The roles of cortisol and pro-inflammatory cytokines in assisting the diagnosis of autism spectrum disorder

Autism spectrum disorders (ASD) is a severe neurodevelopmental disorder characterized by impairments in social interaction and repetitive behaviors. Diagnosis of ASD is currently phenotype based with no reliable laboratory test available to assist clinicians. The desire for clinically useful and reliable biomarkers is strong. Researches have shown that individuals with autism often exhibit dysfunction of hypothalamic-pituitary-adrenal (HPA) axis and cytokines. The purpose of this study was to evaluate diurnal variation of cortisol (cortisol VAR), interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α) as potential biomarkers for ASD. The present results demonstrated that in comparison to the healthy controls, the individuals with autism showed a lower level of cortisol VAR, higher level of IL-6 and TNF-α. The levels of cortisol VAR, IL-6 and TNF-α have significantly correlations with the severity of ASD measured by CARS scores. The results of ROC analysis indicated the cortisol VAR, IL-6 and TNF-α were potential biomarkers in diagnosis of ASD. The combination of three factors performed the best sensitivity and specificity for diagnosis of ASD. Therefore, the present study may reveal a simple clinical approach with great potential for assisting the diagnosis of ASD.