title: Eosinophils in infection and intestinal immunity.
abstract: OBJECTIVE
  Inflammatory bowel diseases (IBDs, e.g., Crohn's disease and ulcerative colitis) are thought to be a consequence of an uncontrolled inflammatory response against luminal antigens, including commensal bacteria. The observed link between eosinophil levels and severity and remission rates in IBD has led to speculation that eosinophils may contribute to the antimicrobial inflammatory response in IBD.
  
  
  RESULTS
  Eosinophils express the necessary cellular machinery (innate immune receptors, proinflammatory cytokines, antibacterial proteins, and DNA traps) to mount an efficient antibacterial response; however, the rapid decline in eosinophil numbers following acute systemic bacterial infection suggests a very limited role for eosinophils in bacterial responses.
  
  
  CONCLUSIONS
  We describe the clinical evidence of eosinophil involvement in IBD, summarize the in-vitro and in-vivo evidence of eosinophil antibacterial activity and the biology of eosinophils focusing on eosinophil-mediated bactericidal mechanisms and the involvement of eosinophil-derived granule proteins in this response, and conceptualize the contribution of eosinophils to a response against commensal bacteria in IBD.
authors.affiliation: Division of Allergy and Immunology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229, USA. simon.hogan@cchmc.org
authors.forename: Simon P
authors.initials: SP
authors.lastname: Hogan
authors.forename: Amanda
authors.initials: A
authors.lastname: Waddell
authors.forename: Patricia C
authors.initials: PC
authors.lastname: Fulkerson
mesh_terms: D001424:Bacterial Infections / Q000150:complications / Q000276:immunology*; D016207:Cytokines / Q000378:metabolism*; D004804:Eosinophils / Q000276:immunology* / Q000378:metabolism*; D006801:Humans; D007113:Immunity, Innate; D015212:Inflammatory Bowel Diseases / Q000276:immunology*; D051193:Toll-Like Receptors / Q000378:metabolism
chemical_list: D016207:Cytokines; D051193:Toll-Like Receptors