Platelet secretion of several soluble mediators affects neutrophil functions under steady-state conditions and inflammation alike: Platelet-derived heterodimers consisting of platelet factor 4 (PF4) and CCL5/RANTES (regulated on activation, normal T cell expressed and secreted) stored in alpha granules (2, 25) promote neutrophil extravasation in acute lung injury (26) and are known to modulate neutrophil function in sterile inflammation (27). The gene discussed is CCL5; the disease is acute lung injury.