IL10 and Crohn disease: Several explanations for why IL-10 treatment has not been a successful therapy for Crohn's disease have been postulated: systemic administration does not result in an effective dose in the intestine; disease phenotype/severity cause differences in response to IL-10; IL-10 treatment is only successful as preventive therapy; treatment with IL-10 alone is not sufficient; or IL-10's immunostimulatory effects counterbalance its immunosuppressive effects [4].