Fluctuation of anti-Ro/SS-A antibody levels in patients with systemic lupus erythematosus and Sjogren's syndrome: A prospective study

Objective To determine whether the titers of anti-Ro/SS-A (Ro) antibodies fluctuate d uring the course of SLE and Sjogren's syndrome (SS) in parallel with diseas e activity, and if such fluctuations could be used to predict disease flare s. We also evaluated whether the anti-Re profile (anti-Ro 52, anti-Re 60) c hanges over time, since such information could provide new insights into th e induction and regulation of anti-Ro autoimmunity. Methods Sixteen patients with SLE and 15 patients with SS, all anti-Ro/SS-A antibod y positive, were followed up for two years at three-month intervals. Clinic al and laboratory parameters of disease activity were examined. Determinati on of the anti-Ro/SS-A titer was performed by counterimmunoelectrophoresis and the fine anti-Re antibody specificity was determined by immunoblotting. Results The titers of anti-Re antibodies fluctuated during the course of the illnes s in both SLE and SS patients. In SLE patients these changes were not (exce pt in one case) associated with disease activity nor were they predictive o f disease flares. The same was true for the SS patients, with the exception of two patients with skin vasculitis in whom anti-Re antibody titers fluct uated in parallel with the disease activity. The anti-Re antibody (anti-Ro 60 kD, anti-Re 52 kD) specificity did not change in any of the patients dur ing the follow-up period. Conclusion Anti-Re antibodies could represent a valuable indicator of disease activity in SS patients with cutaneous disorders. They do not, on the other hand, r eflect disease activity inpatients with SLE. The stable antibody profile in both SLE and SS patients supports the hypothesis that autoantibody product ion is predominantly genetically regulated.