Figure 1.

Hematopoietic stem cell transplantation (HSCT) is a complex multistep procedure involving mobilisation and harvesting of hematopoietic stem cells (HSCs) from blood or bone marrow, immunoablative therapy, followed by administration of HSCs. HSCs can be obtained from the patient (autologous), an identical twin (syngeneic), or an HLA-matched donor (allogeneic). The procedure of autologous HSCT starts with stem cell mobilisation from the peripheral blood, typically with granulocyte colony-stimulating factor (G-CSF) and cyclophosphamide. Stem cells are collected by plasmapheresis and selection for CD34⁺ cells. Conditioning with 200 mg/kg cyclophosphamide with or without antithymocyte globuline (ATG) is then performed, followed by reinfusion of peripheral HSCs. Cyclophosphamide with or without ATG is considered as nonmyeloablative, whereas the combination of cyclophosphamide with total body irradiation or busulfan is considered as myeloablative conditioning. i.v., intravenous; s.c., subcutaneous.