Preformed anti-HLA DQA1/DQB1 DSA possibly responsible for graft failure in haploidentical stem cell transplantation

Primary graft failure (PGF) is a life-threatening complication of allogeneic hematopoietic stem cell transplants (HSCT) and is associated with poor outcomes. Most clinical studies have focused on donor-specific anti-HLA antibodies (DSAs) against HLA-A, -B, and -DR molecules.

We present the first reported case of PGF associated with a preformed high-level DSA against HLA-DQ alone. The 39-year-old patient was diagnosed with acute myeloid leukemia. She received a haploidentical graft from her son and suffered PGF. She had persistently high levels of DSAs against her son's HLA-DQA1 and HLA-DQB1 molecules after desensitization. No alternative donor was available.

To circumvent the second graft failure, we adopted an approach of combining two units of unrelated cord blood (CB) and G-CSF-primed bone marrow (BM) and peripheral blood stem cells (PBSCs) from her son's transplants. The BM short tandem repeats (STRs) assay showed that one unit of the CB was fully engrafted, and the grafts from her son still failed to engraft.

We conclude that high levels of anti-HLA DQA1/DQB1 DSA could be associated with PGF in our case. Besides DSAs against HLA-A, -B, and -DR, attention should also be paid to DSAs against the HLA-DQ molecule.