Scientists find markers in COVID patients

Canadian immunologists say they’re finding telltale markers in patients’ blood that help predict the severity of COVID-19 and could lead to more targeted treatments.

David Kelvin, a Dalhousie University professor of immunology, is co-author of a study that draws links between severity of the illness and the presence of large amounts of the virus’s genetic material ribonucleic acid, or RNA - in blood samples.

He and Spanish scientist Jesus Bermejo-Martin of the Institute of Biomedical Investigation of Salamanca led a group of 36 medical researchers tracking patients coming into Spanish hospital wards and ERs, and looking for about 30 so-called “biomarkers” in their blood plasma.

The work occurred during the first wave of the pandemic in the spring.

Though less publicized than research on vaccines, biomarkers are seen as key to tracking and predicting illness, and they can identify which proteins are being released that prevent the immune system from coping.

The study, which has been published online and is currently in the final stages of peer review for the journal Critical Care, concludes that the presence of the virus’s RNA in blood is “associated to critical illness.”

Kelvin says the work could lead to partnering with a pharmaceutical firm to develop standard and rapid blood-testing looking for the genetic marker in patients who test positive.

While North American hospitals often do test for the presence of the virus’s genetic material in the blood of severely ill COVID-19 patients, Kelvin says more rapid, standardized tests are needed for patients when they arrive in hospital.

The paper found 78 per cent of critically ill patients had the genetic material as a biomarker, compared to just a quarter of the general ward patients and two per cent of outpatients.

Kelvin said his study also noted the presence of three molecules associated with repressing the immune system in the critically ill patients studied, a finding that other scientists can pursue.

There seemed to be a link between the trio of molecules Interleukin-10, Interleukin-1 RA and PDL-1 - and the presence of the virus’s genetic material in the blood, he said. The molecules occur naturally in the body and are used clinically to treat autoimmune diseases.

The detection of the molecules in critically sick patients comes on the heels of similar findings by British scientists.

Immunologist Mark Cameron, who worked with Kelvin studying the 2003 SARS outbreak in Toronto, says the findings are helpful on several levels.

In the short term, the linking of the virus’s RNA with critical illness helps clinicians in diagnosing severity of the illness, said Cameron, a Canadian based at Case Western Reserve University in Cleveland, Ohio.

Meanwhile, identifying proteins that signal the immune system isn’t reacting properly can lead to targeted therapies, he added.

Cameron said often the main treatment for severe COVID-19 is steroids, but his hope is the biomarkers will allow for more precise therapies.