Thread by @GANyborg

So it's clear:
SARS-CoV-2 infects T lymphocytes, preferably activated CD4+ cells in vitro, independently of the ACE2 receptor and induces pronounced programmed cell death potentially contributing to the lymphopenia seen in ~80% of hospitalized C19 patients nature.com/articles/s4139…

Among those tested in this study, after SARS-CoV-2 infection "CD4+ and CD8+ T lymphocytes almost declined to zero in some patients", while B and NK cells were unaffected. Technically: Both Jurkat and M4 cell lines were infected in vitro.

Several recent studies have found SARS-CoV-2 infects several immune cell populations: neutrophils, macrophages, monocytes, plasma B cells, T cells, and NK cells. Here, monocytes were infected independently of ACE2, leading to massive cell death: nature.com/articles/s4158…

Question: What are the long term implications for human health?
Here is @Forbes take on the paper in OP⬆️: "As research continues to develop, it will be interesting to discover exactly how this virus attacks and dismantles one of our key defense systems" forbes.com/sites/williamh…

@Forbes Authorities should be aware of this.
We still don't know the long term impact of this virus for human health. Evidence so far & experience from those affected by SARS1 point to serious long term effects. It would be wise to prevent transmission until new vaccines/more knowledge.

What happens over time, and what does this mean?
Here, "Five of 35 cases (14%) had Lymphopenia in the later follow-up range of 80–102 days... subgroup analyses showed that patients with lymphopenia experienced more frequently persistent symptoms"
nature.com/articles/s4159…

Here too CD4+ lymphopenia persisted over some time: A decrease in CD4+ T cells "was observed in 60% (9/15), 60% (9/15), and 46.7% (7/15) of total patients at 0, 8, and 16 weeks after discharge, respectively"

jtd.amegroups.com/article/view/5…

"Based on our knowledge of HIV pathophysiology, we hypothesized that SARS-CoV-2 infection-mediated lymphopenia could also be related to T cell apoptosis"
If T cells can be infected by SARS-CoV-2 in vivo, leading to apoptosis, this can explain the findings
nature.com/articles/s4141…

Here, they found lung-resident macrophages (another immune cell population) were infected by SARS-CoV-2, leading to massive death of these macrophages through pyroptosis. The cells dying prevented further replication of the virus in those cells nature.com/articles/s4158…

Early in the pandemic, an article reporting infection of Jurkat T cells was retracted due to methodological issues. In the OP, this finding is replicated. Still much is unknown, but in sum, it is clear that SARSCoV2 can lead to substantial disturbances in immune cell populations.

🧵recap:
Several studies have found that the virus causing COVID can infect different cell types in our immune system & many of these cells then die. This may theoretically lead to immune dysfunction/imbalance. It's too early to know the clinical effects from this now& in future.