Researchers from a multicenter study co-led by Cedars-Sinai have identified a biological pathway by which immune cells can prevent the lungs from healing after viral infections like COVID-19. The findings, published in Nature, may pave the way for new therapeutic treatments to prevent long-term lung damage.
Understanding the Link Between Viral Infections and Lung Scarring
The COVID-19 pandemic has highlighted how viral infections can leave lasting effects, a condition known as long COVID or post-acute sequelae of SARS-CoV-2. One particularly severe outcome is pulmonary fibrosis—a type of lung scarring that can cause significant breathing difficulties. In extreme cases, patients require oxygen supplementation or even lung transplants, with limited treatment options available.
“This study sought to understand the pathways that led to abnormal repair in the lungs that produced a scar-forming environment,” said Peter Chen, MD, co-corresponding author and interim chair of the Department of Medicine at Cedars-Sinai. “Our findings may lead to therapeutic strategies to prevent fibrotic lung disease after viral illnesses.”
CD8+ T Cells Identified as a Key Factor in Lung Damage
To investigate how lung fibrosis develops after viral infections, researchers used models of post-viral lung disease, applying molecular profiling and imaging techniques. They identified a specific type of immune cell—CD8+ T cells—as a key player in preventing lung tissue from properly repairing itself post-infection. Immune Cells
The research team further validated these findings using patient samples from individuals suffering from post-acute sequelae of SARS-CoV-2 pulmonary fibrosis. Their data confirmed that abnormal immune responses were linked to the persistence of lung scarring, strengthening the study’s conclusions.
“Although we based the work on post-acute sequelae of SARS-CoV-2 pulmonary fibrosis, other viral pandemics in the past have also revealed their ability to cause lung scarring after infection—like swine flu,” said Jie Sun, PhD, co-corresponding author and professor of Medicine at the University of Virginia School of Medicine. “The research and broader medical field must be prepared and better understand how to prevent adverse outcomes stemming from these viruses.”
Future Implications for Treating Lung Fibrosis: Immune Cells
The study’s findings suggest that targeting immune pathways involved in lung repair could offer new treatment options for those suffering from long-term complications following viral infections. The research team believes this work could have broader implications beyond COVID-19, providing new insights into other forms of lung fibrosis caused by viral diseases.
Chen, Sun, and their team of collaborators—including experts from Cedars-Sinai and other institutions—hope these findings will contribute to the development of therapies that can prevent or reverse lung damage, ultimately improving outcomes for patients affected by post-viral lung disease.
Reference: Jesse L. Goodman, Rick A. Bright, Nicole Lurie. H5 Influenza Vaccines — Moving Forward Against Pandemic Threats. JAMA, 2024.
