With human relevance, the potent PGC-1α activator, SIRT1, has recently been found to be expressed in both acute and chronic plaques of MS brains, co-localizing with T helper lymphocytes, cells with the monocyte lineage, oligodendrocytes, and astrocytes, and a significant decrease of SIRT1 expression in peripheral blood mononuclear cells (PBMCs) during relapse has been documented [142]. The gene discussed is SIRT1; the disease is myeloid sarcoma.