Cytokine profile in SARS-CoV-2 infection and the effect of tocilizumab and convalescent plasma therapy

COVID-19 is an infectious disease caused by the SARS-CoV-2 virus. It mainly affects the respiratory tract, but due to the production of a wide range of cytokines it can exert severe effects on the entire human body. Our aim was to determine the alterations in cytokine profile among COVID-19 patients at intensive care unit. We enrolled 126 patients with COVID-19 and measured the concentration of 20 cytokines with Magpix Luminex Xmap (Merck). We compared the results between patients who recovered from COVID-19 disease to subjects who passed away. Furthermore, cytokine levels were compared among patients who received IL-6 receptor inhibitor tocilizumab or the convalescent plasma therapy vs. those who received neither intervention.Wefound higher IL-6, IL-8, IL-10, IL-15, MCP-1 and TNF-α levels in patients who passed away compared to those who recovered (median [quartile] pg/mL;36.1 [3.2-90.5] vs. 120.2 [24.3-440.0], 22.9 [18.5-34.9] vs. 43.3 [24.8-74.3], 15.7 [2.6-53.8] vs. 65.6 [19.9-241.0], 13.1 [8.2-19.3] vs. 19.0 [10.5-36.3], 569.8 [367.0-903.0] vs. 918.5 [628.1-2029.0], 31.7 [20.5-49.5] vs. 44.4 [28.5-75.2], respectively, p<0.001). In addition, IL-8 and IL-10 levels were higher under plasma therapy compared to tocilizumab administration (44.7 [28.7-72.0] vs. 23.7 [20.0-37.7] and 75.4 [38.8-360.3] vs. 15.7 [2.6-42.9] pg/mL), respectively, while IL-10 was also higher without any of these therapies compared to tocilizumab treatment (48.4 [9.8-114.8] vs. 15.7 [2.6-42.9] pg/mL). In conclusion, high cytokine levels represent a major mortality risk in COVID-19 disease and while tocilizumab has some effect on cytokine profile, a higher level of inhibition is needed to effectively reduce the cytokine storm during intensive care unit therapy.