Immune signature discovered for Long Covid

Severe covid 19 disease is characterized by excessive immune and inflammatory processes in the body. Conversely, long covid syndrome is likely to have a strong anti-inflammatory immune status. Scientists have now found this out with extensive blood plasma analyses of vaccinated persons without subsequent disease, persons with completely survived covid 19 infection and long covid patients. The scientific work of the team led by study director Christopher Gerner from the Faculty of Chemistry at the University of Vienna and researchers from MedUni Vienna has now been published as a pre-proof in the open access online journal "iScience".

-Since the onset of the pandemic, it has also become apparent that not all patients recover fully after SARS Cov-2 infection. Initially, the symptoms of affected individuals were mainly attributed to psychological factors such as anxiety and stress. It is now recognized that chronic persistent covid-19 symptoms following acute infection represent a new somatic condition called post-acute covid-19 syndrome (PACS) or long covid-19 syndrome-, the study states.

Many questions about long covid have not yet been clarified, the authors of the study state: -Aufallenderweise sich das Long Covid-Syndrom sich unabhängig von der Schwere der Covid-19-Erkrankung entwickelt. Possible risk factors and concomitant diseases are hardly understood.- Chronic fatigue syndrome, concentration disorders, cardiac arrhythmias, respiratory distress, etc. would in any case severely impair the quality of life of those affected. So far, however, there are no precise markers available to confirm a possible long covid diagnosis.

The Viennese scientists wanted to identify precisely such laboratory characteristics in their work. To this end, they analyzed the blood plasma of three times 13 comparable test persons for their immune status: a group of healthy Covid-19 vaccinated persons without subsequent infection, a second group of recovered Covid-19 affected persons without lasting symptoms (at least twelve weeks after the acute illness) and finally a third group of ex-Covid-19 patients (also at intervals of three months after the infection) with persistent chronic states of exhaustion. The blood plasma was examined at a special facility of the Faculty of Chemistry at the University of Vienna (Joint Metabolome Facility).
The results seem to indicate that the immune status of long covid patients is significantly different from that of recovered patients without persistent symptoms: -A multifaceted analysis of cytokine (immune messenger) profiles showed slightly elevated pro-inflammatory cytokine concentrations in subjects who had recovered from covid 19 disease compared to long covid syndrome patients.

Conversely, significantly lower levels of interleukin-18, tumor necrosis factor receptor II, and other inflammatory parameters were found in the blood plasma of the Long Covid patients. The difference between the Long Covid patients and those vaccinated only against Covid-19 was smaller than that between the subjects who had completely survived SARS-CoV-2 infection and those with persistent symptoms of fatigue. It is likely that in the group of those who have completely recovered, the inflammation levels in the blood are elevated for a longer period of time.

On the other hand, increased blood levels of anti-inflammatory proteins, so-called oxylipins, omega-3 fatty acids, taurine, etc., were characteristic of long covid patients. According to the scientists, this is probably due to so-called M2 macrophages, which have an anti-inflammatory effect. In any case, scientists write that their results could be important for the future: Overall, it appears that there are typical marker characteristics in the blood plasma that are present in long covid patients. This could facilitate the diagnosis of the syndrome and the search for therapies.

According to the German Robert Koch Institute, international studies have shown widely varying rates of long covid syndrome: In these studies, the incidence after acute covid-19 ranged from 7.5 percent to 41 percent in adults without hospitalization for SARS-CoV-2 infection. In patients hospitalized for covid-19, a long covid frequency of nearly 37 percent was observed. (apa)

Publication: iScience
A multi-omics based anti-inflammatory immune signature characterizes long COVID-19 syndrome
Johannes J. Kovarik, Andrea Bileck, Gerhard Hagn, Samuel M. Meier-Menches, Tobias Frey, Anna Kaempf, Marlene Hollenstein, Tarik Shoumariyeh, Lukas Skos, Birgit Reiter, Marlene C. Gerner, Andreas Spannbauer, Ena Hasimbegovic, Doreen Schmidl, Gerhard Garhöfer, Mariann Gyöngyösi, Klaus G. Schmetterer, Christopher Gerner
iScience, Voume 26, Issue 1, 20 January 2023