Association between immune reconstitution and graft rejection in pediatric patients with NMD following URD HCT with Aba GVHD prophylaxis. Compared to nongraft failure patients, patient ID 5 (with secondary graft failure in setting of early CMV reactivation) had baseline and persistent lymphocytosis driven primarily by B and CD8 T cells, with high Ki67 and Granzyme B expression (data not shown). Patient ID 7 (with primary graft failure with low infused TNC dose) had leukopenia at baseline, with lymphocytic/monocytic dominance. WBC, white blood cell.