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

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.