[Antibodies against ds-DNA and nucleoprotein in systemic lupus erythematosus--comparison of various determinative...

Five methods for the detection of antibodies against ds-DNA and nucleoprotein were compared with respect to their usefulness for the diagnosis and monitoring of SLE: filter radio-immunoassay (filter RIA), enzyme immunoassay (EIA N) and Crithidia lucilia assay (CL-IF) for detecting anti-ds-DNA antibodies as well as enzyme-immunoassay (EIA NP) and a latex test (LE test NP) for detecting anti-NP antibodies. In testing 32 SLE patients we obtained the following sensitivities: filter RIA 78%, EIA N 87%, CL-IF 47%, EIA NP 73% and LE test NP 25%. Among 95 patients having ANA greater than or equal to 1:100 in their sera, but who had no clinical signs of SLE, anti-ds-DNA antibodies were detectable in 12% (filter RIA), 16% (EIA N) and 4% (CL-IF) as well as anti-NP antibodies in 35% (EIA NP) and 4% (LE test NP). Only filter RIA and EIA N were of significant value in differentiating active from inactive SLE.