Antidesmoglein 1 and 3 serum IgG and positivity by direct immunofluorescence microscopy is associated with relapse in pemphigus in a prospective bicontinental study.

Background: Prospective studies identifying immunological parameters that can predict clinical relapse in pemphigus are scarce.

Objective: To periodically assess immunological parameters in patients with pemphigus vulgaris and foliaceous in remission to understand immunological events preceding clinical relapse.

Methods: A total of 105 patients were included. Baseline assessment included direct immunofluorescence (DIF), serum IgG against desmoglein (Dsg) 1, IgG, IgG1, and IgG4 against Dsg 3, IgG against the extracellular domains 1 and 2 of Dsg 3, IgG against muscarinic (M3)-AchR, and peripheral CD19+CD27+ memory B cells/plasma cells, repeated every 3 months for up to 12 months or until clinical relapse. DIF was repeated at month 12 and on relapse.

Results: About 29 of 105 patients (28%) experienced a relapse. Longer duration of clinical remission, presence of pruritus and positive anti-Dsg1 at baseline correlated with higher relapse rates. Compared with the visit immediately preceding relapse, a significantly increased number of patients with positive anti-Dsg1 (38% vs 31.1%,  = .01), anti-Dsg3 (51.7% vs 41.4%,  = .01) and IgG positivity by DIF (85.7% vs 25%,  < .001) was observed at the time of relapse.

Conclusion: Regular monitoring of anti-Dsg 1 and anti-Dsg 3 serum levels and DIF positivity during the course of the disease in remission may predict relapse.