Acetylator phenotype in idiopathic systemic lupus erythematosus

The acetylator phenotypes of 21 patients from New York City and 29 patients from Israel with idiopathic systemic lupus erythematosus (SLE) were determined with dapsone or isoniazid. Thirty were slwo acetylators, 17 were rapid, and 3 indeterminate. These cases plus published studies of acetylator phenotypes in idiopathic SLE show a worldwide distribution of 150 slow to 77 rapid instead of the expected 122:105 (P less than 0.001). The relationship between acetylator phenotype and possible etiologic agents is discussed.