SIGIRR and colitis: Preclinical studies in transgenic mice expressing the full-length IL-37b isoform (IL-37Tg) or treatment with recombinant IL-37 have shown that this cytokine plays anti-inflammatory roles, in most cases in an IL-1R8-dependent manner, under several infectious or sterile conditions, including LPS challenge, pulmonary aspergillosis, colitis, heart ischemia, liver injury, obesity-induced inflammation and insulin resistance, allergic airway inflammation, and arthritis [45, 50–52].