The Sentinel Flap: A Visible Canvas for Organ Transplant Care

Abstract

Transplantation remains the treatment of choice for end-stage organ failure, restoring both survival and quality of life. Yet despite advances in immunosuppression, rejection remains the principal threat to long-term graft survival. Rejection is common across organ types, clinically heterogeneous and often detected only after irreversible graft injury has occurred. Current surveillance strategies include intermittent serum biomarkers, organ-specific functional tests and protocol or for-cause biopsies. These modalities remain episodic, invasive, and fundamentally reactive. They provide only a narrow snapshot of a continuously evolving alloimmune response and fail to capture the earliest phases of immune activation.

No validated biomarker in routine practice reliably predicts impending rejection. Newer molecular assays including gene-expression panels and donor-derived cell-free DNA have generated considerable interest but their signals often emerge late, are confounded by infection or non-specific inflammation and may be less informative in rapidly evolving rejection syndromes...