IL21 and myeloid sarcoma: In a pilot experiment, we measured 18 soluble factors (i.e. IL-6, IL-7, IL-8, IL-10, IL-12p40, IL-12p70, IL-17, IL-21, IL-23, granzyme B, IFN-γ, vascular endothelial growth factor (VEGF), oncostatin M, lymphotoxin-α (LT- α), tumor necrosis factor-α (TNF-α), CX3CL1, CCL19 and CXCL13) in 10-fold concentrated CSF collected from 16 untreated patients with highly active inflammatory MS [6].