CCL4 and hemorrhagic fever with renal syndrome: Neither Sin Nombre virus nor Hantaan virus induces IL-8, MCP-1, MIP-1a, or MIP-1b within 72 h of in vitro infection of human lung microvascular endothelial cells (78), and only HTNV induces IL-8 at times later than 72 h (79), suggesting that IL-8 may be more relevant to HFRS than to HPS.