TRIM21 and peeling skin syndrome: Identification of 24 potential autoantibody biomarkers that could discriminate patients with pSS from both patients with SLE and healthy subjects. Four saliva autoantibody biomarkers, anti-transglutaminase, anti-histone, anti-SSA, and anti-SSB, were further tested in independent groups of pSS and SLE patients and healthy control subjects and all were successfully validated with ELISA.