CCL3 and viral infectious disease: Gro-α/CXCL1, MIP-1α/CCL3, and IL-8/CXCL8 are found to be elevated in viral infections and play contradictory roles, ranging from enhanced viral clearance to enhanced pathology, and they are attractants for macrophages, monocytes, and neutrophils; thus, they can trigger inflammatory reactions and blood–organ barrier breakdown, as shown for CXCL1 expression and the blood–brain barrier in viral encephalitis [52,53].