title: Sensitivity of different assays for the serological diagnosis  of epidermolysis bullosa acquisita: analysis of a cohort of 24  Italian patients.
abstract: BACKGROUND
  Epidermolysis bullosa acquisita (EBA) is an autoimmune blistering disease characterized by tissue-bound and circulating autoantibodies to the dermal-epidermal junction. The autoantibody target is type VII collagen (Col VII) which is involved in dermal-epidermal adhesion. Diagnosis is made by clinical and histopathological findings, linear deposition of autoantibodies at the dermal-epidermal junction detected by direct immunofluorescence, and binding to the dermal side of salt-split skin by indirect immunofluorescence (IIF). However, the detection of specific anti-Col VII reactivity has an important confirmatory value.
  
  
  METHODS
  The humoral immune response in EBA sera was analysed by (i) IIF on human skin, (ii) a commercial Col VII ELISA, and (iii) immunoblotting on Col VII produced by an epithelial cell line.
  
  
  OBJECTIVE
  The aim of this study was to compare the sensitivity of different approaches for the serological diagnosis of EBA.
  
  
  RESULTS
  The vast majority of EBA sera (79.2%) bound to the Col VII non-collagenous domains by a commercial ELISA, while a small proportion of patients (12.5%) exclusively reacted to the collagenous domain by immunoblotting. Of note, the autoantibodies reactivity to Col VII was more frequently detected by IB (91.7%) than by IIF (83.3%) and ELISA (79.2%). Interestingly, 2 out of 24 sera recognized Col VII epitopes undetectable in the native secreted protein but present in the context of extracellular matrix proteins, as assessed by immunomapping on Col VII-deficient skin.
  
  
  CONCLUSIONS
  Our findings show that the use of multiple assays allows to improve diagnostic performance. An algorithm for efficient serological diagnosis of EBA is proposed.
authors: V
authors: V
authors: Calabresi
authors: A
authors: A
authors: Sinistro
authors: E
authors: E
authors: Cozzani
authors: C
authors: C
authors: Cerasaro
authors: F
authors: F
authors: Lolicato
authors: M
authors: M
authors: Muscianese
authors: A
authors: A
authors: Parodi
authors: B
authors: B
authors: Didona
authors: G
authors: G
authors: Zambruno
authors: G
authors: G
authors: Di Zenzo
mesh_terms: D015331:Cohort Studies; D004820:Epidermolysis Bullosa / Q000175:diagnosis* / Q000276:immunology; D006801:Humans; D056724:Immunity, Humoral; D007558:Italy; D012189:Retrospective Studies