Selection of the Appropriate Control Group Is Essential in Evaluating the Cytokine Storm in COVID-19

Cytokine levels in critically-ill COVID-19 and non-COVID-19 patients. IL-6 (A), IL-8 (B), IL-10 (C), and TNF-α (D) were measured on ICU admission in 36 critically-ill COVID-19 patients and 30 critically-ill non-COVID-19 patients. Two-group comparisons were performed using the non-parametric Mann-Whitney test for skewed data. Data are presented as scatter plots showing median and interquartile range. Line in the middle, median value; upper and lower lines, 25th to 75th centiles. *p<0.05, **p<0.01, ****p<0.0001. COVID-19: Coronavirus disease 19, IL: Interleukin, TNF-α: tumour necrosis factor-α.