Infliximab- and azathioprine-related severe neutropenia and thrombocytopenia in a case with Crohn's disease.

A 25-year-old female patient with Crohn's disease had been using azathioprine and metronidazole for an extended period because of recurrent perianal and rectovaginal fistulae. Infliximab was added to the treatment regimen following postoperative recurrence of a rectovaginal fistula. Upon the development of severe neutropenia and thrombocytopenia after the third dose of infliximab, azathioprine and infliximab were stopped. Neutropenia work-up did not reveal any other cause. Neutropenia was ameliorated with use of granulocyte colony-stimulating factor. Treatment was restarted with infliximab alone upon leakage from the rectovaginal fistula with no hematologic toxicity. This case was considered as a serious adverse effect of infliximab and azathioprine combination therapy.