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Liisa Selin and Anna Gil study links between viral infections and ME/CFS

NIH grant to study T cell function after viral illnesses may have implications for long COVID

Liisa Selin, MD, PhD, and Anna Gil, PhD, will seek insights into links between myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and viral infections, now including COVID-19, with a five-year, $2.5 million grant from the National Institute of Allergy and Infectious Diseases. The research may have implications for those who experience long-term post-viral illness from COVID-19, commonly known as long COVID.

Liisa Selin, MD, PhD, and Anna Gil, PhD

Dr. Selin, professor of pathology and principal investigator for the grant, and Dr. Gil, instructor in pathology, are examining the role of malfunctioning T cells in the development of ME/CFS. Not yet well understood, it is a complex disease with a constellation of disabling symptoms including exhaustion and cognitive dysfunction that affects up to 2.5 million Americans.

In four of five patients, a viral or bacterial infection preceded its onset. New research anticipates 10 to 50 percent of COVID-19 patients will experience long COVID symptoms, many similar to those of ME/CFS, after their initial infection has cleared.

“We are finding that an aberrant response to an immunological trigger, like an infection, results in a dysregulated immune system that is partially immunosuppressed due to exhaustion of the CD8 T cells, which fight infection,” said Selin. “A comprehensive understanding of the mechanisms associated with the generation and modulation of immunological T cell memory will lead to a better understanding of how the immune system not only controls viral infections but can also cause immune-mediated pathology.”

In preliminary studies, Selin and Gil found that certain CD8 T cells were altered in patients with chronic ME/CFS as compared to those who do not have ME/CFS. This suggests that an aberrant response to an immunological trigger, like infection, results in a permanently dysregulated immune system, as a result of CD8 T cell exhaustion, a phenomenon they previously discovered in patients who developed ME/CFS following an infection with the Epstein-Barr virus.

With ongoing studies, they hope to identify biomarkers and mechanisms driving the immunopathogenesis of ME/CFS, with a goal of identifying targets for therapies. Their new study will further examine whether the unique subset of T cells is increased in all ME/CFS patients, or only occurs in a subgroup.

“Millions in the United States already have ME/CFS. Millions more will soon be presenting with long COVID,” said Selin. “We hope our research translates into concrete help for patients.”