Cyclophosphamide therapy in Sweet's syndrome complicating refractory Crohn's disease − Efficacy and mechanism of action.

BACKGROUND

Sweet's syndrome is a rare extraintestinal manifestation of Crohn's disease that is usually treated by corticosteroids. Cyclophosphamide therapy has been shown to be effective in steroid-refractory Crohn's disease with extraintestinal manifestations. The mechanism of action remains obscure. Here, we report about a case of steroid-refractory Sweet's syndrome accompanying Crohn's colitis treated by cyclophosphamide.

METHODS

At baseline and two weeks after initiating cyclophosphamide pulse therapy, clinical symptoms were evaluated and apoptosis in mononuclear cells of the colon mucosa was quantified via immunofluorescence TUNEL-labeling. Ongoing clinical follow-up lasts for more than three years.

RESULTS

Cyclophosphamide pulse therapy resulted in complete resolution of luminal activity and extraintestinal manifestations. TUNEL-marked CD4(+), CD8(+) and CD68(+) cells in intestinal biopsies showed a 338% increase as compared to baseline.

CONCLUSIONS

Cyclophosphamide therapy was highly effective in steroid-refractory Crohn's colitis accompanied by Sweet's syndrome for induction of remission. Furthermore, apoptosis of mononuclear cells in the colon mucosa, including CD68(+) macrophages as well as CD4(+) and CD8(+) cells, appears to be a component of the anti-inflammatory effect of cyclophosphamide in Crohn's disease.