IL1B and polyarticular arthritis: A20myel‐KO mice, generated by crossing floxed‐A20/Tnfaip3 mice with Lysozyme‐Cre transgenic mice, which leads to conditional A20 deletion in the myeloid compartment, were previously shown to develop an erosive TNF‐independent but NLRP3 inflammasome‐ and IL‐1β‐dependent polyarthritis resembling rheumatoid arthritis.