IL15 and rheumatoid arthritis: In the presence of Treg cells, although considerable interdonor differences were observed, similar overall levels of suppression were found in the majority of RA patients and healthy controls with regard to suppression of IL‐6, IL‐8/CXCL8, IL‐12, IL‐15, IFNγ‐inducible protein 10/CXCL10, RANTES/CCL5, and TNF.