Clinical and serological predictors of relapse in pemphigus: a study of 143 patients

Background: Pemphigus is an autoimmune bullous disease mediated by autoantibodies targeting epithelial cell-cell adhesion molecules. Predictors of relapse have not yet been uniquely identified. Objectives: To identify factors at diagnosis and during follow-up which could be predictors of relapse. Methods: Clinical and immunopathological data at diagnosis, clinical remission, and first relapse from patients with pemphigus vulgaris or foliaceus and at least a 36-month follow-up were retrospectively collected. Based on autoantibody profile at diagnosis, three serological patients' subsets were devised: anti-desmoglein (Dsg)1-positive/anti-Dsg3-negative; anti-Dsg1-negative/anti-Dsg3-positive; anti-Dsg1/anti-Dsg3-positive. Results: Data from 143 patients were collected. No significant differences were found between relapsers (n=90) and non-relapsers (n=53) in terms of time to remission and anti-Dsg1/anti-Dsg3 titers at diagnosis and remission. Considering all patients, a Body Surface Area (BSA) of 3 compared to BSA<3 (OR=3.30, 95%CI:1.17-9.28; p=0.0240) and a positive titer in either anti-Dsg1 or anti-Dsg3 autoantibodies at remission compared to having both negative (OR=2.42, 95%CI 1.21-4.85, p=0.0130) predicted a higher risk of relapse. In patients with anti-Dsg3-positive/anti-Dsg1-negative at diagnosis, failure to achieve anti-Dsg3 negativity at clinical remission was a significant relapse predictor (OR=7.89, 95%CI:2.06-30.21; p=0.0026). Conversely, failure to achieve anti-Dsg1 negativity at clinical remission was a significant relapse predictor in patients with both anti-Dsg1 and anti-Dsg3 positivity at diagnosis (OR=5.74, 95%CI:1.15-28.61; p=0.0331), but not in those with positive anti-Dsg1-positive/anti-Dsg3-negative at diagnosis (OR=1.08, 95%CI:0.27-4.30; p=0.9093). Conclusion: Regardless of pemphigus subtype, autoantibody titer negativity at clinical remission in patients classified based on their anti-Dsg1/anti-Dsg3 profile at diagnosis and BSA were useful tools in predicting relapse.