[Articular inflammation of microcrystalline origin].

Microcrystals of sodium urate, calcium pyrophosphate, hydroxyapatite and corticosteroids may induce acute arthritis by similar mechanisms in which neutrophils play the most important role. Interactions between neutrophils and microcrystals result in the release of several phlogogenic substances, e.g. lysosomal enzymes, chemotactic factor (CCF) or leukotrienes. Various proteins may be adsorbed to the surface of microcrystals, and this protein coating seems to be instrumental in modulating the neutrophil-microcrystal interaction. The Hageman factor and the complement system may also be activated. The mechanisms starting off and resolving articular attacks are discussed.