Immunologic prediction of relapse in patients with pemphigus vulgaris (PV) in clinical remission.

Background: Pemphigus vulgaris (PV) is characterized by multiple relapses, occurring especially in patients on minimal therapy or off therapy.

Objective: To identify immunologic predictors (anti-desmoglein [Dsg] 1 and 3 antibodies; direct immunofluorescence [DIF]) for relapse in PV patients.

Methods: Eighty-nine patients in complete clinical remission for at least 6 months and receiving less than or equal to 10 mg prednisolone daily and no immunosuppressive drugs were evaluated using DIF (n=89) and Dsg ELISA (n=46). They were followed until relapse or for at least 18 months.

Results: DIF was positive in 44 of 89 patients (49.5%); anti-Dsg 3 antibodies were detected in 18 of 46 patients (39.1%) and anti-Dsg 1 antibodies were detected in 4 of 46 patients (8.7%). Relapse occurred in 38 patients (42.7%). Mean relapse-free time was significantly shorter in anti-Dsg 3-positive patients compared to anti-Dsg 3- negative patients (P = .015) and in DIF-positive patients compared to DIF-negative patients (P = .047), but not in anti-Dsg 1- positive patients compared to anti-Dsg 1-negative patients (P = .501). Sensitivity and predictive values of neither of these tests were high.

Limitations: Small number of anti-Dsg 1-positive patients and use of conventional ELISA.

Conclusion: Positive anti-Dsg 3 ELISA and, to a lesser degree, positive DIF are predictors of relapse in PV patients in clinical remission. Decision on discontinuing treatment should be based on the results of these tests as well as on clinical findings.