Severe courses of CoV are more likely to be caused by an immune reaction than by direct destruction of the alveoli. This shows a new study.
According to a new study by the Berlin Charité, the Covid 19 pathogen can only infect human alveoli cells directly to a very limited extent. A research group reached this conclusion after successfully simulating a CoV infection in human lungs.
Simulation on live laboratory-cultured lung samples therefore yielded important insights into the mechanism of infection. The researchers found that the viruses infect only a very few epithelial cells that line the surface of the alveoli. As a result, they do only very little direct tissue damage. Most viruses that reach the lungs, on the other hand, are absorbed directly by macrophages – cells of the innate immune system. In these, it triggers a targeted immune activation.
How the coronavirus destroys the lungs
Lung damage most likely due to immune reaction
“Our study suggests that the severe lung damage in Covid-19 is due to immune activation triggered by macrophages, rather than the direct destruction of alveoli by the virus,” said research team leader Andreas Hocke. The research thus makes a significant contribution to the understanding of the development of Covid-19 in the initial phase of a possible pneumonia.
It also shows why SARS-CoV-2, in contrast to MERS coronaviruses, has a rather moderate course in most cases. It can be assumed that local immunological mechanisms in the respiratory tissue eliminate SARS-CoV-2 viruses very efficiently in the vast majority of cases and limit the inflammatory reaction.
“If it doesn’t, which can be influenced by individual risk factors, serious and fatal strokes can occur in rare cases,” Hocke said. Subsequent work will therefore focus on the influence of general risk factors such as age, sex, concomitant illnesses and other medications.
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