IFNG and rheumatoid arthritis: For PAP with RA the first cluster contains IL-17E, IL-2, IL-9, IL-23, IL-28A, IFNγ, CCL20, TNFα, IL-15, IL-33, GM-CSF, IL-13, while the other cluster contained IL-10, IL-6, IL-21, and IL-27 (Fig. 5c).