Antibodies to Nuclear Antigens in Patients Treated with Procainamide or Acetylprocainamide

ANTIBODIES to nuclear antigens develop in patients who have been treated with procainamide. The prevalence of antinuclear antibodies ranges from 50 to 80 per cent1 2 3 4 5 6 7 and increases with the duration of therapy. A syndrome like systemic lupus erythematosus develops in 29 per cent5 of patients receiving long-term procainamide. Procainamide lupus erythematosus is uniformly associated with the presence of antinuclear antibodies.8 This syndrome shares certain clinical and serologic features with "idiopathic" lupus erythematosus. Antibodies to single-stranded DNA (sDNA),9 , 21 ribonucleoprotein,10 and a histone-DNA complex11 develop in patients taking procainamide. In contrast, antibody to native DNA has infrequently been observed in serum samples . . .