Collection of a mobilized peripheral blood apheresis product from a patient with mucopolysaccharidosis type VII and subsequent CD34+ cell isolation

The effectiveness of bone marrow transplantation for lysosomal storage diseases like mucopolysaccharidosis type VII (MPSVII) suggests that a gene therapy strategy targeting autologous hematopoietic progenitor cells could be successful. Given the severe systemic manifestations of MPSVII including storage disease in the bone and bone marrow, it was unclear whether sufficient numbers of hematopoietic progenitor cells (CD34+) could be mobilized into the peripheral circulation and subsequently purified from these patients. As reported here, G-CSF mobilization and apheresis were successful, providing a product of 4 × 10¹⁰ nucleated cells containing 0.3% CD34 + progenitors. CD34 + cells were magnetically separated from the product to a final purity of 85% with a 64% yield. These results indicate that hematopoietic progenitors can safely be gathered from an MPSVII patient in numbers sufficient for the trial of clinical gene therapy applications.