Serum Biomarkers of Neuroaxonal and Astroglial Damage in Autism Spectrum Disorder: Relationship With Symptom Severity, Behavioural Dimensions and Age

Purpose: Autism spectrum disorder (ASD) is a neurodevelopmental condition characterized by persistent deficits in social communication and the presence of restrictive, repetitive patterns of behaviour. Although its exact aetiology remains multifaceted and partially understood, recent clinical interest has shifted towards neurobiological substrates, specifically neuroaxonal and astroglial integrity. This study aims to compare serum levels of Neurofilament Light Chain (NfL), Glial Fibrillary Acidic Protein (GFAP), Tau and S100B between children with ASD and healthy controls, while investigating the influence of these biochemical variables on autism severity and behavioural manifestations. Methods: The study cohort consisted of 44 children (aged 24–72 months) diagnosed with ASD according to DSM-5-TR criteria and 40 age-matched healthy controls. Clinical assessments were conducted using the Childhood Autism Rating Scale (CARS), the Aberrant Behaviour Checklist (ABC) and the Autism Behaviour Checklist. Serum concentrations of the targeted biomarkers were measured using the ELISA method from venous blood samples. Results: Serum NfL, Tau, GFAP and S100B concentrations did not differ significantly between children with ASD and healthy controls. Exploratory analyses suggested possible associations between selected biomarkers and clinical characteristics; however, these associations did not remain statistically significant after age adjustment and correction for multiple comparisons. Further studies using larger cohorts and ultrasensitive analytical platforms are needed to validate these preliminary findings. Conclusion: These findings indicate that serum NfL, Tau, GFAP and S100B did not differentiate children with ASD from healthy controls. Exploratory biomarker–clinical associations did not remain statistically significant after age adjustment and correction for multiple comparisons. Larger longitudinal studies using ultrasensitive analytical platforms are warranted. © 2026 International Society for Developmental Neuroscience.