High levels of soluble ST2 and low levels of IL-33 in sera of patients with HIV infection.

摘要

IL-33, a novel member of the IL-1 family, was recently identified as a ligand for the orphan receptor ST2 (Schmitz etai, 2005). ST2 is selectively and stably expressed on the cell surface of T-helper 2 (Th2) cells, but not Th1 cells (Xu etai., 1998). IL-33-ST2 interactions exacerbate Th2- and mast cell-mediated inflammatory diseases (Prefontaine et ai, 2009). The soluble form of ST2 functions as a decoy receptor, which neutralizes IL-33 and acts as a negative regulator of Th2 cytokine production by IL-33 signaling (Hayakawa et al., 2007). Although IL-33 was highly expressed in lesional skin of atopic dermatitis (AD), serum IL-33 levels in AD patients were not increased (Pushparaj et al., 2009). On the other hand, serum soluble ST2 levels are elevated in patients with asthma (Oshikawa ef a/., 2001). IL-33 is important in the lesion sites in Th2 type immune responses, while soluble ST2 seems to be a more sensitive serum marker for Th2 diseases. IL-33 also has important roles in host protection against infections (Humphreys ef a/., 2008; Alves-Filho etf al., 2010; Jones et al., 2010) and prevention of atherosclerosis (Sanada ef a/., 2007).