A blood test could reduce liver transplant rejections

Liver transplants save lives, but a significant number of patients experience organ rejection or other complications. Determining which patients may respond best or worst to a transplant would improve the success rates of this surgery. That's the aim of a team from Georgetown University and MedStar Health (USA), whose study, published in Nature Communications , shows how a single blood sample can be used to detect problems in their early stages, enabling personalized treatment to prevent organ failure.

The research represents an important step toward developing a liquid biopsy that could not only rapidly detect post-transplant complications but also determine their cause. This technology would largely eliminate the need for more invasive testing.

Liver transplants are only performed on people who urgently need them; unlike other organs such as kidneys, which can receive dialysis, there are no machines or treatments that can save a patient when their liver fails.

Because the availability of livers for transplant is limited, preventing organ damage is critical, says study co-author Alexander Kroemer .

"We need a much better and more detailed understanding of the causes of transplant failure," says Anton Wellstein, lead author of the study. "With this technology, we can take a blood sample and get an overview of the patient's condition."

There are several ways a transplanted organ can be damaged. The transplant process itself can damage the new liver, overwhelm nearby organs, and trigger an immune response.

Today, blood tests are used to detect possible damage, and genetic tests are used to determine whether the damaged cells originate from the donated liver or the patient's own body. However, identifying the precise cause often requires expensive imaging studies or invasive follow-up tests, such as a liver biopsy.

The new technology works by capturing DNA fragments present in the remains of dying cells circulating in the bloodstream. Wellstein's team discovered that the chemical signatures left behind in these DNA fragments could be used to identify the original cell type and origin with great precision.

"The novelty is that we can now determine the cellular origin of the damage," explains Wellstein. "We can precisely identify the cell types, whether in the transplanted organ or in the host, in other tissues that are suffering damage or at risk of suffering it."

In addition to being faster and less invasive than a traditional tissue biopsy, the blood test is also potentially more accurate.