Gene expression of CD40L but not CD69 is decreased in term and preterm neonatal cord blood–derived T cells compared with adult T cells during 18 hours after activation. Real-time quantitative RT-PCR was performed on RNA obtained from T cells activated at the indicated time. The amount of mRNA for CD40L (A) and CD69 (B) was normalized relative to β-actin mRNA, and the graphs were generated with the relative values obtained after normalization. Data are shown as mean (± SEM) of 10 independent experiments using 10 independent adult (AB), cord (CB), or preterm cord (PreCB) blood samples with each assay performed in triplicate. Statistically significant differences are shown. *P < .001; **P ≤ .005.