While MS patients showed an increased percentage of CD4+CD25high T cells with a total (intracellular + surface) expression of CTLA-4 in comparison to controls, independently of IFN-β treatment, the percentage of CD25high CD4+ T cells with surface expression of CTLA-4 was more decreased in untreated MS patients compared to healthy controls and increased after IFN-β treatment [88]. The gene discussed is IFNB1; the disease is myeloid sarcoma.