Cerebrospinal Fluid Neurofilament Light Chain Is Associated with Kynurenine Pathway Metabolite Changes in Multiple Sclerosis.

Neurofilament light (NFL) has proved to be a good prognostic factor in multiple sclerosis (MS), as its level is proportionally elevated with extended neuraxonal damage. The involvement of the kynurenine pathway in neuroinflammation has been proved. The precursor of this pathway is the essential amino acid tryptophan, which is catabolized 95% towards kynurenine metabolites. Quinolinic acid (QUIN) within the brain is only produced in activated microglia and macrophages, leading to axonal degeneration via the activation of N-Methyl-D-aspartate receptors. Neopterin is a biomarker for inflammation produced by macrophages. The association of these biomarkers has not previously been investigated. Our aim was to assess whether there is an association of the neurodegenerative biomarker NFL with the markers of neuroinflammation, e.g., kynurenine metabolites and neopterin, in the cerebrospinal fluid (CSF). CSF samples of patients with MS (pwMS; n = 37) and age-matched controls (n = 22) were compared for NFL levels by ELISA, while the kynurenine pathway metabolites tryptophan and neopterin were detected with mass spectrometry. Spearman's correlation showed that NFL is an independent predictor of neurological disability in the MS group. Significant correlations were found between NFL, neopterin, and QUIN, and between kynurenine and neopterin. Receiver operating characteristic (ROC) curve analysis was used to plot the top three best predictors of MS-related disability that yielded the best specificity and sensitivity. Normalized NFL (AUC: 0.923), QUIN (AUC: 0.803), and neopterin (AUC: 0.843) were the best independent predictors of neurological disability in pwMS. The CSF NFL and CSF QUIN, together with neopterin, were elevated in the CSF of pwMS compared to controls. The combination of the neurodegenerative biomarkers together with biomarkers of neuroinflammation could provide additional information on the underlying pathomechanism of disease activity, which is essential for the identification of patients at risk of developing cumulative disabilities.

A longitudinally extensive H3 K27M-mutant diffuse midline glioma in an elderly patient clinically mimicking central nervous system inflammation: a case report.

Diffuse midline gliomas, H3 K27M-mutant, World Health Organization (WHO) grade IV represent a distinct glioma entity with a predominantly paediatric presentation and remarkably poor prognosis. This report presents a case of a 73-year-old woman with a diffuse midline glioma, H3 K27M-mutant, WHO grade IV with a remarkable longitudinal extension, extending from the cervical myelon to the basal ganglia. On imaging, the lesion was predominantly suggestive of inflammatory oedema, and it was clinically associated with progressive hemi- and later tetraparesis with severe autonomic and bulbar symptoms. Laboratory examinations suggested a generalized inflammatory process; however, neither infectious nor autoimmune aetiology could be confirmed. Biopsy was deemed unfeasible given the critical localization. Presuming a seronegative autoimmune encephalomyelitis, high-dose corticosteroid therapy and plasma exchanges were conducted, resulting in a modest but transient relief. The patient passed away two months after hospitalization. Neuropathological examination of the lesion revealed a high-grade diffuse glioma with H3 K27M mutation (grade IV). Although originally considered as a paediatric entity, our case confirms reports from recent years that diffuse midline gliomas, H3 K27M-mutant, WHO grade IV can occur in adults, even among the elderly, and can mimic inflammatory alterations, posing diagnostic difficulty. Our case is one of the oldest patients reported with this pathology, the oldest with an extensive diffusely infiltrating growth pattern, and with the most extensive lesion reported in adulthood.