IL18 and Arthritis: Zymosan caused systemic inflammation with a marked elevation in multiple pro- and anti-inflammatory cytokines TNF-α, IFN-γ, IL-13, G-CSF, M-CSF, IL-6, IL-18, IL-1α and IL-4 in arthritic rats (all arthritis groups pooled) versus the non-arthritic controls (0.001<p<0.05) (Fig 6).