Plots showing upregulation of TCR-MAPK-AP1 signaling in the cord blood CD4⁺ T cells. (A) Gene expression profile of naive CD4⁺ T cells from cord blood and peripheral blood donors were compared to derive enrichment plots of TCR and MAPK signaling and transcript values of the 2 important transcription factors FOS and JUN (AP-1 complex). FOS and JUN upregulation is expressed as mean (and, where possible, as standard deviation). (B) When naive CD4⁺ T cells from the 2 posttransplant lymphopenic conditions (ie, CBT vs BMT) were compared, reconstituting CD4⁺ T cells after CBT were observed to have an upregulated TCR and MAPK signaling.