The post hoc analysis revealed that the ASD adolescents were characterized by significantly higher levels of IL-1α, IL-2, IL-4, IL-8, IL-10, and anti-inflammatory profile, and significantly lower levels of TNF-α, M1 profile, and Th1/Th2+Treg ratio compared to the ADHD adolescents (p = 0.010; p < 0.001; p < 0.001; p = 0.002; p = 0.007; p < 0.001; p < 0.001; p = 0.011; p < 0.001; respectively). This evidence concerns the gene CXCL8 and attention deficit-hyperactivity disorder.