A Review of the Impact of Sjögren's Syndrome and/or the Presence of Anti-Ro/SS-A Antibodies on Therapeutic Strategies for Rheumatoid Arthritis.

Rheumatoid arthritis (RA) is an immune-mediated disease characterized by polyarthritis that affects the small joints of the bilateral upper and lower extremities. RA shares several common clinical symptoms with Sjögren's syndrome (SS), another rheumatic disease caused by the lymphocytic infiltration of exocrine glands, with dry eye and dry mouth being the two most common symptoms. Anti-Ro/SS-A antibodies, a diagnostic biomarker of SS, are positive in patients with RA at a certain rate. The coexistence of SS and/or positivity for anti-Ro/SS-A antibodies in patients with RA influences disease activity and the effectiveness of several classes of disease-modifying antirheumatic drugs (DMARDs). Furthermore, RA, SS, and certain DMARDs, including methotrexate, are associated with the onset of lymphoproliferative disorders (LPD). In contrast, several biological DMARDs, such as tocilizumab and rituximab, are plausible options without the risk of LPD relapse. Considering the results of the studies introduced in this article, RA with SS and/or positivity for anti-Ro/SS-A antibodies could be considered a phenotype different from isolated RA from the perspective of refractoriness to DMARD therapy and LPD risk. Hence, rheumatologists should observe caution when choosing DMARDs. Further studies are needed to establish the appropriate treatment for patients with RA, SS, and/or the presence of anti-Ro/SS-A antibodies.