In SS, IL-33 is expressed in acinar, ductal, and endothelial cells, and is released in damaged tissues during inflammatory infiltration, which is in agreement with that IL-33 is increased in tissues with Chisholm scores of 2 or 3 and decreased in tissues with Chisholm scores of 4, both indicating that IL-33 can be released to the extracellular to exert its function (20, 128). Here, IL33 is linked to synovial sarcoma.