Background: Primary Sjögren's Syndrome (PSS) mainly affects women (9:1 female:male ratio) and is one of the commonest autoimmune diseases with a prevalence of 0.1 - 0.6% of adult women. For patients with PSS there is currently no effective therapy that can alter the progression of the disease. The aim of the TRACTISS study is to establish whether in patients with PSS, treatment with rituximab improves clinical outcomes. Methods/design: TRACTISS is a UK multi-centre, double-blind, randomised, controlled, parallel group trial of 110 patients with PSS. Patients will be randomised on a 1:1 basis to receive two courses of either rituximab or placebo infusion in addition to standard therapy, and will be followed up for up to 48 weeks. The primary...