However, it should be noted that, in contrast to previous studies that showed associations between increased CCL2 and impairments in behavioral functions among individuals with ASD (6), the lack of between-group differences for the ASD + ADHD group and the absence of a significant association of CCL2 with any of the cognitive or behavioral measures considered in the present study warrants future work to delineate the role of CCL2 in the expression of autistic traits. Here, CCL2 is linked to attention deficit-hyperactivity disorder.