IL1RL1 and Arthritis: Furthermore, IL-33-ST2-mediated signaling seems to be involved in the development and exacerbation of non-allergic inflammatory conditions including arthritis, chronic obstructive pulmonary disease (COPD) with cigarette smoke, experimental autoimmune encephalomyelitis (EAE), periodontitis, and retina inflammation in murine models (12), although it remains unclear whether IL-33-ST2-ILC2s axis is involved in the pathogenesis of corresponding diseases in humans.