In addition, during MS, CD8+ T cells upregulate cell adhesion molecules involved in immune trafficking into the CNS; increased frequency of CCR5+ and CXCR3+ CD8+ T cells in peripheral blood correlates with increased annualized MS lesion load (28) and increased PSGL-1+CD8+ T cell frequency is observed in active MS (29). This evidence concerns the gene CD8A and myeloid sarcoma.