The observed infiltration of immune cells after infection with swH1N1 agrees with the upregulation of chemotactic factors (AMCF-II, CXCL8/IL8, CXCL2, CXCL10, and CCL20) and their receptors (CCR1 and CXCR2) at the transcriptional level (Supplementary Table S5). This evidence concerns the gene CXCR2 and infection.