The body’s immune system is probably out of balance for longer

“Symptoms that persist for more than twelve weeks after a severe SARS-Cov-2 infection are called post-coronavirus (Covid) syndrome (PCS). The identification of new biomarkers to predict its occurrence or course (…) would be crucial,” wrote Max Augustin of the University Clinic of Internal Medicine at the University of Cologne and his co-authors, including Viennese infectiologist Christoph Wenisch (Klinik Favoriten) in Frontiers in Medicine (doi:10.3389/fmed.2023.1129288).

10 to 20% feel the effects of the infection
With nearly 700 million people worldwide sickened during the Covid-19 pandemic, consequences such as long Covid or post-Covid syndrome are of enormous concern after the waves of acute infections. In the current German expert guideline, the frequency of long-term symptoms is described as follows: “All studies have one thing in common: a significant proportion of Covid-19 patients appear to be affected. In the beginning, about ten to fifteen of out of 100 symptomatic patients, after eight weeks there are still about five and after twelve weeks there are still more than two in a hundred uncertainties The World Health Organization (WHO) assumes that a total of ten to twenty percent of the Covid 19 affected feel any kind of long term effects from the infection.

Three groups studied
The German-Austrian team of scientists has tackled the possible causes of post-Covid. Using high-tech technologies, they observed the immunological parameters of three groups of people between April 2020 and December of that year: 16 subjects had developed post-Covid syndrome after recovery from an acute SARS-CoV-2 infection (after six weeks and seven days months). Another 16 patients showed no such long-term problems (exhaustion, fatigue, smell and taste disturbances, etc.) neither after six weeks nor after seven months. The third group consisted of ten uninfected controls. All participants in the study were not vaccinated, which was not possible at the time (April to December 2020).

The experts repeatedly examined the status and subtype distribution of immune cells and other parameters in the laboratory. The concentrations of immune messenger substances (cytokines) were also measured in the subjects’ blood. It has been shown that in PCS patients the immune system apparently becomes unbalanced over time. The scientists: “Patients with PCS already showed increased numbers of CD4-positive and CD8-positive T lymphocytes that specifically respond to SARS-CoV-2 and release interferon gamma and tumor necrosis factor at six weeks and seven months after disease onset . symptoms (…)”

At the same time, these cells also had the so-called CD40 ligand surface molecule as a marker. In general, this speaks for a continued high activation of the immune system. Elevated levels of tumor necrosis factor in the blood are also considered a sign of inflammatory processes. So-called dendritic cells, which for example take up antigens and present them to the immune system or are important in inflammatory responses, were increasingly registered in people with PCS. On the other hand, according to the authors. It is also “remarkable” that immune cells, which slow down immune responses, and the cytokine interleukin-4, which dampens such processes, were also found in greater numbers. The latter slows down inflammatory reactions.

Important notes for future research
The work, according to the authors, at least describes changes in the immunological situation between people who survived Covid-19 with or without the resulting long-term health problems. “This could have potential for future epidemiological research and targeted therapies,” the abstract reads. Overall, however, there was evidence that the altered immunological parameters in those affected by the post-Covid syndrome decreased over time.