• Elevated inflammation persists in immune

    From ScienceDaily@1:317/3 to All on Tue Mar 15 22:30:44 2022
    Elevated inflammation persists in immune cells months after mild COVID-
    19

    Date:
    March 15, 2022
    Source:
    Karolinska Institutet
    Summary:
    There is a lack of understanding as to why some people suffer from
    long- lasting symptoms after COVID-19 infection. A new study now
    demonstrates that a certain type of immune cell called macrophages
    show altered inflammatory and metabolic expression several months
    after mild COVID-19.



    FULL STORY ========================================================================== There is a lack of understanding as to why some people suffer from
    long-lasting symptoms after COVID-19 infection. A new study from
    Karolinska Institutet in Sweden, the Helmholtz Center Munich (HMGU)
    and the Technical University of Munich (TUM), both in Germany, now
    demonstrates that a certain type of immune cell called macrophages show
    altered inflammatory and metabolic expression several months after mild COVID-19. The findings are published in the journal Mucosal Immunology.


    ==========================================================================
    "We can show that the macrophages from people with mild COVID-19 exhibit
    an altered inflammatory and metabolic expression for three to five
    months post- infection," says Craig Wheelock, docent at the Department of Medical Biochemistry and Biophysics, Karolinska Institutet, and one of
    the study's authors. "Even though the majority of these people did not
    have any persistent symptoms, their immune system was more sensitive
    than that of their healthy counterparts." Long-term symptoms are
    relatively common after severe COVID-19 infection but may also affect
    some individuals with previous mild disease. More research is needed
    to understand the long-term immune aberrations in patients who have
    recovered from the acute phase of the infection.

    To examine this aspect, the researchers in the current study analysed
    blood samples from 68 people with previous mild COVID-19 infection and
    a control group of 36 people who had not had COVID-19.

    The researchers isolated the macrophages in the laboratory and
    stimulated them with spike protein, steroids and lipopolysaccharides
    (LPS), a molecule that triggers the immune system. The cells were then
    RNA sequenced to measure active genes. The researchers also measured
    the presence of eicosanoid signaling molecules, which are a fundamental
    feature of inflammation.

    "It is not surprising to find a large number of eicosanoid molecules
    in people with COVID-19 as the disease causes inflammation, but it was surprising that they were still being produced in high quantities several months after the infection," Craig Wheelock says.



    ==========================================================================
    The study also showed a higher concentration of leukotrienes, which are
    a type of pro-inflammatory molecules known for causing asthma.

    "It's very striking that the concentration of leukotrienes remains
    elevated in macrophages in people who have had mild COVID-19," says
    the study's corresponding author Julia Esser-von Bieren, research group
    leader at the Helmholtz Center Munich and the Technical University of
    Munich. "Leukotrienes are key mediators of asthma, but they're also
    involved in the antiviral host defence against influenza. A sustained
    increase after SARS-CoV-2 infection could cause a greater sensitivity
    to respiratory inflammation, but could also improve antiviral immunity
    to SARS-CoV-2 or other viruses." The blood samples were collected on
    two occasions, at three to five months after SARS-CoV-2 infection and
    after 12 months. At three to five months, around 16 percent reported
    persistent mild symptoms while the rest were symptom-free.

    At 12 months, none reported persistent symptoms and there was no longer
    any difference in inflammatory markers between those with previous
    COVID-19 infection and the healthy control group.

    The researchers note that the post-COVID diagnosis was not specifically examined in the study and as such more research is needed to determine if
    these results can be directly linked to what is also known as long COVID.

    "We would like to do a corresponding study in which we involve both
    people with severe COVID-19 and people without COVID-19 but who have
    another kind of respiratory disease, such as influenza," Esser-von
    Bieren says. "We'll then examine if what inflicts COVID-19 patients also inflicts those with, say, seasonal influenza." The study was financed
    by the Swedish Heart-Lung Foundation, the German Research Foundation
    (DFG) and the Helmholtz Association.

    One of the authors has received funding from Allergopharma, PLS Design
    and Zeller AG.


    ========================================================================== Story Source: Materials provided by Karolinska_Institutet. Note: Content
    may be edited for style and length.


    ========================================================================== Journal Reference:
    1. Sina Bohnacker, Franziska Hartung, Fiona Henkel, Alessandro
    Quaranta,
    Johan Kolmert, Alina Priller, Minhaz Ud-Dean, Johanna Giglberger,
    Luisa M. Kugler, Lisa Pechtold, Sarah Yazici, Antonie Lechner,
    Johanna Erber, Ulrike Protzer, Paul Lingor, Percy Knolle, Adam
    M. Chaker, Carsten B.

    Schmidt-Weber, Craig E. Wheelock, Julia Esser-von Bieren. Mild
    COVID-19 imprints a long-term inflammatory eicosanoid- and chemokine
    memory in monocyte-derived macrophages. Mucosal Immunology, 2022;
    DOI: 10.1038/ s41385-021-00482-8 ==========================================================================

    Link to news story: https://www.sciencedaily.com/releases/2022/03/220315095020.htm

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