['The overall aim of this study is to identify clinical and serological features that are associated with B lymphocyte stimulator (BLyS) elevation in a homogeneous Caucasian SLE population and thereby identify patients who are most likely to benefit from BLyS blockade.', 'Patients with SLE (as per ACR criteria) were recruited. Clinical history, disease activity measures and laboratory measures of disease were recorded. BLyS levels were determined by ELISA.', 'BLyS elevation was defined as being higher than the 95th percentile of BLyS levels measured in controls. Patients were divided into two groups: those with elevated BLyS levels (group 1, n = 23) and those with normal BLyS levels (group 2, n = 22). Elevated BLyS levels were significantly associated with patients of younger age and shorter disease duration. In keeping with previous reports, patients with elevated BLyS levels had more active disease (SLEDAI 5.1 vs 0.86, P < 0.001); however, our analysis also demonstrates that BLyS elevation was significantly associated with increased organ damage at 5-year follow-up [Systemic Lupus International Collaborating Clinics/ACR Damage Index (SLICC/ACR DI) 0.53 vs 0.13, P = 0.012]. Furthermore, the presence of Sm autoantibody significantly predicted elevated BLyS levels in a Caucasian population. BLyS levels were significantly higher in those with musculoskeletal involvement, malar rash, renal disease and evidence of immunological activity.'] Are elevated B lymphocyte stimulator levels associated with increased damage in an Irish systemic lupus erythematosus cohort?