Pemphigus is an acquired autoimmune intraepidermal blistering disease that is divided into 2 major subtypes: pemphigus vulgaris (PV) and pemphigus foliaceus (PF). Patients with pemphigus have circulating anti-desmoglein (Dsg)1 and/or anti-Dsg3 IgG autoantibodies. Recently, a novel commercial enzyme-linked immunosorbent assay (ELISA) against Dsg1 and Dsg3 has been established and found to be extremely sensitive and specific. To date, the usefulness of Dsg1 and Dsg3 ELISA in the diagnosis of pemphigus in the Taiwanese population has never been reported.
Serum samples were obtained from 143 patients, including 20 patients with PV, 9 patients with PF, 72 patients with bullous pemphigoid, 1 patient with dermatitis herpetiformis and 41 patients with non-autoimmune blistering diseases. They were tested for anti-Dsg1 and anti-Dsg3 reactivity by ELISA.
Seventeen of 20 PV sera (85%) exceeded the cut-off value of Dsg3 ELISA, and 9 of 9 PF sera (100%) exceeded the cut-off value of Dsg1 ELISA, while only 1 (0.88%) and 3 (2.6%) of 114 non-pemphigus sera exceeded the cut-off values of Dsg3 and Dsg1 ELISAs, respectively. Thus, the sensitivity and specificity of Dsg3 ELISA were 85% and 99.1%, while the sensitivity and specificity of Dsg1 ELISA were 100% and 97.4%, respectively. The correlation between ELISA scores and disease activity along the time course was examined in 6 PV patients and 1 PF patient, and the result was equivocal.
Dsg1 and Dsg3 ELISAs provide a simple, highly sensitive and specific method that can serve as a useful adjunct tool for the initial diagnosis of pemphigus.