Published studies reporting findings on thymic reconstitution after UCBT
| Reference . | Patients (Median age, y) . | Conditioning and no. of UCB units . | TRECs . |
|---|---|---|---|
| 32 | UCBT: 24 pediatric patients (7.7) | MAC, no ATG, 1 UCB unit | No significant differences between the 2 groups. sjTRECs and βTRECs dropped at 3 mo and returned to ∼ pretransplant levels at 6 mo |
| Haplo HSCT: 33 pediatric patients (4.7) | |||
| 33 | 10 adult patients (29.3) | Variable, ATG, 1 UCB unit | 7 of 10 adult patients had detectable sjTRECs at 18 mo after UCBT, with median 325 copies per μg DNA at a median of 36 mo. All pediatric patients had detectable sjTRECs at 12 mo (earliest time point tested), median 6741 copies per μg DNA at median of 30 mo |
| 8 pediatric patients (4.6) | |||
| 34 | 30 pediatric patients (1) | No ATG, 1 UCB unit | TRECs detectable at 3 mo and substantially increased at 6-12 mo |
| 35 | 29 patients: | Variable ATG, 1 UCB unit | Normal levels at 1 y; comparable between UCBT and BMT groups. At 2 y, UCBT recipients had statistically higher TRECs than BMT recipients and young adults |
| UCBT: 10 patients (12.6) | |||
| MSD BMT: 19 patients (15) | |||
| 13 | 32 patients (33.5) | Variable, ATG, 1 UCB unit | 6 of 21 patients had detectable sjTRECs at baseline; 24 of 26 had undetectable sjTRECs during first year after UCBT |
| 40 | dUCBT: 29 patients (36) | MAC without ATG, 2 UCB units | TRECs lower in dUCBT recipients at 3 mo vs MRD/MUD group, but comparable in the 2 groups by 6 mo. Levels remained lower than normal in both groups at 12 mo |
| MSD BMT: 33 patients (45) | |||
| Matched unrelated: 33 patients (41) | |||
| 41 | 27 patients (48) | RIC, ATG, 2 UCB units | All evaluable patients had detectable sjTRECs at baseline; 3 of 10 at day 100; 10 of 15 at 6 mo (median 117 copies per μg DNA); 14 of 15 at 1 y (median 2136 copies per μg DNA) |
| 42 | 13 patients (42) | MAC without ATG (9 patients) and RIC + ATG (4 patients), + post-UCBT PTH, 2 UCB units | All patients had detectable sjTRECs at baseline; 3 of 7 at day 100; 4 of 6 at 6 mo (median 442 copies per μg DNA); all patients alive at 1 and 2 y had normal (>2000 copies per μg DNA) levels |
| Reference . | Patients (Median age, y) . | Conditioning and no. of UCB units . | TRECs . |
|---|---|---|---|
| 32 | UCBT: 24 pediatric patients (7.7) | MAC, no ATG, 1 UCB unit | No significant differences between the 2 groups. sjTRECs and βTRECs dropped at 3 mo and returned to ∼ pretransplant levels at 6 mo |
| Haplo HSCT: 33 pediatric patients (4.7) | |||
| 33 | 10 adult patients (29.3) | Variable, ATG, 1 UCB unit | 7 of 10 adult patients had detectable sjTRECs at 18 mo after UCBT, with median 325 copies per μg DNA at a median of 36 mo. All pediatric patients had detectable sjTRECs at 12 mo (earliest time point tested), median 6741 copies per μg DNA at median of 30 mo |
| 8 pediatric patients (4.6) | |||
| 34 | 30 pediatric patients (1) | No ATG, 1 UCB unit | TRECs detectable at 3 mo and substantially increased at 6-12 mo |
| 35 | 29 patients: | Variable ATG, 1 UCB unit | Normal levels at 1 y; comparable between UCBT and BMT groups. At 2 y, UCBT recipients had statistically higher TRECs than BMT recipients and young adults |
| UCBT: 10 patients (12.6) | |||
| MSD BMT: 19 patients (15) | |||
| 13 | 32 patients (33.5) | Variable, ATG, 1 UCB unit | 6 of 21 patients had detectable sjTRECs at baseline; 24 of 26 had undetectable sjTRECs during first year after UCBT |
| 40 | dUCBT: 29 patients (36) | MAC without ATG, 2 UCB units | TRECs lower in dUCBT recipients at 3 mo vs MRD/MUD group, but comparable in the 2 groups by 6 mo. Levels remained lower than normal in both groups at 12 mo |
| MSD BMT: 33 patients (45) | |||
| Matched unrelated: 33 patients (41) | |||
| 41 | 27 patients (48) | RIC, ATG, 2 UCB units | All evaluable patients had detectable sjTRECs at baseline; 3 of 10 at day 100; 10 of 15 at 6 mo (median 117 copies per μg DNA); 14 of 15 at 1 y (median 2136 copies per μg DNA) |
| 42 | 13 patients (42) | MAC without ATG (9 patients) and RIC + ATG (4 patients), + post-UCBT PTH, 2 UCB units | All patients had detectable sjTRECs at baseline; 3 of 7 at day 100; 4 of 6 at 6 mo (median 442 copies per μg DNA); all patients alive at 1 and 2 y had normal (>2000 copies per μg DNA) levels |
ATG, anti-thymocyte globulin; BMT, bone marrow transplantation; dUCBT, double-unit UCBT; haplo, haploidentical; HSCT, hematopoietic stem cell transplantation; MAC, myeloablative conditioning; MRD, matched related donor; MSD, matched sibling donor; MUD, matched unrelated donor; PTH, parathyroid hormone; RIC, reduced-intensity conditioning; sjTREC, signal joint TREC; TREC, T-cell receptor excision circle; UCB, umbilical cord blood; UCBT, UCB transplantation.