Abstract
We studied the influence of graft populations on the hematological recovery of PBPC transplants. The data shown is a retrospective study of 36 patients (median age 41, range 16–67) who underwent allogeneic transplant from HLA-matched siblings and 29 patients (median age 25, range 20–68) who underwent autologous PBPC transplants between June 2002 and July 2005. The cell populations studied were: total nucleated cells (TNC), CD34+ cells, T cells (CD3+) and NK cells (CD3−/CD56+). The hematological engraftment was evaluated by the following parameters: time to absolute neutrophil count (ANC)>0.5x109/L, platelets>20x109/L, absolute lymphocyte count (ALC)>0.5x109/L and ALC at day +15. The median cell doses infused in patients are summarised in Table 1
PBPC cell population infused per Kg of patient body weight
| . | TNC x 108 . | CD34+ cells x 106 . | T cells x 108 . | NK cells x 106 . |
|---|---|---|---|---|
| *median **range | ||||
| Allogeneic | 12.8 * | 7.5 | 3.2 | 36.8 |
| 3.6 – 30.7 ** | 3.4 – 10.5 | 0.7 – 9.8 | 4.2 – 136.6 | |
| Autologous | 12 | 3.26 | 3.5 | 29 |
| 4.1– 51.0 | 2.2 – 7.0 | 0.1– 0.4 | 7.4 – 351 | |
| . | TNC x 108 . | CD34+ cells x 106 . | T cells x 108 . | NK cells x 106 . |
|---|---|---|---|---|
| *median **range | ||||
| Allogeneic | 12.8 * | 7.5 | 3.2 | 36.8 |
| 3.6 – 30.7 ** | 3.4 – 10.5 | 0.7 – 9.8 | 4.2 – 136.6 | |
| Autologous | 12 | 3.26 | 3.5 | 29 |
| 4.1– 51.0 | 2.2 – 7.0 | 0.1– 0.4 | 7.4 – 351 | |
Spearman correlation analysis showed for the allogeneic PBPC grafts, correlation between TNC and NK cells collected (p=0.002), whereas for the autologous grafts there was correlation between TNC and NK cells (p=0.000) and CD34+ cells (p=0.004) collected.
To asses the importance of cell dose infused in the hematologic engraftment of the two patient groups, neutrophil, platelet and lymphocyte recovery was determined (Table 2).
Patient engraftment
| . | Day to ANC>0.5x109/L . | Day to platelets>0.2x109/L . | Day to ALC>0.5x109/L . | ALC day +15 cell/μl . |
|---|---|---|---|---|
| *median **range | ||||
| Allogeneic | 11 * | 12 | 11 | 715 |
| 8 – 15 ** | 8 – 29 | 2 – 14 | 190 – 4670 | |
| Autologous | 11 | 11 | 12 | 1178 |
| 7 – 13 | 8 – 18 | 10 – 21 | 230 – 4410 | |
| . | Day to ANC>0.5x109/L . | Day to platelets>0.2x109/L . | Day to ALC>0.5x109/L . | ALC day +15 cell/μl . |
|---|---|---|---|---|
| *median **range | ||||
| Allogeneic | 11 * | 12 | 11 | 715 |
| 8 – 15 ** | 8 – 29 | 2 – 14 | 190 – 4670 | |
| Autologous | 11 | 11 | 12 | 1178 |
| 7 – 13 | 8 – 18 | 10 – 21 | 230 – 4410 | |
For both groups of patients, engraftment occurred within the expected time and ALC day +15 cell/μl was different (median 715 cell/μl and 1178 cell/μl for allogeneic and autotransplanted patients respectively).
For the allogeneic transplanted patients, Spearman correlation analysis showed that the dose of NK cells infused was significantly correlated with ALC at day +15 (p=0.021). There was also correlation between the time to platelets and ANC engraftment (p=0.008) and time to platelets engraftment and ALC at day +15 (p=0.046).
For the autologous patients there was no correlation between cell populations of the grafts and the hematologic engraftment. Our data provide evidence that in allogeneic transplants the NK dose influences early ALC recovery. However, it is important to continue this study to balance the importance of cell population doses both in allogeneic and autologous transplants.
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