Successful desensitization of donor-specific antibodies in a single cord blood transplant recipient.

Umbilical cord blood (UCB) represents a valuable graft source in the absence of a human leukocyte antigen (HLA)-matched donor for hematopoietic cell transplantation (HCT). Donor-specific anti-HLA antibodies (DSAs), targeting grafts with mismatched HLA antigens, pose a significant obstacle by increasing the risk of primary graft failure, delayed engraftment, and decreased survival. Existing literature on HLA desensitization has primarily focused on haploidentical transplants, and there is a lack of experience regarding the optimal strategy in UCB transplantation. We report our successful desensitization strategy in a 42-year-old woman with acute lymphoblastic leukemia receiving a single UCB unit. The only suitable donor option for this patient, who had no relatives and uncommon HLA haplotypes, was a UCB graft against which the patient had DQ7 DSAs. DSA levels were reduced before transplantation through a combination of plasma exchange, intravenous immunoglobulins, and rituximab with close monitoring of DSA mean fluorescent intensity levels. After desensitization, the patient underwent UCB transplantation, achieved successful engraftment and remained in complete remission, free from graft-versus-host disease. When other suitable donors without DSAs are unavailable, our desensitization modality offers a safe option for single-unit UCB transplantation.