Interleukin-10 is an anti-inflammatory cytokine that curbs IL-6, TNF-alpha, and IL-8 pro-inflammatory activity.[I]
Research suggests that it is instrumental in controlling autoimmunity and angiogenesis,[ii] resolving inflammation, and healing wounds.[iii] IL-10 is also the “most widely studied anti-inflammatory and pro-resolution cytokine” in acute ARDS.[iv]
During a cytokine storm, IL-10 induces an “immunoparalysis” that downregulates the function of neutrophils and monocytes. Short-term immunoparalysis may be beneficial but prolonged immunosuppression may contribute to mortality even in those who survive the initial cytokine storm.[v]
Research suggests that evaluating the ratio of IL-6 to IL-10 may be more clinically useful than measuring either cytokine alone.
Evaluation of the IL-6 to IL-10 ratio has been used to predict the severity of injury in trauma patients. Early IL-6:IL-10 ratio of 3.11 correlated significantly with severity of injury and APACHI II scores.[vii]
Calculation of the ratio of IL-6:IL-10 was integrated into the “Dublin-Boston score” used to determine the severity of infection for hospitalized COVID-19 patients. Both the day four change in IL-6:IL-10 ratio as well as the linear Dublin-Boston score were more valuable in predicting clinical outcome at day seven than measuring IL-6 alone. Each 0.1 unit increase in IL-6:IL-10 ratio day 1-4 increased the odds of a more severe clinical outcome.[viii]
Circulating cytokines reflect the underlying inflammatory battle that occurs with COVID-19. Failure to establish balanced cytokine profiles can lead to increased morbidity and mortality.
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[i] Rea, Irene Maeve et al. “Age and Age-Related Diseases: Role of Inflammation Triggers and Cytokines.” Frontiers in immunology vol. 9 586. 9 Apr. 2018, doi:10.3389/fimmu.2018.00586
[ii] Labcorp. Serum IL-10.
[iii] Burmeister, Amanda R, and Ian Marriott. “The Interleukin-10 Family of Cytokines and Their Role in the CNS.” Frontiers in cellular neuroscience vol. 12 458. 27 Nov. 2018, doi:10.3389/fncel.2018.00458
[iv] McElvaney, Oliver J et al. “A linear prognostic score based on the ratio of interleukin-6 to interleukin-10 predicts outcomes in COVID-19.” EBioMedicine, vol. 61 103026. 8 Oct. 2020, doi:10.1016/j.ebiom.2020.103026 [R]
[v] Tisoncik, Jennifer R et al. “Into the eye of the cytokine storm.” Microbiology and molecular biology reviews : MMBR vol. 76,1 (2012): 16-32. doi:10.1128/MMBR.05015-11
[vi] Labcorp. Serum IL-10.
[vii] Taniguchi, T et al. “The ratio of interleukin-6 to interleukin-10 correlates with severity in patients with chest and abdominal trauma.” The American journal of emergency medicine vol. 17,6 (1999): 548-51. doi:10.1016/s0735-6757(99)90194-8
[viii] McElvaney, Oliver J et al. “A linear prognostic score based on the ratio of interleukin-6 to interleukin-10 predicts outcomes in COVID-19.” EBioMedicine, vol. 61 103026. 8 Oct. 2020, doi:10.1016/j.ebiom.2020.103026