Organ transplantation, often the only remaining option for end-stage organ failure, is a highly complex field that presents numerous challenges. Among these, transplant rejection has long been a major concern for both the medical community and patients.
Traditional methods for monitoring transplant rejection present several limitations:
- Biopsies, considered the gold standard, are invasive, costly, and prone to sampling bias.
- Conventional biomarkers, such as creatinine, lack specificity and often fail to detect early rejection.
Fortunately, emerging biomarkers and advances in molecular imaging are opening up promising new non-invasive avenues.
Our recommended read this month: “Advancements in noninvasive techniques for transplant rejection: from biomarker detection to molecular imaging”[1]
This review explores the latest progress in non-invasive tools for monitoring transplant rejection and includes the following information :
Highlights on Biomarkers:
- Donor-derived cell-free DNA (dd-cfDNA): Sensitive to graft injury and rejection; already adopted in clinical practice.
- MicroRNAs (miRNAs): Stable, organ-specific markers useful for diagnosis and prognosis.
- Gene Expression Profiling (GEP): Recommended for screening acute rejection in heart transplants.
- Chemokines (CXCL9/CXCL10): Effective in detecting kidney transplant rejection.
- Other biomarkers: Include long non-coding RNAs (lncRNAs), Fas/FasL, and tissue-specific injury markers.
Advances in Molecular Imaging:
- Fluorescence Imaging: Enables high-resolution visualization of immune responses (e.g., granzyme B activity) in preclinical models.
- Ultrasound Imaging: Real-time imaging using targeted microbubbles for markers like granzyme B and C4d.
- MRI: Tracks immune cells using contrast agents such as superparamagnetic iron oxide nanoparticles (SPIOs).
- Nuclear Medicine Imaging (SPECT/PET): Provides detailed visualization of immune activity using radiolabeled probes — with PET showing strong clinical potential.
It’s important to note: Biomarkers offer insights at the molecular level, while imaging provides spatial and temporal resolution. Combined, they form a synergistic approach to precision transplant monitoring.
Looking Ahead:
- Integration of biomarkers and imaging for more holistic monitoring.
- Application of artificial intelligence (AI) to analyze complex data and enhance diagnostic accuracy.
- Development of cost-effective, accessible technologies for everyday clinical use.
At 4Bases, we are proud to contribute to the development of cutting-edge technologies for monitoring graft rejection in solid organ transplantation — and we’ll be sharing exciting news in this area very soon… stay tuned!
[1] Song Y, Wang Y, Wang W, Xie Y, Zhang J, Liu J, Jin Q, Wu W, Li H, Wang J, Zhang L, Yang Y, Gao T, Xie M. Advancements in noninvasive techniques for transplant rejection: from biomarker detection to molecular imaging. J Transl Med. 2025 Feb 3;23(1):147. doi: 10.1186/s12967-024-05964-4. PMID: 39901268; PMCID: PMC11792214.
