TRANSPLANTATION AND CELLULAR ENGINEERING
Harvesting autologous stem cells from a patient with red blood cell abnormalities of β-thalassemia intermedia
Autologous stem cell transplants in patients with hemoglobinopathies are limited. Previous reports used granulocyte–colony-stimulating factor (G-CSF) for mobilization of stem cells; there are no reported cases undergoing plerixafor mobilization. We report such a patient, providing guidance for peripheral blood stem cells collection when aberrant red blood cells (RBCs) disrupt normal separation.
Study Design and Methods
A patient with β-thalassemia intermedia and hereditary persistence of fetal hemoglobin presented for peripheral blood stem cell collection for autologous transplant for myeloma. He underwent splenectomy for anemia secondary to hemoglobinopathy and chemotherapy, ceasing RBC transfusions. The patient was mobilized using plerixafor after collection with G-CSF failed.
Collections were performed using an apheresis system, processing 24 L daily. Peripheral blood and apheresis product CD34 determinations were performed daily. On Day 1, the product yield was 0.04 × 106 CD34 cells/kg, less than expected based on white blood cell count and CD34-positive cells. Peripheral blood smear showed nucleated RBCs and RBC morphologic abnormalities. Changes in instrument variables were made after consultation with Terumo BCT to adjust for variable distribution of mononuclear and stem cells during centrifugation. Collecting stem cells at a deeper location and centrifuging faster improved collection, and a cumulative total of 4.40 × 106 CD34 cells/kg was achieved after four collections. The patient underwent tandem autologous transplantation and engrafted within 12 to 13 days of each transplant.
Adjustments in apheresis variables allowed successful collection of peripheral blood stem cells from a patient with RBC anomalies of β-thalassemia that interfered with standard stem cell harvesting.