The Possible Role of Neurofilament Light Chain as a Serum Biomarker in Anorexia Nervosa: Clinical Implications

Background: Neurofilament light chain (NfL) is a well-established biomarker of neu-roaxonal damage, detectable in serum through immunoassays. Its potential relevance in psychiatric conditions, including anorexia nervosa (AN), is currently under investigation. This study aims to quantify serum NfL levels in individuals with AN, evaluate their correlation with autoantibodies detection, and critically examine the specificity of NfL as a biomarker in this context. Methods: A total of 100 participants were enrolled, comprising 50 individuals diagnosed with AN and 50 age-matched, normal-weight controls. Serum concentrations of NfL and immunoglobulin G (IgG) antibodies reactive to hypothalamic antigens were measured using validated immunoassay techniques. Results: Serum NfL concentrations were markedly higher in the AN group compared to healthy controls. Interestingly, NfL levels tended to decrease with longer disease duration and with the recovery of body mass index (BMI), indicating a possible association between clinical improvement and reduced neuroaxonal damage. Furthermore, the results confirmed the presence of anti-hypothalamic autoantibodies and revealed a positive correlation between their levels and serum NfL concentrations. Conclusion: Clinical remission in AN appears to be linked to a decrease in both markers neuronal damage and hypothalamic auto-immunity. However, as elevated serum NfL is observed across a spectrum of neurological and psychiatric disorders, its specificity as a biomarker for AN should be further inves-tigated. While NfL may reflect neuroaxonal injury in AN, its interpretation should be contextualized within a broader clinical and immunological framework.