Streptococcal infections, autoimmunity, and innate immune system in adult ADHD: A preliminary study

Abstract

Introduction High rate of streptococcus-like infections and related titers has been found in adult ADHD patients. No studies have expressively investigated innate immune system in ADHD patients. Objectives To evaluate the relationship between streptococcal infections, autoimmunity and innate immune system in adult ADHD patients. Methods The study sample consisted of adult DSM-5 ADHD outpatients referring to the adult ADHD center of “San Luigi Gonzaga” University Hospital and non-clinical adult controls recruited among general population (screened using Adult ADHD Self-Report Scale - ASRS-v.1). All titers were determined in patients’ plasma by specific microwell ELISA kits, whereas genetic polymorphisms were determined by PCR methodology. We compared anti-streptolysin O (ASO), anti-deoxyribonuclease B (anti-DNase B), and anti-basal ganglia antibodies (ABGA) titers of patients with those of controls. Data about history of previous streptococcus/ streptococcus-like infections were collected by ad-hoc form. Furthermore, to investigate the susceptibility to Gram+-borne infections of adult ADHD patients, due to innate immune system impairment, we also evaluated the polymorphism of Toll-like receptors 2, 4, and 9. Results Although ADHD patients did not show higher rate of both previous infections (52.7% vs. 66.7%, p=.678) and ASO titers (18.2% vs. 0.0%, p=.577), they had really higher levels of anti-DNase B (85.5% vs. 16.7%, p=.001) and ABGA titers (78.2% vs. 33.3%, p=.036). Genetic analysis did not underline differences in polymorphism compared to general population (GENOME browser). Conclusions The high association between previous streptococcal infections, basal ganglia autoimmunity among ADHD patients was confirmed. TLR polymorphism does not seem to be involved in this type of vulnerability. Disclosure No significant relationships.