TNF and rheumatoid arthritis: Overexpression of miR-155a could also change the expression level of other cytokines and chemokines such as IL-1β, IL-6, IL-8, TNF-α, chemokine ligand (CCL) 3, CCL4, CCL5, CCL8 and downregulate the synthesis of IL-10 and C-C chemokine receptor type 2 (CCR2) in synovial fluid of RA patients (21, 54).