Since 2020, many people who appeared to have recovered from the SARS-CoV-2-viral infection continued to report symptoms, the U of U reported. These symptoms included fatigue, memory loss, shortness of breath, and loss of sense of smell and taste.
According to the University, an estimated 14 million Americans who survived the virus developed long COVID, and, according to the Centers for Disease Control and Prevention, at least 3,500 people have died from long COVID complications.
The University of Utah Health said they aimed to uncover the underlying cause of long COVID with a study that appeared in the Journal of Clinical and Cellular Immunology. The U of U reported that their findings in this study could lead to new treatments for long COVID.
The scientists in the study found that levels of a particular set of proteins, which are crucial in controlling the growth and activity of immune system cells, were nearly undetectable among individuals with long COVID. As a result, it is suspected that the lungs and other organs are unable to fully heal in order to fight other illnesses. This reportedly only happens once a person is infected with the virus that causes COVID-19.
“It appears that the cells responsible for producing certain proteins called cytokines are not being stimulated to produce them where they are needed,” said Vicente Planelles, Ph.D., the study’s senior author and a professor of pathology at U of U Health. “We propose that cells producing these cytokines are either immunologically exhausted or are possibly dying and are not there to be stimulated in the first place.”
According to the research, individuals with long COVID had undetectable levels of two cytokines, which are involved in the repair of damaged tissue as well as a 70% decrease in another cytokine that reportedly promotes inflammation in body tissue.
“These results were surprising because better-known post-viral syndromes caused by other viruses are thought to be triggered by an increase in cytokines that increase and prolong inflammation in the body,” said Research Study Conductor Elizabeth S.C.P. Williams, Ph.D. “The same sort of pro-inflammatory cytokine process was detected in early studies of long COVID as well, but in our study, we detect an opposite result––that the activity of at least four pro-inflammatory cytokines is diminished or nonexistent.”
The researchers theorized that this happens because the immune cells (responsible for producing these cytokines) are exhausted during the COVID-19 infection and are no longer capable of secreting these cytokines. Because of this, damaged cells in the lungs and other organs can’t be properly repaired, the U of U stated.
“The damage done by the initial viral infection isn’t being healed properly,” Williams said. “Damaged tissue is a source of inflammation. If the damage persists, so will the inflammation, and you’ll continue to have symptoms.”
According to the U of U, further studies are needed to understand long COVID better. The U of U noted that the findings of this study were based on a small sample size, and conducted in a very specific area of the country. They said that there could possibly be differences leading to the onset of long COVID. The U of U also stated that the study did not determine if different strains of the virus causing COVID-19 had any influence on long COVID.
To read more about the study, you can visit the University of Utah Health page.