The IgG "lupus-band" deposition pattern of pemphigus erythematosus: association with the desmoglein 1 ectodomain as revealed by 3 cases.
BACKGROUND
Pemphigus foliaceus is an autoimmune skin disease characterized by subcorneal blistering and IgG antibodies directed against desmoglein 1. In the skin, these antibodies deposit intraepidermally. On rare occasions,an additional “lupus band” of granular depositions of IgG and complement is seen along the epidermal basement membrane zone. This combined pattern has been connected with a variant of pemphigus foliaceus named pemphigus erythematosus.


METHODS
We describe 3 pemphigus foliaceus cases in which phototherapy was administered after a misdiagnosis of psoriasis. This treatment resulted in a flare of skin lesions. Direct immunofluorescence of skin biopsy specimens that were obtained several weeks later demonstrated intraepidermal and granular basement membrane zone depositions. The basement membrane zone depositions consisted of IgG, complement, and the ectodomain of desmoglein 1 and were located below the lamina densa.


CONCLUSIONS
High doses of UV light are likely to induce the cleaving of the desmoglein 1 ectodomain. In patients with pemphigus foliaceus, the circulating anti–desmoglein 1 antibodies precipitate this cleaved-off ectodomain along the basement membrane zone, resulting in a lupus band–like appearance. In pemphigus erythematosus, a similar mechanism may be active, which might explain the lupus-band phenomenon.
Center for Blistering Diseases, Department of Dermatology, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands.
Dyah A M
DA
Oktarina
Angelique M
AM
Poot
Duco
D
Kramer
Gilles F H
GF
Diercks
Marcel F
MF
Jonkman
Hendri H
HH
Pas
D000368:Aged; D000369:Aged, 80 and over; D000954:Antigens, Surface / Q000276:immunology; D001485:Basement Membrane / Q000378:metabolism; D015932:Complement C3c / Q000378:metabolism; D051183:Desmoglein 1 / Q000276:immunology* / Q000378:metabolism; D003951:Diagnostic Errors; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000378:metabolism*; D008297:Male; D011701:PUVA Therapy / Q000009:adverse effects; D010392:Pemphigus / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology
D000954:Antigens, Surface; D051183:Desmoglein 1; D007074:Immunoglobulin G; D015932:Complement C3c