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.

Table 1.

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. 
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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.

Disclosures:

Jantunen:Genzyme: Honoraria. Kuittinen:Roche: Consultancy.

Topics:
chemotherapy regimen, granulocyte colony-stimulating factor, lymphocyte subset, plerixafor, recombinant granulocyte colony stimulating factor, tissue transplants, cd34 antigens, cd19 antigens, stem cell harvesting, antagonists

Author notes

*

Asterisk with author names denotes non-ASH members.

© 2011 by The American Society of Hematology
2011
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