The findings of a preliminary analysis suggest that coronavirus disease 2019 (COVID-19) may not be characterized by cytokine storm and therefore the benefit of anticytokine therapies remains to be determined, according to a research letter published in JAMA.1
An abnormally strong proinflammatory response known as “cytokine storm” may play an important role in the pathophysiology of COVID-19, although to what extent is unclear.1 Previous data demonstrated that although interleukin (IL)-6 levels are elevated in severe COVID-19, they are lower than levels usually observed in non-COVID-19 acute respiratory distress syndrome (ARDS).2
Therefore, researchers compared cytokine levels in critically ill patients with COVID-19 with levels in patients with other critical illnesses who were admitted to the intensive care unit of Radboud University Medical Center.1 There were 46 patients with COVID-19 with ARDS, 51 with septic shock with ARDS, 15 with septic shock without ARDS, 30 with out-of-hospital cardiac arrest (OHCA), and 62 with multiple traumas. In COVID-19, cardiovascular insufficiency was more common, overall disease severity and leukocyte counts were lower, and lung injury was more severe compared with the other groups.
Results demonstrated that levels of all 3 cytokines were significantly lower in patients with COVID-19 than in patients with septic shock with ARDS. Patients with COVID-19 also displayed significantly lower IL-6 and IL-8 concentrations compared with patients with septic shock without ARDS. Tumor necrosis factor levels in patients with COVID-19 were higher than those in trauma patients, whereas no differences between patients with COVID-19 and OHCA or trauma were present for IL-6. Lower concentrations of IL-8 were found in patients with COVID-19 compared with patients with OHCA, while no differences compared with the trauma group were observed.
“In this study, critically ill patients with COVID-19 with ARDS had circulating cytokine levels that were lower compared with patients with bacterial sepsis and similar to other critically ill patients,” the authors concluded.1
1. Kox M, Waalders NJB, Kooistra EJ, Gerretsen J, Pickkers P. Cytokine levels in critically ill patients with COVID-19 and other conditions. Research letter. JAMA. Published online September 3, 2020. doi:10.1001/jama.2020.17052
2. Sinha P, Matthay MA, Calfee CS. Is a “cytokine storm” relevant to COVID-19? Editorial. JAMA Intern Med. 2020;180(9);1152-1154.