Managing antibody-mediated rejection in heart transplant

Area of Science:

• Cardiology
• Immunology
• Transplantation Science

Background:

• Antibody-mediated rejection (AMR) remains a significant challenge in heart transplantation, with current clinical management lacking robust evidence.
• Recent discoveries reveal natural killer (NK) cells play a central role in AMR pathogenesis, beyond traditional donor-specific antibody (DSA) complement activation.
• NK cells contribute to vascular damage through antibody-dependent cellular cytotoxicity (ADCC) and DSA-negative endothelial injury via 'missing-self' recognition.

Purpose of the Study:

• To review current understanding of AMR pathophysiology, emphasizing the role of NK cells.
• To discuss emerging therapeutic strategies targeting NK cells in AMR.
• To highlight the need for improved diagnostic and classification methods for AMR.

Main Methods:

• Literature review and synthesis of recent research on AMR mechanisms.
• Analysis of the role of NK cells, Fcγ receptors, and 'missing-self' recognition in transplant rejection.
• Discussion of potential therapeutic targets and clinical trial requirements.

Main Results:

• NK cells are implicated in both DSA-dependent and DSA-independent endothelial injury in AMR.
• Targeting NK cells presents a promising therapeutic avenue for AMR.
• Sparse and heterogeneous clinical data currently limit the adoption of new strategies.

Conclusions:

• Effective management of AMR requires a refined, heart-specific classification system and validated noninvasive biomarkers.
• Early detection and monitoring using biomarkers like dd-cfDNA and NK-activity signatures are crucial for clinical trials.
• Advancing NK-cell-targeting therapies necessitates reproducible assays, multicenter validation, and standardized reporting for clinical adoption.