TRAF2 and inflammatory bowel disease: Furthermore, TRAF2 KO mice exhibited increased proinflammatory cytokine expression and colonic epithelial cell apoptosis, leading to the spontaneous development of inflammatory bowel disease (IBD).18 However, research has indicated that TRAF2 KO mouse embryonic fibroblasts (MEFs) are resistant to cell death induced by reactive oxygen species (ROS),19 suggesting that TRAF2 can promote ROS-induced cell death.