Diagnostic specificities and sensitivities of anti dsDNA, anti membrane DNA and anti nucleosomes autoantibodies

The aim of this study is to evaluate, from369 routine sera of SLE and control patients, the worth of anti double stranded nuclear DNA, anti nucleosomes autoantibodies and anti membrane DNA for the diagnosis of SLE. Cell membrane associated DNA (mDNA) has been described on B lymphocytes and monocytes, but not on T cells. Antibodies to mDNA were identified by an indirect immunofluorescence assay using a B cell line fixed but notpermeabilised. At a 1:40 serum dilution, anti mDNA is almost associated with the diagnosis of systemic lupus erythematosus (SLE). Anti mDNA were shown to be different in specificity as compared with anti double stranded nuclear DNA. We compare its characteristics as diagnostic procedure to the conventional anti dsDNA antibody detection and to the recently introduced anti nucleosome antibody test documented as associated with SLE. It appears that the best sensitivity (0.65) and specificity (0.98) is given by the antimDNA test.