ABSTRACT
The gastrointestinal tract is affected by several chronic inflammatory conditions, but few have a serious impact as inflammatory bowel disease (IBD), demonstrated by an ever expanding number of publications on IBD. This chapter discusses the basic components of CD and UC pathogenesis and touches upon how new knowledge of epidemiology, genetics, the intestinal microbiota and the immune response help improve and expand therapeutic options for IBD patients. In addition, more recently identified systems that contribute to modulate the overall immune and inflammatory response will also be discussed, including sterile inflammation, inflammasome, epigenome and microRNAs. Innate immunity represents the first line of defense against invading microbes and other noxious agents; it develops in a few minutes to a few hours, is largely non-specific, and has no immunological memory. Adaptive immunity represents the second line of defense against invading microbes and a vast array of other antigens; it develops in a few hours to several days, is antigen-specific, and has immunological memory.
