IRF5 and rheumatoid arthritis: Indeed, multiple single-nucleotide polymorphisms (SNPs) of the IFN regulatory factor 5 gene (IRF5), a major regulator of the type I IFN induction, have been associated with different rheumatic disorders such as SSc, systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), and Sjögren’s syndrome (SS) [7], [8], [9], [10].