A rapid screening enzyme linked immunosorbent assay for autoantibodies to extractable nuclear antigens.

An enzyme linked immunosorbent assay (ELISA) has been developed to detect antinuclear antibodies to extractable nuclear antigens (ENA)--a rabbit thymus nuclear derivative. A second ELISA has also been developed (ENA RNA-ase ELISA) to analyse the relative contribution of the components of ENA (nucleoprotein and RNA antigens) to antibody binding as detected by the ELISA assays. Both ELISA assays provide a rapid screening method for antibodies to soluble, diffusable nuclear antigens that could otherwise go undetected by immunodiffusion or the indirect immunofluorescent method that uses unfixed frozen sections of rat liver. The considerable improvement that these ELISA assays offer in efficiency and both diagnostic and serological sensitivity over the traditional immunodiffusion method used for specificity characterisation of ENA autoantibodies is discussed.