High-density lipoproteins (HDL) diminish monosodium urate (MSU) crystal-induced CCL2 transcript levels. Fibroblast-like synoviocytes (FLS) were cultured for 18 hours alone or with MSU crystals (50 μg/ml) in the presence or absence of HDL (100 μg/ml), as indicated. Total RNA was prepared as described in Materials and Methods. CCL2 mRNA levels were determined with duplex quantitative real-time polymerase chain reaction (PCR) analysis of triplicates normalized to the levels of the 18S mRNA. The relative expression levels of CCL2 mRNA are presented as mean ± SD of the percentage of relative CCL2 mRNA expression. The value of mRNA levels in MSU crystal-stimulated FLS (MSU) is arbitrarily considered as 1.0. Results are representative of three distinct experiments.