Brazilian Pemphigus Foliaceus, Endemic Pemphigus Foliaceus, or Fogo Selvagem (Wild Fire)

Histopathology of autoimmune bullous dermatoses: What's new?

Autoimmune bullous dermatoses are characterized by the presence of tissue-bound and often circulating pathogenic autoantibodies targeting structural components of the skin and/or mucous membranes. The diagnostic workup for this heterogeneous group of disorders consists of a multi-step process, of which the light microscopic examination is a crucial component. This review is organized following a classification scheme that is based on two main histopathologic features, namely level of intraepithelial split and composition of the inflammatory infiltrate. Overall, we aim to place emphasis on the histopathologic clues that can assist pathologists in differential diagnosis and review the updates in the literature.

Cytokine and Chemokines Alterations in the Endemic Form of Pemphigus Foliaceus (Fogo Selvagem)

INTRODUCTION

The endemic form (fogo selvagem-FS) of pemphigus foliaceus is an autoimmune disease characterized by the presence of IgG autoantibodies against desmoglein-1. Despite the array of findings, the role of chemokines and cytokines that dictate the immune response and disease outcome is still poorly investigated.

MATERIALS AND METHODS

Serum from 64 patients diagnosed with FS was used to draw and establish the levels of these molecules on this disease and establish the levels of these molecules with the severity of FS, and influence of treatment.

RESULTS

In comparison to healthy subjects, FS patients, newly diagnosed and still without therapeutic intervention, had higher levels of IL-22 and CXCL-8, and reduced levels of IFN-γ, IL-2, IL-15, and CCL-11. Furthermore, treatment using immunosuppressant drugs augmented the production of IFN-γ, IL-2, CCL-5, and CCL-11 besides reducing the levels of IL-22 and CXCL-10. Immunosuppressive therapy seemed to have long-lasting effects on the production of higher amounts of IFN-γ, IL-2, and CCL-5, besides keeping lowered the levels of IL-22 in remission FS patients.

CONCLUSION

Taken together, our findings suggest a putative role of IL-22 in the pathogenesis of FS. Finally, data presented here may contribute for better understanding the immune aspects that control disease outcome.

Update on fogo selvagem, an endemic form of pemphigus foliaceus

Pemphigus are organ-specific autoimmune diseases, where autoantibodies (mainly immunoglobulin [Ig]G) directed against epidermal targets (glycoproteins of the desmosomal core) are detected. Endemic pemphigus foliaceus or fogo selvagem (FS) is one of the variants of pemphigus foliaceus pemphigus foliaceus that shares the same clinical and immunopathological features of the classic non-endemic pemphigus foliaceus form, including pathogenic IgG (mainly IgG4) autoantibodies directed against the ectodomain of desmoglein 1 (Dsg1), that lead to acantholysis. Pathogenesis of FS is complex, involving genetic, environmental and immunological factors. Human leukocyte antigen (HLA)-DRB1 alleles DRB1*0404, *1402, *1406 or *0102 have been previously identified as risk factors for FS (relative risk, >14). Individuals exposed to hematophagous insects are more susceptible to develop the disease. Non-pathogenic anti-Dsg1 antibodies of the IgG1 subclass, directed against the extracellular 5 domain of Dsg1, are detected in patients in the preclinical stage of the disease, and also in healthy controls living in endemic areas. In counterpart, patients with FS show pathogenic anti-Dsg1 IgG4 autoantibodies that bind the pathogenic extracellular 1 and 2 domains of Dsg1, emphasizing the intramolecular epitope-spreading hypothesis. A possible explanation for the development of the autoimmune process would be antigenic mimicry, initiated by environmental stimuli in those genetically predisposed individuals. Characterization of the pathogenesis of FS will allow the development of specific therapeutic targets, and the elucidation of other autoimmune processes.

An Erythrodermic Variant of Pemphigus Foliaceus with Puzzling Histologic and Immunopathologic Features

Background:

Pemphigus foliaceus is an autoimmune blistering disorder that affects the skin owing to autoantibodies against desmoglein 1.

Methods:

We employed clinical, histologic, immunopathologic, and serum laboratory studies to investigate a case of an erythrodermic variant of pemphigus foliaceus in an elderly man following treatment with bisoprolol-hydrochlorothiazide.

Results:

Early histopathology revealed psoriasiform dermatitis, but later biopsies showed subcorneal and granular layer separation with neutrophilic infiltrate. Direct immunofluorescence showed intercellular deposits of immunoglobulin G throughout the epidermis, granular staining of C3 along the basement membrane zone, and fibrin and C3 deposition around the blood vessels. Indirect immunofluorescence on monkey esophagus showed a titer of greater than 1:1,280. Indirect immunofluorescence on rat bladder, antinuclear antibody, lupus panel, and kidney function panel were all negative.

Conclusion:

There are no reports in the literature of pemphigus foliaceus being induced by bisoprolol, but reports exist of propanolol resulting in drug-induced pemphigus foliaceus.

Profile of Trypanosoma cruzi reactivity in a population at high risk for endemic pemphigus foliaceus (Fogo selvagem)

Fogo selvagem (FS) is an autoimmune bullous disease with pathogenic IgG autoantibodies recognizing desmoglein 1 (Dsg1), a desmosomal glycoprotein. In certain settlements of Brazil, a high prevalence of FS (3%) is reported, suggesting environmental factors as triggers of the autoimmune response. Healthy individuals from endemic areas recognize nonpathogenic epitopes of Dsg1, and exposure to hematophagous insects is a risk factor for FS. Fogo selvagem and Chagas disease share some geographic sites, and anti-Dsg1 has been detected in Chagas patients. Indeterminate Chagas disease was identified in a Brazilian Amerindian population of high risk for FS. In counterpart, none of the FS patients living in the same geographic region showed reactivity against Trypanosoma cruzi. The profile of anti-Dsg1 antibodies showed positive results in 15 of 40 FS sera and in 33 of 150 sera from healthy individuals from endemic FS sites, and no cross-reactivity between Chagas disease and FS was observed.

Activating KIR and HLA Bw4 ligands are associated to decreased susceptibility to pemphigus foliaceus, an autoimmune blistering skin disease

The KIR genes and their HLA class I ligands have thus far not been investigated in pemphigus foliaceus (PF) and related autoimmune diseases, such as pemphigus vulgaris. We genotyped 233 patients and 204 controls for KIR by PCR-SSP. HLA typing was performed by LABType SSO reagent kits. We estimated the odds ratio, 95% confidence interval and performed logistic regression analyses to test the hypothesis that KIR genes and their known ligands influence susceptibility to PF. We found significant negative association between activating genes and PF. The activating KIR genes may have an overlapping effect in the PF susceptibility and the presence of more than three activating genes was protective (OR = 0.49, p = 0.003). A strong protective association was found for higher ratios activating/inhibitory KIR (OR = 0.44, p = 0.001). KIR3DS1 and HLA-Bw4 were negatively associated to PF either isolated or combined, but higher significance was found for the presence of both together (OR = 0.34, p<10⁻³) suggesting that the activating function is the major factor to interfere in the PF pathogenesis. HLA-Bw4 (80I and 80T) was decreased in patients. There is evidence that HLA-Bw4(80T) may also be important as KIR3DS1 ligand, being the association of this pair (OR = 0.07, p = 0.001) stronger than KIR3DS1-Bw4(80I) (OR = 0.31, p = 0.002). Higher levels of activating KIR signals appeared protective to PF. The activating KIR genes have been commonly reported to increase the risk for autoimmunity, but particularities of endemic PF, like the well documented influence the environmental exposure in the pathogenesis of this disease, may be the reason why activated NK cells probably protect against pemphigus foliaceus.

Pathogenesis of endemic pemphigus foliaceus

Pemphigus refers to a group of human autoimmune blistering diseases involving skin and/or mucous membranes. Endemic pemphigus foliaceus (EPF), or fogo selvagem is an organ-specific autoimmune blistering disease, first reported in the beginning of the 20th century in rural areas of Brazil. The disease follows the course of streams and creeks, and vanishes after urbanization of the endemic areas. The auto-antigen related to EPF is desmoglein 1, a 160 kDa glycoprotein of the desmossomal core, targeted by in situ and circulating IgG autoantibodies, mainly of the IgG4 subclass.

Antibodies against desmoglein 1 in healthy subjects in endemic and nonendemic areas of pemphigus foliaceus (fogo selvagem) in Peru

BACKGROUND

Endemic pemphigus foliaceus or fogo selvagem is an autoimmune skin disease characterized by the presence of subcorneal superficial blisters and antibodies of the immunoglobulin G4 (IgG4) class specific for the desmosomal glycoprotein, desmoglein 1. In Peru, no studies have been published on the seroprevalence of antibodies against desmoglein 1 in healthy subjects from endemic foci.

SUBJECTS AND METHODS

This was a cross-sectional study. The sample included 82 healthy subjects, 41 from the Pueblo Libre community, a focus of endemic pemphigus foliaceus, and 41 from a nonendemic urban area in Pucallpa City. Enzyme-linked immunosorbent assay (ELISA) was used to determine the presence of antibodies against desmoglein 1. Samples were processed and tested at the Department of Dermatology and Cutaneous Surgery, School of Medicine, University of Miami, Miami, Florida.

RESULTS

It was found that 31.7% of healthy individuals (13 subjects) from the endemic focus had anti-desmoglein 1 antibodies. A statistically significant association was found between the distance from the endemic focus and the presence of antibodies against desmoglein 1 in subjects living within the endemic focus [Mantel-Haenszel odds ratio (OR), 3.34; P = 0.03; 95% confidence interval (CI), 1.06-10.48]. Agriculture as an occupation showed a statistically significant association with the presence of antibodies against desmoglein 1 (Mantel-Haenszel OR, 7.84; P < 0.001; 95% CI, 2.47-24.87).

CONCLUSIONS

Antibodies against desmoglein 1 are present in healthy subjects exposed to an endemic focus of pemphigus foliaceus (fogo selvagem). Agriculture is associated with a high risk of development of antibodies against desmoglein 1 in the endemic focus of the Pueblo Libre community.

Use of intravenous immunoglobulin therapy in autoimmune blistering diseases

Autoimmune mucocutaneous blistering diseases (AMBD) are an interesting group of rare diseases that affect the mucous membranes and the skin and are frequently or potentially fatal. The clinical presentation is significantly variable, as is the course and prognosis. The immunopathology is well characterized and the target antigens to which the autoantibodies are directed have been studied by various investigators. A significant majority of the patients respond to conventional therapy, which consists of high-dose long-term systemic corticosteroids and immunosuppressive agents. This treatment program has significantly improved the prognosis in many patients. In such patients, significant side effects of the drugs may appear and produce a very poor quality of life. In patients with progressive diseases, especially those with mucous membrane pemphigoid, the significant sequela; such as blindness, aphonia, and stenosis of the anal and vaginal canals can occur. In several patients treated with conventional immunosuppressive therapy, death occurs as a consequence of prolonged immune suppression leading to opportunistic infections. In this manuscript, the published data on the use of immunoglobulins intravenous (IGIV) in patients with AMBD is presented. The most important features of IGIV in patients with AMBD are: 1) the ability to clinically control the disease; 2) the ability to induce and maintain a long-term clinical remission; 3) a lower incidence of side effects; and 4) a higher quality of life. The important characteristic of the IGIV therapy in the AMBD is two-fold. First, the therapy, when given according to a published protocol, produces a lasting and long-term clinical remission, rather than a temporary arrest of the disease. Second, the therapy, as described in the protocol, has a very definitive endpoint. Consequently, once the patients are treated and go into long-term remission, the therapy is no longer required. The significant positive results obtained with IGIV are to a large extent also due to the associated aggressive topical therapy that was used and the frequent use of sublesional injections with triamcinolone. The rapid and early detection of cutaneous and mucosal infections and their treatment with systemic antibiotics is also a very important feature of IGIV therapy. When patients are under long-term conventional therapy, the infections are often not detected because they lack the ability to mount signs of inflammation. It is also becoming increasingly clear for patients to have a successful outcome, in treatment with IGIV therapy, it is critical that the physician spends a significant amount of time with each patient, monitor the therapy closely, and be familiar with the overall health of the patient. It is also best if the therapies are instituted by a physician who has significant interest and experience in blistering diseases and IGIV therapy.

Pênfigo foliáceo endêmico: características sociodemográficas e incidência nas microrregiões do estado de Goiás, baseadas em estudo de pacientes atendidos no Hospital de Doenças Tropicais, Goiânia, GO

FUNDAMENTOS: O pênfigo foliáceo endêmico é doença auto-imune, cutânea, bolhosa, com incidência maior na região Centro-Oeste do Brasil e menor em alguns países sul-americanos. Embora tenha sido demonstrado seu caráter auto-imune pela presença de auto-anticorpos e a importância da predisposição genética, não estão ainda claramente estabelecidos os fatores ambientais intervenientes. OBJETIVOS: Conhecer as características sociodemográficas da doença, bem como sua distribuição no Estado de Goiás. MÉTODOS: Foram analisados 210 prontuários com diagnóstico estabelecido no período de1996 a 2001. As informações demográficas foram correlacionadas com as da população do estado, e a incidência da doença, determinada em cada uma de suas microrregiões. RESULTADOS: Maior incidência da doença na terceira década e na zona rural, leve ocorrência familiar e sem predileção por sexo. O maior contingente (74,3%) de pacientes foi do Estado de Goiás, e a maior incidência, nas microrregiões de Anicuns, Chapada dos Veadeiros, Rio Vermelho, Vale do Rio dos Bois, Iporá e Aragarças. CONCLUSÕES: Houve predomínio da doença na terceira década e naqueles com domicílio ou atividade na zona rural. Foram detectadas, pelo cálculo do coeficiente de incidência, áreas de concentração da doença em algumas microrregiões, principalmente na zona central do Estado de Goiás. Novas pesquisas são necessárias para esclarecer as causas dessa concentração ecológica.

Perfil histórico da imunopatogenia do pênfigo foliáceo endêmico (fogo selvagem)

O fogo selvagem, ou pênfigo foliáceo endêmico, é doença órgão-específica, em que auto-anticorpos IgG, especialmente da subclasse IgG4, se dirigem contra ectodomínios da desmogleína 1, culminando no processo de acantólise. Influências genéticas e ambientais modulam essa resposta auto-imune específica; nota-se maior susceptibilidade ao pênfigo foliáceo endêmico nos indivíduos que apresentam uma determinada seqüência de alelos (LLEQRRAA) nas posições 67-74 da terceira região hipervariável do HLA-DRB1, e naqueles expostos a insetos hematófagos, em especial o Simulium nigrimanum. Uma possível explicação para o desencadeamento do processo auto-imune seria o mimetismo antigênico, iniciado por estímulos ambientais, nos indivíduos geneticamente predispostos.

Treatment of autoimmune mucocutaneous blistering diseases with intravenous immunoglobulin therapy

Autoimmune mucocutaneous blistering diseases (AMBDs) are a group of rare diseases that affect the skin and mucous membranes and are potentially fatal. They have variable clinical presentation, course and prognosis. Their immunopathology is well-characterised and target antigens have been studied. Many patients respond to conventional therapy, which consists of high-dose long-term systemic corticosteroids with an immunosuppressive agent, but side effects develop that can produce a poor quality of life. Many patients develop significant sequelae, such as blindness, loss of voice, vaginal and anal stenosis. In most patients cause of death is opportunistic infections secondary to immune suppression. To date, intravenous immunoglobulin (IVIg) has been reported to have benefited 156 patients with AMBDs. Its most important features include the ability to reduce or eliminate conventional therapy, the enabling of clinical control, the ability to induce and maintain long-term clinical remission, the capacity for usage based on a defined protocol with a described end point and a resulting increase in quality of life. IVIg produces the best clinical outcome when combined with aggressive topical therapy, sublesional injections of triamcinolone and rapid detection, and early treatment of cutaneous and mucosal infection. Successful therapy requires a physician to spend significant time with each patient. This manuscript provides the opinion of the author on the current use of IVIg to treat AMBDs.

The intraepidermal blistering conditions

The intraepidermal vesiculobullous disorders constitute a wide variety of pathogenically unrelated disorders that share in common the formation of cleft or bullae formation within the epithelium. The etiologic, pathogenic, clinical and, in particular, the histopathologic attributes of the most important intraepidermal blistering conditions are described.

Blistering diseases in the elderly: diagnosis and treatment

This article discusses the major blistering diseases in the geriatric population. The diagnosis of both immune- and non-immune-mediated blistering disorders can be confirmed with the help of histologic and immunopathologic studies. Various serologic assays, which are more specific, also can be used to confirm the diagnosis of autoimmune blistering diseases. These techniques have facilitated the diagnosis and allowed the institution of early treatment. The treatment of blistering disorders has included both localized and systemic treatments. Localized treatment involves topical care including the following measures: the prevention of trauma; soaking of blisters in antiseptic (potassium permanganate or aluminum subacetate) solutions; topical and intralesional corticosteroids; and the prevention and early treatment of infections with local or systemic antibiotics. Conventional oral systemic therapies that have proved to be beneficial include systemic corticosteroids, anti-inflammatory agents, and immunosuppressive agents. Because the elderly are more prone to the side effects of these systemic agents, it is crucial that routine hematologic tests be done and monitored until the treatments have been discontinued. Recently, newer alternative treatment modalities have proved to be successful in patients who failed to respond or developed multiple side effects to the conventional oral systemic agents. In conclusion, as clinicians gain a greater understanding into the pathogenesis of these diseases, more specific molecular-targeted treatments will most likely become available.

Analysis of desmosomal cadherin-adhesive function and stoichiometry of desmosomal cadherin-plakoglobin complexes

Desmosomes are intercellular adhesive junctions that associate with the intermediate filament cytoskeleton. The two major classes of transmembrane desmosomal glycoproteins, desmogleins and desmocollins, are widely considered to function as adhesion molecules. This assumption is based in part on their homology to the cadherin family of calcium-dependent homophilic adhesion molecules. In addition, autoantibodies from pemphigus patients bind directly to desmoglein family members and are thought to cause epidermal blistering by inhibiting the function of these cadherins. To directly test the ability of the desmosomal cadherins to mediate adhesion, desmoglein-1 (Dsg1), desmocollin-2 (Dsc2a) and plakoglobin were expressed in mouse L cell fibroblasts. Similar to catenin:classical cadherin complexes, plakoglobin:Dsc2a complexes exhibited an approximately 1:1 stoichiometry; however, plakoglobin:Dsg1 complexes exhibited a 6:1 stoichiometry. When L cells expressing the desmosomal cadherins were tested for the ability to aggregate in suspension, L cells expressing E-cadherin exhibited extensive aggregation, but L cells expressing Dsg1 or Dsc2a did not aggregate. In addition, L cells co-expressing Dsg1, Dsc2a, and plakoglobin failed to aggregate. The cytoplasmic domain of E-cadherin is thought to play a central role in the adhesive function of E-cadherin by providing a link to the actin cytoskeleton. Therefore, two chimeric cadherins comprising the cytoplasmic domain of E-cadherin and the extracellular domain of either Dsg1 or Dsc2a were expressed in L cells. Both chimeras formed a complex with alpha- and beta-catenin. Nevertheless, neither of these chimeras supported aggregation of L cells when expressed individually or when co-expressed. These data suggest that the extracellular domains of the desmosomal cadherins exhibit functional properties distinct from those of the classical cadherins, such as E-cadherin.