Anti-SS-A/Ro antibody is commonly found in the sera of patients with rheumatic disease. The antigenic components of SS-A/Ro are 60kD. and 52kD-Ro protein. Only anti-60kD SS-A/Ro antibody is detected by commonly used tests in clinical laboratories. "UniCAP EliA SS-A/Ro" is a new reagent using fluorescence enzyme immunoassay (FEIA) based on a mixture of both 60kD- and 52kD-Ro antigens. We evaluated the efficacy of detecting both anti-60kD and 52kD SS-A/Ro antibodies.
We collected sera from 264 rheumatic disease patients and 106 healthy subjects. Anti-SS-A/Ro antibodies were measured by the new reagent along with conventional method. Anti-52kD and 60kD SS-A/Ro antibodies were measured by ELISA kit in rheumatic disease patients.
Anti-SS-A/Ro antibody levels were higher in patients with Sjögren's syndrome than those with SLE or RA. The prevalence of anti-SS-A/Ro antibody in rheumatic disease patients and healthy subjects were comparable with the conventional method, and patients with Sjögren's syndrome had highest prevalence of anti-SS-A/Ro antibody. Concordance rate between EliA and conventional method, and EliA and DID, were 96.6% and 94.3%, respectively. ELISA analysis revealed that patients with Sjögren's syndrome had anti-52kD SS-A/Ro antibody at high rates, while anti-60kD SS-A/Ro antibody was widely found in rheumatic disease patients. Three patients were positive only for anti-52kD SS-A/Ro antibody.
Taken together, "UniCAP EliA SS-A/Ro" is useful as a screening test for anti-SS-A/Ro antibodies.