The dual pro- and anti-inflammatory activities of the BLT2 receptor have added complexity, since BLT2-deficient mice exhibited reduced severity in arthritis models [12], whereas the deletion of BLT2 caused more severe colitis induced by dextran sulfate possibly due to the loss of BLT2-dependent intestinal barrier function [13]. This evidence concerns the gene LTB4R2 and arthritic joint disease.