17(R)-Protectin D1 is an aspirin-triggered epimer of the specialized pro-resolving mediator protectin D1 .1It decreases leukotriene B4-induced transendothelial migration of human polymorphonuclear (PMN) neutrophils when used at concentrations ranging from 0.1 to 10 nM. 17(R)-Protectin D1 (0.01-10 ng) reduces the recruitment of neutrophils in a mouse model of TNF-α-induced peritonitis.