Rucsanda Pinteac and colleagues in 2021 explained that as within CNS lesions of MS patients, CHI3L1 expression was present both in macrophages/microglial cells and astrocytes, with an important contribution of protoplasmic astrocytes to CHI3L1 expression as a result of active chronic lesions classified as having high degree of chronic inflammatory activity, reactive gliosis, and axonal loss [2]. This evidence concerns the gene CHI3L1 and myeloid sarcoma.