Study Finds Altered Toll-Like Receptor Expression in Children with Autism Spectrum Disorder

October 9, 2026 2 Min Read

New Insights into Immune System Differences in Autism

Recent research has identified changes in the expression of certain toll-like receptors (TLRs) in children and adolescents diagnosed with Autism Spectrum Disorder (ASD). These receptors play a key role in the body’s innate immune response, suggesting a potential link between immune system activity and ASD symptoms.

Study Overview

In a study published ahead of print in the Journal of Psychiatric Research, researchers examined both the messenger RNA (mRNA) expression and serum protein levels of all ten human TLRs (TLR1 through TLR10) in 31 drug-naive children and adolescents with ASD, compared to 31 age- and sex-matched healthy controls aged 4 to 18 years.

Key Findings

The ASD group showed significantly increased mRNA expression and serum protein levels of TLR1, TLR4, TLR5, and TLR8.
Conversely, TLR6 expression and protein levels were notably decreased in the ASD group.
No significant differences were observed for TLR2, TLR3, TLR7, TLR9, or TLR10 between the groups.
Levels of TLR1, TLR4, TLR5, TLR6, and TLR8 correlated with the severity of ASD symptoms and behavioral assessments, including scores on the Childhood Autism Rating Scale (CARS) and the Aberrant Behavior Checklist (ABC).

Context and Implications

TLRs are critical components of the innate immune system, responsible for recognizing pathogens and activating immune responses. Prior research has suggested immune dysregulation and neuroinflammation may contribute to ASD, but comprehensive evaluations of the entire TLR family have been limited.

This study expands on previous findings by demonstrating coordinated alterations in multiple TLR subtypes beyond the well-studied TLR4. The associations between specific TLR levels and clinical symptoms raise the possibility that TLR-mediated immune signaling could influence neurobehavioral features of ASD.

Considerations and Future Directions

While these findings are promising, it is important to note that the study shows associations rather than causation. The sample size was relatively small, and participants were limited to drug-naive children and adolescents, which may affect generalizability.

Further research is needed to explore how these immune changes develop over time and whether they could serve as biomarkers or targets for therapeutic intervention in ASD.

For more detailed information, see the original study here.