It was reported that 90% of the children with ADHD had detectable IL-2 (mean: 1.65 ng/mL± 0.87), 60% had detectable IFN-γ levels (mean: 0.47 ng/mL ± 0.27), 70% had detectable TNF-β levels (mean: 2.45 ng/mL ± 0.60), 62% had detectable IL-5 (mean: 1.05 ng/mL ± 0.42), 7% had detectable IL-10 (mean: 0.29 ng/mL ± 0.09) and none had any detectable IL-4. This evidence concerns the gene IL2 and attention deficit-hyperactivity disorder.