When the RA patients were divided into three groups based on 28-joint disease activity score (DAS28) (low: DAS28 ≤ 3.2 [n = 37], moderate: 3.2 < DAS28 ≤ 5.1 [n = 79], and high disease activity: DAS28 > 5.1 [n = 57]), urinary IL-6, CCL2, and IL-8 levels significantly increased in the subgroup with high disease activity (Fig. 1D,F). This evidence concerns the gene CCL2 and rheumatoid arthritis.