Past studies employing conventional Treg descriptions, typically combinations of CD25(+), CD127(lo/−) and FoxP3(+), have found that the frequency of Treg in patients with MS is not significantly different to that of HC.5 In support of these earlier findings, the percentage of FoxP3+CD25+CD127lo cells was not significantly different between the CIS and HC groups in the present study (mean (s.d.)4.50% (0.91) and 4.70% (0.79) of CD4+ T cells, respectively, P=0.473). Here, FOXP3 is linked to myeloid sarcoma.