Circulating activated neutrophils in COVID-19: an independent predictor for mechanical ventilation and death

Dennison, David; Khabori, Murtadha Al; Mamari, Sahimah Al; Aurelio, Allan; Hinai, Houda Al; Maamari, Khuloud Al; AlShekaili, Jalila; Khadouri, Ghalib Al

Objectives Critical illness in COVID-19 is attributed to an exaggerated host immune response. Since neutrophils are the major component of innate immunity, we hypothesize that the quantum of activated neutrophils in the blood may predict adverse outcome. Design In a retrospective study of 300 Omani adult patients with confirmed COVID-19, we analyzed the impact of neutrophil activation (NEUT-RI), interleukin-6 (IL-6) and the established clinical risk factors of age, diabetes, obesity and hypertension on the clinical outcome. Results Significant predictors of the need for mechanical ventilation were NEUT-RI (OR = 1.22, p < 0.001), diabetes (OR = 2.56, p = 0.00846) and obesity (OR 6.55, p < 0.001). For death, the significant predictors were NEUT-RI (OR = 1.14, p = 0.00432), diabetes (OR = 4.11, p = 0.00185) and age (OR = 1.04, p = 0.00896). The optimal cut-off value for NEUT-RI to predict mechanical ventilation and death was 52 FI (sensitivity 44%, specificity 88%, AUC 0.67 and 44%, 86%, AUC 0.64 respectively). Conclusion This finding supports an aberrant neutrophil response in COVID-19, likely due to uncontained viral replication, tissue hypoxia and exacerbated inflammation, introduces a novel biomarker for rapid monitoring, and opens new avenues for therapeutic strategies.