It is not clear yet, but this increase in CD200 expression favors survival of the pathogen, perhaps because CD200 affects normal Th1 lymphocyte development which is essential for immune response against Leishmania; in fact, IFN-γ-activated macrophages produce NO to kill intracellular Leishmania major, but if CD200 is increased, it can avoid this immune response which can lead to the development of systemic Leishmaniasis [84]. The gene discussed is CD200; the disease is leishmaniasis.