SIGIRR and arthritic joint disease: The role of TIR8/SIGIRR as an inhibitor of inflammation was confirmed in vivo, since Tir8/Sigirr-deficient mice developed a more severe disease in both the zymosan-induced arthritis and collagen antibody-induced arthritis models, which was due to increased cellular infiltration into the affected joints (Drexler et al., 2010).