CCL2 and viral infectious disease: It is also well documented that plasma concentrations of cytokines, including interleukin (IL)-6, tumor necrosis factor alpha (TNF-α), monocyte chemotactic protein 1 (MCP-1/CCL2), and IL-18, are higher in HIV-infected patients than in uninfected individuals; furthermore, these differences persist even in patients with well-controlled viral disease [9–12].