Evaluation of Interleukin 6 Levels in Severe COVID-19 Patients

Abstract

Objectives: Interleukin 6 (IL-6) plays a leading role in the proliferation and differentiation of immune cells. Level of IL-6 is manifestly increased under many inflammatory conditions, including cytokine release syndrome. We evaluated the IL-6 levels of patients who were hospitalized with the diagnosis of COVID-19.
 Methods: In the study, the test results of 19 cases whose IL-6 levels were measured between March 11, 2020 and May 31, 2020 retrospectively. The inpatients in the covid service (Group 1) and the patients admitted to the Intensive Care Unit (ICU) of our hospital (Group 2) were compared and evaluated. In addition, patients with positive and negative RT-PCR test results were checked for IL-6.
 Results: While 8 (Group 1) of 19 patients observed in the clinic were transferred to the ICU, 11 patients (Group 2) were observed in the covid service until their discharge. Group 1 IL-6 levels (median 34 pg/mL) and Group 2 IL-6 levels (median 116 pg/mL) were found to be high in both groups (p = 0,099). However, it was found to be significantly higher in patients with positive COVID-19 RT-PCR test (median 90.60 pg/mL) than in negative patients (median 29.90 pg/mL) (p = 0.018).
 Conclusion: No significant difference in IL-6 levels between the patients who were monitored in the clinic and transferred to the ICU was found in this study. The significant difference between IL-6 levels among COVID-19 RT-PCR positive and negative patients reveals the importance of IL-6 level with regard to tocilizumab treatment in COVID-19 patients in cytokine storm.
 Keywords: COVID-19, Interleukin 6, Cytokine Storm, Macrophage Activation Syndrome