title: Epitope mapping of BP230 leading to a novel enzyme-linked immunosorbent assay for autoantibodies in bullous pemphigoid.
abstract: BACKGROUND
  Bullous pemphigoid (BP) is an autoimmune subepidermal blistering disease characterized by circulating autoantibodies against BP180 and BP230. For BP180, the NC16A domain has previously been identified as the main antigenic target in BP, while data about the diagnostic value of epitopes on BP230 were inconclusive.
  
  
  OBJECTIVE
  To identify the most appropriate epitopes on BP230 to be applied in a simple, sensitive, and highly specific enzyme-linked immunosorbent assay (ELISA) for routine detection of serum autoantibodies.
  
  
  METHODS
  Ten overlapping linear fragments covering the whole length of BP230 were expressed in Escherichia coli. Based on Western blot analysis with sera from patients with BP (n = 49) and healthy controls (n = 94), the diagnostic performance of the fragments was compared by receiver operating characteristics curve analysis. The BP230-C3 fragment comprising the C-terminal portion (amino acids 2326-2649) was subsequently applied in a novel ELISA. The operating characteristics of this ELISA were analysed by probing sera from patients with BP (n = 118), pemphigus vulgaris (n = 50), rheumatoid arthritis and other inflammatory arthritides (n = 170), and systemic lupus erythematosus (n = 56), and from healthy blood donors (n = 483).
  
  
  RESULTS
  Among all the fragments, BP230-C3 provided the best efficiency in serologically diagnosing BP by Western blot. An ELISA employing BP230-C3 revealed a diagnostic sensitivity of 56·8% and specificity of 97·6%. Its diagnostic added value amounted to 4·2% compared with the anti-BP180-NC16A-4X ELISA alone.
  
  
  CONCLUSIONS
  Recombinant BP230-C3 is a suitable target antigen for the detection of serum autoantibodies against BP230.
authors.affiliation: Institute of Experimental Immunology, EUROIMMUN AG, Lübeck, Germany.
authors.forename: I M
authors.initials: IM
authors.lastname: Blöcker
authors.forename: C
authors.initials: C
authors.lastname: Dähnrich
authors.forename: C
authors.initials: C
authors.lastname: Probst
authors.forename: L
authors.initials: L
authors.lastname: Komorowski
authors.forename: S
authors.initials: S
authors.lastname: Saschenbrecker
authors.forename: W
authors.initials: W
authors.lastname: Schlumberger
authors.forename: W
authors.initials: W
authors.lastname: Stöcker
authors.forename: D
authors.initials: D
authors.lastname: Zillikens
authors.forename: E
authors.initials: E
authors.lastname: Schmidt
mesh_terms: D001323:Autoantibodies / Q000276:immunology / Q000378:metabolism*; D015153:Blotting, Western; D002352:Carrier Proteins; D016022:Case-Control Studies; D003598:Cytoskeletal Proteins; D000071821:Dystonin; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D018604:Epitope Mapping / Q000379:methods*; D006801:Humans; D008562:Membrane Glycoproteins / Q000378:metabolism*; D009419:Nerve Tissue Proteins; D010391:Pemphigoid, Bullous / Q000175:diagnosis / Q000276:immunology*; D012372:ROC Curve; D011994:Recombinant Proteins
chemical_list: D001323:Autoantibodies; D002352:Carrier Proteins; D003598:Cytoskeletal Proteins; C486268:DST protein, human; D000071821:Dystonin; D008562:Membrane Glycoproteins; D009419:Nerve Tissue Proteins; D011994:Recombinant Proteins