Multiple steps are needed to trigger inflammation in gout. (1) Recognition of monosodium urate (MSU) crystals by components of the innate immune system - Toll-like receptor (TLR) 2/TLR4, triggering receptor expressed on myeloid cells (TREM), and so forth. (2) Uptake of MSU by phagocytotic cells (for example, macrophages and eventually mast cells). (3) Activation of the NALP3 inflammasome by MSU (see details in Figure 1). (4) Release of IL-1β from the cell. (5) Endothelial IL-1β receptor type 1 (IL-1R) activation. (6) Proinflammatory mediators, including IL-8, release a potent chemokine for neutrophil recruitment. (7) Neutrophil recruitment into the site of inflammation. (8) Release of proinflamatory compounds by neutrophils, including more IL-1β.
Busso and So Arthritis Research & Therapy 2010 12:206 doi:10.1186/ar2952