One year in review 2017: primary Sjögren's syndrome.

Primary Sjögren's syndrome (pSS) is a complex and heterogeneous disease. Last year, a great deal of basic and clinical research was carried out in pSS. Following the previous reviews of this publishing series, we will herewith provide a critical digest of the most recent literature on pSS pathogenesis, clinical manifestations and treatment. More specifically, we will focus on the heterogeneity of the disease, on the underlying pathogenetic pathways and on the possible new targeted treatments on the horizon.