CCR1 and infection: Histological findings of immune cell infiltration in tracheal tissues after infection with swH1N1 was in line with induction of cytokines and chemotactic factors (AMCF-II, CXCL8/IL8, CXCL2, CXCL10, and CCL20) as well as receptors (CCR1 and CXCR2) in lower trachea after this infection.