title: IgA anti-p200 pemphigoid.
abstract: BACKGROUND
  Anti-p200 pemphigoid is a rare autoimmune subepidermal blistering disorder. Clinically, it may resemble bullous pemphigoid, linear IgA bullous dermatosis, or dermatitis herpetiformis. Immunologically, anti-p200 pemphigoid is characterized by the development of IgG antibodies directed against a basement membrane zone protein with a molecular weight of 200 kDa.
  
  
  METHODS
  We report the first case, to our knowledge, of anti-p200 pemphigoid associated with IgA antibodies and having clinical features resembling pemphigus herpetiformis or dermatitis herpetiformis localized on traumatized areas. Histopathological examination of lesional skin showed dermal-epidermal separation and microabscesses composed of neutrophils in the dermal papillae. Direct immunofluorescence disclosed the presence exclusively of linear in vivo-bound IgA along the basement membrane zone. With the use of laser scanning confocal microscopy, in vivo-bound IgA was localized above collagen type IV and colocalized with laminin 332. Indirect immunofluorescence showed circulating IgA antibodies against basement membrane zone at a titer of 1:160 that reacted with the floor of an artificial blister of salt-split skin. Western immunoblot analysis using dermal extract confirmed the reactivity of circulating IgA antibodies with the 200-kDa antigen corresponding to laminin γ1; however, immunoblotting using recombinant protein of 107 amino acid C-terminus of laminin γ1 was negative for circulating IgA antibodies. Immunoelectron microscopy disclosed the reactivity of circulating IgA autoantibodies within the lower lamina lucida.
  
  
  CONCLUSIONS
  To the best of our knowledge, this is the first case fulfilling the immunopathological criteria for anti-p200 pemphigoid associated with IgA antibodies and having unusual clinical features.
authors: Department of Dermatology, Medical University of Warsaw, Koszykowa 82a St, 02-008 Warszawa, Poland. kwozniak@wum.edu.pl
authors: Katarzyna
authors: K
authors: Wozniak
authors: Takashi
authors: T
authors: Hashimoto
authors: Shunpei
authors: S
authors: Fukuda
authors: Bungo
authors: B
authors: Ohyama
authors: Norito
authors: N
authors: Ishii
authors: Hiroshi
authors: H
authors: Koga
authors: Teruki
authors: T
authors: Dainichi
authors: Cezary
authors: C
authors: Kowalewski
mesh_terms: D000368:Aged; D001323:Autoantibodies / Q000276:immunology*; D001485:Basement Membrane / Q000276:immunology; D015153:Blotting, Western; D015815:Cell Adhesion Molecules / Q000276:immunology; D005260:Female; D019085:Fluorescent Antibody Technique, Direct; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D007070:Immunoglobulin A / Q000276:immunology*; D007797:Laminin / Q000276:immunology; D018613:Microscopy, Confocal / Q000379:methods; D016253:Microscopy, Immunoelectron; D009504:Neutrophils / Q000378:metabolism; D010391:Pemphigoid, Bullous / Q000276:immunology* / Q000503:physiopathology; D000097794:Kalinin
chemical_list: D001323:Autoantibodies; D015815:Cell Adhesion Molecules; D007070:Immunoglobulin A; D007797:Laminin; D000097794:Kalinin; C089141:laminin gamma 1