Early reports investigating the role of Tr1 cells in MS pathogenesis showed that an alteration in the expression of the isoforms of the co-stimulatory molecule CD46, important for a shift from a proinflammatory to an anti-inflammatory immune response, resulted in a reduced ability to induce IL10-producing CD4+ T cells in MS patients (91). The gene discussed is CD46; the disease is myeloid sarcoma.