Contribution of immunoenzymatic technics to the assay of anti-native DNA antibodies in the biological diagnosis of lupus erythematosus disseminatus

Anti native DNA antibodies (anti nDNA Ab), which are a highly specific feature of systemic lupus erythematosus (SLE) were measured by 3 methods: an enzyme linked immunosorbent assay (ELISA), an indirect immunofluorescence test on Crithidia luciliae (IFCL) and the Farr assay (reference test). 114 sera from patients with SLE or another connective tissue disease or without autoimmune rheumatic disease were tested. This study showed that ELISA seemed to be a more sensitive and specific test than IFCL (classical test). ELISA was also as sensitive as the Farr assay. ELISA should replace IFCL for the diagnosis and the follow up of patients with SLE. In other connective tissue diseases, ELISA might give more positive results. Thus these had to be confirmed, especially in the case of low antibodies levels, by using another method (e.g., the Farr assay).