Cutting Edge: IL-6 Is a Marker of Inflammation with No Direct Role in Inflammasome-Mediated Mouse Models

IL-6 is a known downstream target of IL-1 beta and is consistently increased in serum from patients with NLRP3 inflammasome-mediated conditions. Therefore, IL-6 could be a therapeutic target in the treatment of IL-1 beta-provoked inflammation. IL-6 was increased in serum with accompanying neutrophilia in tissues of an inducible mouse model of Muckle-Wells syndrome. However, an IL-6-null background failed to provide phenotypic rescue and did not significantly impact inflammatory cytokine levels. In a second model of IL-1 beta-driven inflammation, NLRP3 activation by monosodium urate crystals similarly increased IL-6. Consistent with our Muckle-Wells syndrome model, ablation of IL-6 did not impact an acute neutrophilic response in this in vivo evaluation of gouty arthritis. Taken together, our results indicate that IL-6 is a reliable marker of inflammation, with no direct role in inflammasome-mediated disease. The Journal of Immunology, 2012, 189: 2707-2711.