TNF and rheumatoid arthritis: Enforced expression of miR-155 in CD14+ blood monocytes from RA and healthy subjects stimulated the production of TNF-α (supplementary Fig. S4, available at Rheumatology Online) consistent with previous observations [6, 11], but in addition, stimulated the production of the chemokines CCL3, CCL4, CCL5 and CCL8 in RA and CCL3 in healthy monocytes compared with controls transfected with CM (Fig. 3).