Clinical value of an integrated ELISA system for the detection of 6 autoantibodies (ssDNA, dsDNA, Sm, RNP/Sm, SSA, and SSB).

An ELISA panel assay (ANA/6) which simultaneously detects IgG autoantibodies against 6 antigens (ssDNA, dsDNA, Sm, RNP/Sm, SSA, and SSB) was evaluated with sera from 98 patients with systemic lupus erythematosus (SLE) and related conditions, 68 disease controls, who were positive or negative by fluorescent ANA (FANA), and 100 healthy controls. The antigen panel specifically identified the particular autoantibodies present and had a high level of sensitivity which was reflected by the frequency of detection of autoantibodies in different patient groups. All active patients with SLE were positive for at least one autoantibody and 80% of these patients had 3 or more autoantibodies compared to only 20% of inactive patients. A large heterogeneity in antibody profiles was also noted. About 90% of patients with positive FANA, but no detectable autoimmune rheumatic disorder, i.e., false positive, were negative by the panel. A new method of standardization was designed to use the ANA/6 quantitatively. Very large differences in the level of all 6 autoantibodies were observed between sera from patients with active and inactive SLE, suggesting a potential usefulness of ANA/6 for patient management.