It is nowclear that the Th17 pathway is critical for the development of inflammation.IL17 is elevated in a variety of inflammatory conditions as shown forrheumatoid arthritis, asthma, and recently IBD [41].Furthermore, it has been shown that IL-23 supports the proliferation of Th17 cells.IL-23 is mainly produced by activated myeloid cells such as macrophages and dendriticcells. This evidence concerns the gene IL17A and inflammatory bowel disease.