PTPN22 and rheumatoid arthritis: Similarly, PTPN22 was shown to mediate dephosphorylation of NLRP3-Y861 to negatively regulate inflammasome activation, and loss of function variants of PTPN22 have been implicated in various autoimmune diseases such as systemic lupus erythematosis, Crohn’s disease, rheumatoid arthritis, and type I diabetes [24].