The clinical significance of the detection of anti-Ro/SS-A and anti-La/SS-B autoantibodies using purified recombinant proteins in primary Sjögren's syndrome.

Recently, an enzyme-linked immunosorbent assay (ELISA), using purified recombinant non-fusion proteins, has been introduced to detect and quantify Ro/SS-A and La/SS-B autoantibodies. We compared this method with anti-Ro/SS-A and anti-La/SS-B detection by means of counterimmunoelectrophoresis and immunoblotting in patients with primary Sjögren's syndrome (SS), patients suspected of the syndrome and controls. The sensitivity and specificity of the newly developed ELISA for anti-Ro/SS-A were 53% and 100%, respectively, and for anti-La/SS-B, 40% and 98%, respectively. No significant difference was found between these results and those obtained from both other assays. Titres of Ro/SS-A and La/SS-B autoantibodies correlated with the presence of an abnormal parotid gland sialogram and hypergammaglobulinaemia. We concluded that the new ELISA did not enhance the diagnostic yield in cases of suspicion of primary Sjögren's syndrome. Longitudinal studies of large groups of patients with primary Sjögren's syndrome are necessary to demonstrate whether following the course of the titres of these autoantibodies would be of value for prediction of disease exacerbations.