Transcriptional signature of naive cord blood CD4⁺ T cells is rich in genes induced in the lymphopenic environment. (A) Scatterplot of pairwise global gene expression comparison comparing gene expression in the 2 posttransplant environments (ie, cord blood transplantation and bone marrow transplantation). Gene expression values are plotted on a log scale, and specific genes upregulated in the lymphopenic environment are highlighted with arrows. (B) Nineteen genes induced in the lymphopenic signature and 41 genes of fetal signature. (C) Bar plot showing mean (and where possible, standard deviation) transcript values of 19 upregulated/downregulated genes representing genes induced in the lymphopenic environment. Interestingly, the differential regulation of 19 genes was higher in the naive CD4⁺ T cells from the cord blood and during early reconstitution after CBT than compared with bone marrow transplantation.