The alpha subunit of the IL-2 receptor (called sIL-2Ra) is released from the surface of T cells and is a poor prognostic marker in follicular lymphoma. Instead of blocking IL-2 activity, binding of sIL-2Ra to IL-2 is agonistic and enhances IL-2 effects on the lymphoma milieu. Effects include promotion of T-reg differentiation, blocking CD8 antitumor activity, and increasing T reg activity via Stat5 signaling and increased FOXP3. Professional illustration by Paulette Dennis.