BACKGROUND AND AIMS: Due to the need for new principles for the treatment of Crohn's disease and due to the documented immunomodulatory effects of interferon alpha, the tolerability and effect(s) of interferon alpha-2b (Introna) in active Crohn's disease were examined in a pilot study.

METHODS: Five patients with active Crohn's disease (activity index (CDAI) scores of 235-517), were treated with interferon alpha-2b for 12 weeks.

RESULTS: All patients tolerated the treatment, but developed influenza-like symptoms, which were fully controlled by paracetamol. Two patients obtained partial remission with a decline in activity index scores of 39% and 50%. The activity of 2',5'-oligoadenylate synthetase, which together with two other interferon-induced proteins, neopterin and beta 2-microglobulin were increased during treatment, indicated clearly an in vivo uptake of interferon. Sedimentation rate, C-reactive protein, orosomucoid, albumin, specific inflammatory markers: soluble interleukin-2 alpha-receptors (sIL-2R) and intercellular adhesion molecule-1 (ICAM-1) did not show any changes before or after treatment.

CONCLUSION: Future multicentre investigations are required to evaluate the clinical effect of interferon alpha-2b treatment in active Crohn's disease.