Detection of auto‐antibodies to DAT in the serum. Interactions with DAT genotype and psychostimulant therapy for ADHD

Interest is rising for auto‐immune contribution in neuro-psychiatry. We evaluated the autoantibodies against dopamine transporter (DAT aAbs) in 63 children (48 who met DSM‐IV‐TR criteria, 15 healthy controls). Methods. ADHD patients were assigned, according to severity as recruited, either to a non‐pharmacological therapy (NPT) or to a pharmacological treatment (PT) with methyilphenidate (MPH). In ADHD children, blood samples were withdrawn at recruitment (T0 basal) and after a 6‐week period (T1), and we also characterized DAT genotype (9‐repeat or 10‐repeat alleles; final n=30). After 18 months of NPT or PT, some patients (carrying at least one 9‐repeat allele) were blood sampled again (T2), for comparison with healthy controls (final n=8). Results. Compared to NPT, basal DAT aAbs titers were higher within most severe patients (then assigned to PT), specifically if carrying a DAT 10/10 genotype. DAT aAbs levels of NPT group resulted highly correlated with distinct subscales of Conners' Parent / Teachers Scales (Rs > 0,34), especially within DAT 10/10 genotype (Rs> 0,53). While T1 titers were elevated over T0 baseline for NPT children, such an increase was not observed in PT patients carrying at least one 9‐repeat allele, who also showed behavioral response to subchronic MPH. After 18‐months MPH exposure, DAT aAbs titers in PT subjects were comparable to those of healthy controls, while titers remained significantly elevated in NPT patients. Data warrant further research on serum DAT aAbs, which could be used to confirm ADHD diagnosis and/or to monitor therapeutic efficacy of MPH.