Phagocytosis of sodium urate and calcium pyrophosphate crystals by leukocytes of gouty, pseudogouty and health donors.

The initial rates of oxygen consumption and of glucose oxidation via the hexose monophosphate shunt were measured during the phagocytosis of sodium urate and calcium pyrophosphate microcrystals. By applying the kinetics of an enzyme-catalyzed reaction, the affinity of the polymorphonuclear leukocytes for crystals, Km, and the maximum rate, Vmax, were determined. When the comparisons are made between the two kinds of crystals, the differences in Vmax are always significant (p less than 0.02). The lesser phlogistic properties of pyrophosphate crystals stem probably in part from different crystal-protein interactions. The influence of the donor is less marked. Part of the weakly depressed phagocytic activity observed with pseudogouty PMN may be attributed to antiinflammatory drugs.