Model of the differential roles of monocytes and macrophages in the inflammatory response to MSU crystals. The model proposes that monocytes play a central role in stimulating an acute attack of gout, whereas differentiated macrophages may play an anti-inflammatory role in terminating an acute attack and in preserving the asymptomatic state (modified from [48], with kind permission from Current Science Ltd). Mo, monocyte; Mφ, macrophage; PMN, polymorphonuclear leukocyte.