A comparison of three anti-double stranded DNA antibody assays on sera from SLE and other diseases.

Systemic lupus erythematosus (SLE) is a multisystem disorder accompanied by a diverse spectrum of serum autoantibodies. Antibodies to double stranded DNA (dsDNA) are considered to be the most specific marker for this disease. In this study the results obtained from three different assays for dsDNA are compared: an indirect fluorescence antibody assay (IFA), a radioimmunoassay (RIA) and, an enzyme-linked immunosorbent assay (ELISA), on 57 SLE sera and 28 Sera from other disorders. Correlation of these anti-DNA results are made with C3, C4, and antinuclear antibody (ANA) titers. Our results show the IFA assay is the most sensitive and the least specific of the three tests. The RIA was found to be the most specific and was approximately as sensitive as the ELISA. We also found significant inverse correlations between anti-dsDNA levels and circulating complement levels among SLE sera for all three assays. ANA titers were significantly correlated with all anti-dsDNA assays as well. However, these anti-dsDNA assays show only modest differences explainable by numerous mechanisms. Hence, a clearly superior anti-dsDNA method does not emerge from our study.