The present invention relates to an in vitro method for diagnosing an acute or relapsing phase of inflammatory bowel disease as well as a method for treating the acute or relapsing phase of inflammatory bowel disease. In addition, the present invention relates to a medicament for use in the treatment of inflammatory bowel disease. Further comprised by the present invention is the use of a nucleic acid molecule of SEQ ID NO: 1 or 2 for monitoring the progression of said disease and in vitro diagnosis of an acute or relapsing phase of said disease. Also a device for the diagnosis of said disease and kits for performing the method of the present invention are envisaged by the present invention.