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Accurate and Simple Measurement of the Pro-inflammatory Cytokine IL-1β using a Whole Blood Stimulation Assay
Published on: March 1, 2011
Serum interleukin-6 is an indicator for severity in 901 patients with SARS-CoV-2 infection: a cohort study
Jing Zhang1, Yiqun Hao2, Wuling Ou1
1Department of Medical Oncology, Hubei Cancer Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430079, Hubei, China.
Background:
Interleukin-6 (IL-6) was proposed to be associated with the severity of coronavirus disease 2019 (COVID-19). The present study aimed to explore the kinetics of IL-6 levels, validate this association in COVID-19 patients, and report preliminary data on the efficacy of IL-6 receptor blockade.
Methods:
We conducted a retrospective single-institutional study of 901 consecutive confirmed cases. Serum IL-6 concentrations were tested on admission and/or during hospital stay. Tocilizumab was given to 16 patients with elevated IL-6 concentration.
Results:
366 patients were defined as common cases, 411 patients as severe, and 124 patients as critical according to the Chinese guideline on diagnosis and treatment of COVID-19. The median concentration of IL-6 was < 1.5 pg/ml (IQR < 1.50-2.15), 1.85 pg/ml (IQR < 1.50-5.21), and 21.55 pg/ml (IQR 6.47-94.66) for the common, severe, and critical groups respectively (P < 0.001). The follow-up kinetics revealed serum IL-6 remained high in critical patients even when cured. An IL-6 concentration higher than 37.65 pg/ml was predictive of in-hospital death (AUC 0.97 [95% CI 0.95-0.99], P < 0.001) with a sensitivity of 91.7% and a specificity of 95.7%. In the 16 patients who received tocilizumab, IL-6 concentrations were significantly increased after administration, and survival outcome was not significantly different from that of propensity-score matched counterparts (n = 53, P = 0.12).
Conclusion:
Serum IL-6 should be included in diagnostic work-up to stratify disease severity, but the benefit of tocilizumab needs further confirmation. Trial registration retrospectively registered.
