In addition, other inflammatory factors such as IL‐12, IL‐15, IL‐18, IL‐32, GM‐CSF, and chemokines such as IL‐8, monocyte chemoattractant protein‐1 (MCP‐1), and C‐X‐C motif ligand 13 (CXCL13), all contribute partially to RA. Here, IL15 is linked to rheumatoid arthritis.