In patients suffering with relapsing-remitting multiple sclerosis (MS), no difference in the expression of IDO2 was recorded in comparison to healthy controls [81]; moreover, in Italian MS patients, it has been demonstrated that IDO2 rs10109853 and rs4503083 polymorphisms are not associated with MS risk, age at onset, or disease progression [82]. This evidence concerns the gene IDO2 and myeloid sarcoma.