Identification of autoantibody biomarkers for primary Sjogren's syndrome using protein microarrays

Sjogren's syndrome (SS) is a chronic, progressive autoimmune disease primarily affecting women. Diagnosis of SS requires an invasive salivary gland tissue biopsy and a long delay from the start of the symptoms to final diagnosis has been frequently observed. In this study, we aim to identify salivary autoantibody biomarkers for primary SS (pSS) using a protein microarray approach. Immune-response protoarrays were used to profile saliva auto-antibodies from patients with pSS (n=14), patients with systemic lupus erythematosus (SLE, n=13), and healthy control subjects (n=13). We identified 24 potential autoantibody biomarkers that can discriminate patients with pSS from both patients with SLE and healthy individuals. Four saliva autoantibody biomarkers, anti-transglutaminase, anti-histone, anti-SSA, and anti-SSB, were further tested in independent pSS (n=34), SLE (n=34), and healthy control (n=34) subjects and all were successfully validated with ELISA. This study has demonstrated the potential of a high-throughput protein microarray approach for the discovery of autoantibody biomarkers. The identified saliva autoantibody biomarkers may lead to a clinical tool for simple, noninvasive detection of pSS at low cost.