Israeli scientists develop blood test that aims to remove need for painful biopsies
Blood test developed at Hebrew University of Jerusalem detects Immune and inflammatory activity in tissues, which could remove need for painful biopsies and expensive imaging
By SAMUEL J HYDE
As it stands, the way to test a healthy immune system is a blood test count which depicts the number of white blood cells in the body. The higher the count the more likely the immune system is fighting an infection in the body.
However, this method of testing often fails to catch immune system activity in the body’s remote tissues, such as those found in bone marrow, lymph nodes and other organs. In those cases, a patient would need to follow up with often invasive measures, such as biopsies, which are not only expensive but potentially harmful due to imaging modalities such as PET/CT scans and MRIs. With that said, this rigorous testing system often ends up missing potentially harmful infections.
Our immune system works hard to protect us against various bacteria, fungi, parasites and cancerous cells, but when the immune system is in a weakened state, we’re at risk of illness or potentially dangerous infections; when the immune system is overactive, we’re are similarly at risk for inflammation and autoimmune diseases. Therefore, accurate monitoring of the immune systems’ activity is of the utmost importance to one’s long-term health.
A group of scientists, led by the Hebrew University of Jerusalem (HU), MD/PhD student Ilana Fox-Fisher and Professor Yuval Dor at HU’s Institute for Medical Research-Israel Canada (IMRIC) have developed a novel method to monitor remote immune processes within the body’s tissue and organs. The work, published recently in eLife, relies on two fundamental principles in biology. First, dying cells, which release fragments of DNA into the bloodstream. Secondly, the DNA of each cell type contains a unique chemical pattern called methylation.
The researchers found proof of concept by testing several medical conditions where the immune system is activated but standard blood cell counts are found to be normal. The first is eosinophilic esophagitis (EoE), a chronic allergic disease that affects mostly young children and has previously been difficult to diagnose. To date, EoE diagnoses require invasive endoscopic biopsies as most patients’ blood counts come back looking normal.
Furthermore, Dor’s team found that EoE patients’ blood contained abnormally high levels of DNA fragments from eosinophils, as identified by their unique DNA methylation pattern.
”Our new non-invasive blood test could go a long way in helping diagnose and monitor this disease,” added Fox-Fisher.
The team found similar success with lymphoma, a cancer that usually doesn’t show up in regular blood testing. However, without the need for bone marrow aspiration and further imaging, this new method picked up DNA fragments left by the immune system.
Currently, Fox-Fisher is conducting a 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,” concluded Fox-Fisher.
**Featured Image: MD/PhD student Ilana Fox-Fisher in the lab. (Photo Credit: Hebrew University of Jerusalem)