Fig. 1.

Enhanced IL-1β and diminished IL-1Ra production in uric acid-primed monocytes. Monocytes were freshly isolated by differential centrifugation and magnetic beads negative selection and were stimulated in vitro with increasing concentrations of uric acid solubilized in RPMI supplemented with 10% human serum. Monocytes were exposed to increasing concentrations of uric acid (UA), 50 mg/dL allantoin (ALL), or medium alone for 24 h (24 h priming). Afterward, the medium was refreshed and the cells were stimulated with 10 ng/mL LPS or LPS + 300 μg/mL MSU crystals for another 24 h. IL-1β (A) and IL-1Ra (B) cytokine production in the supernatant of cells was measured by ELISA after 24 h of priming and after another 24 h of stimulation. Data are shown as means ± SEM of at least six donors from three independent experiments; data were analyzed using Friedman test. *P < 0.05, ***P < 0.001.