Interleukin is a type of cytokine produced by and acting on a variety of cells. Interleukin 6 (Interleukin 6, abbreviated IL-6) is an important member of the cytokine network, and it has been widely used in many clinical fields. PCT has been widely recognized clinically in differential diagnosis of bacterial infection, risk stratification of sepsis and guidance of antibiotic use. IL-6 is an important cytokine expressed in the initial response of the innate immune system to injury and infection, and plays an important role in the early diagnosis of acute infection. IL-6 combined with PCT has complementary advantages, improves detection sensitivity and specificity, and better facilitates the management of the whole course of sepsis. IL-6 is also one of the important monitoring indicators during the diagnosis and treatment of COVID-19.

IL-6 is used for early warning of sepsis

After the occurrence of inflammation, IL-6 is the first inflammatory marker. IL-6 will be involved in the occurrence and development of many diseases, and its blood level is closely related to inflammation, viral infection and autoimmune diseases, and its changes are earlier than CRP and PCT. Studies have shown that IL-6 increases rapidly after bacterial infection, PCT increases after 2h, and CRP increases rapidly after 6h [1]. So IL-6 can be used for early warning of sepsis.

IL-6 is used to evaluate the prognosis of sepsis

Studies have shown that the high IL-6 concentration during the treatment of sepsis indicates the poor prognosis of patients and the higher mortality rate at the later stage of treatment. The expert consensus on the interpretation of the clinical significance of infection-related biomarkers mentioned that IL-6> at 1000 pg/mL suggests a poor prognosis. Therefore, the detection of IL-6 is also of great significance for the prognosis assessment of sepsis.

Application of IL-6 in COVID-19

a) Key laboratory indicators for COVID-19 patient assessment

b) IL-6 levels in 99 confirmed COVID-19 patients

Figure (a) In a retrospective multicentric study of 150 confirmed COVID-19 cases, IL-6 in the deceased patients was significantly higher than that in other cases [2].

Figure (b) In a study of 99 patients published in the January 29 Lancet, IL-6 was significantly elevated in more than half of the 52 percent of patients. Many patients were complicated with organ function impairment, including 17 cases complicated with acute respiratory distress syndrome and 8 cases complicated with acute respiratory injury [3].

Assist in guiding clinical selection of appropriate treatment strategies

Patients with severe COVID-19 were associated with significantly elevated IL-6. These results suggest that anti-IL-6 mAb could theoretically be used for the treatment of cytokine storm caused by 2019-nCoV infection. There are currently clinical trials evaluating the efficacy and safety of IL-6 in COVID-19 therapy. [4]

Biotime offers both procalcitonin (PCT) and interleukin-6 (IL-6) kits directly. Biotime IL-6+PCT combined detection solutions, Test report issued in 15 minutes, against time, comprehensive detection, to help the rapid diagnosis.

[1] Konrad Reinhart, Michael Meisner, Frank M. Brunkhorst. Markers for Sepsis Diagnosis: What is Useful? Crit Care Clin , 2006,22:503–519

[2] Ruan Qiurong, Yang Kun, Wang Wenxia, et al. Correction to: Clinical predictors of mortality due to COVID-19 based on an analysis of data of 150 patients. 2020, 46(6):1294-1297.

[3] Nanshan Chen, Min Zhou, Xuan Dong, et al. Epidemiological and clinical characteristics of 99 cases of 2019 novel coronavirus pneumonia: a descriptive study. 2020.

[4] Aberrant pathogenic GM-CSF+ T cells and inflammatory CD14+CD16+ monocytes 2 in severe pulmonary syndrome patients of a new coronavirus