Interleukin-10-based therapy for inflammatory bowel disease

In recent years it has become clear that chronic inflammatory bowel disease (IBD), especially Crohn's disease (CD), is caused by a loss of tolerance against the autologous bacterial flora of the intestine. Tolerance against the indigenous flora requires optimal recognition of antigens by pattern recognition receptors and the presence of important regulatory cells and cytokines. Interleukin-10 (IL-10) has a major role in the regulatory network of cytokines controlling mucosal tolerance, and it is, therefore, not surprising that this cytokine is proposed as a potent anti-inflammatory biological therapy in chronic IBD. This review will discuss the characteristics of IL-10, its immunoregulatory properties in mice and humans, and the use of IL-10 as a treatment for CD. The review will summarise the clinical studies that have taken place and discuss the lessons learned from these trials. Finally, the advantages and disadvantages of promising new strategies of IL-10 treatment, including gene therapy and the use of genetically modified bacteria, will be discussed. Both novel therapies have been shown to be successful in animal models of disease, and clinical testing is currently underway. The future goal of IL-10 treatment should be focused on mucosal delivery and remission maintenance instead of remission induction. In conclusion, it can be said that despite the disappointing results of IL-10 therapy so far, there is still enough rationale for the use of IL-10 as an anti-inflammatory biological treatment in chronic IBD.