• Ongoing 'immune injuries' might cause pe

    From ScienceDaily@1:317/3 to All on Wed Mar 9 21:30:48 2022
    Ongoing 'immune injuries' might cause persistent breathlessness after
    COVID-19

    Date:
    March 9, 2022
    Source:
    Imperial College London
    Summary:
    Long-lasting immune activity in the airways might be the cause
    of persistent breathlessness following COVID-19, according to
    new research.



    FULL STORY ========================================================================== Long-lasting immune activity in the airways might be the cause of
    persistent breathlessness following COVID-19.


    ==========================================================================
    This is according to a new study of 38 people who were previously
    hospitalised with severe COVID-19.

    The results, published in Immunity, suggest these patients have an
    altered landscape of immune cells in their airways and signs of ongoing
    lung damage.

    However, the preliminary results hint that this might improve over time.

    The researchers say that their findings need to be confirmed by a larger
    study, but suggest that recovery from COVID-19 might be accelerated by treatments that dampen the immune system and reduce inflammation.

    Joint lead author, Dr James Harker, from Imperial's National Heart &
    Lung Institute, said: "Our study found that many months after SARS-CoV-2 infection, there were still abnormal immune cells in the airways of
    patients with persistent breathlessness. We also identified a protein 'signature' in the lungs indicating ongoing injury to the airways."
    Joint senior author, Professor Pallav Shah, also from Imperial's
    National Heart & Lung Institute, said: "These findings suggest that
    persistent breathlessness in our group of COVID-19 patients is being
    caused by failure to turn off the immune response, which leads to airway inflammation and injury. The next steps of our research will be to see if
    there are treatments that can reduce the immune activity and whether they
    help to reduce the persistent breathlessness some patients experience." Previous studies have examined the causes of post-COVID-19 breathlessness
    by looking at markers in the blood, but the new study looks directly at
    which immune cells are active in the lungs too.



    ==========================================================================
    The researchers studied CT scans of the lungs and how well the lungs functioned, as well as analysing samples of fluid from within the lungs
    and blood samples to determine the presence of nearly 500 proteins.

    Overall, the study included 38 post-COVID-19 patients three to six months
    after they left hospital and 29 healthy volunteers (who had no underlying diseases and had not had COVID-19) to compare against.

    At three to six months, the researchers found that there were more
    immune cells in the lungs of the post-COVID-19 participants than in the
    healthy controls.

    However, there appeared to be no difference in the immune cells seen in
    the blood of the post-COVID-19 and the healthy participants.

    Co-author, Dr Bavithra Vijayakumar, also from Imperial's National Heart
    & Lung Institute, said: "Other research has found that the immediate
    response to COVID-19 involves an uptick in various types of immune cells
    in the blood and in the lungs to fight the virus. For severe infections,
    like those seen in our study participants, there also tends to be
    heightened signs of inflammation.

    However, after three to six months, it appears that these signs in
    the blood return to normal, while those in the lungs take longer to
    resolve. Our finding that the immune response in the blood doesn't appear
    to match that of the lungs emphasizes the importance of assessing airway immunity in order to better understand persistent respiratory symptoms
    post COVID-19." Although the immune cells in the lungs varied for each post-COVID-19 patient, they all tended to have higher levels of immune
    cells linked to cell death, epithelial damage and tissue repair.



    ========================================================================== There also appeared to be distinct roles for the different immune cells
    in the lungs. For example, higher numbers of cytotoxic T cells led to
    damage to the lung tissue and greater airway dysfunction, while having
    more B cells was associated with greater signs of lung abnormalities on
    CT scans (such as scarring and physical changes in the lung tissue).

    A group of 17 post-COVID-19 participants were re-assessed a year after
    they had left hospital, and 14 of them saw improvements in their symptoms
    and fewer lung abnormalities on CT scans. The other three participants
    still showed lung abnormalities on CT scans, but the numbers of immune
    cells present in their airways was greatly reduced compared to their
    earlier assessments. The researchers say that this suggests that these
    immune responses may improve over time.

    The authors note that their study includes patients who had severe
    COVID-19 disease (requiring hospitalisation and ongoing monitoring)
    and it is unclear if their results would apply to people with less
    severe disease. They were only able to study the participants' lungs
    after COVID-19, and so are unable to determine if any of the signs they discovered were present before infection.

    They note that the participants of their study had COVID-19 before
    vaccines were available.

    The study was funded by the Wellcome Trust, with staff supported by the
    UKRI, CW+ and the Westminster Medical School Research Trust, Asthma UK, Community Jameel and the Imperial College London President's excellence
    fund. The study included collaborators from the National Heart and Lung Institute and the Department of Immunology and Inflammation at Imperial
    College London, Chelsea and Westminster Hospital, Royal Brompton and
    Harefield Hospitals and the Asthma UK Centre for Allergic Mechanisms
    of Asthma.


    ========================================================================== Story Source: Materials provided by Imperial_College_London. Original
    written by Emily Head.

    Note: Content may be edited for style and length.


    ========================================================================== Journal Reference:
    1. Bavithra Vijayakumar, Karim Boustani, Patricia P. Ogger, Artemis
    Papadaki, James Tonkin, Christopher M. Orton, Poonam Ghai,
    Kornelija Suveizdyte, Richard J. Hewitt, Sujal R. Desai, Anand
    Devaraj, Robert J.

    Snelgrove, Philip L. Molyneaux, Justin L. Garner,
    James E. Peters, Pallav L. Shah, Clare M. Lloyd, James
    A. Harker. Immuno-proteomic profiling reveals aberrant immune
    cell regulation in the airways of individuals with ongoing
    post-COVID-19 respiratory disease. Immunity, 2022; 55 (3): 542 DOI:
    10.1016/j.immuni.2022.01.017 ==========================================================================

    Link to news story: https://www.sciencedaily.com/releases/2022/03/220309104456.htm

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