Researchers find new way to slow scarring in rare disease
A molecule normally used to fight cancer may hold the key to halting a disease that slowly transforms the body's internal organs into rigid scar tissue.
Facts about systemic sclerosis
Systemic sclerosis is a rare autoimmune disease. The disease causes scar tissue formation in the skin and internal organs and can result in symptoms such as shortness of breath, abdominal pain, finger ulcers, weight loss, and fatigue.
No curative treatment currently exists.
The immune system's own brake may become a new weapon against a serious disease that slowly transforms the body's organs into stiff scar tissue.
That is the finding of a new study from Aarhus University, which points to a surprising treatment strategy for systemic sclerosis – a disease that around 1,200 Danes live with and which today can only be treated to a limited extent.
"We have found the mechanism that links inflammation and scarring in this disease. That is new, and it means that for the first time we now have a concrete target for treatment," says Stinne R. Greisen, associate professor at the Department of Biomedicine at Aarhus University.
Central to the discovery is a molecule called PD-1, known from cancer immunotherapy, but which in patients with systemic sclerosis – also known as scleroderma – plays an entirely different and more complex role.
Slowing scar tissue formation
In cancer, doctors block PD-1 to unleash the immune system. In scleroderma, the new study points in the opposite direction – that by supplying the body with an artificially produced PD-1 protein, it is possible to dampen the chronic inflammation driving the disease.
This may slow the scar tissue formation that gradually destroys the organs.
"Imagine the immune system as a car going too fast. PD-1 is the brake. In scleroderma, the brake is engaged all the time – not because of an infection, but because the body is mistakenly attacking itself," says Stinne R. Greisen, adding:
"The constant braking paradoxically ends up creating more scar tissue instead of healing. You can think of it as a form of excessive healing. And precisely because we understand that mechanism, we can now attempt to intervene."
Promising results in both laboratory and animal studies
In the study, the researchers demonstrated that administering artificially produced PD-1 can reduce both the inflammatory response and scar tissue formation in cell studies and in animal models.
The results are promising, but the researchers are cautious about making too many promises.
"We are not there yet. But we know that we can slow the scarring, and the next step is to test this in humans – a process that will likely take a number of years," says Stinne R. Greisen.
Potential beyond scleroderma
Although the study focuses on systemic sclerosis, the researchers note that the discovery could have implications well beyond this single disease.
"Scar tissue formation is not only a problem in scleroderma. It plays a role in pulmonary fibrosis, heart disease, and cancer. If we can learn to control that process, it could in time benefit far more patients than those we are focused on in this study," says Stinne R. Greisen.
About the research
Study type: Translational study
Collaborators: Aarhus University Hospital; University College London, UK
External funding: The Danish Rheumatism Association, the Lundbeck Foundation, the LEO Foundation
Potential conflicts of interest: None relevant
Link to scientific article: https://doi.org/10.1016/j.ard.2026.01.008
Contact
Associate Professor Stinne R. Greisen
Aarhus University – Department of Biomedicine
Phone: +45 2245 1114
Email: srg@biomed.au.dk