Characterization of N-glycosylation remodeling in cerebrospinal fluid extracellular vesicles in children with purulent meningitis and viral meningitis: an exploratory glycomics study based on MALDI-TOF/TOF–MS

To investigate differences in cerebrospinal fluid (CSF) N-glycosylation profiles among children with purulent meningitis (PM), viral meningitis (VM), and disease controls (DC). This retrospective exploratory study included six children with PM, three with VM, and three children with leukemia in complete remission without central nervous system infection. CSF-derived extracellular vesicles(CSF-EVs)were characterized by transmission electron microscopy, nanoparticle tracking analysis, and Western blotting. N-glycans were released using PNGase F, purified by porous graphitized carbon solid-phase extraction, and analyzed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Fifteen derived glycan traits were quantified. Group differences were assessed using Kruskal-Wallis tests with pairwise comparisons, and associations with clinical inflammatory markers were evaluated using Spearman correlation. CSF N-glycan profiles showed distinct patterns across the three groups. Hierarchical clustering based on glycan traits separated PM, VM, and DC samples. Compared with DC, both PM and VM showed altered sialylation, but their remodeling patterns differed. PM showed increased highly sialylated glycan traits, whereas VM showed increased disialylation and reduced galactosylation- and core fucosylation-associated traits. Bisecting GlcNAc-related traits were reduced in both infection groups. Total bisecting GlcNAc (B Total) was positively correlated with serum procalcitonin (PCT) levels (r = 0.681, P = 0.015). Pediatric CNS infections were associated with distinct CSF N-glycan remodeling patterns. These findings provide preliminary evidence of infection-associated glycosylation alterations and support further validation in larger cohorts.