Successful allogeneic stem cell transplantation for a patient with high titers of donor-specific antibody after multiple desensitization procedures.

A 66-year-old woman who was diagnosed with acute myeloid leukemia, myelodysplasia-related underwent allogeneic peripheral blood stem cell transplantation (PBSCT) from her human leukocyte antigen (HLA)-mismatched daughter after primary induction failure. The patient had a high donor-specific antibody (DSA) titer to the mismatched HLA antigen and received multiple desensitization treatments including rituximab, intravenous immunoglobulin, and random platelet concentrate transfusions, which resulted in a slight decrease in the DSA titer. The donor was a poor mobilizer and the patient could have received a limited number of CD34-positive cells in the PBSCT with a relatively high CD34-negative fraction. Although the graft rejection was a great concern, the patient achieved delayed but successful engraftment and complete remission. The extent of the DSA reduction was greatest after transplantation, indicating that a relatively greater number of infused CD34-negative cells had a certain effect on antagonizing the DSAs. The DSAs were detected even after engraftment, suggesting that other factors, such as HLA expression levels and HLA epitopes, might affect the engraftment outcome.