Elevated IL-16 expression is associated with development of immune dysfunction in children with autism.

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by impairments in communication skills and social behaviors. Several studies have suggested that neuroimmune dysfunction plays a significant role in the pathogenesis of ASD; however, its exact etiology is unknown. Interleukin-16 (IL-16), a chemoattractant, is associated with various inflammatory processes. However, its role in children with ASD is unclear. This study aimed to investigate whether IL-16 expression is associated with immune dysfunction in children with ASD. We examined IL-16 expression in CD4, CD8, CD14, CCR3, and CXCR7 cells in typically developing (TD) controls and children with ASD using flow cytometry in peripheral blood mononuclear cells (PBMCs). We also investigated the expression of IL-1βIL-16, IL-6IL-16, and TNF-αIL-16 in TD controls and children with ASD. We further explored IL-16 mRNA and protein expression using RT-PCR and western blotting. CD4IL-16, CD8IL-16, CD14IL-16, CCR3IL-16, and CXCR7IL-16 cells increased significantly in children with ASD compared with TD controls. We also showed that expression of IL-1βIL-16, IL-6IL-16, and TNF-αIL-16 was elevated in children with ASD compared with TD controls. Moreover, IL-16 mRNA and protein expression was significantly induced in children with ASD compared with TD controls. These results suggest that IL-16 expression could play an essential role in immune alteration in children with ASD.