PFS and OS are higher in patients with regeneration of thymic function than in patients with impaired thymic regeneration after UCBT. A cohort of adult recipients of dUCBT treated with 1 protocol of pretransplant conditioning and posttransplantation immunosuppression41 was categorized into 2 groups: (1) patients with TREC values ≥2000 copies per μg DNA at 1 year after transplantation and (2) patients with TREC values <2000 copies per μg DNA at 1 year after transplantation. Kaplan-Meier estimates of PFS and OS were calculated as a function of the maximum TREC concentration attained at 1 year. Patients with TREC levels exceeding 2000 copies per μg DNA had a significantly improved PFS (P = .01) (A) and OS (P = .03) (B) compared with patients with TREC levels <2000 copies per μg DNA (n = 22).
