RESUMEN
Type VII collagen is the main component of the anchoring fibrils connecting the basement membrane to the underlying interstitial matrix. Mutations in the type VII collagen gene cause dystrophic epidermolysis bullosa. Increased levels of type VII collagen in the skin have been reported in patients with systemic sclerosis (SSc), whereas reduced levels in the airways have been related to asthma. This indicates that type VII collagen plays an important part in upholding tissue integrity and that its remodeling may lead to pathological states. The aim of this study was to investigate the role of type VII collagen remodeling in fibroproliferative disorders. We produced monoclonal antibody targeting a specific fragment of type VII collagen (C7M) released to the systemic circulation and developed a neo-epitope specific competitive enzyme-linked immunosorbent assay (ELISA). Biological relevance was evaluated in serum from patients with SSc or chronic obstructive pulmonary disease (COPD). The C7M ELISA was technically robust and specific for the C7M neo-epitope. Serum C7M levels were significantly elevated in two cohorts of patients with SSc and in patients with COPD as compared with healthy individuals (P < 0.0001). The C7M ELISA enabled quantification of type VII collagen turnover in serum. Elevated serum C7M levels indicated that the turnover rate of type VII collagen was significantly increased in patients with SSc or COPD, suggesting a pathological role. Thus, the C7M ELISA may become useful in future investigations of type VII collagen turnover in fibroproliferative disorders, and it may prove a valuable tool for evaluating novel anti-fibrotic drugs.
Asunto(s)
Colágeno Tipo VII/sangre , Epítopos/sangre , Enfermedad Pulmonar Obstructiva Crónica/sangre , Esclerodermia Sistémica/sangre , Anciano , Estudios de Cohortes , Colágeno Tipo VII/metabolismo , Ensayo de Inmunoadsorción Enzimática , Epítopos/metabolismo , Femenino , Humanos , Masculino , Persona de Mediana Edad , Enfermedad Pulmonar Obstructiva Crónica/metabolismo , Esclerodermia Sistémica/metabolismoRESUMEN
Vancomycin (VCM) is known to induce linear IgA bullous dermatosis (LAD). However, in contrast to conventional LAD, in which circulating IgA autoantibodies against basement membrane proteins are commonly detected, patient sera from VCM-induced LAD yields negative results in indirect immunofluorescence microscopy, and the targeted autoantigen remains undetermined. By using sera from a typical patient with VCM-induced LAD, we identified that co-incubation of sera with VCM resulted in linear IgA deposition at the basement membrane zone by indirect immunofluorescence. Patient sera reacted with the dermal side of 1 mol/L NaCl-split skin and with the recombinant noncollagenous (i.e., NC1) domain of type VII collagen by both immunoblot and ELISA in the presence of VCM. The investigation of an additional 13 patients with VCM-induced LAD showed that 10 out of the 14 sera (71.4%) reacted with the NC1 domain of type VII collagen by ELISA when spiked with VCM, whereas only 4 (28.6%) tested positive without it. The enhancement of reactivity to NC1 by VCM, as determined by optical density via ELISA, was observed in 10 out of the 14 sera (71.4%). These findings indicate that type VII collagen is a target autoantigen in VCM-induced LAD and that VCM mediates IgA autoreactivity against type VII collagen, providing an insight into mechanisms involved in drug-induced autoimmune disease.
Asunto(s)
Antibacterianos/efectos adversos , Inmunoglobulina A/inmunología , Dermatosis Bullosa IgA Lineal/inmunología , Úlcera Cutánea/tratamiento farmacológico , Vancomicina/efectos adversos , Anciano , Autoanticuerpos/sangre , Autoantígenos/inmunología , Autoinmunidad/efectos de los fármacos , Membrana Basal/inmunología , Biopsia , Calcinosis/tratamiento farmacológico , Calcinosis/etiología , Colágeno Tipo VII/sangre , Colágeno Tipo VII/inmunología , Ensayo de Inmunoadsorción Enzimática , Femenino , Humanos , Inmunoglobulina A/sangre , Dermatosis Bullosa IgA Lineal/sangre , Dermatosis Bullosa IgA Lineal/inducido químicamente , Dermatosis Bullosa IgA Lineal/patología , Enfermedad Mixta del Tejido Conjuntivo/complicaciones , Enfermedad Mixta del Tejido Conjuntivo/tratamiento farmacológico , Prednisolona/uso terapéutico , Pruebas Serológicas/métodos , Piel/citología , Piel/inmunología , Piel/patología , Úlcera Cutánea/etiologíaRESUMEN
BACKGROUND: Serologic diagnosis of autoimmune blistering disease (AIBD) usually follows a sophisticated multistep algorithm. OBJECTIVE: We sought validation of a multivariant enzyme-linked immunosorbent assay (ELISA) in the routine diagnosis of AIBD. METHODS: The multivariant ELISA comprising 6 recombinant immunodominant forms of major AIBD target antigens, ie, desmoglein 1, desmoglein 3, envoplakin, BP180, BP230, and type VII collagen was applied in: (1) a cohort of well-characterized AIBD (n = 173) and control sera (n = 130), (2) a prospective multicenter study with 204 sera from patients with newly diagnosed AIBD with positive direct immunofluorescence microscopy, and (3) a prospective monocenter study with 292 consecutive sera from patients with clinical suspicion of AIBD in comparison with the conventional multistep diagnostic algorithm. RESULTS: Concordant results in the multivariant ELISA compared with direct immunofluorescence microscopy were seen in 94% of patients with pemphigus and 71% of patients with pemphigoid (Cohen κ value, 0.95 and 0.66) and with the conventional multistep diagnostic approach in 91% of patients with pemphigus and 88% of patients with bullous pemphigoid and 93% of autoantibody-negative sera (Cohen κ, 0.95, 0.84, and 0.78). LIMITATIONS: IgA autoantibodies and less common target antigens were not analyzed. CONCLUSIONS: The multivariant ELISA is a practical, highly standardized, and widely available novel diagnostic tool for the routine diagnosis of AIBD.
Asunto(s)
Enfermedades Autoinmunes/sangre , Enfermedades Autoinmunes/diagnóstico , Enfermedades Cutáneas Vesiculoampollosas/sangre , Enfermedades Cutáneas Vesiculoampollosas/diagnóstico , Algoritmos , Autoantígenos/sangre , Colágeno Tipo VII/sangre , Desmogleína 1/sangre , Desmogleína 3/sangre , Distonina/sangre , Ensayo de Inmunoadsorción Enzimática/métodos , Técnica del Anticuerpo Fluorescente Directa , Humanos , Proteínas de la Membrana/sangre , Microscopía , Colágenos no Fibrilares/sangre , Estudios Prospectivos , Precursores de Proteínas/sangre , Curva ROC , Proteínas Recombinantes/inmunología , Colágeno Tipo XVIIRESUMEN
BACKGROUND: Liver fibrosis is the main predictor of the progression of nonalcoholic fatty liver disease. Transient elastography (FibroScan), which measures liver stiffness, is a novel, noninvasive method to assess liver fibrosis. AIM: We investigated the usefulness of liver stiffness measurement in the evaluation of liver fibrosis in nonalcoholic fatty liver disease patients. STUDY POPULATION: A total of 97 nonalcoholic fatty liver disease patients. METHODS: Transient elastography was performed for liver stiffness measurement in 97 nonalcoholic fatty liver disease patients. And the relationship between histological parameters and liver stiffness measurement was studied by multivariate analysis. Moreover, we investigated the relationship between liver stiffness measurement and the serum levels of hyaluronic acid and type IV collagen 7s domain. RESULTS: The liver stiffness was well correlated with the stage of liver fibrosis (Kruskal-Wallis test p < 0.0001). The areas under the receiver-operating characteristic curves were 0.927 for > or = F1, 0.865 for > or = F2, 0.904 for > or = F3, 0.991 for > or = F4. Only fibrosis stage was correlated significantly with liver stiffness measurement by multiple regression analysis. Liver stiffness was also strongly correlated with the serum levels of type IV collagen 7s domain (r = 0.525, p < 0.0001) and hyaluronic acid (r = 0.457, p < 0.0001). CONCLUSIONS: Our results show a significant correlation between liver stiffness measurement and fibrosis stage in nonalcoholic fatty liver disease patients, as confirmed by the results of liver biopsy, which remains the gold standard for evaluation of the severity of liver fibrosis in patients with nonalcoholic steatohepatitis.