Researchers at Radboud University Medical Center said in their study published in the journal JAMA that the novel coronavirus is not characterised by a cytokine storm.
Cytokine is an inflammatory protein that plays a significant role during the immune response. If the immune response is aggressive, it creates cytokine storms.
In earlier studies, including a study conducted by Japanese researchers, cytokine storms lead to inflammation and make Covid-19 patients severely ill.
Researchers of the new study measured the concentration of three essential cytokines in the blood of patients admitted to the ICU with several distinct conditions.
This was done in patients with Covid-19 who met the criteria for a severe acute respiratory infection (ARDS), patients with bacterial septic shock (with and without ARDS), and patients who had been admitted to the ICU after a cardiac arrest or severe trauma.
The cytokines were measured using the same methods for each of the groups of patients, the study added.
Researcher Matthijs Kox said in a statement: “The level of cytokines was significantly less elevated in Covid-19 patients than in patients with septic shock and ARDS. Compared to patients with septic shock without ARDS.”
He added: “So without the severe pulmonary disease, patients with Covid-19 also displayed markedly lower levels of IL-6 and IL-8 (two distinct groups of cytokines). The cytokine concentrations in Covid-19 patients were similar to those in IC patients with trauma or cardiac arrest, conditions that are not noted for a cytokine storm.”
The researchers concluded that Covid-19 is not characterised by a cytokine storm.
Peter Pickkers, Professor of Intensive Care Medicine, said in an official statement: “The severe disease observed in critically ill Covid-19 patients is therefore not explained by strongly elevated levels of inflammatory proteins in the blood. This means that critically ill Covid-19 patients may not benefit from specific anti-cytokine therapies.”