AUTHOR=Filz von Reiterdank Irina , Jain Rohil , de Clermont-Tonnerre Eloi , Tchir Alexandra , Cetrulo Curtis L. , Lellouch Alexandre G. , Coert J. Henk , Mink van der Molen Aebele B. , Tessier Shannon N. , Uygun Korkut 

TITLE=Thermal Rejection Assessment: New Strategies for Early Detection

JOURNAL=Transplant International

VOLUME=Volume 38 - 2025

YEAR=2025

URL=https://www.frontierspartnerships.org/journals/transplant-international/articles/10.3389/ti.2025.14108

DOI=10.3389/ti.2025.14108

ISSN=1432-2277

ABSTRACT=Background: Skin pigmentation can pose challenges for physicians to diagnose pathologies. In Vascularized Composite Allotransplantation (VCA), this increases the difficulty of diagnosing rejection by clinical observation, which could be improved by noninvasive monitoring, thereby completely avoiding or aiding in guiding location for invasive diagnostics.Methods: Pigmented and non-pigmented allogeneic and non-pigmented syngeneic control transplant recipients underwent daily thermal assessment using infrared (IR) gun and forward-looking IR (FLIR) imaging of VCAs using a rodent partial hindlimb transplant model. Daily clinical assessment was performed, and biopsies were taken on POD 1, 3, and 7.Results: Clinical and histological assessments indicated signs of rejection on postoperative day (POD) 3. In contrast, thermal assessment using the IR gun detected significant differences as early as POD 1, notably a decrease in temperature, when compared to syngeneic control transplants. This demonstrates the capability of thermal assessments to identify early signs of rejection before clinical symptoms become apparent.The findings suggest that thermal assessments can serve as a non-contact, objective adjunct tool for early detection of graft rejection, with consideration of skin pigmentation. This approach may reduce the need for invasive biopsies, thereby improving patient comfort and reducing potential complications associated with current diagnostic methods.