Abstract: The present invention provides a method and system for diagnosing a central nervous system disease, and a composition, and a kit. The diagnosing system comprises: a first detection module, used for detecting a central nervous system-derived marker in a biological body fluid of a subject; a second detection module, used for detecting a central nervous system disease-related marker in the biological body fluid of the subject; and a diagnosis module, diagnosing, on the basis of central nervous system-derived marker and central nervous system disease-related marker detection results respectively obtained by the first detection module and the second detection module, whether the subject suffers from a central nervous system disease.

Abstract: The application relates to a method for enriching CNS-derived exosomes from a biological fluid such as blood, serum, plasma, or saliva. The method comprises: contacting a biological fluid containing CNS-derived exosomes with an anti-L1CAM antibody to form an immunocomplex, binding CNS-derived exosomes in the biological fluid to a solid phase through the immunocomplex; and separating the solid phase bound exosomes from the biological fluid to enrich the CNS-derived exosomes. Biomarkers from the CNS-derived exosomes can be measured for detecting a neurological disease, differentiating among different neurological diseases, monitoring disease progression or objectively assessing existing and future medical treatments.