RESUMO
BACKGROUND: Anti-desmoglein (Dsg)1 is produced in pemphigus foliaceus (PF), affecting exclusively the skin. Pemphigus vulgaris (PV) shows the production of anti-Dsg3 in the mucosal form, and anti-Dsg1 and 3 in the mucocutaneous form. Anti-Dsg3 autoantibodies have been rarely reported in PF. OBJECTIVES: To determine the factors associated with the production and pathogenicity of anti-Dsg3 in PF. METHODS: Comparative analytical study of three patients groups: 16 PF-anti-Dsg3+, and 42 PF-anti-Dsg3(-) and 22 PV treatment-naïve cases. Serum was used in the anti-Dsg1 and 3 ELISA, and in immunoblotting (IB) with human epidermis extract. The expression of Dsg1 and 3 in paraffin sections was analyzed by immunohistochemistry (IHC). HLA-DRB1 alleles were compiled from a database. RESULTS: In the PF-anti-Dsg3+ group: age range similar to that of the PV group (pâ¯>â¯0.9999); predominance of the generalized form of PF (pâ¯=â¯0.002); anti-Dsg3 titers lower than those of PV (pâ¯<â¯0.0001); IB confirmed Dsg3 identification in one (8.33%) of 12 patients; IHC showed exclusive cytoplasmic internalization of Dsg1; HLA-DRB1 alleles of susceptibility to PF, with the absence of alleles associated with PV, in the five typed patients. STUDY LIMITATIONS: Most of the patients in the PF-anti-Dsg3+ group were undergoing treatment. CONCLUSION: The presence of anti-Dsg3 antibodies in PF was related to older age (comparable to that of PV) and the generalized form of PF. The non-pathogenicity of anti-Dsg3 antibodies in PF can be attributed to the low serum anti-Dsg3 titers, the lack of Dsg3 internalization as detected by IHC, and the absence of PV-associated HLA-DRB1 alleles.
Assuntos
Autoanticorpos , Desmogleína 1 , Desmogleína 3 , Imuno-Histoquímica , Pênfigo , Humanos , Pênfigo/imunologia , Desmogleína 3/imunologia , Autoanticorpos/imunologia , Autoanticorpos/sangue , Feminino , Masculino , Pessoa de Meia-Idade , Adulto , Idoso , Desmogleína 1/imunologia , Ensaio de Imunoadsorção Enzimática , Adulto Jovem , Immunoblotting , Cadeias HLA-DRB1/genética , Cadeias HLA-DRB1/imunologia , Idoso de 80 Anos ou mais , AdolescenteRESUMO
Fogo selvagem (FS) is a blistering skin disease caused by pathogenic IgG4 autoantibodies to desmoglein 1 (DSG1). Preclinical FS and leishmaniasis are endemic to certain regions of Brazil and exhibit nonpathogenic anti-DSG1 antibodies. Recurring bites from Lutzomyia longipalpis, the sand fly vector of leishmaniasis, immunize individuals with L. longipalpis salivary antigens LJM17 and LJM11. We measured the antibody responses to LJM17, LJM11, and DSG1 in normal settlers and patients with FS from an endemic focus of FS and nonendemic control populations. We also immunized mice with these antigens and assessed the IgG response. Healthy individuals and patients with FS from endemic areas had significantly higher values of IgG4 anti-LJM17 antibodies than nonendemic controls (P < 0.001 for both). The levels of IgG anti-DSG1 and IgG4 anti-LJM17 and anti-LJM11 antibodies correlated positively in normal settlers and patients with FS. Mice immunized with recombinant LJM17 produced IgG1 antibodies (human IgG4 homolog) that strongly cross-reacted with recombinant DSG1; these IgG1 antibodies were inhibited by LJM17, LJM11, and DSG1 in a dose-dependent manner. However, they did not bind human or mouse epidermis by indirect immunofluorescence. Lastly, we identified short-sequence homologies of surface-exposed residues within the human DSG1 ectodomain and LJM17. Inoculation by LJM17 from L. longipalpis-elicited DSG1-cross-reactive IgG4 antibodies may lead to FS in genetically predisposed individuals.
Assuntos
Mordeduras e Picadas/imunologia , Desmogleína 1/imunologia , Proteínas de Insetos/imunologia , Pênfigo/imunologia , Psychodidae/imunologia , Animais , Autoanticorpos/imunologia , Autoantígenos/imunologia , Mordeduras e Picadas/epidemiologia , Mordeduras e Picadas/patologia , Brasil/epidemiologia , Reações Cruzadas , Modelos Animais de Doenças , Doenças Endêmicas , Epiderme/imunologia , Epiderme/patologia , Humanos , Insetos Vetores/imunologia , Insetos Vetores/parasitologia , Leishmaniose Cutânea/epidemiologia , Leishmaniose Cutânea/imunologia , Leishmaniose Cutânea/parasitologia , Camundongos , Pênfigo/epidemiologia , Pênfigo/patologia , Psychodidae/parasitologia , Proteínas Recombinantes/imunologia , Proteínas e Peptídeos Salivares/imunologiaRESUMO
Pemphigus foliaceus (PF) is a blistering autoimmune skin disease rare in most of the world but endemic in certain regions of Brazil. PF is characterized by the detachment of epidermal cells and the presence of autoantibodies against desmoglein 1. In previous studies, we have shown that genetic polymorphisms and variable expression levels of certain leucocyte receptor complex (LRC) genes were associated with PF. However, the role of the LRC on PF susceptibility remained to be investigated. Here, we analysed 527 tag single nucleotide polymorphisms (SNPs) distributed within the 1·5â Mb LRC. After quality control, a total of 176 SNPs were analysed in 229 patients with PF and 194 controls. Three SNPs were associated with differential susceptibility to PF. The intergenic variant rs465169 [odds ratio (OR)â =â 1·50; Pâ =â 0·004] is located in a region that might regulate several immune-related genes, including VSTM1, LILRB1/2, LAIR1/2, LILRA3/4 and LENG8. The rs35336528 (ORâ =â 3·44; Pâ =â 0·009) and rs1865097 (ORâ =â 0·57; Pâ =â 0·005) SNPs in LENG8 and FCAR genes, respectively, were also associated with PF. Moreover, we found four haplotypes with SNPs within the KIR3DL2/3, LAIR2 and LILRB1 genes associated with PF (Pâ <â 0·05), which corroborate previously reported associations. Thus, our results confirm the importance of the LRC for differential susceptibility to PF and reveal new markers that might influence expression levels of several LRC genes, as well as candidates for further functional studies.
Assuntos
DNA Intergênico/genética , Genótipo , Leucócitos/fisiologia , Pênfigo/genética , Receptores Imunológicos/genética , Autoanticorpos/metabolismo , Brasil , Desmogleína 1/imunologia , Regulação da Expressão Gênica , Frequência do Gene , Estudos de Associação Genética , Predisposição Genética para Doença , Humanos , Polimorfismo de Nucleotídeo Único , Análise Serial de TecidosRESUMO
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.
Assuntos
Anticorpos/sangue , Desmogleína 1/imunologia , Malondialdeído/sangue , Estresse Oxidativo/fisiologia , Pênfigo/imunologia , Pênfigo/metabolismo , Adolescente , Adulto , Estudos de Casos e Controles , Estudos Transversais , Desmogleína 1/sangue , Doenças Endêmicas , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Peroxidação de Lipídeos/fisiologia , Masculino , Pessoa de Meia-Idade , Peru , Valores de Referência , Remissão Espontânea , Estatísticas não Paramétricas , Adulto JovemRESUMO
Abstract: 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.
Assuntos
Humanos , Masculino , Feminino , Adolescente , Adulto , Adulto Jovem , Pênfigo/imunologia , Pênfigo/metabolismo , Estresse Oxidativo/fisiologia , Desmogleína 1/imunologia , Malondialdeído/sangue , Anticorpos/sangue , Peru , Valores de Referência , Remissão Espontânea , Ensaio de Imunoadsorção Enzimática , Peroxidação de Lipídeos/fisiologia , Estudos de Casos e Controles , Estudos Transversais , Estatísticas não Paramétricas , Doenças Endêmicas , Desmogleína 1/sangueRESUMO
Fogo Selvagem (FS), the endemic form of pemphigus foliaceus, is mediated by pathogenic IgG4 autoantibodies against the amino-terminal extracellular cadherin domain of the desmosomal cadherin desmoglein 1 (Dsg1). Here we define the detailed epitopes of these pathogenic antibodies. Proteolytic footprinting showed that IgG4 from 95% of FS donor sera (19/20) recognized a 16-residue peptide (A129LNSMGQDLERPLELR144) from the EC1 domain of Dsg1 that overlaps the binding site for an adhesive-partner desmosomal cadherin molecule. Mutation of Dsg1 residues M133 and Q135 reduced the binding of FS IgG4 autoantibodies to Dsg1 by â¼50%. Molecular modeling identified two nearby EC1 domain residues (Q82 and V83) likely to contribute to the epitope. Mutation of these residues completely abolished the binding of FS IgG4 to Dsg1. Bead aggregation assays showed that native binding interactions between Dsg1 and desmocollin 1 (Dsc1), which underlie desmosome structure, were abolished by Fab fragments of FS IgG4. These results further define the molecular mechanism by which FS IgG4 autoantibodies interfere with desmosome structure and lead to cell-cell detachment, the hallmark of this disease.
Assuntos
Autoanticorpos/metabolismo , Desmogleína 1/imunologia , Desmossomos/metabolismo , Epitopos de Linfócito B/imunologia , Imunoglobulina G/metabolismo , Pênfigo/imunologia , Peptídeos/imunologia , Animais , Autoanticorpos/imunologia , Brasil/epidemiologia , Células Cultivadas , Doenças Endêmicas , Mapeamento de Epitopos , Humanos , Imunização Passiva , Imunoglobulina G/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Mutagênese Sítio-Dirigida , Pênfigo/epidemiologia , Ligação Proteica , Conformação ProteicaAssuntos
Autoanticorpos/sangue , Autoantígenos/imunologia , Desmogleína 1/imunologia , Desmogleína 3/imunologia , Distonina/imunologia , Colágenos não Fibrilares/imunologia , Penfigoide Bolhoso/sangue , Autoanticorpos/metabolismo , Ensaio de Imunoadsorção Enzimática , Humanos , Immunoblotting , Imunoglobulina G/metabolismo , Penfigoide Bolhoso/metabolismo , Colágeno Tipo XVIIRESUMO
BACKGROUND: The objective of this study was to determine the presence of anti-Dsg1 and Dsg3 antibodies in healthy subjects of the high Peruvian Amazon (Tuemal, Rodriguez de Mendoza province, department of Amazonas) to establish the theoretical presence of environmental factors or triggers in the area. MATERIALS AND METHODS: Cross-sectional study. The study population included persons of any age or gender, clinically healthy, who were evaluated by a dermatologist to confirm the absence of blistering diseases. Blood samples were analyzed by indirect immunofluorescence (IIF), immunoprecipitation (IP), anti-Dsg1 IgM antibody (Ab) enzyme-linked immunosorbent assay (ELISA), as well as anti-Dsg1 and anti-Dsg3 IgG Ab ELISA. RESULTS: Participants included 21 healthy subjects comprised of 61.9% males and 38.1% females; 47.6% had a positive anti-Dsg1 Ab ELISA for total IgG (or any subclasses). IIF detected antibodies against intercellular spaces in one subject. Anti-Dsg1 Ab IP was mildly positive in 33.3% of the subjects. Anti-Dsg1 IgG subclasses found positive were: IgG1 (19.0%), IgG2 (33.3%), and IgG3 (28.6%); none of the samples were positive for anti-Dsg1 Ab IgM ELISA, and 23.8% of the subjects were positive for anti-Dsg3 Ab ELISA. The age distribution was similar for subjects positive for anti-Dsg1 and anti-Dsg3 Ab ELISA, with higher frequencies found among the 20-29 and 40-49 year-old age groups. CONCLUSION: A fraction of healthy subjects of the high Peruvian Amazon developed anti-Dsg1 and anti-Dsg3 antibodies, demonstrating the possible presence of environmental factors for endemic pemphigus (EP) at a higher altitude than previously described.
Assuntos
Autoanticorpos/sangue , Desmogleína 1/imunologia , Desmogleína 3/imunologia , Doenças Endêmicas , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Pênfigo/epidemiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Altitude , Criança , Estudos Transversais , Meio Ambiente , Ensaio de Imunoadsorção Enzimática , Feminino , Técnica Indireta de Fluorescência para Anticorpo , Voluntários Saudáveis , Humanos , Imunoprecipitação , Masculino , Pessoa de Meia-Idade , Pênfigo/imunologia , Peru/epidemiologia , Adulto JovemRESUMO
BACKGROUND: Black fly and sandfly bites are related to the endemicity of pemphigus foliaceus (PF); however, an immune reaction against the salivary proteins from these flies still requires confirmation in the case of PF patients living in southeastern Brazil. PURPOSE: To georeference the distribution of Simuliidae (Diptera: Simuliidae) and Phlebotominae (Diptera: Psychodidae) and of PF cases in the northeastern region of São Paulo State, and to assess the humoral immune response against salivary gland extracts (SGEs) from biting flies in PF patients, relatives, and neighbours. METHODS: PF patients' medical information recorded between 1965 and 2014 were obtained from the database of the University Hospital. Data on the distribution of fly species were collected from scientific reports and epidemiological databases. Spatial maps relating the distribution of biting flies with PF cases were plotted. Serum IgG antibodies against the SGEs from Simulium nigrimanum, Nyssomyia neivai, and Aedes aegypti (as control) were determined by ELISA. RESULTS: Two hundred and eighty-five PF cases were distributed in 60 municipalities with a prevalence of 57.5 per million inhabitants, revealing well-defined geographical clusters. S. nigrimanum and N. neivai specimens were registered in eight (13.3%) and 26 (43.3%) of these municipalities, respectively. PF patients, and their relatives presented higher levels of IgG against the SGEs of S. nigrimanum and N. neivai (P<0.001 for both), but not against the SGE from A. aegypti (P=0.115 and P=0.552, respectively), as compared to controls. IgG against the SGEs from S. nigrimanum and N. neivai but not against the SGE from A. aegypti correlated with levels of anti-Desmoglein 1 in PF patients (r=0.3848, P=0.039; and r=0.416, P=0.022, respectively). CONCLUSION: An epidemiological link between biting flies and PF in southeastern Brazil is proposed, implying a possible role of the salivary proteins from these flies in PF etiopathogenesis.
Assuntos
Mordeduras e Picadas de Insetos/epidemiologia , Mordeduras e Picadas de Insetos/imunologia , Pênfigo/epidemiologia , Pênfigo/imunologia , Psychodidae/imunologia , Simuliidae/imunologia , Adulto , Animais , Brasil/epidemiologia , Estudos de Casos e Controles , Desmogleína 1/imunologia , Ensaio de Imunoadsorção Enzimática , Feminino , Mapeamento Geográfico , Humanos , Imunoglobulina G/sangue , Masculino , Pessoa de Meia-Idade , Prevalência , Glândulas Salivares/imunologia , Extratos de Tecidos/imunologiaRESUMO
Rare are the family studies that include siblings affected by pemphigus vulgaris (PV) and in whom HLA class II alleles are related. HLA-DR and -DQ genotyping and profiling of antibodies against desmogleins (Dsg) 1 and Dsg3 were performed in ten members of a family including monozygotic twins affected by PV. The twin sisters were heterozygotes; they presented the haplotypes most commonly associated with increased susceptibility to PV (DRB1∗04:02-DQA1∗03:01-DQB1∗03:02 and DRB1∗14:04-DQA1∗01:01-DQB1∗05:03). Their parents and five siblings had only one or none of these two haplotypes in combination with the alleles or haplotypes associated with resistance to PV (DRB1∗07:01-DQA1∗02:01-DQB1∗02:02 and DRB1∗13:01-DQA1∗01:03-DQB1∗06:03). Only the monozygotic twins presented IgG antibodies against both Dsg1 and Dsg3. According to our knowledge based on a review of published literature on the topic, this is the first report of PV affecting monozygotic twins.