Increased risk of multiple myeloma in primary Sjögren's syndrome is limited to individuals with Ro/SSA and La/SSB autoantibodies

Primary Sjogren’s syndrome is a systemic autoimmune disease characterised by chronic inflammation of exocrine glands, primarily the salivary and lacrimal glands. In the glands, ectopic lymphoid tissue may form, with germinal centre-like structures promoting B-cell DNA rearrangements and Ro/SSA and La/SSB autoantibody production.1 The presence of autoantibodies correlate with disease severity and influence long-term outcome.2 High circulating levels of BAFF also contributes to the polyclonal B-cell activation, and increased plasmablast differentiation and hypergammaglobulinaemia are common.3 4 The autoantibodies can induce production of type I interferons, which further a positive feed-forward loop of chronic B-cell activation.3 Patients with primary Sjogren’s syndrome have a 5–15 times higher risk of lymphoma than the general population, corresponding to a lifetime risk of 5%–10%.5 The malignancies are commonly B-cell non-Hodgkin lymphomas, predominantly marginal zone lymphomas. However, whether there is an increased risk of multiple myeloma in Sjogren’s syndrome has not been unequivocally defined (see online supplementary text).6 Considering the abundance and activity of …