COVID-19 triggers depletion of immune system cells: Study

COVID-19 patients have significantly low counts of a cell type that plays a crucial role in immune response, with lower numbers of these cells indicating more severe disease, according to a study whose findings may lead to the development of new therapeutics against the disease.

The study, published in the journal Frontiers in Immunology, assessed COVID-19 patients in China, and found that an adverse immune response triggered in the body may affect disease severity by lowering the counts of T cells, which are a type white blood cells that play important roles in the immune system.

According to the scientists, including those from the Army Medical University in China, COVID-19 patients had a high concentration of cytokines, a protein that normally helps fight off infection.

They said an increased concentration of these molecules can trigger an excessive inflammatory response known as a cytokine storm, which causes the proteins to attack healthy cells.

Coronavirus, the study said, does not attack T cells directly, but rather triggers the cytokine release, which then drives the depletion and exhaustion of T cells.

The findings, according to the researchers, offer clues on how to target treatment for COVID-19.

"We should pay more attention to T cell counts and their function, rather than respiratory function of patients," said study co-author Yongwen Chen of Third Military Medical University in China, adding that "more urgent, early intervention may be required in patients with low T lymphocyte counts."