title: Lichenoid dermatitis in paraneoplastic pemphigus: a pathogenic trigger of epitope spreading?
abstract: BACKGROUND
  In select cases, lichen planus has been observed to be a paraneoplastic condition sometimes associated with paraneoplastic pemphigus, a disease featuring autoantibodies directed against plakin proteins, desmogleins 3 and 1, and a still uncharacterized 170-kd antigen. Epitope spreading describes the phenomenon where underlying chronic inflammation leads to the sequential recognition of new epitopes on self-proteins over time.
  
  
  METHODS
  Five of 6 patients diagnosed as having paraneoplastic pemphigus had concomitant clinical and histological features of lichen planus. In 1 patient, results of the initial indirect immunofluorescence on rat bladder were negative and only 2 of the 5 antigens were identified by immunoprecipitation. After 1 year of worsening disease, repeated testing confirmed the presence of antibodies directed against all 6 of the implicated antigens, supportive of our hypothesis that epitope spreading may occur in paraneoplastic pemphigus.
  
  
  CONCLUSIONS
  Lichenoid eruptions may predispose to an early evolutionary stage of paraneoplastic pemphigus. Cell-mediated autoimmunity at the dermoepidermal junction may promote the exposure of self-antigens and the development of subsequent and progressive humoral autoimmunity. As such, paraneoplastic pemphigus may demonstrate epitope spreading in a human, humoral-mediated autoimmune disease.
authors.affiliation: Department of Dermatology, University of Utah, Salt Lake City 84132, USA. gbowen@derm.med.utah.edu
authors.forename: G M
authors.initials: GM
authors.lastname: Bowen
authors.forename: N T
authors.initials: NT
authors.lastname: Peters
authors.forename: D P
authors.initials: DP
authors.lastname: Fivenson
authors.forename: L D
authors.initials: LD
authors.lastname: Su
authors.forename: H C
authors.initials: HC
authors.lastname: Nousari
authors.forename: G J
authors.initials: GJ
authors.lastname: Anhalt
authors.forename: K D
authors.initials: KD
authors.lastname: Cooper
authors.forename: S R
authors.initials: SR
authors.lastname: Stevens
mesh_terms: D000328:Adult; D000368:Aged; D000818:Animals; D001323:Autoantibodies / Q000097:blood; D001324:Autoantigens / Q000276:immunology*; D001943:Breast Neoplasms / Q000175:diagnosis; D002285:Carcinoma, Intraductal, Noninfiltrating / Q000175:diagnosis; D000939:Epitopes / Q000276:immunology*; D017809:Fatal Outcome; D005260:Female; D019085:Fluorescent Antibody Technique, Direct; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D008010:Lichen Planus / Q000150:complications / Q000276:immunology / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D010257:Paraneoplastic Syndromes / Q000150:complications / Q000276:immunology / Q000473:pathology*; D010392:Pemphigus / Q000150:complications / Q000276:immunology / Q000473:pathology*; D011233:Precipitin Tests; D051381:Rats
chemical_list: D001323:Autoantibodies; D001324:Autoantigens; D000939:Epitopes