Anti–Ro/SS‐A and Anti–La/SS‐B autoantibody levels in relation to systemic lupus erythematosus disease activity and congenital heart block

Abstract

Objective. To analyze the anti–Ro/SS‐A and anti–La/SS‐B autoantibody responses, both quantitatively and qualitatively, in relation to the occurrence of congenital heart block (CHB) and disease activity in a patient with systemic lupus erythematosus. Methods. The patient's course was carefully documented for a period of 80 months. Specific enzyme‐linked immunosorbent assays, a HeLa cell immunoblotting test, and an RNA precipitation assay were used to determine autoantibody levels and fine specificities. Results. Anti–Ro/SS‐A and anti–La/SS‐B antibody did not disappear. Levels of anti–Ro/SS‐A appeared to fluctuate more frequently than levels of anti–La/SS‐B. Fluctuations were unrelated to disease activity or immunosuppressive treatment. There was no characteristic relationship between levels of these antibodies and the occurrence of CHB. Conclusion. The occurrence of CHB cannot be predicted by frequent measurement of anti–Ro/SS‐A and anti–La/SS‐B levels. The immunoregulatory control of anti–Ro/SS‐A and anti–La/SS‐B antibodies differs from that of anti‐DNA and anti–tetanus toxoid antibodies.