Background : Immunodeficiency syndromes associated with a Crohn's-like illness suggest innate immune defects may lead to Crohn's disease. Anecdotal cases using haemopoietic colony-stimulating factors report improvement in intestinal disease associated with these syndromes.

Aim : To test the safety and efficacy of recombinant human granulocyte colony-stimulating factor in active Crohn's disease.

Methods : In an open-labelled 12-week trial, patients with a Crohn's Disease Activity Index between 220 and 450 were treated with recombinant human granulocyte colony-stimulating factor (filgrastim, Neupogen). Concomitant immunosuppressants were prohibited except prednisone ≤20 mg/day. Patient's received recombinant human granulocyte colony-stimulating factor 300 mcg daily subcutaneously adjusted to achieve an absolute neutrophil count between 25 and 35 × 109/L.

Results : Twenty patients were enrolled with a mean initial Crohn's Disease Activity Index of 307 (range: 234–428). Fifteen patients (75%) completed 8 weeks; 13 patients (65%) completed 12 weeks with the mean Crohn's Disease Activity Index for patients continuing through those times of 196 (range: 36–343) and 162 (range: 20–308), respectively. At week 12, 11 patients (55%) demonstrated a decrease of at least 70 points; five (25%) achieved a sustained remission. The mean decrease was statistically significant at each assessment time-point. Three of four patients with fistulae had a positive response. Adverse effects included bone pain, mostly mild resolving with continued treatment. One patient was hospitalized with a viral-like syndrome but it is uncertain if this was treatment related.

Conclusion : Recombinant human granulocyte colony-stimulating factor is safe and potentially effective therapy for active Crohn's disease.