Future directions in haploidentical hematopoietic stem cell transplantation

Area of Science:

• Hematology
• Immunology
• Transplantation Medicine

Background:

• Haploidentical hematopoietic stem cell transplantation (haplo-SCT) outcomes have significantly improved, with reduced graft failure and graft-versus-host disease (GVHD).
• Increased use of haplo-SCT has led to extensive research on donor selection, conditioning regimens, GVHD prophylaxis, donor-specific anti-HLA antibodies (DSA), and relapse prevention.
• Donor-specific anti-HLA antibodies (DSA) remain a challenge, but multimodality desensitization protocols are effective for highly sensitized patients.

Purpose of the Study:

• To review recent advancements and key factors influencing haploidentical stem cell transplantation outcomes.
• To highlight strategies for overcoming limitations such as donor-specific antibodies and disease relapse.
• To discuss emerging approaches for improving post-transplant results and patient survival.

Main Methods:

• Review of current literature on haploidentical stem cell transplantation outcomes.
• Analysis of factors influencing engraftment, GVHD, and relapse.
• Evaluation of desensitization protocols for donor-specific antibodies.
• Assessment of donor selection criteria and the role of natural killer (NK) cells.

Main Results:

• Younger donors are associated with better outcomes; younger haploidentical donors may outperform older matched unrelated donors.
• Multimodality desensitization protocols (plasma exchange, rituximab, IVIG, buffy coat) are standard for highly sensitized patients with high DSA levels.
• Higher early post-transplant natural killer (NK) cell counts correlate with improved outcomes and reduced relapse.
• Prospective studies are investigating NK cell administration to decrease relapse rates.

Conclusions:

• Haploidentical SCT is increasingly utilized due to improved outcomes and donor availability.
• Addressing DSA and optimizing donor selection are crucial for successful haplo-SCT.
• Enhancing NK cell activity and exploring cell-based therapies like CAR-T cells hold promise for further reducing relapse post-transplant.