The prevalence of antibodies to histones induced by procainamide in old people, in cancer patients, and in rheumatoid-like disease.

Antibodies to histones were found to be most commonly responsible for the positive antinuclear antibody (ANA) test in asymptomatic patients treated with procainamide, in old people, in patients with neoplastic diseases, and in young women affected with a rheumatoid-like disease. Only in a very few patients were antibodies to dDNA and nucleoproteins demonstrated. Antibodies to nDNA were not found. The antibodies to histones were demonstrated by two methods: absorption of ANA-positive sera with a histone solution and subsequent performance of an ANA test; and acid elution of histones from thyroid sections followed by histone reconstitution.