Serum Interleukin-6 Level in Children With Attention-Deficit Hyperactivity Disorder (ADHD)

Abstract

Introduction: Attention-deficit hyperactivity disorder (ADHD) is a common neurobehavioral disorder in children, but its specific etiology and pathophysiology are still incompletely understood. Objectives: This case-control study aimed to measure the level of serum interleukin-6 (IL-6) as a predictor of the immunologic status in children with ADHD, and to study its correlation with severity of symptoms. Subjects and Methods: 60 ADHD children who met the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition, criteria for ADHD and 60 control children were subjected to complete history taking, clinical examination, and psychometric tests. Serum interleukin-6 of ADHD patients and control children was measured by enzyme-linked immunosorbent assay. Results: The mean serum level of IL-6 was 22.35 (95% confidence interval [CI], 17.68-26.99) in ADHD patients, and it was 5.44 (95% CI, 4.81-6.06) in controls. A significantly higher level of IL-6 was reported in ADHD patients compared with controls (P ¼ .001). No significant correlation was found between serum IL-6 level and either the Intelligence Quotient (IQ) or the Conners' Parent Rating Scale score. Conclusion: Serum IL-6 values were significantly higher in ADHD patients compared to healthy control children. Increased production of IL-6 may play a role in the pathogenesis of ADHD.

Evaluation of the Indicators of Inflammation in Children and Adolescents with Attention Deficit and Hyperactivity Disorder: Effect of Sex and Subtype

“…There are different results in the studies investigating the relationship between ADHD and inflammation in the literature. In cytokine studies, IL-6 levels were found to be higher in ADHD patients, but not correlated with ADHD severity (16). In another study, IL-6, IL-10, and anti-YO antibodies reported to be significantly higher in ADHD (10).…”

Serum Galectin-3 Levels in Children with Attention-Deficit/Hyperactivity Disorder

“…Recent evidence suggests that patients with ADHD have higher serum cytokine levels than controls. 9,11,32,33 Galectin-3 was suggested to lead to increased inflammatory response by suppressing the anti-inflammatory cytokine interleukin-10 (IL-10) production. 34 An in vitro survey also documented that galectin-3 induces IL-6 expression, while galectin-3 inhibition decreases IL-1β expression, implying that galectin-3 regulates the expression concentrations of cytokines associated with ADHD.…”

Antioxidants as a Potential Target against Inflammation and Oxidative Stress in Attention-Deficit/Hyperactivity Disorder

“…Moreover, serum levels of IL-6 and IL-10 were significantly higher in ADHD children compared with healthy controls. However, IL-6 levels did not correlate with the severity of ADHD symptoms [32,33]. In an animal model of ADHD, using spontaneously hypertensive rats (SHR), the serum levels of IL-1α, MCP-1, RANTES, and IP-10 were elevated in five-week-old compared to control rats.…”