Progranulin has been previously found to have anti-inflammatory effects against rheumatoid arthritis by preventing TNF-α from binding to its receptor.50 However, the role of progranulin in the inflammatory process is more complicated, and it seems that this adipokine is divided into a smaller peptide called granulin, which has proinflammatory effects and neutralizes the anti-inflammatory properties of progranulin. Here, GRN is linked to rheumatoid arthritis.