CLINICAL OBSERVATIONS, INTERVENTIONS, AND THERAPEUTIC TRIALS Mobilization and collection of peripheral blood CD341 cells from patients with Fanconi anemia

A potential therapeutic option for patients with Fanconi anemia is collection of peripheral blood stem cells prior to the development of severe pancytopenia. These hematopoietic cells potentially could be infused when symptomatic bone marrow failure develops, as autologous rescue after chemotherapy in the event of leukemic transformation, or as targets for gene therapy. Eight patients with Fanconi anemia were mobilized with 10 mg/kg per day of granulocyte colony-stimulating factor (median, 10 6 4 days) to determine the feasibility of collecting peripheral blood stem cells for future use. Six patients achieved a peripheral blood CD341 count of > 6/mL and underwent apheresis. The collection goal was 2 3 106 CD341 cells/kg based on a predicted weight 5 years from the date of collection. A mean of 2.6 6 0.9 3 106 CD341 cells/kg of the weight at the time of collection were collected, which corresponded to 1.9 6 0.4 3 106 CD341 cells/kg of the target weight. The collections required a mean of 4 6 3 days (range, 2-8 days) of apheresis. Six of the 8 subjects had > 1 3 106 CD341 cells/kg cryopreserved based on both actual and target weights, and 4 subjects had> 2 3 106 CD341 cells/kg cryopreserved based on the target weight. These results suggest that some patients with Fanconi anemia can have adequate numbers of CD341 cells mobilized and collected from the peripheral blood prior to the onset of severe bone marrow failure, but they may require an extended mobilization and multiple days of collection. (Blood. 2001;98: 2917-2921)