Varying distribution of acetylation phenotypes in RA patients with and without Sjögren's syndrome.

The acetylator phenotype status was studied in 61 patients with rheumatoid arthritis (RA), of whom 27 had associated Sjögren's syndrome (SS). The acetylation tests were carried out by means of isoniazid and in 24 patients also with the use of dapsone; there was complete agreement between the outcome of the two tests. The results showed that the frequency of slow acetylators in the whole material was 59%. In RA patients with SS, however, the frequency of slow acetylators was as great as 78%, while it was only 44% among patients without SS (p less than 0.02). Thus, there appears to exist a (pharmaco) genetic difference between RA patients with and without SS. In addition, toxicodermias were found to be more frequent in RA patients with than without SS (P less than 0.01). However, this could not be systematically correlated to slow acetylation.