Primary Sjögren's syndrome: clinical phenotypes, outcome and the development of biomarkers.

Primary Sjögren's syndrome is a complex, autoimmune disease with distinct clinical phenotypes and variable outcomes. The systemic form of the disease is characterized by immune complex-mediated manifestations and is complicated by lymphoma as a result of a polyclonal B cell hyperactivity that is evolving into B cell malignancy. In the past decades, well-established clinical and serological markers have been described in the literature to identify high-risk patients and predict lymphoma development. However, specific biological treatments have proven ineffective to control the disease. Significant research effort has been made to reveal the major underlying biological events in this subgroup and identify biomarkers for early diagnosis, prognosis and response to treatment. In this review, we summarize the current data for the proposed histological, molecular and genetic biomarkers.