Recent developments in immune activation by uric acid crystals.

Uric acid crystals, the causative agent of gout, have recently gained widespread attention due to their role as a natural endogenous adjuvant. Uric acid crystals, first sensed extracellularly by membrane lipid alterations, are internalized and subsequently activate the NLRP3 inflammasome. Currently, various aspects of this particular novel pathway are poorly defined. This short review will focus on some recent discoveries regarding this simple crystalline structure and address areas requiring further investigation. The fact that uric acid crystals activate innate host defense mechanisms, triggering robust inflammation and immune activation, may lead to engineering potent adjuvants for future vaccines. Furthermore, the elucidation of uric acid's mechanism of inflammation may lay the foundation for other solid inflammatory structures such as silica, asbestos, and alum.