XAF1 and rheumatoid arthritis: A further 8 DE genes in this category, including DEAD (Asp-Glu-Ala-Asp) box polypeptide 58 (RIG-I) (DDX58), IFI27, IFI44L, interferon-induced protein with tetratricopeptide repeats 1, 2 and 3 (IFIT1, IFIT2, IFIT3), radical S-adenosyl methionine domain containing 2 (RSAD2) and XIAP associated factor 1 (XAF1), were elevated in both RA and UA cohorts (Additional File 2C).