Hematopoietic stem cell transplantation (HSCT) is one of the best, and sometimes the only, option for the treatment of leukemia, particularly for patients with advanced-stage leukemia. However, relapse rate was still very high for advanced-stage leukemia.

It was found in our previous study that infusion of granulocyte colony-stimulating factor (G-CSF)-primed peripheral blood progenitor cells (GPBPC) instead of non-primed lymphocytes exhibited a comparative or stronger graft-versus-leukemia (GVL) effect and comparative or less incidence of GVHD, rarely being complicated with pancytopenia. When GPBPC infusion was combined with the use of short-term immunosuppressant for GVHD prophylaxis, the incidence of fatal GVHD complicated with GPBPCI was further reduced. Our primary data showed the GPBPCI combined with the use of short-term immunosuppressant was feasible in patients with advanced leukemia to prevent relapse after HLA-mismatched HSCT.

The study hypothesis:

Prevention of relapse using granulocyte colony-stimulating factor-primed peripheral blood progenitor cells following hematopoietic stem cell transplantation in patients with advanced-stage acute leukemia can

• reduce relapse rate
• improve survival

A G-CSF-primed PBPCI was planned within day 60 post-transplantation before hematologic relapse was diagnosed in patients for which no GVHD occurred or free of GVHD after 2 weeks off immunosuppression for patients receiving GPBPCI after day 90 post HSCT. Before administration of GPBPCI, serious infection had to be cleared and no serious organ failure could be present. The GPBPCI regimen was comprised of G-CSF-primed PBSCs instead of harvested non-primed donor lymphocytes and short-term immunosuppressive agents for prevention of GVHD after GPBPCI. Chimerism status was examined before and after prophylactic treatment with GPBPCI.

Inclusion Criteria:

• high-risk leukemia after HSCT

Exclusion Criteria:

• active GVHD
• early relapse