Based on our current understanding of MS pathogenesis, CD4+ autoreactive T cells and their differentiation into a Th1 phenotype are crucial events in disease development, and these cells are probably also important players in the long-term evolution of the disease [24], while NK cells have been suggested to play a regulatory role by killing myelin-specific T cells and immature dendritic cells, promoting regulatory T cells and enhancing Th2-like responses [25]. The gene discussed is CD4; the disease is myeloid sarcoma.