Microglia Regulatory and T‐Helper Cytokine Profiles in Autism Spectrum Disorder

OBJECTIVE: This study aimed to evaluate serum levels of the microglia-regulating cytokines IL-34 and CSF-1, as well as T-helper cytokines IL-12, IFN-γ, IL-4, IL-10, TGF-β, IL-17 and IL-23, in individuals with autism and healthy controls, and to investigate the relationships between these parameters and the severity of autism symptoms. METHODS: The study sample consisted of 42 children diagnosed with autism spectrum disorder (ASD) and 40 healthy participants. The severity of autism in the patient group was assessed using the Childhood Autism Rating Scale (CARS). Serum levels of IL-34, CSF-1, IL-12, IFN-γ, IL-4, IL-10, TGF-β, IL-17 and IL-23 were measured using the ELISA method. RESULTS: Serum levels of IL-34, CSF-1, IFN-γ, IL-4, IL-10 and IL-17 were significantly higher in the ASD group compared to the control group. IL-34, CSF-1, IFN-γ, IL-4, IL-10 and IL-17 showed significant discriminative power in distinguishing ASD (p < 0.05). ROC analysis indicated that IL-10 had the highest area under the curve (AUC = 0.743; p < 0.001), and Delong test results demonstrated that its discriminative ability was statistically stronger than that of the other parameters. No significant correlations were observed between the examined cytokine levels and autism severity. CONCLUSION: Our findings indicate that IL-34 and CSF-1, along with T-helper-related cytokines (IFN-γ, IL-4, IL-10 and IL-17), were elevated in the ASD group. These alterations may reflect underlying pathophysiological processes. However, due to the cross-sectional design and limited sample size, the findings should be interpreted with caution, and their clinical utility requires further investigation in larger, longitudinal studies.