PRF1 and systemic lupus erythematosus: In addition to these linage-specific cytokines and transcription factors, other genes such as HTR1A [33], LFA-1 [34], CD70 [35,36], perforin [37], and CD40L [38] have been found to be demethylated in lupus CD4+ T cells and have been associated with the pathogenesis of SLE.