Multicenter validation of recombinant, natural and synthetic antigens used in a single multiparameter assay for the detection of specific anti-nuclear autoantibodies in connective tissue disorders

We investigated the feasibility of using a single multi-parameter test based mainly on recombinant autoantigens for the detection of anti-nuclear autoantibodies, and analyzed the agreement between this test format and conventional techniques. The presence of autoantibodies was determined by a line immunoassay (LIA) in 755 sera derived from patients with different autoimmune connective tissue disorders. All sera were previously tested by standard assays that are routinely used at the 8 participating European centers. The overall sensitivity and specificity of autoantibody detection by LIA was similar or higher as compared to combined conventional techniques (CCT). In particular, the detection of anti-Ro52 in systemic lupus erythematosus (SLE) sera (P = 0.004) and anti-LA in both SLE (P < 0.0009) and in Sjögren's syndrome (P < 0.0009) sera was significantly more sensitive when using LIA compared to CCT. By contrast, CCT was never more sensitive than LIA for any of the markers. The LIA is a reliable alternative to a combination of conventional techniques for the detection of specific anti-nuclear autoantibodies. The multi-parameter test also reveals autoantibody reactivities that may not be detected when only a limited number of conventional techniques are applied.