Increased levels of YKL‐40 in the cerebrospinal fluid (CSF) are associated with a variety of neuroimmune and neuroinflammatory diseases, such as MS, autoimmune encephalitis, and stroke (Chen et al., 2018; Correale & Fiol, 2011; Hjalmarsson et al., 2014; Oldoni et al., 2020; Qi et al., 2020). This evidence concerns the gene CHI3L1 and myeloid sarcoma.