serum and saliva of mucous membrane pemphigoid patients.

Prevalence of Anti-Desmoglein-3 Antibodies in Endemic Regions of Fogo Selvagem in Brazil

Fogo selvagem (FS), the endemic form of pemphigus foliaceus (PF), is an autoimmune blistering disease characterized by autoantibodies against desmoglein 1. The Terena reservation of Limao Verde in Mato Grosso do Sul, Brazil, is a previously identified focus of disease. Autoantibodies against desmoglein 3 (Dsg3) have also been detected in sera from patients with FS. In an effort to further characterize the serological, geographical, and clinical epidemiology of the disease, we sought to determine the prevalence of anti-Dsg3 autoantibodies in sera from normal subjects living outside of and in an endemic area using an ELISA. Anti-Dsg3 antibodies were detected in 53 of 146 normal subjects from Limao Verde (36%), and in eight of 140 normal subjects from surrounding areas (6%). A significant trend was observed in the proportion of positive tests relative to distance from the endemic area (P < 0.001). Our seroepidemiological observations support the concept that the likely environmental trigger of the antibody response in FS is located in this endemic area, and that the population at risk to develop FS may also be at risk to develop an endemic form of pemphigus vulgaris as reported by our co-investigators from Brasilia.

Transition from pemphigus foliaceus to pemphigus vulgaris: case report with literature review

The transition between the main subtypes of pemphigus, pemphigus vulgaris (PV), and pemphigus foliaceus (PF) has rarely been reported. Moreover, the development of PV in a patient with PF is much more unusual than that of PF in a patient with PV. We report a 48-year-old man who presented with cutaneous lesions showing the typical clinical and histological features of PF. Five years later, his skin lesions became extensive and he developed oral erosions. His condition did not respond well to steroids and azathioprine. Histological examination of a vesicle disclosed suprabasal acantholysis in contrast to the subcorneal acantholysis discovered upon initial histological evaluation. Indirect immunofluorescence revealed IgG antikeratinocyte cell surface antibodies at a titer of 1:640. The titer was 1:160 at initial diagnosis. Upon immunoblotting, the patient's serum reacted with 130 kiloDalton (kDa) and 160 kDa proteins, suggesting desmoglein (Dsg) 3 and 1, respectively. We herein report an unusual case of PV that developed from PF during the disease's flare-up.

Three cases of transition from pemphigus vulgaris to pemphigus foliaceus confirmed by desmoglein ELISA

We report 3 cases of pemphigus vulgaris (PV) confirmed by histology and direct and indirect immunofluorescence that showed transition to pemphigus foliaceus (PF) 2-4 years from the time of disease onset. Desmoglein (Dsg) ELISA testing of the sera from these 3 patients in the later stages of their disease showed the presence of anti-Dsg1 antibodies and the absence of anti-Dsg3 antibodies. These patients were on prednisolone and immunosuppressives at the time the sera were tested, and it is unclear if the transition from PV to PF is a permanent one or whether it is due to preferential suppression of Dsg3 antibodies below a certain threshold. Previously reported cases of transition from PV to PF and PF to PV are summarized.

Number II Pemphigus vulgaris

Pemphigus is a group of potentially life-threatening autoimmune diseases characterized by cutaneous and/or mucosal blistering. Pemphigus vulgaris (PV), the most common variant, is characterized by circulating IgG antibodies directed against desmoglein 3 (Dsg3), with about half the patients also having Dsg1 autoantibodies. There is a fairly strong genetic background to pemphigus with linkage to HLA class II alleles and ethnic groups such as Ashkenazi Jews and those of Mediterranean and Indian origin, are especially liable. Oral lesions are initially vesiculobullous but readily rupture, new bullae developing as the older ones rupture and ulcerate. Biopsy of perilesional tissue, with histological and immunostaining examination are essential to the diagnosis. Serum autoantibodies to either Dsg1 or Dsg3 are best detected using both normal human skin and monkey oesophagus or by enzyme-linked immunosorbent assay. Before the introduction of corticosteroids, PV was typically fatal mainly from dehydration or secondary systemic infections. Current treatment is largely based on systemic immunosuppression using corticosteroids, with azathioprine or other adjuvants or alternatives but newer therapies with potentially fewer adverse effects, also appear promising.

Neonatal pemphigus foliaceus

The term "pemphigus" refers to a group of diseases that are characterized by the presence of cutaneous or mucosal blisters and erosions, and antiepidermal autoantibodies. There are several case reports of neonatal pemphigus vulgaris in the literature. Although pemphigus foliaceus antibodies have been shown to cross the placenta, to our knowledge, this is only the second reported case of neonatal pemphigus foliaceus. The proposed mechanism of disease transfer is the passive transfer of maternal IgG antibodies across the placenta.

Targetting of desmoglein 1 in inherited and acquired skin diseases

Desmoglein 1 is a member of the desmosomal cadherin family that comprise the desmogleins and desmocollins. The desmoglein 1 gene (DSG1) is centromeric to the desmoglein gene cluster and spans approximately 45 kb of 18q12, comprising 15 exons. The transcript encodes a precursor protein of 1049 amino acids that is cleaved to yield a mature protein of 1000 residues. This mature protein is expressed in certain specialized epithelia, and in the epidermis is expressed within the superficial layers. Within the desmosome the extracellular domain of the protein is essential for calcium dependent heterophilic binding to the desmocollins, whereas the intracellular domain is essential for binding to the desmosomal plaque protein, plakoglobin. Desmoglein 1 has been implicated in several human diseases. Mutations within the extracellular domain lead to autosomal dominant striate palmoplantar keratoderma, whereas autoantibodies and strains of Staphylococcus aureus target the extracellular domain in the acquired bullous disorders pemphigus foliaceus and staphylococcal scalded skin syndrome, respectively. Therefore, intact and functionally active desmoglein 1 is essential to epidermal integrity. Here, we review the expression, protein structure, genetics, and molecular interactions of desmoglein 1 and outline the role it plays within the desmosome and how it becomes defective in human disease.

Recent advances in the study of the pathophysiology of pemphigus

Recent rapid advances in the basic research into pemphigus have provided many insights into its pathophysiology. In particular, a recently developed enzyme-linked immunosorbent assay (ELISA) for desmogleins 1 and 3 (Dsg1 and Dsg3), antigens for pemphigus foliaceus (PF) and pemphigus vulgaris (PV), respectively, has led to great progress in the diagnosis and classification of pemphigus, as well as in understanding its pathomechanisms. Studies with the anti-Dsg1 and anti-Dsg3 antibodies have indicated that there are two types of PV, the mucosal dominant type and the mucocutaneous type. The same ELISA has identified the antigens in pemphigus herpetiformis. The autoantigens detected by this ELISA correlate well with the clinical features in pemphigus patients in showing the shift between PV and PF. In addition, the Dsg compensation theory proposed by Stanley and Amagai can reasonably explain the different depths of skin lesions and the different occurrences of skin and oral mucosal lesions between PV and PF. Furthermore, a complicated profile of autoantigens in paraneoplastic pemphigus (PNP) has been indicated in various biochemical studies, and IgG anti-Dsg1 and anti-Dsg3 antibodies have been detected in serum from all the PNP patients by the above ELISA. On the other hand, serum from subcorneal pustular dermatosis type IgA pemphigus patients have been shown to react with Dsc1, another type of desmosomal cadherin, by a novel cDNA transfection method. In addition, IgA anti-Dsg1 and anti-Dsg3 antibodies have been detected in a few patients with IgA pemphigus by an ELISA for IgA antibodies. Various autoimmune bullous diseases, including several types of pemphigus, are the only diseases in which the pathogenic role of circulating autoantibodies has been confirmed using the newborn mouse animal model. Therefore, studies of the pathophysiology of pemphigus are extremely important as a paradigm for research into various types of autoimmune diseases in other fields.

Pemphigus vulgaris: update on etiopathogenesis, oral manifestations, and management

Pemphigus is a group of potentially life-threatening diseases characterized by cutaneous and mucosal blistering. There is a fairly strong genetic background to pemphigus with linkage to HLA class II alleles. Certain ethnic groups, such as Ashkenazi Jews and those of Mediterranean origin, are especially liable to pemphigus. Pemphigus vulgaris (PV), the most common and important variant, is an autoimmune blistering disease characterized by circulating pathogenic IgG antibodies against desmoglein 3 (Dsg3), about half the patients also having Dsg1 autoantibodies. Oral lesions are initially vesiculobullous but readily rupture, new bullae developing as the older ones rupture and ulcerate. Biopsy of perilesional tissue, with histological and immunostaining examinations, is essential to the diagnosis. Serum autoantibodies to either Dsg1 or Dsg3 are best detected by both normal human skin and monkey esophagus or by enzyme-linked immunosorbent assay (ELISA). Before the introduction of corticosteroids, pemphigus vulgaris was typically fatal mainly from dehydration or secondary systemic infections. Current treatment is largely based on systemic immunosuppression using systemic corticosteroids, with azathioprine, dapsone, methotrexate, cyclophosphamide, and gold as adjuvants or alternatives, but mycophenolate mofetil and intravenous immunoglobulins also appear promising.

IgG/IgA pemphigus with IgG and IgA antidesmoglein 1 antibodies detected by enzyme-linked immunosorbent assay

Pemphigus is an autoimmune mucocutaneous bullous disease characterized by autoantibodies against the cell surfaces of epidermal keratinocytes. Six cases with deposition of both IgG and IgA on keratinocyte cell surfaces have been reported in the recent literature. We provisionally termed these cases IgG/IgA pemphigus. We describe a 42-year-old Japanese woman with clinical and histopathological features resembling herpetiform pemphigus who demonstrated in vivo bound and circulating anticell surface autoantibodies of both IgG and IgA classes on immunofluorescence examination. Enzyme-linked immunosorbent assay using baculovirus-expressed recombinant desmoglein (Dsg) 1 and Dsg 3 showed that both IgG and IgA antibodies reacted with Dsg1. The reactivity was completely adsorbed with preincubation of serum with Dsg1 baculoprotein, further confirming the exclusive reactivity of both IgG and IgA antibodies with Dsg1. This is the second case of IgG/IgA pemphigus in which the human target antigens for both IgG and IgA antibodies have been unequivocally identified. This study provides further evidence that IgG/IgA pemphigus is a distinct disease entity.

Isotypes and antigenic profiles of pemphigus foliaceus and pemphigus vulgaris autoantibodies

In this study we systematically characterized isotype profiles and antigenic and tissue specificity of antidesmoglein autoantibodies from patients with pemphigus foliaceus (PF) and pemphigus vulgaris (PV) using enzyme-linked immunoabsorbent assays (ELISA), indirect immunofluorescence (IIF) staining, and immunoblotting (IB). In PF, we found that IgG1 antidesmoglein-1 (Dsg1) reacts with a linear epitope(s) on the ectodomain of Dsg1, while its IgG4 counterpart recognizes a conformational epitope(s). These two subclasses of anti-Dsg1 are both capable of recognizing tissues from monkey esophagus and adult human skin, but IgG1 is not able to react with mouse skin, which may explain why this isotype of anti-Dsg1 failed to induce PF-like lesions in the passive transfer animal model. In mucosal PV patients, we found that both IgG1 and IgG4 only recognized monkey esophagus tissue by IIF, except in one patient, indicating that these antibodies react with a unique conformational epitope(s) that is present in mucosal but not skin tissue. In generalized PV, IgG1 anti-Dsg3 autoantibodies appeared to recognize a linear epitope(s) on the Dsg3 ectodomain. In contrast, IgG4 anti-Dsg3 antibodies recognized both linear and conformational epitopes on the Dsg3 molecule. Interestingly, the IgG1 anti-Dsg3 antibodies failed to react with human and mouse skin tissues, suggesting that this subclass of autoantibodies may not play an essential role in the development of PV suprabasilar lesions. In summary, we conclude that this study further elucidates the pathological mechanisms of PF and PV autoantibodies by revealing their distinct isotype and antigenic profiles. This information may help us to better understand the autoimmune mechanisms underlying the development of pemphigus.

Monitoring disease activity in pemphigus with enzyme-linked immunosorbent assay using recombinant desmogleins 1 and 3

BACKGROUND

Pemphigus is an antidesmoglein (Dsg) autoimmune disease that is divided into two major subtypes: pemphigus foliaceus (PF) and pemphigus vulgaris (PV). We previously developed enzyme-linked immunosorbent assays (ELISAs) using recombinant Dsg1 and Dsg3 to detect IgG autoantibodies in patients with pemphigus. The protocol for the ELISAs was optimized for serological diagnosis, but under the conditions used, these assays were not particularly useful for monitoring disease activity in certain patients. That is, the sera from some patients with high-titre antibodies continued to show high index values in the ELISA after clinical improvement.

OBJECTIVES

In the study reported here, we modified the ELISA protocol to obtain 'true' index values that exhibit a better correlation with disease activity.

METHODS

We tested two cases of pemphigus foliaceus (PF) and four cases of pemphigus vulgaris (PV), each with ELISA index values greater than 150 for Dsg1 or Dsg3. We ran an ELISA with sera from these patients serially diluted from 1 : 100 to 1 : 12,800. We then performed ELISA with a series of PV No. 1 sera diluted to 1 : 800 and PV No. 2-4 and PF No. 1-2 sera diluted to 1 : 1600, after which we plotted the ELISA index values against the time course of disease activity.

RESULTS

In each of these cases, there was no apparent decline, over the course of the disease activity, in the ELISA index values at a serum dilution of 1 : 100, probably because the antigen-antibody reaction was saturated at that dilution. After running an ELISA with sera serially diluted from 1 : 100 to 1 : 12,800 we found that a linear dose-dependency between the dilution value and the index value was only observed when sera were diluted to 1 : 800 or more in one case (PV No.1) and to 1 : 1600 or more in the other five cases (PV No. 2-4, PF No. 1-2). After performing ELISA with these series as outlined above we plotted the ELISA index values against the time course of disease activity and found that the index values obtained from these appropriately diluted sera fluctuated in parallel with disease activity, and declined with clinical improvement.

CONCLUSIONS

These findings indicate that when appropriate dilutions are used in Dsg1 and Dsg3 ELISA, these assays can provide useful serological information for assessing disease activity in PF and PV.

A subset of pemphigus foliaceus patients exhibits pathogenic autoantibodies against both desmoglein-1 and desmoglein-3

In pemphigus vulgaris the major pathogenic antibody binds desmoglein-3, and mediates mucosal disease. Development of cutaneous disease is associated with acquisition of antibodies to desmoglein-1. In pemphigus foliaceus, and its endemic form, fogo selvagem by contrast, the major pathogenic antibody recognizes desmoglein-1 and mediates cutaneous disease only. In this study, we sought to determine the prevalence of antibodies to desmoglein-3 in patients with pemphigus foliaceus and fogo selvagem. We produced recombinant desmoglein-1 and desmoglein-3, and used them in highly sensitive and specific enzyme-linked immunosorbent assays, as well as immunoprecipitation assays. We detected antibodies to desmoglein-3 in 19 of 276 patients with pemphigus foliaceus and fogo selvagem, who had cutaneous disease only. We showed that these antibodies to desmoglein-3 could be absorbed in a concentration-dependent manner by desmoglein-3 but not by desmoglein-1. Also antibodies to desmoglein-1 could be absorbed in a concentration-dependent manner by desmoglein-1 but not desmoglein-3. This suggests that two separate species of antibody are present rather than one antibody capable of cross-reacting with both desmoglein-1 and desmoglein-3. Finally, it was shown that affinity-purified antibodies to desmoglein-3 from patients with pemphigus foliaceus and fogo selvagem induced a pemphigus vulgaris-like skin disease in mice by passive transfer. These results suggest that a subset of patients with pemphigus foliaceus and fogo selvagem have antibodies to desmoglein-3 that may be involved in the pathogenesis of their cutaneous disease.

The transition of pemphigus vulgaris into pemphigus foliaceus: a reflection of changing desmoglein 1 and 3 autoantibody levels in pemphigus vulgaris

The transition of pemphigus vulgaris (PV) into pemphigus foliaceus (PF) is rare and the immunological changes underlying this event are not well understood. We report a 44-year-old woman who presented with oral and cutaneous erosions typical of PV. Over a 9-year period, the clinical features evolved into those of PF. To examine whether quantitative changes in desmoglein (Dsg) antibodies were associated with this transition, Dsg1 and Dsg3 antibody levels were measured by enzyme-linked immunosorbent assay in 82 sequential serum samples collected over this period. At presentation, when the phenotype was PV with oral and cutaneous erosions, antibodies to both Dsg1 and Dsg3 were detected. The disappearance of oral involvement was associated with a decline in Dsg3 antibodies, which are now undetectable, while the development of more severe skin involvement was associated with rising Dsg1 antibody levels. These data strongly suggest that the change in clinical features is a reflection of qualitative and quantitative changes in antibody profile. It is not known whether the transition to PF is permanent or whether disease relapses in the future may be associated with the re-emergence of Dsg3 antibodies, oral ulceration and a PV phenotype.

Diagnostic features of pemphigus vulgaris in patients with pemphigus foliaceus: detection of both autoantibodies, long-term follow-up and treatment responses

There are several studies that describe the simultaneous presence and conversion of pemphigus foliaceus into pemphigus vulgaris and vice versa. We describe eight patients with clinical, histological and immunopathological features of pemphigus foliaceus, at the time of the initial diagnosis. After a mean period of 2.5 years, additional serological features of pemphigus vulgaris were observed. During a long-term follow-up, systemic therapies, their durations and treatment outcomes were recorded. These patients did not respond to conventional systemic therapy and developed multiple side-effects from these drugs. Hence, they were treated with intravenous immunoglobulin therapy (IVIg). Prior to the initiation of IVIg therapy, different assays were performed to detect the presence of autoantibodies, including indirect immunofluorescence (IIF), immunoblot assay using bovine gingival lysate, and ELISA. Twenty-five healthy normal individuals, 12 patients with pemphigus vulgaris, and eight patients with pemphigus foliaceus served as controls for comparison of serological studies. At the time of initial diagnosis, the sera of all eight study patients also demonstrated binding on an immunoblot assay to a 160-kDa protein (desmoglein 1) only. This is typically observed in pemphigus foliaceus. Prior to staring IVIg therapy, binding was observed to both the 160 kDa and 130 kDa (desmoglein 3) proteins on an immunoblot assay which was characteristic of pemphigus vulgaris. The antidesmogleins, 1 and 3 autoantibodies, were predominantly of the IgG4 subclass in all eight patients studied. IVIg therapy induced remission in four patients and control in four of the eight patients. The total follow-up period ranged from 2.6 to 9.5 years (mean 5.3 years). It is difficult to determine the exact time at which these patients with pemphigus foliaceus developed pemphigus vulgaris. It is possible that the disease was nonresponsive to conventional immunosuppressive therapy owing to the simultaneous presence of two autoantibodies.

Pemphigus vulgaris: environmental factors. Occupational, behavioral, medical, and qualitative food frequency questionnaire

BACKGROUND

There have been reports suggesting the involvement of environmental factors in the disease process of pemphigus. Factors suggested include exposure to pesticides or certain drugs.

OBJECTIVE

To analyze the association of pemphigus with environmental exposure to various agents, including smoking, recreational and occupational insults, drugs, and food.

DESIGN AND SETTING

In-person interviews of pemphigus patients and control subjects were conducted by trained medical investigators using a structured questionnaire. Questions included occupational, behavioral, medical, and qualitative food frequency details. The multicenter study was conducted at outpatient services of teaching hospitals in Bulgaria, Brazil, India, Israel, Italy, Spain, and the USA.

PARTICIPANTS

A total of 126 pemphigus patients (55 men, 71 women; age, 54 +/- 17 years) and 173 healthy controls (87 men, 86 women; age 50 +/- 19 years) were interviewed in the period between October 1, 1999 and March 31, 2000. The diagnosis of pemphigus was based on clinical, histologic, immunohistologic, and immunohistochemical criteria. The disease duration was 2-27 years (8.4 +/- 7.2 years). Individuals with skin diseases other than pemphigus were selected as control subjects.

MAIN OUTCOME MEASURE

Information on drugs, foods, and occupational, environmental, constitutional, and other possible risk factors was analyzed by t-tests and chi-squared tests as applicable. A multivariate logistic regression model was applied to the data to study simultaneously the independent relationship between each risk factor and pemphigus vulgaris.

RESULTS

The risk for pemphigus vulgaris was lower for ex-smokers and current smokers than for patients who had never smoked. Exposure to pesticides and occupational exposure to metal vapor were associated with an increased risk of pemphigus. Pemphigus patients had more pregnancies than controls. There were differences in environmental factors between countries, with exposure to gardening materials and pesticides being highest among patients from Bulgaria, followed by Israel. Disease characteristics also exhibited differences between countries. Bulgarian patients less frequently had oral mucous membrane lesions: 66% compared to 92% for Israeli patients and 83% for Italians. The distribution of the disease in skin and mucous membranes was similar among patients from all countries. Exclusive skin involvement was seen in 50% of patients, mucous membranes alone in 23% of patients, and both skin and mucous membranes in 27% of patients.

CONCLUSIONS

The beneficial effect of smoking on pemphigus might be explained by its effect on the immune system. In addition, smoking has an antiestrogenic effect, while pesticides have an estrogenic effect. The lower numbers of smokers among patients, the higher exposure rates to pesticides, and the higher number of female patients who had been pregnant may point to the contribution of estrogens to the disease process. It remains to be determined whether measures, such as avoiding exposure to pesticides or metal vapor, may be beneficial in the clinical context. As the present study was a survey, more definitive studies should be conducted to validate the results.

Immunodiagnosis of pemphigus and mucous membrane pemphigoid

Pemphigus and pemphigoid are two of a group of bullous diseases affecting oral mucosa and skin. Mucous membrane pemphigoid (MMP) comprises a heterogeneous group of disorders characterized by subepithelial separation and the deposition of immunoglobulins and complement along the basement membrane zone (BMZ). The target antigens in the epithelium and BMZ determine the nature of the condition, and recently there have been considerable improvements in our understanding of the BMZ antigenic composition. Pemphigus vulgaris (PV) is characterized by autoantibodies of the IgG isotype to the desmosomal glycoprotein desmoglein (Dsg) 3, whereas pemphigus foliaccus targets Dsg1, although at least 50% of PV patients have additional autoantibodies to Dsg1. The clinical phenotype appears to be determined by the relative amounts of Dsg1 and Dsg3. Patients with oral or mucosal PV have predominantly Dsg3 autoantibodies. The most frequently targeted antigen in MMP is bullous pemphigoid antigen 180 (BP180), although bullous pemphigoid antigen 230 (BP230), laminin 5, and beta 4 integrin are also involved. Circulating IgG and IgA antibodies may bind to different epitopes of BP180 namely the NC 16A domain or COOH -terminal domain. Pure ocular disease has been associated with IgA antibodies to a 45-kDa antigen and IgG antibodies to the 205-kDa antigen b4 integrin. The use of salt-split skin substrate enables differentiation between epidermal and dermal 'binders'. Since both the specificity and the antibody titer appear to have direct relationships with the disease severity, and a combination of clinical score and antibody titer provides valuable prognostic data, these investigations should be carried out on a more routine basis.

The clinical transition between pemphigus foliaceus and pemphigus vulgaris correlates well with the changes in autoantibody profile assessed by an enzyme-linked immunosorbent assay

BACKGROUND

There are a number of reports of pemphigus with clinical shifting between pemphigus foliaceus (PF) and pemphigus vulgaris (PV). On the other hand, a novel enzyme-linked immunosorbent assay (ELISA) against recombinant baculoproteins of desmoglein 1 (Dsg1) (PF antigen) and Dsg3 (PV antigen) has been established and found to be extremely sensitive and specific.

OBJECTIVES

To characterize the change in the antibody profiles in a series of pemphigus cases with mixed features of PF and PV by various methods, including the novel ELISA. Patients/methods Sera were obtained from eight cases undergoing a shift between PF and PV and three cases of coexistent PF and PV. The autoantigens were analysed by ELISA, as well as by immunofluorescence using normal human skin sections and immunoblotting using normal human epidermal extracts.

RESULTS

The results of the ELISA, immunofluorescence and immunoblotting studies showed that the transition between PF and PV correlates well with the changes of autoantibodies against either Dsg1 or Dsg3.

CONCLUSIONS

The clinical phenotype at each stage is defined by the anti-Dsg antibody profile in the serum of these pemphigus patients showing mixed features of PF and PV. In addition, ELISA using recombinant baculoproteins was particularly useful in distinguishing PF and PV.

Use of domain-swapped molecules for conformational epitope mapping of desmoglein 3 in pemphigus vulgaris

Pemphigus vulgaris is an autoimmune blistering disease caused by autoantibodies against desmoglein 3, a member of the desmosomal cadherin family. These autoantibodies recognize conformation-dependent epitopes on desmoglein 3. In this study we attempted to map the conformational epitopes of desmoglein 3 in pemphigus vulgaris using recombinant desmoglein 3 produced by the baculovirus expression system. We developed a series of domain-swapped molecules between desmoglein 3 and desmoglein 1, which have similar structures but distinct epitopes. These were developed by substituting deleted segmental regions of desmoglein 3 by the corresponding desmoglein 1. Thus domain-swapped molecules containing desmoglein 3 residues 1-403, 1-161, 163-566, and 405-566 were constructed and used as competitors for competition enzyme-linked immunosorbent assay against the entire extracellular domain of desmoglein 3 with 25 pemphigus vulgaris sera. Considering more than 50% absorption as significant, residues 1-403 and 1-161 showed significant absorption in 24 out of 25 (96%) and 18 out of 25 (72%) pemphigus vulgaris sera, respectively, whereas only one serum and no sera showed significant absorption by residues 163-566 and 405-566, respectively. Furthermore, no apparent change in their major epitopes was seen during the time course in four pemphigus vulgaris cases tested. These findings indicate that the domain-swapping approach is useful for conformational epitope mapping in pemphigus and that amino-terminal residues 1-161, which are considered to include a region essential for cell-cell adhesion in cadherins, contain the critical residues of the conformational epitope of desmoglein 3 recognized by the autoantibodies in pemphigus vulgaris sera.