PF-06650833, a highly selective IL-1 receptor-associated kinase 4 (IRAK4) small molecule inhibitor (IC50 = 0.2 nM), could be orally absorbed, has good ADME characteristics, and inhibits the production of inflammatory factors (such as TNF, IFN, IL-1, IL-6, IL-12) and macrophage activation in RA, CIA and SLE animal models to reduce inflammatory symptoms (267). Here, IL6 is linked to rheumatoid arthritis.