Antihistone Antibody Profile in Sulfasalazine Induced Lupus

Two patients developed drug induced lupus secondary to sulfasalazine (SSZ). One patient was receiving SSZ for Crohn's disease and was subsequently treated with olsalazine, which lacks the sulfapyridine component of SSZ. Her inflammatory bowel disease (IBD) remained controlled and she did not develop a recurrence of lupus, suggesting that olsalazine is safe in patients with IBD and a history of SSZ induced lupus. The SSZ induced antibodies were predominantly IgG against the (H2A-H2B)-DNA complex. Since lupus induced by 7 other drugs was associated with a similar antibody response, our findings support the existence of a common pathway for autoantibody induction.