Antidesmoplakin antibodies in pemphigus vulgaris.
BACKGROUND
Besides being present in paraneoplastic pemphigus (PNP), circulating antidesmoplakin (DP) antibodies have been found anecdotally in other bullous diseases, including pemphigus foliaceus and pemphigus vulgaris.


OBJECTIVE
To verify how frequent anti-DP antibodies are in pemphigus vulgaris.


METHODS
We studied 48 sera from patients with proven pemphigus vulgaris (29 mucosal dominant pemphigus and 19 mucocutaneous pemphigus) by indirect immunofluorescence (IIF) with rat bladder epithelium (RBE) as a substrate and by immunoblotting (IB) on human keratinocyte cultures enriched in DP.


RESULTS
Ten sera (21%) were positive in IIF on RBE. By IB, eight sera proved to have antibodies to both DP I (250 kDa) and DP II (210 kDa), one serum had antibodies directed to DP I only, and two sera to DP II only.


CONCLUSIONS
Our data confirm that RBE is not a specific IIF substrate for the serological diagnosis of PNP. It remains a sensitive and specific substrate for the detection of anti-DP antibodies, which, in patients with pemphigus vulgaris, are probably caused by an epitope-spreading phenomenon.
Cozzani
E
E
Di.S.E.M. Section of Dermatology, University of Genoa, Viale Benedetto XV 7, 16132 Genoa, Italy.
Dal Bello
M G
MG
Mastrogiacomo
A
A
Drosera
M
M
Parodi
A
A
D000818:Animals; D001323:Autoantibodies / Q000097:blood*; D001327:Autoimmune Diseases / Q000276:immunology; D002478:Cells, Cultured; D051183:Desmoglein 1 / Q000276:immunology; D051180:Desmoplakins / Q000276:immunology*; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D015603:Keratinocytes / Q000276:immunology; D008297:Male; D008875:Middle Aged; D010392:Pemphigus / Q000276:immunology*; D051381:Rats; D012189:Retrospective Studies; D051185:gamma Catenin
D001323:Autoantibodies; D051183:Desmoglein 1; D051180:Desmoplakins; C495292:JUP protein, human; D051185:gamma Catenin