Successful non-T cell-depleted HLA haplo-identical three-loci mismatched hematopoietic stem cell transplantation from mother to son based on the feto-maternal microchimerism in chronic myelogenous leukemia.

A 17-year-old male with chronic myelogenous leukemia in blast crisis received a non-T cell-depleted (TCD) HLA haplo-identical three-loci mismatched hematopoietic stem cell transplant (HSCT) from his mother. Long-term feto-maternal microchimerism was detected by nested polymerase chain reaction with sequence-specific primer typing. The post-transplantation prophylaxis against graft-versus-host disease (GVHD) was tacrolimus with minidose methotrexate. Sustained engraftment was obtained. Acute GVHD (grade 2) developed, but improved rapidly. Bone marrow aspiration on day 120 showed complete remission. Non-TCD HLA haplo-identical HSCT based on feto-maternal microchimerism might be feasible and has important implications in the selection of alternative family donors in HSCT.