Serial analysis of Ro/SSA and La/SSB antibody levels and correlation with clinical disease activity in patients with systemic lupus erythematosus

Objective: To investigate the temporal correlation between anti-Ro/SSA and anti-La/SSB antibody levels and compare them with variation in clinical disease activity in patients with systemic lupus erythematosus (SLE). Methods: Sequential serum samples collected over 18-44 months from 18 anti-Ro/SSA positive patients with systemic lupus erythematosus were analysed by ELISA with recombinant Ro60, Ro52 and La antigens. Disease activity was assessed by the BILAG index. Results: Limited antibody level variation over time was found in most patients, but a subset displayed more changes and a co-variation between the levels of separate specificities was found in 40% of patients. In two patients antibody levels fluctuated with the global score. Antibodies also correlated with separate organ/systems involvment in individual patients. Conclusion: The Ro60, Ro52 and La antibody profile is fixed at an early stage of disease and in most patients hardly changes. Patients with fluctuating levels tend to have a co-ordinated expression of these autoantibodies.