Hematopoietic stem cells are derived from bone marrow of adenosine deaminase (ADA)-deficient patients.
Mononuclear cells were isolated by means of density gradients, and CD34+ cells were purified with the use of immunomagnetic beads. Cells were stimulated with cytokines (fms-related tyrosine kinase 3 ligand, KIT ligand, thrombopoietin, and interleukin-3).