E-cadherin autoantibody profile in patients with pemphigus vulgaris

Pemphigus vulgaris (PV) is an autoimmune skin blistering disease. The main targets of autoantibodies are the desmosomal proteins desmoglein (Dsg)3 and Dsg1. Anti-E-cadherin antibody is the second most frequent antibody found in pemphigus foliaceus (fogo selvagem), but the frequency in PV is unknown.

To determine the anti-E-cadherin antibody profile in the two major subtypes of PV: mucosal PV (mPV) and mucocutaneous PV (mcPV).

Sera from 80 patients with PV and 80 controls were tested. Patients with PV were subdivided into mPV (n = 18) and mcPV (n = 62). Samples were tested by E-cadherin, Dsg1 and Dsg3 enzyme-linked immunosorbent assays (ELISAs), and immunoprecipitation coupled with Western blotting (IP-WB).

Both mPV and mcPV sera have antibodies against E-cadherin as demonstrated by ELISA and IP-WB. Both subtypes of PV have low levels of anti-E-cadherin antibodies, but significantly higher levels than healthy controls by ELISA (P < 0·0001). No difference exists in antibody levels between subgroups (P = 0·82). By IP-WB, 78% of mcPV sera reacted to E-cadherin, vs. 33% of mPV sera tested. Correlation analysis suggests a moderate correlation between anti-E-cadherin antibodies and Dsg1 antibodies (average r = 0·61), but no correlation with Dsg3 antibodies (average r = 0·19). Patients with mPV can have lower levels of Dsg1 antibodies compared with controls by ELISA (P < 0·0001). A few mPV sera also reacted to Dsg1 protein by IP-WB (17%).

Anti-E-cadherin antibodies are present in both major subtypes of PV. A moderate correlation exists between E-cadherin and Dsg1 antibodies. Patients with mPV can have low levels of both E-cadherin and Dsg1 antibodies.