Subsets of autoantibodies to extractable nuclear antigens (ENA) as assayed by ELISA correlate with specific clinical abnormalities in SLE.

A clinicopathological study of antinuclear antibodies was performed in 43 patients with SLE. Autoantibodies to double-stranded DNA, measured by RIA, were found in 56% of subjects and were associated with the presence of mesangioproliferative glomerulonephritis, Raynaud's phenomenon and cryoglobulinaemia. Antibodies to extractable nuclear antigens (ENA), when assayed by ELISA, were found in 81% of subjects and were associated with photosensitivity and thrombocytopaenia. Antibodies to RNA-ase-resistant ENA were found in 42% and were associated with cryoglobulinaemia and sclerodactyly, while antibodies to RNA-ase sensitive ENA which had a 49% prevalence were associated with haemolysis and neutropaenia. RNP antibodies (detected by immunodiffusion in 40%) were also associated with photosensitivity. RNP antibody positive and negative sera differed from each other by virtue of their relationship with other autoantibodies, and because RNP-positive sera had significantly higher ENA antibody titres and affinities than did RNP-negative sera. We therefore concluded that various combinations of antinuclear antibodies may predispose to the development of specific clinicopathological lesions in SLE.