A saliva test could predict the risk of suffering a severe COVID-19 condition

A study by the University of Utah Health, in the United States, found that a series of proteins found in saliva could be used as a marker to predict severe cases of COVID-19.

Scientists found that a group of proteins occurs at elevated levels in the saliva of hospitalized patients with COVID-19. These are ephrine ligands, which could be useful as biomarkers that would allow the identification of people most at risk of having a serious condition of the disease.

“Ephrines are detectable in saliva samples and could serve as complementary markers to monitor the progression of COVID-19 disease. We can collect saliva without harm or discomfort for most patients, which can reveal patients' responses to COVID-19 and potentially guide care,” said study author Erika Egal, postdoctoral fellow in Patrice Mimche's laboratory, in the Department of University of Utah Health pathology, Infosalus reported.

The research work was put for consideration by other scientists at the annual meeting of the American Society of Physiology during the 2022 Experimental Biology (EB) meeting, held in Philadelphia.

The research consisted of the analysis of saliva samples from patients admitted to the emergency department of the University of Utah Hospital with respiratory symptoms. Sixty-seven of the patients tested positive for COVID-19, while another 64 tested negative. In the comparison, they detected that the presence of ephrine ligands in saliva was strongly associated with the diagnosis of severe COVID-19.

Since the start of the pandemic, scientists have investigated which markers can predict severe cases of COVID-19, which would save lives with an early prognosis.

The study of the saliva of patients, according to the specialists involved in the research, could contribute to understanding the biological processes involved in the serious reactions of infection with the SARS-CoV-2 virus. Previous studies have suggested that ephrines play a role in injury and inflammation.

Even so, the experts themselves admitted, more research will be needed to know precisely whether ephrine concentrations are related to a greater likelihood of serious illness or death.

On the other hand, the emergence of new variants of the coronavirus calls into question existing COVID-19 tests as to their ability to accurately detect infections with emerging mutations. If the usefulness of markers in saliva is confirmed, it could be evaluated in a simple and non-invasive way whether there is inconsistency between test results and clinical picture, Egal explained.

“Saliva is full of information beyond the detection of the COVID-19 infection itself. We demonstrated that immune cells, cytokines and soluble proteins can be reliably measured from saliva samples. Our findings provide a starting point for research looking for the causal pathways between infection and poor medical outcomes,” Mimche said.

Other experts have disseminated their own research on markers that could warn of serious cases of COVID-19. Last September, it became known that, after examining the blood samples of nearly 200 patients, researchers discovered underlying metabolic changes that regulate the immune cell reaction to the disease. These changes are associated with the severity of the disease and could be used to predict the survival of patients, as published in the journal Nature Biotechnology.

“We know that there are a range of immune responses to COVID-19, and the biological processes underlying those responses are not well understood. We analyzed thousands of biological markers linked to the metabolic pathways that underlie the immune system and found some clues as to what immunometabolic changes may be fundamental in serious illness.” Co-first author Jihoon Lee, a graduate student at the Fred Hutchinson Cancer Research Center, in the United States, noted that they hope these observations of immune function “will help others rebuild the body's response to COVID-19.”

On the other hand, scientists from the United States and Colombia found that elevated levels of special molecules that are part of the defense of the immune system are closely related to the poor evolution of people hospitalized with COVID-19. The team of researchers was led by scientists Ana Rodriguez and Claudia Gomes, from the Grossman School of Medicine at New York University in the United States. Among other researchers, Maria Fernanda Yasnot-Acosta, from the University of Cordoba, Monteria, Cordoba, Colombia, also collaborated. They published their research in the journal in the journal Life Science Alliance, an open access publication of EMBO Press, Rockefeller University Press, and Cold Spring Harbor Laboratory Press, in the United States.

Other work was carried out by researchers at the University of Copenhagen, in Denmark, and could be a much-needed aid in combating the virus. The study showed that the analysis of a specific protein on the cell surface can predict who is at risk of suffering a serious infection caused by the virus, as explained by adjunct professor Rajan Gogna, lead author of the new study that was published in the journal EMBO Molecular Medicine.

“Cells have a so-called fitness state, and by analyzing it we could predict hospitalization or death in patients with COVID-19, which could turn this biomarker into an early prediction tool, especially because it can be detected from common COVID-19 nasal swab tests,” said Gogna, who is part of the Won Group of the Center for Biotechnology Research and Innovation.

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