Preservation of naïve CD4⁺ T cells in pediatric patients with NMD receiving Aba GVHD prophylaxis. Within CD3⁺ T cells, the CD8⁺ fraction proportionally recovered before CD4⁺ T cells. Within the CD4⁺ T-cell fraction, central memory T cells (TCM) were the dominant population early post-HCT, and an increasing proportion of naïve T cells were seen over time. The proportion of effector memory T cells (TEM) within the CD4⁺ fraction decreased during the period of Aba administration, and the T effector memory CD45RA⁺ cells (TEMRA) proportion remained low throughout the follow-up period. Data shown as individual patient and mean with standard error of the mean (red line).