Differences in the Interleukins profile in Inatentive-ADHD prepubertal children are probably related to comorbidities

Abstract Background. Inflammatory cytokines are involved in attention deficit/hyperactivity disorder (ADHD), a highly prevalent neurodevelopmental disorder. Objetive. To quantify baseline levels of pro- and anti-inflammatory cytokines and their changes after treatment with methylphenidate (MPH) in prepubertal children with ADHD. Methods. A total of 31 prepubertal children with ADHD were recruited. Based on the scores of the NICHQ Vanderbilt scales, the children were subclassified in only two ADHD presentations: ADHD-Attention Deficit (n= 13) or ADHD-Combined (n= 18). The children were also screened for Oppositional Desafiant Conduct Disorder (ODCD) and Anxiety Disorder. Blood samples were drawn at 09:00 h and after 4,63 ± 1,87 months of treatment. Four proinflammatory cytokines [interleukin-1 beta (IL-1β), IL-5, IL-6, and tumour necrosis factor alpha (TNFα)] and three anti-inflammatory cytokines (IL-4, IL-10, IL-13) were measured using a Luminex® assay. Statistic: Factorial analysis (Stata 15.1) was performed using instants (baseline – post-treatment), presentations, and ODCD as factors. Results. Overall, there were no differences induced by treatment in the concentrations of interleukins (ILs) analysed in our group of pre-pubertal children with ADHD. Grouped by Presentations, the differences detected are present almost exclusively in ADHD-AD Presentation, usually with a concentration profile opposite to that observed in ADHD-C, and with interactions between comorbid Factors, with the ILs that reach the greatest statistical significance being IL-1β (p = 0.01) and IL-13 (p = 0.006). These differences are probably related to the ODCD factor, and these differences disappear after treatment. Conclusion. The changes that we described in inflammatory cytokines in prepubertal children only in ADHD-AD presentation are probably related to comorbidities (specifically ODCD) and disappear after treatment, but do not be involved in the highly clinically favourable response to MPH in prepubertal children.