CCL4 and acute respiratory distress syndrome: Interestingly, Lena-infected pigs showed 5 DEGs, which were upregulated from 1 to 13 dpi, with three of them (CSF1, CCL4, and EDN1) showing striking inflammatory properties, such as monocyte and macrophage proliferation and differentiation (CSF1) (60), vasoconstriction and pro-inflammatory response associated with acute lung injury (ALI) (EDN1) (61), or neutrophil migration (CCL4) (62).