Medical Express: Researchers identify key role of immune cells in brain infection (2020)

[Ravn]

In mice.

A new study has detailed the damaging role played by the immune system in a severe brain condition most commonly caused by the cold sore virus.

Researchers have identified the specific type of immune cell that induces brain inflammation in herpes simplex virus (HSV) encephalitis. Crucially, they have also determined the signaling protein that calls this immune cell into the brain from the bloodstream.

Using a mouse model, the researchers showed that neutrophils (a type of immune cell) made the blood-brain barrier more permeable and contributed to the brain damage associated with HSV encephalitis. They also found that these neutrophils were not needed to control the virus.

https://medicalxpress.com/news/2020-09-key-role-immune-cells-brain.html

An interesting bit from the very technical and way above my head paper the above is based on: immune cells get through the BBB into the brain even as the virus is being cleared by antiviral treatment, and the timing with which those immune cells arrive is awfully similar to my PEM. Most probably a coincidence, I don't have viral encephalitis nor am I a mouse, but just couldn't help noticing.

Remarkably, the influx of both neutrophils (CD45hi/CD11b+/Ly6Ghi/Ly6Cint) and inflammatory monocytes (CD11b+/CD45hi/Ly6C+/Ly6G−) was observed despite acyclovir treatment and viral clearance (Figure1H). Although neutrophil migration was noted as soon as 6h post-infection, inflammatory monocytes did not increase until 24h post-infection (Figures 1I and 1J)

Cell Reports: Astrocyte- and Neuron-Derived CXCL1 Drives Neutrophil Transmigration and Blood-Brain Barrier Permeability in Viral Encephalitis (2020)
https://www.cell.com/cell-reports/fulltext/S2211-1247(20)31139-6?

I did a very quick google of the 2 molecules investigated in the paper in relation to ME.
Didn't find anything for CXCR2. But CXCL1 has cropped up in past studies (have only glanced at the abstracts):

Cytokine signature associated with disease severity in chronic fatigue syndrome patients; Montoya; 2017

Seventeen cytokines had a statistically significant upward linear trend that correlated with ME/CFS severity: CCL11 (Eotaxin-1), CXCL1 (GROα)

https://pubmed.ncbi.nlm.nih.gov/28760971/

And another one from the same stable: Value of Circulating Cytokine Profiling During Submaximal Exercise Testing in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome, 2018

The most discriminatory cytokines post exercise were CD40L, platelet activator inhibitor, interleukin 1-β, interferon-α and CXCL1.

https://www.nature.com/articles/s41598-018-20941-w
thread here: https://www.s4me.info/threads/value...nic-fatigue-syndrome-2018-montoya-et-al.2345/

And a search on S4ME also brings up this: https://www.s4me.info/threads/the-r...ations-with-symptoms-2019-jonsjö-et-al.13063/