antinuclear antibody (ANA) /-no̅o̅″klē·ər/ , an autoantibody directed against nuclear antigens. Antinuclear antibodies are found in the blood serum of patients with rheumatoid arthritis, systemic lupus erythematosus, Sjögren’s syndrome, polymyositis, scleroderma, Raynaud’s disease, mixed connective tissue disease, and a number of nonrheumatic disorders ranging from lymphomas, leukemias, primary biliary cirrhosis, thyroiditis, chronic active hepatitis, and adverse drug reactions. The antibodies are often detected with an immunofluorescent assay technique.
