Plasma in Autism Spectrum Disorder: Diagnostic and Treatment Implications
Plasma is not used as a standard treatment or primary diagnostic tool for autism spectrum disorder (ASD), though plasma biomarkers are being actively researched for potential diagnostic applications.
Diagnostic Approach for ASD
The diagnosis of autism spectrum disorder relies primarily on clinical assessment rather than biological markers:
- ASD diagnosis is based on careful examination of the child through standard psychiatric assessment, including interviews with the child and family, review of past records, and direct observation focusing on social interaction and restricted, repetitive behaviors 1
- Currently, no biological diagnostic markers, including plasma-based tests, are available for routine clinical use in diagnosing ASD 1
- The diagnostic process should follow DSM-5 criteria, which focuses on two core domains: social communication/interaction deficits and restricted, repetitive patterns of behavior 1
Current Recommended Diagnostic Approach
A multidisciplinary assessment is the standard of care:
- All children with suspected ASD should undergo a medical assessment including physical examination, hearing screen, Wood's lamp examination for tuberous sclerosis, and genetic testing 1
- Genetic testing may include G-banded karyotype, fragile X testing, or chromosomal microarray, with chromosomal microarray having the highest diagnostic yield (24%) 1
- Various standardized assessment instruments supplement but do not replace informed clinical judgment 1
- Screening should include inquiries about core symptoms of ASD, including social relatedness and repetitive or unusual behaviors 1
Emerging Research on Plasma Biomarkers
While not yet clinically validated for routine use, several plasma biomarkers are being investigated:
- Metabolomic studies have identified plasma biomarkers associated with ASD, including O-phosphotyrosine and alterations in glutathione metabolism 2
- Phospholipid biomarkers, particularly poly-unsaturated long chain fatty acids (PUFA) and saturated very long chain fatty acids (VLCFA)-containing ethanolamine phospholipids, have been found to be statistically elevated in autistic subjects 3
- Children with ASD have been found to have lower plasma oxytocin (OXT) levels than gender-matched controls, with potential correlations between plasma OXT concentrations and verbal communication impairment 4
- Proteomic analyses indicate altered levels of many proteins in plasma/serum in ASD, suggesting that a panel of proteins may potentially provide a blood biomarker for ASD in the future 5
- Significant increases in plasma levels of several cytokines, including IL-1β, IL-6, IL-8, and IL-12p40, have been observed in ASD compared to typically developing controls 6
Limitations and Caveats
Important considerations regarding plasma biomarkers in ASD:
- Despite promising research, no plasma biomarkers have been validated for clinical diagnosis of ASD 1
- The American Academy of Child and Adolescent Psychiatry does not endorse any plasma-based tests for diagnosis or treatment monitoring of ASD 1
- Diagnostic overshadowing (failing to diagnose comorbid conditions when a more noticeable condition is present) is a significant concern in ASD assessment 1
- Alternative or complementary treatments, including those involving blood products, generally have limited empirical support for use in children with ASD 1
- Specifically, oral human immunoglobulin (derived from plasma) has not shown benefit in randomized controlled trials for ASD 1
Conclusion
While plasma biomarker research shows promise for future diagnostic applications in ASD, current clinical practice relies on behavioral assessment and observation for diagnosis. No plasma-derived treatments are currently recommended for ASD management based on available evidence.