I had suggested that one possibility for the CD8 T cells disappearing from the blood was related to them appearing in the lung. This I don’t think is correct and maybe relates to what is important into why SARS-CoV-2 becomes severe in some people.

The virus infects cells via the angiotensin converting enzyme two and this is found in many tissues such as the gut, which is why you secrete virus from your pooh and also in the lungs which is why you secrete virus when you cough.

From the research published on SARS (Severe Acute Respiratory Syndrome), it is known that CD8 T cells are improtant for removing the virus. It looks like this will be part of the story for COVID-19 virus. But in people with severe problems there is a noticable drop in these cells. If you look in the lung of the people who died with COVID19 there are few CD8 T cells in the lung. Whats the difference?.. Seems the answer is here.

Yep I now have to read Chinese…Thank heavens for Google Translate.

However you don’t need to read Chinese to look at pictures and you can see the cell at the centre of the problem is the macrophage/monocyte.

Zang et al. l https://doi.org/10.7326/L20-0227

This is reporducible and I have seen in two other papers

The good guy or the bad guy…I suspect a bit of both as time matters and what happens in the first week or two is probably key. Sadly this would be the time to get anti-virals, so we are doing the hardest experiment again but treating people once they are hospitalised.

However, remember most MS drugs are not going to touch this element, so your journey could be the same, MS drug or not. I think one will hit this proces soon after delivery and one will probably will target this. The experiment has happened to see if this is a good or bad thing, what will the answer be, it will come out in the MS registries.

However do MS drugs hit CD8 T cells? . The answer is substantially yes for for one, maybe for another and not that much for most. At the moment I think I would like the CD8 T cells to be around. They may be dropping because the COVID-19 virus can get into T cells and whilst they are not going to become virus factories, they can be triggered to commit suicide. The lymph glands are also shrinking due to viral activity. If the CD8 T cells drop too much, it is a bad indicator for severe things to come.

However, it suggests the solution is not simple, but I don’t think the recommendations for MS have taken into account the biology. However, what does the biology mean? As for use of steroids in severe COVID-19 currently being trialled, answers are emerging of the likely outcome. Time will tell.

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  • “However do MS drugs hit CD8 T cells? . The answer is substantially yes for for one, maybe for another and not that much for most”. Please expand on which MS drug hits CD8 cells substantially. For those of us in that drug it will help us determine the extent to which we and our families need to social distance especially in the USA where (misguided) states are starting to open back up

    • Which drug depletes T lymphocytes the best…begins with Alem and ends in Mab..We have done a review and I will post this on-line shortly

  • Would HAVING CoVid19 CAUSE a drop in CD8 (and would that show up as a drop in monocytes in blood serum?)

    I had presumptive coronavirus prior to starting Mavenclad (started about seven days after recovery). Bloodwork 33 days post showed clobbered monocytes. 0.38 down to 0.1 and lymphocytes halved. I’d mentioned this previously as an outcome of treatment.

    I’ve had first official bloodwork and monocytes are recovering well. All markers low normal.

    I’m intrigued by the possibility that it wasn’t Mavenclad that lowered monocytes by almost 80%, but possibly a response to a virus.

    Just a hypothetical question after reading today’s article. I also wonder if you would speak to those taking an ARB or ACE inhibitor (cardiac/bp are high risk) since they also affect the ACE 2 pathway.

    Thank you!

    • In some of the studies there can be a drop in minor monocytes as you kill your lymphocytes you have to clear up the cellular garbage and whilst it is not lytic the apoptotic cells still need removing. However, there is evidence of COVID effects on monocytes, and also on CD8 T cells. Cell numbers drop due to COVID and it is worse with severe COVID the virus hits the macrophage in the lymph glands.

      There are a number of drugs that potentially increase ACE2 including hypertensive agents

      • VERY interesting. So I suspect it was less the Mavenclad than the virus affecting monocytes.

        My various symptoms were spot on – my central sleep apnea while sick increased 28 fold. I was very sick but managed at home.

        Thank you!

        • Glad to here you have recovered make sure yur story goes to a registry and hopefully you can be confirmed as a viral

          • NO way to confirm because only travelers were being tested at the time. My husband brought it home from a conference. Someone there had obviously traveled. Neither of us ever get sick so that alone was strange .. the breathing difficulties were the scary element. Cough and fever.

            Without an actual positive test, no way to register.

            Thank you so much though. This has been super helpful!

    • Yes but whats does it mean if lymphocytes go down the Neutrophil ratio goes up if the neutrophils go up the ratio goes up if one goes up and the other goes down it goes up. I know there is a neutrophila (neutrophils go up) but show me where there are loads in the lung, the histology todate indicates mononuclear infiltrate the neutrophils seem to be less common but sure you can find them. They would go up if you have an infection and the pneumonia is going to cause secondary infections.

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