Jul 08, 2024 06:00:00

Whole-body scans of patients suffering from 'Long COVID,' an aftereffect of the new coronavirus, reveal 'abnormal activation of T cells in tissues throughout the body'

Long-COVID, in which various symptoms such as fatigue, shortness of breath, and muscle weakness continue even after recovery from COVID-19, has been reported to affect work and daily life. When a research team from the University of California, San Francisco and other institutions conducted a full-body scan of a patient who had recovered from COVID-19, they found abnormal activation of T cells in tissues such as the brain stem, spinal cord, and bone marrow.

Tissue-based T cell activation and viral RNA persist for up to 2 years after SARS-CoV-2 infection | Science Translational Medicine
https://www.science.org/doi/10.1126/scitranslmed.adk3295

COVID's Hidden Toll: Full-Body Scans Reveal Long-Term Immune Effects: ScienceAlert

https://www.sciencealert.com/covids-hidden-toll-full-body-scans-reveal-long-term-immune-effects

The research team used positron emission tomography (PET) to scan the entire bodies of 24 patients who had recovered from COVID-19, and found abnormal activation of T cells in the brain stem, spinal cord, bone marrow, nose, throat, some lymph nodes, heart and lung tissue, and intestinal wall, compared with whole-body scans taken before the COVID-19 pandemic.

These results were obtained from 18 subjects suffering from Long COVID and 6 subjects who had fully recovered from COVID-19. Further investigation revealed that T cell activation in some tissues, such as the spinal cord and intestinal wall, was more frequently reported by patients with Long COVID symptoms than by those who had fully recovered. Patients with respiratory symptoms due to Long COVID also revealed abnormal activation of T cells in the lungs and pulmonary artery walls.

On the other hand, even in subjects who fully recovered from COVID-19, persistent changes in T cell activity in many organs were reported compared to pre-pandemic levels, with some cases showing T cell activation even two and a half years after initial COVID-19 infection, according to the research team.

'In some patients, T cell activation has been shown to persist for years after the initial COVID-19 onset, which may be associated with the symptoms of long COVID,' the researchers wrote. 'Taken together, these observations suggest that even clinically mild COVID-19 infections may have long-term effects on tissue-based immune homeostasis.'

Previous research has suggested that COVID-19 infection may awaken other viruses in the body, such as the Epstein-Barr virus, which is

believed to causemyalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) .

Brain scans of patients also showed that ME/CFS is ' clearly biological ' with multiple internal organ systems affected. 'This study challenges the conventional wisdom that COVID-19 is a transient, acute infectious disease,' the researchers said.

'As interest in techniques to map the effects of long COVID on the immune system grows, these findings need to be confirmed in larger cohorts,' Science Alert said.