Non-pathogenic anti-desmoglein 3 IgG autoantibodies in Fogo Selvagem

The endemic form of pemphigus foliaceus, fogo selvagem, is caused by IgG autoantibodies directed against desmoglein 1 (Dsg1). Hilario-Vargas and his colleagues describe a high prevalence of IgG autoantibodies against Dsg3, the target antigen of pemphigus vulgaris, in a Brazilian population where fogo selvagem is endemic, although those patients do not develop any apparent clinical phenotype of pemphigus vulgaris.     

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.     

Endemic pemphigus vulgaris

BACKGROUND: Investigators from Brasilia, Brazil, observed several patients with a mucocutaneous disease that resembles pemphigus vulgaris clinically and histologically but with epidemiological features of fogo selvagem. Our objective was to characterize antidesmoglein 3 and antidesmoglein 1 autoantibody profiles in these unique patients who reside in Goiania and Brasilia, Brazil, known endemic regions of fogo selvagem. OBSERVATIONS: We performed serological evaluation of 8 patients with a mucocutaneous disease clinically and histologically consistent with pemphigus vulgaris, as well as 27 healthy relatives of patients with fogo selvagem who reside in these endemic areas. Serum samples from all 8 patients bound desmoglein 3 by cold immunoprecipitation and from 6 patients by enzyme-linked immunosorbent assay, while serum samples from 4 patients bound desmoglein 1 by cold immunoprecipitation and by enzyme-linked immunosorbent assay. Antidesmoglein 3 autoantibodies were detected in 4 of 27 healthy donors by cold immunoprecipitation and by enzyme-linked immunosorbent assay, whereas antidesmoglein 1 autoantibodies were detected in 6 individuals by cold immunoprecipitation and in 3 individuals by enzyme-linked immunosorbent assay. CONCLUSION: These findings provide serological evidence of a new endemic variant of pemphigus vulgaris.     

Mycophenolate mofetil as an adjuvant therapy for classic and endemic pemphigus foliaceus

Pemphigus foliaceus is an autoimmune cutaneous disease with subcorneal acantholysis and pathogenic IgG4 autoantibodies directed against desmoglein 1. We present our experience with mycophenolate mofetil (MMF) in the treatment of one case of endemic pemphigus foliaceus (fogo selvagem) and two cases of the classic form. All patients had severe, refractory disease and developed marked adverse effects due to long-term corticosteroid therapy. MMF proved to be an effective corticosteroid-sparing agent at doses varying from 35 to 45 mg/kg/d. It was well tolerated, and we found no significant adverse effects from this drug.     

Immunopathologic characterization of the tissue response in endemic pemphigus foliaceus (fogo selvagem)

BACKGROUND: The research on endemic pemphigus foliaceus (fogo selvagem) has mainly focused on the humoral immune response, but little attention has been given to the function of cell-mediated immune response and the nature of the cellular elements of the tissue reaction in the lesions of fogo selvagem. OBJECTIVE: The purpose of this study was the immunophenotype characterization of the inflammatory cells as well as the expression of adhesion molecules and HLA-DR in the perilesional and lesional skin of fogo selvagem. METHODS: Twenty biopsy specimens of lesional and perilesional skin were analyzed by immunohistochemical techniques. The panel of monoclonal antibodies consisted of CD8, CD4, CD1a, HLA-DR, IL-2R, LFA-1, ICAM-1, and PAN-B. RESULTS: The semiquantitative analysis of the cell population revealed a predominance of CD4 T lymphocytes in the tissue response of perilesional and lesional skin. The population of epidermal Langerhans cells was decreased in lesional skin when compared with the perilesional skin, whereas CD1a(+) dermal dendritic cells predominated in lesional skin. Keratinocyte expression of ICAM-1 and HLA-DR was negative in both lesional and perilesional skin. CONCLUSION: The overall results suggest the participation of the cell-mediated immunity in endemic pemphigus foliaceus (fogo selvagem). The lack of keratinocyte ICAM-1 expression may be related to the pattern of cytokines secreted by the CD4(+) T cells of the tissue reaction in fogo selvagem.     

Brasilianischer Pemphigus foliaceus (Fogo selvagem)

Zusammenfassung Die klinischen, histologischen und immunhistologischen Merkmale des brasilianischen Pemphigus foliaceus (BPF) gleichen weitgehend denen des Pemphigus foliaceus. Beide Erkrankungen sind durch dünnwandige Blasen und sekund?re Pusteln, Erosionen und ausgepr?gte Verkrustungen, meist in seborrhoischen Arealen der Haut charakterisiert. Schleimh?ute sind so gut wie nie betroffen. Histologisch zeigt BPF eine subkorneale akantholytische Blase. In der direkten Immunfluoreszenz finden sich in der gesamten Epidermis interzellu?re Ablagerungen von Autoantik?rpern, vor allem vom IgG₄-Isotyp. Im Serum fast aller Patienten mit BPF sind zirkulierende IgG-Autoantik?rper nachweisbar, die mit den Desmosomen geschichteter Plattenepithelien reagieren. Die Autoantik?rper bei BPF sind wahrscheinlich wie bei endemischem Pemphigus foliaceus gegen Desmoglein 1, ein 160 kD gro?es epidermales Adh?sionsmolekül, gerichtet. Dieses Antigen liegt innerhalb der Desmosomen als Komplex zusammen mit Plakoglobin (85 kD) vor. BPF tritt in einigen Gebieten Brasiliens endemisch auf. Dabei beobachtet man eine charakteristische H?ufung bei Kindern, Heranwachsenden und jungen Erwachsenen. Diese epidemiologischen Beobachtungen lassen vermuten, da? es sich bei BPF um eine übertragbare Erkrankung handelt, gegen die im sp?teren Lebensalter Immunit?t erworben werden kann. Das infekti?se Agens wird m?glicherweise durch Insektenstiche übertragen, die Vektoren konnten bis heute nicht identifiziert werden. Summary Most of the clinical, histological and immunohistological features of fogo selvagem resemble those of idiopathic pemphigus foliaceus (PF). Both diseases are clinically characterized by small flaccid bullae evolving into to scaly and crusted lesions, sometimes with pustules, mainly in seborrhoic areas of the skin. Mucosal surfaces are mostly spared. The main histologic feature of endemic pemphigus foliaceus is a subcorneal acantholytic blister. Standard immunofluorescence studies demonstrate intercellular IgG deposits throughout the entire epidermis. These IgG antibodies are mainly of the IgG₄-subclass. Almost all patients have circulating IgG-autoantibodies in their serum directed against stratified epithelial desmosomes. The fogo selvagem autoantibodies and the PF antibodies are directed against the 160 kD desmosomal glycoprotein desmoglein 1 which together with plakoglobin (85 kD) forms a complex of adhesion proteins with desmosomes of stratified epithelia. Fogo selvagem occurs in endemic foci in some areas of Brazil and possibly in neighbouring South American countries, very often in children, adolescents and young adults. The etiology of fogo selvagem is still unknown. The frequent association with insect bites has lead to the concept of fogo selvagem being a transmissible disease with acquired immunity in adulthood. However, the infectious agent and possible vectors have not yet been identified. Eingegangen am 19. Februar 1996 Angenommen am 14. Juni 1996     

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.     

Oxidative stress in patients with endemic pemphigus foliaceus and healthy subjects with anti-desmoglein 1 antibodies

Background:Previous studies have shown oxidative stress in pemphigus vulgaris and pemphigus foliaceus, nevertheless, it remains unknown whether a similar response is characteristic of endemic pemphigus foliaceus in Peru.Objectives:To determine the oxidative stress response in endemic pemphigus foliaceus patients and subjects with positive for anti-desmoglein1 antibodies (anti-dsg1) from endemic areas of Peru.Subjects and methods:This is a cross-sectional study. The study population included 21 patients with Endemic Pemphigus foliaceus and 12 healthy subjects with anti-dsg1 antibodies from the Peruvian Amazon (Ucayali), as well as 30 healthy control subjects. Malondialdehyde, an indicator of lipid peroxidation by free radicals, was measured in serum.Results:We collected 21 cases of endemic pemphigus foliaceus, 15 of them with active chronic disease and 6 in clinical remission. Serum malondialdehyde values in patients with chronic active evolution and healthy subjects with anti-dsg1 antibodies were statistically higher than those of healthy controls (p<0.001). There was no significant difference between serum values of localized and generalized clinical forms.Study limitations:The main limitation of this present study is the small number of patients with endemic pemphigus and healthy subjects positive for desmoglein 1 antibodies.Conclusions:The increased serum levels of malondialdehyde in patients with chronic active endemic pemphigus foliaceus and healthy subjects from endemic areas with anti-dsg1 antibodies may suggest a contribution of systemic lipid peroxidation in the pathogenesis of endemic 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.     

PEMPHIGUS IN EL SALVADOR

Of 23 patients with pemphigus seen between 1970 and 1977, 18 had foliaceus and five had vulgaris (ratio of 3.73:1). The characteristics of pemphigus foliaceus (age of onset, disease among sisters, presence of lesions resistant to corticotherapy) suggest Brazilian pemphigus foliaceus (fogo selvagem).     

Prognostic factors for life expectancy in nonagenarians with nonmelanoma skin cancer: implications for selecting surgical candidates

BACKGROUND: Pemphigus foliaceus is a cutaneous, autoimmune, blistering disease comprising two major categories: endemic and sporadic. The endemic form, also known as fogo selvagem, primarily affects children and young adults in rural Brazil. In contrast, the sporadic form of pemphigus foliaceus is generally a disease of the middle-aged and elderly. Objective and methods: Because the sporadic form of pemphigus foliaceus rarely affects children, information specific to this unique group is lacking. We describe a 3-year-old boy with the disease and retrospectively review data from 28 past cases. RESULTS: In comparison to pediatric cases of pemphigus vulgaris, sporadic pemphigus foliaceus in children tends to follow a generally benign course of relatively short duration. However, long-term outcome studies are lacking. A pattern of skin lesions described as "arcuate," "circinate," or "polycyclic" appears to be a unique and specific presentation of this disease in children. Occasionally, as in our case, the diagnosis may prove difficult to establish by using routine histology or immunopathology. CONCLUSION: The commercial availability of antigen-specific techniques such as enzyme-linked immunosorbent assay for serum desmoglein 1 autoantibody should eliminate delay in diagnosis. Hydroxychloroquine may be another treatment option for those children with photodistributed lesions. Further experience and long-term outcome studies in children are needed to determine whether some medication side effects may outweigh the risks from the disease itself.     

Common human leukocyte antigen alleles in pemphigus vulgaris and pemphigus foliaceus Italian patients.

Pemphigus refers to a group of autoimmune blistering skin diseases, mainly identified as pemphigus vulgaris and pemphigus foliaceus, both characterized by the presence of autoantibodies against keratinocyte adhesion molecules, leading to loss of cell-cell adhesion with consequent blister formation. Pemphigus vulgaris is reported to be associated with human leukocyte antigen DR4 and/or DR6 whereas no data are available on pemphigus foliaceus, except for the endemic Brazilian form (fogo selvagem), which is reported to be associated with DR1 and DR4. We here report human leukocyte antigen molecular typing on a total of 87 patients, 61 with pemphigus vulgaris and 26 with pemphigus foliaceus, versus 128 healthy matched controls. Generic typing showed an increase of DRB1*04 and DRB1*14 and a decrease of DRB1*07 in both pemphigus vulgaris and pemphigus foliaceus patients. Molecular subtyping of DR4+ and DR14+ subjects showed a highly significant association between the DRB1*1401 and both pemphigus vulgaris (p < 0.0001) and pemphigus foliaceus patients (p < 0.0001) together with a significant increase of the linked DQB1*0503 (pemphigus vulgaris p < 0.0001; pemphigus foliaceus p < 0.0001). Moreover, whereas the association between DRB1*0402 and pemphigus vulgaris (p < 0.0001) has been confirmed, no significant association between a specific allele of the DR4 group and pemphigus foliaceus, has been found. Therefore, at least in Italian patients, pemphigus vulgaris and pemphigus foliaceus share DRB1*1401 and DQB1*0503, as susceptible human leukocyte antigen alleles, whereas DRB1*0402 is only found associated with pemphigus vulgaris. The observation that both diseases, pemphigus vulgaris and pemphigus foliaceus, carry the same susceptible human leukocyte antigen alleles has been interpreted as a common genetic background predisposing to pemphigus as, like in other autoimmune disorders, it is not sufficient to explain the onset of the disease on the basis of the sole aforementioned alleles. Other linked genes and/or environmental factors should play a facilitating role in the outbreak of pemphigus, either pemphigus vulgaris or pemphigus foliaceus.     

Ultrastructural aspects of mucosas in endemic pemphigus foliaceus

OBJECTIVE: To investigate whether ultrastructural changes present in clinically normal oral mucosa could occur in the mucosas of patients with endemic pemphigus foliaceus (EPF) or fogo selvagem (wildfire). PATIENTS: Surgical biopsy specimens were taken from the foreskin of 8 patients with EPF and 3 control subjects, the uterine cervix and vaginal wall of 9 patients with EPF and 2 controls, and the oral mucosa of 5 patients with EPF and 4 controls. The patients received a clinical and histopathologic diagnosis of EPF and all had clinically normal oral and genital mucosas. RESULTS: In the patients with EPF, widening of the intercellular spaces and distended, elongated cytoplasmic projections, the tips of which contained desmosomes and were sometimes disassembled, were evident in all 4 regions studied. At the periphery of the spinous cells, cytoplasmic vesicles apparently containing intact or fragments of desmosomes or half-desmosomes were seen. CONCLUSIONS: The ultrastructural lesions found in the mucosas studied are similar to those previously described in the literature for the oral mucosa of patients with EPF. In the cases of EPF, even though the desmosomal changes occurred in all epithelial layers, blisters did not occur in the mucosas by possible coexpression of desmoglein 1 and desmoglein 3.     

Anti-desmoglein 1 antibodies in healthy related and unrelated subjects and patients with pemphigus foliaceus in endemic and non-endemic areas from Tunisia

Background  Pemphigus foliaceus is an autoimmune blistering skin disease characterized by the production of pathogenic IgG autoantibodies directed against desmoglein 1.
Aim  To determine the prevalence of anti-desmoglein 1 antibodies in healthy subjects and their distribution in the different regions of Tunisia and to better identify endemic areas of pemphigus foliaceus.
Methods  We tested, by enzyme-linked immunoserbent assay, sera of 270 normal subjects recruited from different Tunisian areas and 203 related healthy relatives to 90 Tunisian pemphigus foliaceus patients.
Results  Seventy-six patients (84.4%), 20 healthy controls (7.4%), and 32 relatives (15.76%) had anti-desmoglein 1 antibodies. In southern regions where pemphigus foliaceus is associated with a significant sex ratio imbalance (9 female : 1 male in the south vs. 2.3 : 1 in the north) and a lower mean age of disease onset (33.5 in the south vs. 45 years in the north), a higher prevalence of anti-desmoglein 1 antibodies in healthy controls was observed (9.23% vs. 5.71% in the north). Interestingly, the highest prevalence of anti-desmoglein 1 antibodies in healthy relatives (up to 22%) was observed in the most rural southern localities. More than half anti-desmoglein 1–positive healthy controls were living in rural conditions with farming as occupation, which suggests that this activity may expose the subjects to particular environmental conditions.
Conclusion  These results show that the endemic features of Tunisian pemphigus foliaceus are focused in these southern areas more than in other areas and that both environmental and genetic factors contribute to the disease.

Conflicts of interest

None declared.     

Analyses of autoantigens in a new form of endemic pemphigus foliaceus in Colombia

BACKGROUND: We previously described a new focus of endemic pemphigus foliaceus in rural areas of El Bagre, Colombia, with clinical and direct immunofluorescence characteristics of pemphigus erythematosus. OBJECTIVE: The aim of this study was to characterize autoantigen profiles for 34 serum samples obtained from patients with this condition. METHODS: Immunofluorescence, various immunoblot analyses with different antigen sources and detection methods, and immunoprecipitation were performed. RESULTS: Immunofluorescence with the use of human skin sections showed IgG autoantibodies against keratinocyte cell surfaces in all 34 serum samples. Some samples also showed weak reactivity with the basement membrane zone. The results of immunoblot and immunoprecipitation analysis indicated that all sera had antibodies reactive with desmoglein 1, the pemphigus foliaceus antigen. In addition, in various immunoblot assays, many sera reacted with several other proteins with molecular weights of 250 kd, 210 kd, and 190 kd, which appear to correspond to desmoplakin I, envoplakin, and periplakin, respectively. CONCLUSION: This endemic pemphigus disease in El Bagre showed immunologic features similar to pemphigus foliaceus or erythematosus. In addition, paraneoplastic pemphigus-like reactivity with various epidermal antigens was detected.     

A soluble and immunoreactive fragment of pemphigus foliaceus antigen released by trypsinization of viable human epidermis

Pemphigus foliaceus (PF) antigen is a transmembrane desmosomal glycoprotein (desmoglein I), part of which is located on the keratinocyte surface. Previous studies have shown that after trypsinization of viable human epidermis, this antigen is no longer detected on the surface of detached keratinocytes. It was not known, however, if this loss of antigenic activity was due to destruction, internalization, or cleavage of the antigen itself. In the present study we investigated the fate of the PF antigen after trypsinization of viable human skin. By using Concanavalin-A agarose affinity chromatography, we could partially purify an antigenic glycoprotein fraction that was released by trypsinization into the medium. This antigenic fraction was radiolabeled and tested by immunoprecipitation using sera from endemic pemphigus foliaceus or fogo selvagem (FS), non-endemic pemphigus foliaceus (NEPF), pemphigus vulgaris (PV), and bullous pemphigoid (BP) patients, and sera from normal subjects as controls. Immunoprecipitated labeled proteins were analyzed by SDS-PAGE and autoradiography. All FS sera (20 of 20 FS and five of five NEPF) and 46% of the PV sera (six of 13) immunoprecipitated a band of 45-kD molecular weight. Sera from FS patients in prolonged clinical and serological remission (seven of 10), sera from BP patients (five of five), and sera from normal donors (nine of nine) did not precipitate this 45-kD band. This study showed that a fragment of the PF antigen is released by trypsinization of human skin as a soluble immunoreactive glycopeptide of 45-kD molecular weight. Additionally, this procedure has generated sufficient quantities of the PF antigen for further biochemical characterization.     

Brazilian pemphigus foliaceus autoantibodies are pathogenic to BALB/c mice by passive transfer

Brazilian pemphigus foliaceus (fogo selvagem) is a cutaneous blistering disease endemic to certain areas of South America that has distinctive epidemiologic features suggestive of an infectious disease transmitted by an insect vector. Patients with the disease have antiepithelial autoantibodies, both circulating in the serum and bound to lesional epidermis. In order to examine the possible pathogenic role of these autoantibodies, IgG from the sera of these patients was purified and injected into the peritoneum of neonatal BALB/c mice. Thirty-four of 46 mice (74%) receiving parenteral IgG fractions from these patients developed cutaneous lesions that were identical to the human disease by clinical, histologic, immunologic, and ultrastructural criteria. High-titer Brazilian pemphigus foliaceus sera produced lesions more consistently and rapidly than low-titer sera. When injections were discontinued, new lesions ceased to appear and old lesions resolved. The extent of disease correlated with the titer of human antiepithelial antibodies detected in the mouse serum (z less than 0.01). Similar concentrations of IgG fractions obtained from sera of unaffected Brazilians living in endemic areas and from American donors did not induce disease when injected into littermates. These results establish that the antiepithelial autoantibodies play an important role in the pathogenesis of the cutaneous lesions in Brazilian pemphigus foliaceus.     

Endemic pemphigus foliaceus in western Parana, Brazil (1976–1988)

Endemic pemphigus foliaceus or fogo selvagem (FS) is a blistering autoimmune disease indigenous to certain states of Brazil. In the state of Parana the disease has been reported in the north-central regions where a total of 632 cases were documented in the period of 1940-80. The present study describes a new focus of FS in the western region of the state of Parana. This focus includes a total of 213 new cases of FS and only 11 cases of pemphigus vulgaris seen in this region from February 1976 to July 1988. Over 90% of these patients were peasants working in agriculture or involved in other outdoor activities.     

The anti-desmoglein 1 autoantibodies in pemphigus vulgaris sera are pathogenic

Pemphigus vulgaris and pemphigus foliaceus are two closely related, but clinically and histologically distinct, autoimmune skin diseases. The autoantigens for pemphigus vulgaris and pemphigus foliaceus are desmoglein 3 and desmoglein 1, respectively. The anti-desmoglein 1 antibodies in pemphigus foliaceus and anti-desmoglein 3 antibodies in pemphigus vulgaris are pathogenic as determined by immunoglobulin G passive transfer animal models. More than 50% of pemphigus vulgaris sera also contain anti-desmoglein 1 autoantibodies; however, the pathogenicity of the anti-desmoglein 1 autoantibodies in pemphigus vulgaris remains unknown. In this study, we used soluble recombinant extracellular domains of desmoglein 1 and desmoglein 3 to obtain affinity-purified anti-desmoglein 1 and anti-desmoglein 3 autoantibodies from pemphigus vulgaris sera and examined the pathogenicity of each fraction separately using the passive transfer mouse model. By immunoprecipitation, the purified anti-desmoglein 1 and anti-desmoglein 3 showed no cross-reactivity. The anti-desmoglein 1 autoantibodies in pemphigus vulgaris induced typical pemphigus foliaceus lesions in neonatal mice, whereas the anti-desmoglein 3 fraction induced pemphigus vulgaris-like lesions. In addition, the pathogenic anti-desmoglein 1 and anti-desmoglein 3 autoantibodies in pemphigus vulgaris had predominant IgG4 subclass specificity. These findings suggest that the anti-desmoglein 1 antibodies in pemphigus vulgaris are pathogenic.     

Ultrastructural localization of Brazilian pemphigus foliaceus (fogo seivagem) antigens in cultured human squamous cell carcinoma cells

The ultrastructural localization of Brazilian pemphigus foliaceus (BPF) (fogo selvagem) antigen(s) in cultured human squamous cell carcinoma cells was studied using immunogold electron microscopy. Five of six BPF sera, which showed positive cell-surface reactivity on immunofluorescence, bound to the cell-cell contact area of cytoplasmic projections. This binding pattern was apparently different from that of non-endemic pemphigus foliaceus and pemphigus vulgaris sera, and mouse monoclonal anti-buman E-cadherin antibody. The results suggest tbat BPF autoantibodies recognize a molecule(s) which is different from non-endemic pemphigus antigens, or different epitope(s) of a molecule identical with non-endemic pemphigus antigens, and that the epitope(s) to which BPF autoantibodies bind is expressed on cell-cell contact areas at a relatively early stage of cell-cell adhesion formation.