The cytokine interleukin-21 (IL-21) regulates immune responses and has potential therapeutic relevance in diseases including cancer, viral infections, autoimmune diseases and allergies. Spolski and Leonard describe our current understanding of IL-21 biology, and discuss progress in harnessing this knowledge therapeutically, including clinical trials of IL-21 itself and molecules that block IL-21 signalling.
- Rosanne Spolski
- Warren J. Leonard