Alternatively, impaired re-localization of Xist RNA to the Xi upon stimulation, a phenomenon that has recently been reported in activated T cells from the MRL/Lpr lupus model (57) and in activated B and T cells of Ciz1−/− mice suffering from lymphoproliferative disorder (58), may lead to sub-efficient secondary repression of Tlr7 Xi copy. The gene discussed is XIST; the disease is systemic lupus erythematosus.