Long COVID, a debilitating illness without a known cure, is far from being psychosomatic. A new study underscores its biological roots, revealing how the SARS-CoV-2 virus affects the immune system.
Researchers from the University of California, San Francisco, CellSight Technologies, and Kaiser Permanente South San Francisco Medical Center used PET (positron emission tomography) imaging to scan the bodies of 24 patients who had recovered from COVID-19. The results were striking: their insides lit up with abnormal T cell activity across multiple organs, compared to pre-pandemic scans.
The study included 18 participants with long COVID symptoms and six who had fully recovered. The PET scans showed abnormal T cell activity in the brain stem, spinal cord, bone marrow, nose, throat, lymph nodes, heart, lung tissue, and the gut wall. The activity was more pronounced in those with long COVID symptoms, According to a report from Science Alert.
Even those who fully recovered from COVID-19 showed persistent T-cell activity changes in multiple organs up to two and a half years after contracting the virus. This suggests that even mild COVID-19 infections can have long-term effects on the immune system and tissue health.
“In some individuals, this activity may persist for years following initial COVID-19 onset and be associated with systemic changes in immune activation as well as the presence of long COVID symptoms,” the UCSF researchers concluded. They suggest that long COVID may involve an active viral reservoir in deeper tissues.
While the findings are correlative, they provide strong evidence that long COVID is linked to the persistence of the SARS-CoV-2 virus and abnormal immune activity.
Long COVID is characterized by a range of unexplained symptoms lasting months or years after a SARS-CoV-2 infection, with over 200 potential symptoms overlapping with other illnesses, such as ‘brain fog’, post-exertional malaise, fatigue, memory loss, and diarrhea.
Studies indicate that long COVID sufferers can experience lingering issues in various organs, including the heart, brain, lungs, skin, kidneys, liver, spleen, gut, thyroid, and ovaries. One hypothesis is that the immune system remains active after the acute phase of the infection, with biomarkers of inflammation found in patients’ blood. told by Nature.
Autopsies have shown the SARS-CoV-2 virus persisting in the body, including the colon, thorax, muscles, nerves, reproductive tract, and eyes, sometimes even 230 days after initial symptoms.
Some studies suggest that SARS-CoV-2 can reactivate dormant viruses, like the Epstein-Barr virus, linked to chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME). CFS/ME shares many symptoms with long COVID-19, leading some scientists to believe they may be related.
Brain scans of long COVID patients reveal changes similar to those in CFS/ME patients. Recent research confirmed that CFS/ME is “unambiguously biological,” affecting multiple organ systems.
Long COVID is increasingly recognized as having neurological underpinnings. The discovery of T cell abnormalities in the spinal cord and brain stem suggests these immune cells may be targeting the central nervous system.
“These observations challenge the paradigm that COVID-19 is a transient acute infection,” the UCSF team noted. The findings, needing confirmation in larger cohorts, show promise for mapping the immune effects of long-term COVID-19 in the body.
