Autism is a neurodevelopmental disorder characterized by deficits in communication and social skills as well as stereotypical behaviors. There are multiple lines of evidence, suggesting that the immune system is involved in autism. Since secretory IgA (SIgA) is the predominant antibody isotype in saliva and a marker of mucosal immunity, the aim of the study was to assess if the severity of clinical and behavioral parameters of autistic children was associated with low levels of sIgA in saliva.

To assess possible associations between salivary levels of sIgA and the severity of behavioral outcomes related to autism. In addition, were studied sIgA in saliva of children with autism and the frequency of respiratory tract infections diagnosed in the first 3 years of life.

Saliva samples were obtained from 3–10 years old autistic children and age-matched typically developing Caucasian children from Patagonia, Argentina.

Autistic children with reduced levels of salivary sIgA had a higher incidence of respiratory diseases compared to controls. The reduction in sIgA levels inversely correlated with the severity of the behavioral disorders. The patients with the most severe impairment in autism-related behaviors had the lowest levels of sIgA in the cohort studied.

These findings suggest that sIgA could be an early non-invasive indicator of the dysregulation of the immune system in some children with autism. Clearly, the characterization of immunological parameters has important implications for detection of subgroups of children with ASD, and should be considered when designing therapeutic strategies to treat behavioral impairments of ASD.

The authors have not supplied their declaration of competing interest.