Researchers at the University of São Paulo (USP) discovered that the concentration of one of the most common viruses found in the human body may be a biomarker of how Covid-19 infection manifests itself in the body.
Torquetenovirus (TTV), also common in monkeys and domestic animals, is not associated with any disease, but when it starts to replicate too much, it is a sign that something in the immune system is not right.
The study was carried out in partnership with the Municipal University of São Caetano do Sul (USCS), which monitored data from patients in the city already infected with Covid-19. According to the researchers, patients with the new coronavirus had a higher TTV viral load than uninfected ones and remained sick longer.
The survey results were published in the journal PLOS ONE.
“We observed that TTV titers increased in those infected with the new coronavirus – the higher, the longer they remained sick – and that the fall in viral load was accompanied by resolution of symptoms. In uninfected individuals, however, the concentration of TTV remained stable throughout the symptomatic period”, said Maria Cássia Mendes-Correa, a professor at the Faculty of Medicine of USP and one of the authors of the article.
Virus as a biomarker
The correlation between high TTV load and immunosuppression has already been used in medicine to monitor transplant patients who need to take medication to prevent organ rejection.
In the study by the University of São Paulo (USP), scientists suggest that the concentration of TTV in the organism of a person infected with SARS-CoV-2 can serve as a marker of intensity and recovery of Covid-19.
“The results show that TTV, in fact, can be a marker of disease evolution and resolution. The more symptomatic the patient was, the greater the load of TTV in the sample,” stated Mendes-Correa.
To arrive at this evidence, we analyzed RT-PCR (gold standard test for detecting viruses such as coronavirus) samples from 91 people with confirmed SARS-CoV-2 infection and another 126 people with flu-like illness whose tests were negative.
The researcher says that all patients included in the survey had mild or moderate Covid-19. Viral load analysis – both TTV and SARS-CoV-2 – was performed using saliva samples.
Through a questionnaire applied to the participants, it was possible to verify that none of them had diseases that cause immunosuppression, such as cancer or AIDS.
According to the researcher, “it is believed that Covid-19, by causing an immunological imbalance, can lead to a certain degree of immunosuppression. And this favors the replication of TTV”.
According to Mendes-Correa, the discovery may contribute to improving Covid-19’s diagnosis and prognosis in the future.
One of the possibilities is to develop a kit capable of measuring several biomarkers of the disease at the same time and then evaluate the results with the help of algorithms, in order to obtain faster and more accurate diagnoses.
“The measurement of TTV load is one of several tests that can be incorporated into these algorithms to support diagnosis. It is in this direction that medicine is heading”, he said.
(With information from FAPESP Agency.)