Autism spectrum disorder is classified as a complex developmental disorder. Recent studies have shown that risk factors for ASD are both genetic and environmental. In our study, we aimed to determine whether inflammatory factors in the stool of children with ASD differ from their siblings.Our study population consisted of 57 children with ASD (48 boys/9 girls) and 57 healthy children (29 boys/28 girls) being their siblings. The mean age did not differ significantly between the ASD (10.4 ± 3.5 years) and control (9.0 ± 3.6 years) groups (median Q1, Q3 7.9 -13.0 years and 6.4 – 11.2 years). The average age difference between the groups was 1.34 ± 3.49 years. The aim of this study was to assess the gut immune status of children with ASD, through comparative measurement of A1AT, IgA and Cal in stool samples from children with ASD with sex- and age-matched sibling control group, with focus on ASD severity. The ratios of IgA1/IgA2 and S100A8/S100A9 were compared between moderate and severe forms on the basis of the CARS rating scale.Children with ASD had higher IgA, lower A1AT-1 and higher Cal levels. The calculated ratio of IgA1/IgA2 for moderate impairment group is higher than for severe group, despite the differences not being statistically significant. The ratio of S100A8/S100A9 does not differ statistically significant. Statistical significance level at p = 0.05Different patterns of protein marker levels observed based on severity of ASD could indicate different mechanisms underpinning GI issue comorbidity and warrants further investigation across the spectrum of ASD.

SOP is published at ZENODO. https://doi.org/10.5281/zenodo.7625076

Our study population consisted of 57 children with ASD (48 boys/9 girls) and 57 healthy children (29 boys/28 girls) being their siblings. The mean age did not differ significantly between the ASD (10.4 ± 3.5 years) and control (9.0 ± 3.6 years) groups (median Q1, Q3 7.9 - 13.0 years and 6.4 – 11.2 years). The average age difference between the groups was 1.34 ± 3.49 years. The demographic features of the ASD and control groups. The study protocol was approved by the National Medical Ethics Committee (0120-201/2016-2 KME 78/03/16). Children in the study group were diagnosed with ASD by an expert paediatrician or a neuropsychiatrist in collaboration with a psychologist. A multidisciplinary team consisting of paediatricians, psychiatrists, and psychologists diagnosed ASD with a clinical assessment and a psychological assessment. The criteria summarized by the DSM-5 were used (American Psychiatric Association, 2013). Parents/guardians are given detailed instructions on how to take samples when they sign the informed consent. The document is attached. Once the stool samples were collected in the packaging previously provided to the laboratory, the sample was brought to the laboratory as soon as possible. If they were unable to do so on the same day due to the distance to the laboratory, the samples were frozen at -20 °C. When the samples were received in the laboratory, they were frozen at minus 80 °C. Transport to the laboratory where the analyses were carried out was on dry ice.