There was a significant correlation between CSF CHI3L1 and NFL concentrations (r = 0.46; p < 0.001; Figure 2D) but, when analyzing this correlation in distinct MS clinical forms it only persisted in RRMS (r = 0.58; p < 0.001) compared to SPMS (r = 0.15; p = 0.195), and PPMS (r = 0.3; p = 0.081). Here, CHI3L1 is linked to myeloid sarcoma.