TNF and rheumatoid arthritis: Similarly, sulfasalazine was found to promote cell apoptosis and to inhibit LPS-induced TNF-α expression in human monocyte-derived macrophages [34], and leflunomide was found to inhibit pro-inflammatory cytokine release and NF-kB expression in synovial macrophages of RA patients co-cultured with Jurkat T cells [35].