To remedy the lack of human leukocyte antigen (HLA)-matched donors and address the problems bedeviling traditional allogeneic hematopoietic stem cell transplantation which induces the resultant graft-versus-host disease, we designed a scheme called HLA-mismatched hematopoietic stem cell microtransplantation (MST) for patients with acute myeloid leukemia (AML), where encouraging results were achieved. In providing answers to such questions as how to select the donors of MST and which factors were involved in the outcome of MST. One hundred thirty-one AML patients from four centers with lower or standard risk of prognosis after complete remission were given three courses of MST: high dose of cytarabine plus infusion of granulocyte colony-stimulating factor mobilized peripheral blood stem cells from HLA-mismatched donors. Leukemia-free survival (LFS) and overall survival were compared, with respect to gender difference, number of HLA-matched loci, killer cell immunoglobulin-like receptor (KIR), and ligand mismatch between donors and recipients. Median LFS of recipients with different KIR ligands from those of donors was found to be significantly higher than that of recipients having identical ligands with donors (P < 0.05). The mean LFS was statistically different between recipients whose donors had HLA-C1/C2 ligand and those whose donors had C1/C1 or C2/C2 ligand (P < 0.05). The following factors were found to promote long-term survival: female recipients of male donors' stem cell, and donors with different KIR ligands from recipients.
Keywords: KIR ligand; NK cells; acute myeloid leukemia; hematopoietic stem cell; microtransplantation.