Research on the clinical effect and in vitro study of HLA-mismatched hematopoietic stem cell infusion for acute myeloid leukemia.

The treatment for acute myeloid leukemia (AML) remains an important clinical problem. Recently, hematopoietic stem cell therapy provides promising outcomes. In this study we examined the clinical effect of HLA-mismatched hematopoietic stem cell infusion combined with chemotherapy as a postremission therapy to improve the survival and reduce the graft-versus-host disease (GVHD). Thirty patients who achieved complete remission were divided into two groups and received different therapeutic regimes. Patients in combined therapy group received stem cell infusion with the chemotherapy. The patients' clinical indexes were monitored in both groups to evaluate therapy responses. Furthermore, the collected cells used in the therapy were also tested for their tumoricidal activity toward U937 cell lines. The combined therapy exhibited an improved effect than conventional chemotherapy. There were no delays in hematopoietic recovery and GVHD after the intense treatment. This method prolonged the 2.5-year disease-free survival as well as overall survival, and increased the therapeutic effect for patients in good/intermediate prognosis. Moreover, the donor microchimerism was detected in four female patients who had male donors. The experimental study revealed that HLA-mismatched hematopoietic stem cell could induce U937 cells death and the tumoricidal activity enhanced proportionally with the increase in effector-target ratio. HLA-mismatched hematopoietic stem cell infusion combined with chemotherapy improved the clinical outcomes and prevented severe GVHD. This comprehensive treatment can be used as a potential postremission therapy for AML.