Cytokine Profile in Autism Spectrum Disorders in Children

The pathogenesis of autism spectrum disorders (ASD) is not completely understood, but there is evidence of associations with altered immune responses. The aim of this study was to determine the serum levels of various cytokines in children with ASD and in healthy controls, in order to determine their role in ASD and its diagnostic subgroups. Sixty-five ASD patients were enrolled from an epidemiological survey in Norway, of which 30 were diagnosed with childhood autism, 16 with Asperger syndrome, 12 with atypical autism, 1 with Rett syndrome, and 6 with another ASD diagnosis. The serum levels of 12 cytokines were measured in all of the patients and in 30 healthy children. The cytokine levels did not differ significantly between the ASD group and the healthy controls. However, the interleukin-8 (IL-8) level was significantly higher (6.82 vs 4.58 pg/ml, p = 0.017) while that of IL-10 was significantly lower (2.24 vs 6.49 pg/ml, p = 0.009) in patients with childhood autism than in controls. Furthermore, the IL-8 level was significantly higher in childhood autism than in Asperger syndrome (6.82 vs 4.05 pg/ml, p = 0.013). Our study shows that the cytokine profile of children diagnosed with ASD, regardless of the subdiagnosis, does not differ from healthy controls. However, differentiation into different diagnostic subgroups reveals significantly different levels of IL-8 and IL-10. This indicates that different mechanisms may underlie the different ASD subdiagnoses. Future research into the pathophysiological mechanisms of ASD should pay more attention to the different subdiagnoses of ASD.