CCR6 and rheumatoid arthritis: CCL20, also known as liver-and-activation-regulated chemokine, macrophage inflammatory protein-3α (MIP-3α), or Exodus-1, and its only known receptor, CCR6, which plays a role in the onset and development in various diseases, including tumors, rheumatoid arthritis, pneumococcal meningitis, and human renal inflammation, have been widely explored [32–35].