Contrary to what scientists suggested, Covid-19 does not seem to trigger a “cytokine storm”, this unsuitable immune system response which can be fatal to patients.
- Contrary to what previous work suggested, Covid-19 does not seem to trigger an exacerbated immune system response called a “cytokine storm”.
- Research shows that the cytokine levels of patients admitted to intensive care for Covid-19 infection are similar to those admitted after trauma or cardiac arrest.
Is Covid-19 aggravated by what scientists call “cytokine storm”, a violent inflammatory response of the immune system which can, in some cases, prove fatal?
While last April, a study conducted by researchers from University College London Hospitals (United Kingdom), suggested that a majority of patients who developed a severe form of Covid-19 were also affected by shock syndrome. cytokine, new work from Radboud University (Netherlands) published in the journal JAMA, show on the contrary that Covid-19 is not characterized by a cytokine storm. According to its authors, this could have consequences for the treatment of patients.
When the immune system goes into overdrive
A cytokine storm is characterized by an excessive production of cytokines triggered by an extremely virulent pathogen and manifested by a violent inflammatory response of the immune system.
Cytokines are polypeptide molecules – notably secreted by cells such as lymphocytes and macrophages and which are involved in the regulation of immune responses. They are released by the body when attacked by a pathogen. But sometimes the immune system “goes crazy” by secreting too many cytokines, which then create lesions in the tissues. This maladaptive immune response is particularly novel and prove fatal.
In the case of Covid-19, previous studies established the hypothesis that the cytokine storm contributed to the severity of the disease. This new work shows that this is not always the case.
No more cytokines than in cardiac arrest
To reach this conclusion, researchers from Radboud University Medical Center’s intensive care department measured the concentration of three essential cytokines in the blood of patients admitted to intensive care with several distinct conditions: some had Covid-19, d Others suffered from severe acute respiratory infection, bacterial septic shock (with or without severe acute respiratory infection), and finally others were admitted patients after cardiac arrest or severe trauma. Cytokine levels were measured using the same methods for each of the patient groups.
Among these five groups of patients, the level of cytokines was found to be significantly lower in patients with Covid-19 than those with septic shock or severe acute respiratory infection. Compared to patients in septic shock without respiratory infection, therefore without serious lung disease, patients with Covid-19 also had significantly lower levels of cytokines.
In reality, “Cytokine concentrations in Covid-19 patients were similar to those in intensive care patients who had suffered trauma or cardiac arrest, conditions that are not scored for cytokine storm”explains the co-author of the work Matthijs Kox.
For Peter Pickkers, Professor of Critical Care Medicine, “The severe disease observed in critically ill patients with Covid-19 is therefore not explained by strongly elevated levels of inflammatory proteins in the blood. This means that critically ill patients with Covid-19 are unlikely to benefit from specific anticytokine therapies”.
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