Usefulness of specific anti‐desmoglein 1 and 3 enzyme‐linked immunoassay and indirect immunofluorescence in the evaluation of pemphigus activity

Objective The objective was to assess the relationship between enzyme‐linked immunoassay ( ELISA ) values of desmoglein ( D sg) 1 and D sg3 antibodies and indirect immunofluorescence ( IIF ) values of anti‐epithelial antibodies with disease activity in patients with pemphigus. Patients and methods In a retrospective study, we analyzed 353 serum samples taken from 35 patients with pemphigus vulgaris ( PV ) and nine with pemphigus foliaceus ( PF ) during the course of the disease. In each sample, we measured anti‐ D sg1 and anti‐ D sg3 antibodies by ELISA . A receiver operating characteristics ( ROC ) curve was calculated to determine a cutoff value for anti‐ D sg1 and anti‐ D sg3 antibodies with optimal sensitivity and specificity. In 263 samples, we compared the ROC curves of anti‐ D sg1 and anti‐ D sg3 antibodies with the ROC curves of the IIF results. Results Activity of pemphigus was associated with a wide range of anti‐ D sg1 and anti‐Dsg3 antibody values. Levels of anti‐ D sg1 antibodies showed a better relationship with cutaneous activity of pemphigus than levels of IIF anti‐epithelial antibodies. The levels of IIF anti‐epithelial antibodies showed a relationship with activity of mucosas similar to the levels of anti‐ D sg3 antibodies. Discussion Abnormal values of anti‐ D sg antibodies are not always associated with disease activity. ELISA detects both pathogenic and nonpathogenic anti‐ D sg antibodies. Conclusions Therapeutic strategies should not be based exclusively on anti‐ D sg antibody values. Anti‐ D sg1 antibodies showed a closer relationship with skin activity than IIF , while anti‐ D sg3 antibodies showed a relationship with mucosal activity similar to the IIF test.