Subsequently, hypomethylation of certain genes have been identified as important in lupus T cells, such as ITGAL (CD11a) (Lu et al., 2002), CD40LG (CD40L) (Callard et al., 1993), TNFSF7 (CD70) (Oelke et al., 2004), Killer-cell immunoglobulin-like receptor (KIR2DL4) (Basu et al., 2009), perforin (PRF1) (Blanco et al., 2005), and CD5 in lupus B cells (Garaud et al., 2009). Here, PRF1 is linked to systemic lupus erythematosus.