Fig 2. Relationship between serum levels of cytokines (IL–6 or TNF–α) and RA disease activity (DAS28–ESR) in the sub–grouped RA patients according to the titers of ACPA.

There were significant positive correlations between serum levels of cytokines (IL–6 or TNF–α) and RA disease activity (DAS28–ESR), and these correlations were not modulated by the status of ACPA titer. The correlations were determined using Spearman’s rank correlation test.