m5C levels and NSUN2 expression are decreased in the CD4+ T cells of systemic lupus erythematosus (SLE) patients, and hypermethylated m5C in SLE is closely associated with the immune- and inflammation-related pathways, including the immune system, cytokine signaling, and interferon (IFN) signaling.318 In the CD4+ T cells of SLE patients, ac4C modification in mRNAs is highly conserved and enriched in mRNA CDS regions and participates in critical immune and inflammatory signaling in SLE pathogenesis.319. Here, CD4 is linked to systemic lupus erythematosus.