PREP and inflammatory bowel disease: Seeing that the uncontrolled release of proinflammatory cytokines and excessive accumulation of inflammatory cells are important factors in intestinal inflammation of IBD, we further assessed the mRNA expression levels of TNF-α, IL-1β, and IL-6 in the colon of PREP-KO mice and WT mice, as well as the degree of neutrophils and macrophages infiltration.