Biomarkers linked to severe COVID-19

Researchers identified new biomarkers associated with the severity of the novel coronavirus (COVID-19) in infected patients, according to a new study published in the Journal of Clinical Investigation.

In the study, researchers from the University of Montreal Hospital Research Centre showed that a set of immune alterations are specifically linked to infection with the SARS-CoV-2 virus, as well as to the severity of COVID-19 disease, its 30-day evolution, and its 60-day mortality.

The researchers used a blood test to inventory the immune cell populations present in 50 patients with SARS-CoV-2, the virus that causes COVID-19, and compare them to those of 22 patients of similar gender and age hospitalized for other acute illnesses, as well as 49 healthy controls.

This immune profiling allowed the researchers to identify subsets of "dysregulated" immune cells specific to patients affected by SARS-CoV-2. Some of these immune alterations were associated with ventilation needs and mortality in these same patients, the researchers said.

These markers specific to SARS-CoV-2 could then help us to identify the patients at greatest risk, and suggest new avenues for developing therapeutic targets, according to Catherine Larochelle, MD, PhD, lead author of the study.

The study also confirms disturbances in the immune system such as neutrophilia or lymphopenia are related to the severity of the disease in hospitalized patients but are not specific to SARS-CoV-2. From a clinical perspective, this could explain why general anti-inflammatory treatments such as steroids seem to work in COVID-19 and other acute diseases, Larochelle said.

These assays could be easily transferred to clinical settings, Larochelle said, because the research team worked with very small amounts of blood, less than one milliliter, to develop these immune profiles. IN an experimental approach, they used techniques commonly employed in hospital laboratories, including the use of surface antibodies to "stain" the cells that express certain markers and flow cytometry or cell characterization and counts. In a clinical setting, this could help track the progress of patients over time and ultimately identify those at high risk who would require closer monitoring, she said.

“I hope that our study will lead to the development of biomarkers that will help us stratify patients based on their risk of developing a severe form of the disease,” Larochelle said in a statement. “This should also allow us to identify new therapeutic targets, and to better select those patients who might benefit from certain available therapeutic approaches." 

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