TNF and irritable bowel syndrome: Alterations of lipid profiles in IBD involve other microbiota-derived fatty acids as well.21,56 One of the hallmarks of UC in our study was the expansion of H. parainfluenzae, which has been associated with increased level of acylcarnitine in IBD.57 Expansion of H. parainfluenzae was found in pediatric UC patients,32,38,58 and its reduction in colonic biopsies of adult UC patients in response to novel anti-TNF neutralizing antibody has been reported,59 suggesting a potential role of H. parainfluenzae in IBD pathogenesis.