Successful stem cell transplantation without cryopreservation from a microchimeric haploidentical sibling for refractory acute myeloid leukemia complicated with critical thrombophlebitis and cellulitis.

We describe the case of a 38-year-old male patient who had acute myeloid leukemia and developed prolonged neutropenia after induction chemotherapy. He developed thrombotic complications at multiple sites. Thrombophlebitis of the hemorrhoidal plexus became exacerbated and developed into critical cellulitis. Because the patient had no human leukocyte antigen-identical sibling, we considered an alternative donor. Because of the necessity for early neutrophil recovery to resolve the critical infection, we proceeded with allogeneic peripheral blood stem cell transplantation (PBSCT) from a microchimeric haploidentical sibling donor. We infused peripheral blood mononuclear cells directly into the patient without cryopreservation and thawing procedures. We aimed for the contaminating granulocytes to act as a granulocyte transfusion. Actually, the neutrophils increased to 1.6 x 10(9)/L on day 1, when the patient showed a temporary resolution of infection. Engraftment was achieved shortly after neutropenic nadir, and acute graft-versus-host disease (GVHD) has been well controlled. Although the patient experiences extensive chronic GVHD, he has been well as an outpatient with a 90% Karnofsky performance status score. The leukemia has been in complete remission for more than 1 year. These findings suggest the clinical utility of a salvage therapy with allogeneic PBSCT from a microchimeric haploidentical donor to treat refractory leukemia concurrent with life-threatening infection.