CXCL8 and pneumonia: In patients with severe pH1N1 pneumonia, the proinflammatory cytokine IL-6 was highly elevated [about 15 times above its reference range (up to 54 times) for normal subjects [8], [15]; and 3–4 times higher than the seasonal influenza group, P<0.05]; there were also increases in CXCL8/IL-8, CCL2/MCP-1, and sTNFR-1 [about 2–4 times above their normal reference ranges (up to 8 times)].