Ex vivo expanded unselected peripheral blood: progenitor cells reduce posttransplantation neutropenia, thrombocytopenia, and anemia in patients with breast cancer

Application of autologous hematopoietic cell therapy to a nonhuman primate model of heterogeneous high-dose irradiation

We developed a model of heterogeneous irradiation in a nonhuman primate to test the feasibility of autologous hematopoietic cell therapy for the treatment of radiation accident victims. Animals were irradiated either with 8 Gy to the body with the right arm shielded to obtain 3.4 Gy irradiation or with 10 Gy total body and 4.4 Gy to the arm. Bone marrow mononuclear cells were harvested either before irradiation or after irradiation from an underexposed area of the arm and were expanded in previously defined culture conditions. We showed that hematopoietic cells harvested after irradiation were able to expand and to engraft when reinjected 7 days after irradiation. Recovery was observed in all 8-Gy-irradiated animals, and evidence for a partial recovery was observed in 10-Gy-irradiated animals. However, in 10-Gy-irradiated animals, digestive disease was observed from day 16 and resulted in the death of two animals. Immunohistological examinations showed damage to the intestine, lungs, liver and kidneys and suggested radiation damage to endothelial cells. Overall, our results provide evidence that such an in vivo model of heterogeneous irradiation may be representative of accidental radiation exposures and may help to define the efficacy of therapeutic interventions such as autologous cell therapy in radiation accident victims.

Culture conditions affect the ability of ex vivo expanded peripheral blood progenitor cells to accelerate hematopoietic recovery

OBJECTIVE

The aim of this study was to evaluate the effect of various ex vivo expansion conditions on the cell products and their ability to accelerate hematopoietic recovery in patients undergoing stem cell transplantation.

PATIENTS AND METHODS

Unselected peripheral blood progenitor cells (PBPCs) from 43 breast cancer patients were seeded into gas-permeable bags containing serum-free media, granulocyte colony-stimulating factor, stem cell factor, and pegylated megakaryocyte growth and development factor. Between 2 and 24 x 10(9) PBPCs were cultured at 1, 2, or 3 x 10(6) cells/mL for 9 to 14 days. The expanded PBPCs and cryopreserved PBPCs containing at least 5 x 10(6) CD34(+) cells/kg were infused following completion of high-dose chemotherapy.

RESULTS

Increasing culture duration from 9 to 11-14 days significantly improved the expanded cell yield and fold expansion, whereas increasing PBPC seeding density above 10(6) cells/mL had the opposite effect. The expanded cell dose was the only culture variable that correlated significantly with the time to neutrophil recovery (r = -0.66; p = 0.0001). Study patients had significantly faster neutrophil (p < 0.0001) and platelet (p = 0.001) recovery, reduced red cell transfusions (p = 0.01), and shorter hospital stays (p < 0.0001) than historical controls. The most clinically efficacious expanded cell product was seeded with 10(10) PBPCs at 10(6) cells/mL, then cultured for 11 days. The six patients in that cohort experienced 2.8 +/- 1 days of absolute neutropenia and had neutrophil recovery 5.7 +/- 0.8 days post-transplant; none had a neutropenic fever or required intravenous antibiotics.

CONCLUSION

Unselected PBPCs expanded ex vivo significantly impact hematopoietic recovery following high-dose therapy. Optimization of the expansion conditions enhances the efficacy of this cell product.