IL‐6 at the center of cytokine storm: Circulating inflammation mediators as biomarkers in hospitalized COVID‐19 patients

INTRODUCTION: The management of hospitalized COVID‐19 patients depends largely on controlling the intensified inflammatory response known as the cytokine storm. Candidate inflammatory cytokines can serve as new biomarkers for the management of hospitalized COVID‐19 patients. METHODS: Patients (80) were recruited into three groups: room air (RA), oxygen (OX) and mechanical ventilator (MV). Blood analysis was performed for RBC, WBC, Hb, Platelets, serum albumin and creatinine, INR, PTT, and hematocrit. ELISA was used to quantify a panel of inflammatory mediators including GM‐SCF, IFN‐α, IFNγ, IL‐1β, IL‐1R, IL‐2, IL‐2Ra, IL‐6, IL‐8, IL‐10, IL‐12p70, IL‐13, MCP‐1, MIP‐1a, and TNF‐α. Correlations between laboratory results and the levels of circulating inflammation mediators were investigated. RESULTS: Patients on MV had low RBC, Hb, albumin, and HCT and high WBC count, PTT, and INR when compared to RA and OX groups. A statistical positive correlation was found between WBC and the levels of IL‐6 and MCP‐1. RBCs correlated negatively with IL‐6 and IL‐10 and positively with IL‐8. Higher TNF‐α correlated with lower platelet counts while higher levels of IL‐1Rα and IL‐10 were associated with lower Hb levels. Increases in IFN‐γ and TNF‐α were indicative of compromised kidney functions as creatinine levels increased significantly. Most significant correlations were found between IL‐6 and lab results, showing positive correlation with WBC and INR, and negative correlation with RBC, albumin, and HCT. CONCLUSIONS: Having the most significant correlations, IL‐6 high levels in mechanically ventilated patients were shown to affect laboratory results, and, therefore, is suggested as a severity biomarker of COVID‐19.