They are involved in the formation of pannus, they are one of the main producers of TNF-α and IL-1β, they participate in the activation of effector T cells, and they also have the ability to produce other cytokines and chemokines important in RA such as IL-6, IL-8, IL-10, CCL2, CCL3, and RANTES. This evidence concerns the gene CCL3 and rheumatoid arthritis.