Muratov V et al. (2006) Down-regulation of interferon-γ parallels clinical response to selective leukocyte apheresis in patients with inflammatory bowel disease: a 12-month follow-up study. Int J Colorectal Dis 21: 493–504

Previous studies have suggested that leukocyte apheresis, which selectively removes about 65% of activated granulocytes and 55% of activated monocytes from peripheral blood, can improve IBD symptoms in patients who cannot tolerate conventional treatments. Muratov et al. have now confirmed that apheresis is well tolerated, and could be used as an adjunct to conventional IBD treatment.

Their unblinded, uncontrolled study enrolled patients (age range 27–51 years) with either Crohn's disease (n = 7) or ulcerative colitis (n = 3), from a single Swedish institute; all patients had mild-to-moderate, chronically active disease. Patients' pre-existing anti-inflammatory regimens were maintained throughout the study, except for prednisolone, which was tapered in patients who responded to apheresis. All patients received five, 1 h, weekly apheresis sessions, and were followed up after 7 weeks and 12 months. Nine patients responded to apheresis, of whom three had a sustained response and five achieved clinical remission by the 12 month follow-up. No severe adverse effects were observed.

Patients with Crohn's disease underwent colonoscopy with biopsies at baseline and after 7 weeks to assess the effects of apheresis on expression of proinflammatory cytokines in mucosal tissue. Clinical improvement was associated with reduced leukocyte infiltration and interferon-γ production, which predicted a sustained response to apheresis. The authors speculate that apheresis could have a previously unrecognized immunomodulatory effect on interferon-γ-producing lymphocytes, which might not be solely attributable to mechanical removal of certain leukocytes.