Another group observed a high number of myeloid-related protein 8 (MRP8) and MRP14-infiltrating macrophages in the synovium of RA patients responding to infliximab [188], whereas a meta-analysis demonstrated that an increased number of inflammatory plasma cells and macrophages, together with elevated tissue levels of the trigger receptor expressed on myeloid-1 cells (TREM-1), the chemokine type 2 receptor (CCR2) and the chemokine ligand 7 (CCL7) could be predictive of the failure of anti-TNF therapy in CD patients [189]. Here, TNF is linked to rheumatoid arthritis.