CCL5 and influenza: Influenza infection also triggers the homing of blood monocytes to the respiratory tract [5], where they differentiate into macrophages capable of producing inflammatory mediators, such as the cytokines, type I Interferons (IFN-1) and tumor necrosis factor-α (TNF-α), and the chemokine CCL5 [6], [7] in response to infection [8].