The Combination of Cortisol Diurnal Variation, IL-6 and TNF-α as Potential Diagnostic Marker in Autism

markers in autism

A study published in the Research in Autism Spectrum Disorders Journal indicates that cortisol, IL-6 and TNF-α may become useful markers for autism spectrum disorder (ASD).

At present, 1 in 68 children in the US, and 1 in 100, in the UK, develop ASD. This is approximately a 30% increase versus the previous estimates reported in 2012.

In spite of this significant increase of ASD, there is no reliable diagnostic test available for these serious neurodevelopmental conditions.

Previous research indicates a sluggish and dysfunctional hypothalamic–pituitary–adrenal (HPA) axis, with altered circadian patterns of the stress hormone cortisol, and several cytokines abnormalities.

These include increased levels and/or expression of interleukin (IL)-6 and tumor necrosis factor (TNF)-α in plasma, the cerebrospinal fluid, or in postmortem brain specimens; and a neuroinflammatory process in the cerebral cortex, white matter, and the cerebellum of autistic patients.

In the Research in Autism Spectrum Disorders study, Chang-Jiang Yang and colleagues from the East China Normal University and Fudan University, Shanghai, China, demonstrate that children with autism have a lower level of cortisol diurnal variation, but higher levels of plasma IL-6 and TNF-α as compared to healthy controls. These changes correlated with the severity of ASD.

Of note, this is perhaps the first study where the authors have used receiver operating characteristics (ROC) analysis to test the specificity and sensitivity of biological markers such as cortisol, IL-6 and TNF-α to detect autism.

Importantly, the results of ROC analysis indicated that the cortisol variation, IL-6 and TNF-α may represent potential biomarkers for ASD. As the combination of the three measurements gave the best sensitivity and specificity values, the authors suggest that this validates their usefulness and reliability as biomarkers.

This may provide a relative simple diagnostic tool in autism, if the findings can be replicated in a larger group of individuals with ASD.

Source: Research in Autism Spectrum Disorders, 2015, 9:174-181.
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