A decline in CCL22 secretion at high YFAK concentrations was also seen in an additional in vitro assay (N.K., unpublished observation), and was paralleled in Phase I clinical trials in secondary progressive MS patients by increased serum concentrations of CCL22, IL-3, and IL-13 at low dosages followed by decreases at higher dosages [9]. Here, IL13 is linked to myeloid sarcoma.