Cytokine storms: the time of immune response to new crown pneumonia or exacerbation of the disease.

A recent study, published in the Journal of medical virology in Wiley, led by Professor Weiming yuan and Professor Sean Quan Du of the Keck School of medicine at the University of Southern California, suggests that adverse interactions between two human defense systems (innate and adaptive immune responses) may trigger an immune overreaction.studies have shown that when the body's immune system overreacts to infection, which leads to the so-called "cytokine storm", the infection of sars-cov-2 and even influenza may be fatal.cytokines are small proteins involved in cell signal transduction and help to recruit immune cells to infection sites.in some people, excessive cytokines can cause excessive inflammation in the infected area (such as the lungs in covid-19), causing severe organ damage and death.therefore, it is concluded that temporary suppression of the immune system in the early stages of covid-19 can help to avoid severe symptoms and death.text in their study, Du and Yuan adopted a general mathematical model called "target cell restriction model" to understand how the immune system of patients with covid-19 reacts compared with those with influenza.the incubation period of influenza virus is about 48 hours, during which the virus will target cells on the surface of upper respiratory tract.because the influenza virus moves very quickly, it kills almost all "target cells" within a few days, thus enabling the innate immune system to respond and clear the virus and vulnerable cells, and then trigger the adaptive immune response after a few days to kill any remaining virus, and mobilize the human body's "heavy weapons" - T cells and B cells.different from influenza virus, sars-cov-2 has a longer incubation period (about six days on average), slow invasion of host and infection of cells in the whole respiratory system.the team's model suggests that adaptive immune responses may begin to work before the innate immune system completes its work, eventually interfering with its ability to eliminate initial infections.Yuan said: "the most dangerous thing is that as the infection continues, it will mobilize all levels of the whole adaptive immune response."the longer the virus is active, the more likely it is for the immune system to overreact - a process known as a cytokine storm - that kills healthy cells and causes tissue damage."influenza infection can almost completely deplete the target cells of the virus within a few days, but the slow progress of covid-19 means that the adaptive immune response can be weakened before the infection reaches its peak, thus minimizing the depletion of virus target cells, leaving a large number of uninfected cells for future infections.Figure 1 influenza virus infection in human cells Figure 2 coronavirus infection in human cells the author said in his study: "this situation is similar to a rampant forest fire.if you just wait and see the fire, when all the trees are burned, the fire will lose its fuel and die quickly.if all efforts are made to put out the fire before that, only part of the fire can be controlled.once the fire is stopped, the fire will return until all the trees are destroyed.we believe that this is why many severe patients cannot leave hospital beds and eventually develop into acute respiratory distress syndrome and multiple organ failure."this hypothesis may also provide an explanation for the recurrence of the disease in patients who have been identified as convalescent a few weeks later.Du added: "some patients with covid-19 may relapse after their symptoms are significantly reduced."the combination of adaptive immunity and innate immune response may temporarily reduce the virus to a lower level.however, if the virus is not completely eliminated and the target cells regenerate, the virus will again dominate and reach another peak. Therefore, the authors suggest that immunosuppressants should be used in the early stage of infection to reduce the interference of adaptive immunity.based on the results of the mathematical model, we propose an counterintuitive idea that short-term immunosuppressive drugs may improve the prognosis of patients in the early stages of the disease process, "Du said." with the right inhibitors, we may be able to delay adaptive immune responses and prevent them from interfering with innate immune responses, thus eliminating viruses and infections more quickly Cells."the next work will involve testing the hypothesis and testing the daily viral load and other biomarkers of covid-19 patients.original link: