GRN and rheumatoid arthritis: PGRN plays an anti-inflammatory role in various inflammatory diseases, including rheumatoid arthritis (RA) (9), Alzheimer’s disease (10), atherosclerosis (11), and bacterial pneumonia (12), via its competitive binding to tumor necrosis factor (TNF) receptors (TNFR1 and TNFR2) (13) and interferes with the interaction between TNFα and TNFR.