Similar studies have explored the DNA methylation patterns between MZ twins with discordant T1D onset and MZ twins with concordant T1D in Epstein Barr virus (EBV)-immortalized B cells (Stefan et al., 2014), peripheral blood (Elboudwarej et al., 2016), CD4+ T cells, CD19+ B cells, CD14+CD16– monocytes (Paul et al., 2016), whole blood cells (Belot et al., 2013), whole peripheral blood and CD14+ monocytes (Cepek et al., 2016). Here, CD19 is linked to type 1 diabetes mellitus.