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Why do I keep getting infections?



On my quest to find why I feel like I am immunosuppressed, and will catch anything whilst the rest of family stay well despite also having had Covid-19 twice, I have found this preprint "Analysis of cell-mediated immunity in people with long COVID" June 2021.


The take home message for me: "Long COVID patients displayed a higher percentage of illnesses related to abnormal immune responses either preceding SARS-CoV-2 infection (43%) or following it in 23% of cases.

It's always been a bit of a joke in my house about just ill I have been for most of my life - recurrent tonsillitis as a child, recurrent chest infections as a child, undiagnosed asthma as a child, recurrent sinusitis and respiratory tract infections in my 20's through to present day leading to broken ribs, courses of antibiotics and hospital admissions, bacterial peritonitis (no cause found), chronic fatigue after a viral illness. Combined with this medical history and the statement above makes me wonder if my immune system has always been compromised....

This paper adds to the complexity that is Long Covid.

In this paper it is found that:

  • T4 lymphocytes are low in 34% of patients - these white cells are the basic pillar of a specific immune response to infections

  • A raised natural killer cell population in 64% which implies a persistent inflamed state.

  • In some patients macrophages persisted which implies a viral persistence or reservoir.


The paper's take home message:

"The immune system appears to have an important involvement in the development of Long Covid and viral persistence could be the cause or consequence of it".

What did they set out to do?

The aim of the study was to analyse the specific immune response against SARS-CoV-2 in those affected by Long Covid, attributable to T cells (cell-mediated immunity) and to carry out a parallel analysis of the humoral response and lymphocyte typing.


What did they do?

A descriptive cross-sectional study of 74 patients with Long Covid for at least 4 months since diagnosis.

The collected data were:

  • Information on the COVID-19 episode and the persistent symptoms

  • Medical history

  • A specific cell-mediated immunity to SARS-CoV-2 through flow cytometry, assessing the release of interferon-gamma (IFN-Ɣ) by T4 lymphocytes, T8 lymphocytes and NK cells.


What did they find?

  • Patients with Long Covid had negative serology for Covid-19 in 89% of cases - i.e. no antibodies to Covid-19, useful if you are still coming up against the comment - "well you have no antibodies so you can't have had acute Covid-19"

  • 96% showed specific cellular immunity to SARS-CoV-2 an average of 9.5 months after infection. Cellular immunity does not involve antibodies. Of these 96%:

  • 89% of this response corresponded to T8 lymphocytes

  • 58% to Natural Killer cells

  • 51% to T4 lymphocytes.

  • Most of them had altered immune cell typing and we found that T4 lymphocyte counts were low in 34% of cases and NK cell high in 64%. T4 lymphocytes are a basic pillar of specific immune response and high NK cells infers a persistent inflamed state.

  • Macrophage populations were detected in the peripheral blood of 7% of them.

  • Patients displayed a higher percentage of illnesses related to abnormal immune responses, either preceding SARS-CoV-2 infection (43%) or following it in 23% of cases. These were asthma, allergies, autoimmune diseases.


What did they conclude?

The immune system appears to have an important involvement in the development of Long Covid and viral persistence could be the cause or consequence of it. Further analysis with a control group should be performed.


Reference

https://www.medrxiv.org/content/10.1101/2021.06.09.21258553v2.full-text

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