TNF and rheumatoid arthritis: CD14+ monocytes from the peripheral blood (PBM) and CD14+ cells from the synovial fluid of patients with RA (likely consisting of monocytes and macrophages and henceforth referred to as SFM) have an activated phenotype [2], [3], [4], [5] and produce pro-inflammatory cytokines such as IL-1β and TNF-α [5], [6], [7].