In MS, the major mediators of the disease progression are the Th1 cells, which produce TNF-α, IL-2, and INF-γ, whereas Th2 cells secrete the interleukins IL-4, IL-5, IL-10, and IL-13, which are considered MS protective factors because of their participation in the regulation and suppression of Th17 cells (Park et al., 2005). The gene discussed is IL13; the disease is myeloid sarcoma.