CD40 and attention deficit-hyperactivity disorder: 7 immune cells were negatively correlated with ADHD risk (OR < 1), serving as protective factors against ASD, including CD40 on CD14+ CD16+ monocyte, SSC-A on monocyte, IgD on IgD+ CD24+, CD40 on CD14− CD16+ monocyte, CD40 on monocytes, CD40 on CD14+ CD16− monocyte, and SSC-A on CD14+ monocyte.