Clinical significance of recipient antibodies to stem cell donor mismatched class I HLA antigens

A stem cell transplant candidate whose best-matched related donor had a mismatch for A68 by virtue of the patient's maternal human leukocyte antigen A/ B (HLA-A/B) recombinant haplotype, was referred to Wilford Hall Medical Center for transplantation. She was determined prior to transplant to have a high-titered antibody to that HLA type and to several crossreactive antigens (A2 and A24). When she initially failed to engraft, plasmapheresis was tried three times with no effect on the antibody titer. Subsequently, plasmapheresis followed by intravenous immunoglobulin treatment and retransplant completely eliminated the donor-specific antibody. Engraftment occurred, and several weeks after the second transplant antibodies to A68 could no longer be detected although the antibodies to other HLA types were still present. This case report should serve to remind stem cell transplant programs of the importance of checking for the presence of recipient antibodies to donor-mismatched antigens and suggests that patients with such antibodies be treated prior to transplant.