Microtransplantation (MST) is an advanced technology to treat malignant hematological diseases and tumors by infusing patients with granulocyte colony-stimulating factor (G-CSF) mobilized human leukocyte antigen (HLA)-mismatched allogeneic peripheral blood stem cells following a reduced-intensity chemotherapy or targeted therapy.
Chemotherapy is used by lower doses only to destroy cancer and partially suppress patient’s immune system, which will be reinitiated by donor’s stem cells soon after transplantation, and will play a role as recipient-versus-tumor (RVT) effect combining donor cells’ graft-versus-tumor (GVT) effect.
[citation needed] Donor’s Requirements: In a randomized controlled trial from 2004 to 2009, 58 AML patients aged 60–88 years were randomly assigned to receive chemotherapy (control group; n=28) or it plus HLA-mismatched G-CSF–mobilized donor peripheral blood stem cell (G-PBSC) (G-PBSC group/ Microtransplantation; n = 30).
[citation needed] To overcome the intolerable severe reactions of high-dose chemotherapy and GVHD, as well as the challenge to find HLA-matched donors for conventional hematopoietic stem cell transplantation, Dr Huisheng Ai, Guo Mei, etc.
developed a new regimen of reduced-intensity chemotherapy plus G-CSF mobilized HLA-mismatched allogeneic peripheral blood stem cell infusion, which was firstly employed for a 75-year-old patient in 2002 and later named as microtransplantation.