Plasma cytokine levels reveal deficiencies in IL-8 and gamma interferon in Long-COVID, 2022, Elizabeth S C P Williams et al

Abstract

Up to half of individuals who contract SARS-CoV-2 develop symptoms of long-COVID approximately three months after initial infection. These symptoms are highly variable, and the mechanisms inducing them are yet to be understood.

We compared plasma cytokine levels from individuals with long-COVID to healthy individuals and found that those with long-COVID had 100% reductions in circulating levels of interferon gamma and interleukin-8 (IL-8). Additionally, we found significant reductions in levels of IL-6, IL-2, IL-17, IL-13, and IL-4 in individuals with long-COVID.

We propose immune exhaustion as the driver of long-COVID, with the complete absence of interferon gamma; and IL-8 preventing the lungs and other organs from healing after acute infection, and reducing the ability to fight off subsequent infections, both contributing to the myriad of symptoms suffered by those with long-COVID.

https://www.medrxiv.org/content/10.1101/2022.10.03.22280661v1

 

This is similar to ME research, where there are some signs of immune dysregulation, as if the immune system is activated in some ways and "exhausted" in others, but research is too preliminary to piece everything together.

 

What are the symptoms of an 'exhausted' system?

There are subsets of pwME that don't get reactivated herpes viruses, flu or cold viruses while others have them all the time. I didn't have viral infections during the first 11 years, but now I'm in the subset that gets reactivated herpes viruses all the time. I don't get the flu or colds.

 

Who knows? It is not a well-defined clinical condition.

I don't find the hypothesis of the paper terribly convincing due to a poor choice in controls. They need to compare to healthy controls who had been infected at a similar time to the cases, but managed to recover.

It is known that SARS-CoV-2 interferes with the production of type 1 interferons, and this is one of the primary reasons why COVID is so deadly - that the normal cytokine response from infected cells is inhibited until it is too late and the infection is out of control. The subsequent immune responses are likely to be biased as a result. (edit - to avoid misunderstanding, ifn-gamma is a type 2 interferon)

Hence the results may simply be a consequence of SARS-CoV-2 infection, rather than specific to LongCOVID.

 

This is what I was thinking too. Most people recover from PVFS, for some it can take a few years longer.

I think my case was the relapse from taking immune modulators that brought on all the reactivations of herpes viruses. It seems to have switched something on.

 

Intriguingly IL-8 is the one thing that might consistently be UP in ME, not down!!