CCL2 and infection: Studies investigating such markers of infection have identified interferon inducing protein (IP)-10, macrophage chemotactic protein (MCP)-1, MCP-2, Interleukin (IL)-2, interleukin-1 receptor antagonist (IL-1Ra) and tumour necrosis factor (TNF)-α, amongst others, as potential alternative markers to IFN-γ [18], [21]–[23], [25], [27].