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. This evidence concerns the gene TRIM21 and systemic lupus erythematosus.