GRN and rheumatoid arthritis: PGRN binds to tumor necrosis factor alfa (TNF-α) through its receptors (TNFR1 and TNFR2), thereby exerting an anti-inflammatory effect in a variety of diseases, including Alzheimer’s disease, rheumatoid arthritis, systemic lupus erythematosus, inflammatory bowel disease, bacterial pneumonia, and atherosclerosis [38,39].