IL6 and periodontitis: In accordance with the results from the multivariate model, the levels of IL-1β IL-4, IL-6, IL-10, IL-12, IL-13, IL-17, TNF-αIFN-γ, FGF-2, macrophage inflammatory protein 1 alpha (MIP-1α) and macrophage-derived chemokine (MDC) did not differ between patients with periodontitis and healthy subjects (S1 Table).