Biomarcadores plasmáticos e salivares para diagnóstico precoce de Transtorno do Espectro Autista: revisão sistemática

Autistic Spectrum Disorder (ASD) is considered a neurological development disorder characterized by different degrees of deficit in communication, social interaction, and learning, accompanied by repetitive and stereotyped patterns of behavior. ASD diagnosis is extremely complex due to the still unknown etiopathology, the diversity of symptoms presented by the individuals, and it is carried out solely from clinical observations of the individual's behavior. This study aims to review the main plasma and salivary biomarkers currently studied for the early diagnosis of ASD. For this systematic literature review, we used the online data directory and database “Google Scholar” and “Publish Medliner” (PubMed), respectively, with the descriptors: “Autism”, “Biomarker”, “Diagnostic”, “Saliva”, and “Plasma”. We selected 564 studies in PubMed and 185 in Google Scholar, by screening the titles. After reading the abstracts, we excluded 647 studies, either due to irrelevance or because they were review articles, genetics studies or did not use plasma or saliva samples. The remaining 102 original studies were evaluated in full, and 83 were excluded. Thus, nineteen complete articles that met the inclusion criteria were included in the qualitative analysis. Results identified Cortisol, glutamate/GABA, glutathione, Lipid peroxidation, markers of oxidative stress, mitochondrial dysfunction, and pro-inflammatory cytokines, especially IL-6, as the main plasma and salivary biomarkers currently studied for the early diagnosis of ASD. However, considering that several results were controversial and inconclusive, further studies are needed to validate specific biomarkers as diagnostic tools. The current findings encourage studies that are controlled, multicentric, prospective, and of greater diagnostic precision.