TRIM21 and peeling skin syndrome: Objectives—The aim of the present study was to characterize the clinical phenotype of patients with primary Sjögren’s syndrome (pSS) with non-identified antinuclear antibodies (ANA) in comparison with that of patients with pSS with negative ANA, positive typical ANA (anti-Ro/SSA and/or La/SSB) and positive atypical ANA.