€1.25m Irish research programme investigates whether donor skin could provide an early warning of organ rejection

19th August 2026

Sentinel Study Ireland is investigating whether a visible patch of donor skin on a recipient’s forearm could flag organ rejection before it becomes clinically apparent, potentially allowing earlier treatment.

An Irish research team is investigating whether a small patch of donor skin transplanted onto a recipient’s forearm could act as a visible early-warning signal of organ rejection, potentially allowing clinicians to intervene before significant damage occurs within the transplanted organ.

Sentinel Study Ireland is led by Professor Róisín Dolan, Chief Investigator and Academic Consultant Plastic, Reconstructive and Hand Surgeon at St. Vincent’s University Hospital. The research is being carried out in liver and simultaneous pancreas-kidney transplant recipients.

The approach, known as the Sentinel Skin Flap, involves transplanting a small patch of vascularised skin from the same donor as the transplanted organ. If the recipient’s immune system begins to reject the donor tissue, this may appear on the flap as a red rash, providing a visible alert for the patient and their clinical team.

Because the flap has no sensation, a small biopsy can be taken from it without pain and examined under a microscope. If acute rejection is confirmed, this could allow treatment to begin before significant damage occurs within the transplanted liver or pancreas.

Rejection can begin before a patient feels unwell or changes in the transplanted organ become clinically apparent. Current monitoring including clinical assessment, blood tests, organ-function testing, imaging and organ biopsy remains essential. The study will examine whether the Sentinel Skin Flap could provide clinicians with an additional and easily accessible source of information.

Professor Róisín Dolan said:

“Skin may give us a visible window into the health of a transplanted organ. Rejection may appear on the Sentinel Skin Flap as a red rash, providing an immediate visual alert. We can then biopsy the rash painlessly and, if rejection is confirmed, treat it rapidly before significant organ damage occurs. The aim is to protect the transplanted organ and improve its long-term survival.

 Every transplant represents an extraordinary gift from an organ donor and their family. Once that gift has been given, our responsibility is to do everything possible to understand, monitor and protect it.”

The multidisciplinary programme brings together expertise in transplant medicine and surgery, plastic and reconstructive surgery, immunology, pathology, genomics, clinical trials, digital health and patient and public involvement. Organ Donation and Transplant Ireland and the Mater Transformational Design Thinking Team are key collaborators.

Professor Dolan’s team at the UCD Conway Institute of Biomolecular and Biomedical Research is leading the programme’s immunology research. Advanced technologies will be used to map how genes and proteins behave in donor skin during rejection and connect these changes with what is happening in the recipient and their transplanted organ.

The wider programme will also investigate an association observed in previous intestinal-transplant research between having a Sentinel Skin Flap in place and experiencing fewer rejection episodes. Researchers will examine whether the flap may influence or dampen the immune response and whether these biological mechanisms could eventually help personalise and reduce the immunosuppressive treatment patients require.

Patient-centred tools, including simulated skin-flap models and secure photo-monitoring pathways, are being developed so that recipients can safely help monitor the flap and report possible changes to their clinical team.

The wider Sentinel programme has secured almost €1.25 million in competitive research and innovation funding. This includes a Health Research Board Emerging Clinician Scientist Award and HSE Spark Innovation Funding, together with Patient and Public Involvement support from PPI Ignite UCD.

Pauline McGrath, Chief Executive Officer of St Vincent’s University Hospital, said:

“Sentinel demonstrates what is possible when patients, clinicians and scientists work together to address a complex clinical challenge. By bringing expertise in transplant care and advanced immunology together, this research could deepen our understanding of rejection and help shape how transplanted organs are monitored in the future.

We are proud that St. Vincent’s University Hospital is leading a programme with the potential to benefit transplant medicine in Ireland and internationally.”

The Irish programme builds on international research led by Professor Henk Giele and colleagues at the University of Oxford and Oxford University Hospitals, where Professor Dolan worked before developing the Sentinel programme in Ireland.

For further information, visit www.sentinelstudy.ie.

Notes to editors

About Sentinel Study Ireland

Sentinel Study Ireland is a multidisciplinary research programme examining the Sentinel Skin Flap in liver and simultaneous pancreas–kidney transplantation.

It is investigating whether a small vascularised patch of skin from the same donor can act as a visible and accessible indicator of immune activity and acute rejection in the transplanted organ.

The Sentinel Skin Flap remains an investigational approach and is not part of standard transplant care. The current feasibility phase is assessing:

• whether the additional procedure is feasible, safe and acceptable to transplant recipients and clinical teams; and
• whether visible and microscopic changes within the flap correspond reliably with immune activity and rejection occurring within the transplanted organ.

The study has been reviewed and approved by the St. Vincent’s Healthcare Group Ethics and Medical Research Committee.

What the study is investigating

The programme will compare visible and microscopic changes in the Sentinel Skin Flap with:

• immune-cell activity;
• blood biomarkers;
• gene-expression patterns;
• skin microbiome changes;
• liver and pancreas function;
• organ-biopsy findings, where available; and
• clinical outcomes.

The study aims to establish whether immune responses observed within donor skin reflect events occurring within transplanted organs.

Existing monitoring methods remain essential components of transplant care. The Sentinel Skin Flap is being investigated as a potential additional source of information and is not intended to replace established clinical monitoring.

Research leadership and collaboration

The programme is led by Prof Róisín Dolan, Chief Investigator of Sentinel Study Ireland, Academic Consultant Plastic, Reconstructive and Hand Surgeon at St. Vincent’s University Hospital and Conway Fellow at University College Dublin.

It brings together clinical, scientific, academic and patient partners in Ireland and internationally, with expertise spanning:

• transplant medicine and surgery;
• plastic and reconstructive surgery;
• immunology;
• pathology;
• genomics;
• clinical trials;
• digital health; and
• Patient and Public Involvement.

Professor Dolan’s team at the UCD Conway Institute of Biomolecular and Biomedical Research is leading the programme’s immunology research, using advanced spatial transcriptomics and proteomics expertise and infrastructure to investigate the cellular and molecular basis of transplant rejection.

Key collaborators include Organ Donation and Transplant Ireland and the Mater Transformational Design Thinking Team.

The Irish programme builds on pioneering research conducted by Professor Henk Giele and colleagues at the University of Oxford and Oxford University Hospitals.

Funding

The wider Sentinel programme has secured almost €1.25 million in competitive research and innovation funding, including:

• €1,108,624 through a Health Research Board Emerging Clinician Scientist Award;
• €140,000 through HSE Spark Innovation Funding; and
• Patient and Public Involvement support through PPI Ignite UCD.

PPI Ignite UCD support enables patients to help co-design the research, influence the study and contribute to the development of patient information and communications.

The funding supports the feasibility study and associated laboratory, digital-monitoring and patient-engagement programmes.

Website

www.sentinelstudy.ie