|Budget Amount *help
¥3,500,000 (Direct Cost : ¥3,500,000)
Fiscal Year 1998 : ¥1,000,000 (Direct Cost : ¥1,000,000)
Fiscal Year 1997 : ¥2,500,000 (Direct Cost : ¥2,500,000)
Pemphigus is an autoimmune blistering disease and has two major subtypes, pemphigus vulgaris (PV) and pemphigus foliaceus (PF). Patients with pemphigus have circulating anti-Dsg1 and/or anti-Dsg3 IgG autoantibodies. We have previously developed ELISAs using recombinant Dsg1 and Dsg3 expressed by baculovirus as a diagnostic tool for pemphigus. The purpose of this study was to evaluate the practical application of these ELISAs for clinical use with a large number of serum samples. We used 81 PV sera, 48 PF sera, 114 bullous pemphigoid (BP) sera, 124 collagen disease sera, 8 sera of other non-pemphigus bullous diseases and 179 normal control sera. A cutoff value was determined by Receiver-Operating-Characteristic (ROC) plots. 47 of 48 PF sera (97.9%) were positive in the Dsg1 ELISA and 79 of 81 PV sera (97.5%) were positive in the Dsg3 ELISA, while only 2(1.1%) and 4(2.2%) of 179 normal sera were positive in Dsg1 and Dsg3 ELISAs, respectively. However, some disease control sera of BP arid collagen diseases exceeded the cutoff value. Introduction of a gray zone helped to decrease the number of those false positive sera. Furthermore, in 11 patients studied, the respective Dsg1 and Dsg3 ELISA scores showed parallel fluctuation with the disease activity along the time course. We proposed a diagnostic criteria for pemphigus based on ELISA reactivity ; if a serum is positive against Dsg3 it indicates diagnosis of PV, regardless of reactivity against Dsg1 ; if a serum is negative for Dsg3 and positive for Dsg1, it indicates diagnosis of PF.We concluded that these Dsg1 and Dsg3 ELISAs provide a simple, sensitive and highly specific assay for the diagnosis of patients with PV and PF and that these ELISAs may be a valuable tool to monitor the disease activity.