Reduced levels of YKL-40 in CSF may be attributed to (i) reduced production of YKL-40 from relieved inflammation and tissue damage in the CNS after treatment; and/or (ii) reduced pro-inflammatory effect of YKL-40, which is similar to the possible associated mechanisms of YKL-40 after immunotherapy in MS (27). The gene discussed is CHI3L1; the disease is myeloid sarcoma.