Lichenoid dermatitis in paraneoplastic pemphigus: a pathogenic trigger of epitope spreading?
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.
Bowen
G M
GM
Department of Dermatology, University of Utah, Salt Lake City 84132, USA. gbowen@derm.med.utah.edu
Peters
N T
NT
Fivenson
D P
DP
Su
L D
LD
Nousari
H C
HC
Anhalt
G J
GJ
Cooper
K D
KD
Stevens
S R
SR
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
D001323:Autoantibodies; D001324:Autoantigens; D000939:Epitopes