Although we found that the serum levels of IL-23A in the MS patients were affected by the variants in IL-23A and IL-23R, these changes were not found in the RIS patients, strongly suggesting differences between MS and RIS in pathogenesis in addition to their differences in clinical characteristics such as onset age, MRI and cerebrospinal fluid (CSF) features, clinical course and morbidity [1] [23] [24]. Here, IL23R is linked to myeloid sarcoma.