Abstract
Abstract 1929
A combination of chemotherapy plus G-CSF (chemomobilization) is commonly used to mobilize CD34+ cells to circulation. Mobilization of CD34+ cells is poor or suboptimal in 20–30 % of patients. Plerixafor, a CXCR4 antagonist, increases the mobilization of CD34+ cells and may also have effect on graft composition subsequently collected. There are no data on lymphocyte subsets in the grafts collected after chemomobilization plus pre-emptively given plerixafor.
We have analyzed lymphocyte subsets (CD3, CD4, CD8, NK cells, CD19) in grafts collected on the next morning after plerixafor injection in 13 chemomobilized patients with non-Hodgkin lymphoma. As controls we had the first collections from 13 NHL patients mobilized with chemotherapy plus G-CSF and with yield of 2–6 × 106/kg CD34+ cells with 1–2 aphaereses.
The median CD34+ content of the analyzed grafts was 1.45 × 106/kg in the plerixafor group compared to 1.8 × 106/kg in the controls (p=n.s.). The number of T-cell subsets and NK cells were significantly higher in plerixafor mobilized grafts (Table 1). CD19+ B cells were infrequent in both groups.
Lymphocyte subsets of the grafts.
| . | Stem cell collection with plerixafor, median (range) . | Stem cell collection without plerixafor, median (range) . | Significance p . |
|---|---|---|---|
| Graft volume (ml) | 100 (43–190) | 80 (45–140) | 0.280 |
| Graft sample preservation time (days) | 299 (31–450) | 291 (103–397) | 0.898 |
| CD34+ cell content (x 106/ kg) after 7-AAD | 1.45 (0.40–4.40) | 1.80 (0.31–4.74) | 0.858 |
| CD3+ cell content (x 106/kg) | 75.3 (14.6–327.3) | 21.3 (9.1–159.4) | 0.004 |
| CD4+ cell content (x 106/kg) | 32.7 (10.6–132.8) | 12.4 (6.9–51.5) | 0.002 |
| CD8+ cell content (x 106/kg) | 33.4 (4.2–200.5) | 8.8 (2.2–125.0) | 0.006 |
| CD19+ cell content (x 106/kg) | 0 (0–0) | 0 (0–0) | NA |
| NK cell content (x 106/kg) | 5.1 (0.2–30.40) | 1.5 (0.3–8.0) | 0.045 |
| CD4+/CD8+ cell ratio | 0.98 (0.34–3.04) | 1.41 (0.28–5.06) | 0.228 |
| 7-AAD, 7-Aminoactinomycin D; NK, natural killer. | |||
| . | Stem cell collection with plerixafor, median (range) . | Stem cell collection without plerixafor, median (range) . | Significance p . |
|---|---|---|---|
| Graft volume (ml) | 100 (43–190) | 80 (45–140) | 0.280 |
| Graft sample preservation time (days) | 299 (31–450) | 291 (103–397) | 0.898 |
| CD34+ cell content (x 106/ kg) after 7-AAD | 1.45 (0.40–4.40) | 1.80 (0.31–4.74) | 0.858 |
| CD3+ cell content (x 106/kg) | 75.3 (14.6–327.3) | 21.3 (9.1–159.4) | 0.004 |
| CD4+ cell content (x 106/kg) | 32.7 (10.6–132.8) | 12.4 (6.9–51.5) | 0.002 |
| CD8+ cell content (x 106/kg) | 33.4 (4.2–200.5) | 8.8 (2.2–125.0) | 0.006 |
| CD19+ cell content (x 106/kg) | 0 (0–0) | 0 (0–0) | NA |
| NK cell content (x 106/kg) | 5.1 (0.2–30.40) | 1.5 (0.3–8.0) | 0.045 |
| CD4+/CD8+ cell ratio | 0.98 (0.34–3.04) | 1.41 (0.28–5.06) | 0.228 |
| 7-AAD, 7-Aminoactinomycin D; NK, natural killer. | |||
All except one patient has received high-dose therapy with blood stem cell support. The median CD34+ cell dose was 3.1 × 106/kg in plerixafor treated group and 3.3 × 106/kg in the control group, respectively. Time to neutrophil engraftment was comparable between the groups. There were two patients in the plerixafor group with late platelet engraftment (1 and 6 months).
Addition of plerixafor to chemomobilization in poor mobilizers results in increased content of T lymphocytes and NK cells in the graft but do not appear to mobilize B lymphocytes. Whether higher T cell and NK cell content are associated with more rapid immune reconstitution and survival should be evaluated in larger patient series with longer follow-up.
Jantunen:Genzyme: Honoraria. Kuittinen:Roche: Consultancy.
Author notes
Asterisk with author names denotes non-ASH members.
