A recent system biology approach on peripheral immune signatures in identical twin pairs discordant for MS showed remarkably similar patterns; however, distinct traits in effector CD4+ T-cells in clinically healthy twins, with signs of prodromal MS, were comparable with those of the overtly affected co-twins, suggesting the importance of these immune traits in subclinical neuroinflammation (45). This evidence concerns the gene CD4 and myeloid sarcoma.