PPBP and rheumatoid arthritis: Activated by the local stimuli, RA synovial macrophages produce predominantly chemokine (C‐X‐C motif) ligand (CXCL)4 and CXCL7 (chemokines recruiting neutrophils and blood monocytes), particularly in early RA 29, and TNF 30 and other proinflammatory cytokines (e.g. IL‐1β 31 and IL‐6 32) and alarmins S100A8/9 33 throughout disease progression.