Patients with persistent Covid retain viral RNA and active T cells for years.

Disease caused by SARS-CoV-2 is back in the news after weeks of steadily rising infections. However, for people with persistent covidIt is difficult to forget about the pathology from the moment of infection.

Call long covid refers to a diverse group of symptoms that may persist in people who have recovered from the condition, ranging from neurological problems and brain fog to heart disease.

A new study published this week in the journal Scientific translational medicineshows that patients with long-term Covid-19 may experience signs of abnormal activation of immune cells in many organs and tissues, as well as SARS-CoV-2 RNA Remains in the Guttwo years after infection.

The study involved 24 people who had recovered from the disease (from 27 to 910 days after the initial infection) and had undergone a course of treatment. Positron emission tomography (PET) whole body. The results are intended to answer long-standing questions about the basis of persistent Covid, which has remained virtually quiescent for more than four years after the pandemic began.

“This study is one of the first to analyze immune activation throughout the body, not just in the blood or microscopic tissue fragments,” he explains to SINC. Michael PelusoResearch Fellow at the University of California, San Francisco (USA) and first author.

“We still have to figure out how this immune activation causes long covid. But we have found pieces of the virus in rectal tissue biopsies from people with the disease. It is possible that these fragments are responsible for this activation, and if so, they could be a target for treatment,” he adds.

The persistence of Covid is a great mystery

About 10% of people who survive the acute phase of the disease may suffer from persistent symptoms 12 weeks after infection. lasting at least two months and not explained by any other pathologyDespite these figures, the nature of this disorder remains shrouded in mystery.

A new study shows that compared to pre-pandemic controls, how recovered patients showed clear signs of activated T cells in the brainstemspinal cord, heart and lung tissue, and many other parts of the body.

Moreover, this activation of T cells correlated with prolonged Covid symptoms; For example, people with ongoing lung problems showed stronger signs of immune activation in the lungs.

The authors also examined colorectal tissue samples from five symptomatic individuals. long covid and observed residual SARS-CoV-2 RNA in intestinal cells, suggesting that viral RNA can persist in the intestine for nearly two years.

“These observations challenge the paradigm that Covid This is an acute transient infection.“, the team concludes.

More investment to investigate causes

On factors determining the variability of symptoms long covid Between individuals, researchers still don’t know the answer: “It’s possible that different types of processes cause different types of symptoms. However, we are getting closer to finding out.“,” Peluso clarifies.

“Several groups have now identified various processes that may contribute to the development of persistent coronavirus infection. We need more investment to study each of these reasons and understand what effect they have. We still have a lot of work to do, and we need to keep up the momentum,” he continues.

The expert insists that Larger studies with more diverse participants (including various types of long-term Covid symptoms) for their answers. “Our work was small and mostly included people before reinfections became common.”

Link:

Michael Peluso et al. “Tissue-based T cell activation and viral RNA persist for up to two years after SARS-CoV-2 infection.” Scientific translational medicine