A new "liquid biopsy" blood test developed at Hebrew University in Jerusalem detects immune and inflammatory activity in tissues, removing the need for painful biopsies and expensive imaging.
The findings were peer-reviewed and published recently in eLife.
Accurate monitoring of the immune system is crucial for humans. A weak system could put the body at risk for infection, while an overactive one could lead to inflammation and autoimmune diseases.
Currently, the primary way to test the immune system’s health is a blood test that counts immune (white blood) cells in the body, but those tests are not always thorough enough to reach lymph nodes and other organs. This leaves patients with no choice but to follow up with invasive measures, such as biopsies and expensive and potentially harmful imaging modalities such as PET/CT scans and MRI’s. And even then, such advanced testing doesn’t always detect the problem.
The new method was developed by Hebrew U. researchers to monitor remote immune processes within those remote tissues and organs. The work relies on two fundamental biological principles. First, dying cells release fragments of DNA into the bloodstream. Second, the DNA of each cell type contains a unique chemical pattern called methylation.
“A key finding is that immune-derived DNA fragments are not a simple reflection of circulating blood cells, but rather an accurate report of immune processes happening in the body,” explained MD/PhD student Ilana Fox-Fisher. “Our research suggests that, in principle, doctors could monitor remote but critical immune processes by measuring the immune battle’s casualties – that is, immune-derived DNA fragments circulating in patients’ blood.”
The team found success while examining lymphoma, a type of cancer that typically doesn’t show up in blood tests. However, the new blood test does pick up DNA fragments left by the immune system’s fight with lymphoma, without the need for bone marrow aspiration and further imaging.
The researchers are currently conducting an additional study of people who’ve been vaccinated against COVID-19 to see whether the levels of DNA released from antibody-producing B-cells increased after they received the vaccine.
“We’re hopeful this new blood test will give clinicians a more accurate picture of the state of their patient’s health, beyond the standard blood counts which often do not tell the whole story and frequently necessitate invasive follow-up tests and biopsies,” said Fox-Fisher.