With the focus on C5a, the importance of LTB4 in IC-ALI has largely been overlooked by all but one research group (48–50), although the pivotal role of LTB4 in other models of lung disease such as LPS-induced ALI- and allergen-induced airway hypersensitivity is well established (13, 53, 54). The gene discussed is C5AR1; the disease is acute respiratory distress syndrome.