A team of clinicians and scientists from the University of Kentucky College of Medicine and College of Health Sciences published new data that shows a potential link between circulating sIL2r, a T-cell receptor, and muscle mitochondrial function in individuals with post-viral fatigue, a.k.a. long COVID.
Long COVID, a persistent feeling of mental and physical exhaustion after the viral infection has cleared the system, can last for weeks, months, or even years and affects millions of people worldwide.
Long COVID is marked by muscle mitochondrial dysfunction — a failure to meet energy demands in muscle tissue. This research revealed that elevated sIL2Rs are a possible cause of mitochondrial dysfunction in post-COVID fatigue, providing novel molecular insight for this condition and a future therapeutic target to reduce post-COVID fatigue.
The research was published in October 2025 in Clinical and Translational Medicine. Yuan Wen, MD, PhD, an assistant professor in the College of Medicine Department of Internal Medicine, division of biomedical informatics, said the research is “a testament to the interprofessional team that is trying to make discoveries and improve outcomes for individuals with fatigue. It is a pleasure to collaborate with clinicians at the bedside and connect to molecular experiments at the bench.”
This work was led by Wen and Kirby P. Mayer, DPT, PhD, associate vice chair of clinical science in the Office of Research and Innovation in Internal Medicine (ORIM), and associate professor in the College of Health Sciences Department of Physical Therapy.
Researchers across the department of internal medicine contributed, including Anna Kalema, MD, and Ashley Montgomery-Yates, MD, in pulmonary, critical care and sleep, Phillip Kern, MD, in endocrinology, and Laura P. Brown, PhD, in biomedical informatics.
The research was supported by the Consortium for Understanding and Reducing Infectious Diseases in Kentucky (CURE-KY), the Kentucky Research Alliance for Lung Disease (K-RALD), and multiple awards from the National Institutes of Health (NIH).
Research reported in this publication was supported by the National Center for Advancing Translational Sciences of the National Institutes of Health under Award Number UL1TR001998, by the National Institute of Arthritis and Musculoskeletal and Skin Diseases of the National Institutes of Health under Award Numbers K23AR079583, R01AR081002 and R00AR081367, and by the National Institute on Minority Health and Health Disparities of the National Institutes of Health under Award Number P50MD019476. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.