CSF2 and myeloid sarcoma: However, the decreased CSF-cell IL10 expression in RRMS compared to NIND patients could also simply reflect a relatively decreased frequency of monocytes in MS patients [2] or a change in the monocyte phenotype, since monocytes transmigrating across the blood–brain barrier change their phenotype [19], and CSF monocytes have decreased CD14 expression [18,30].