Interleukin-6: A Versatile Biomarker in the Clinical Chemistry Laboratory in the COVID-19 Era
Published: December 1, 2021 | DOI: https://doi.org/10.7860/JCDR/2021/51061.15713
Surupa Basu
1. Associate Professor and Head, Department of Biochemistry, Institute of Child Health, Kolkata, West Bengal, India.
Correspondence
Dr. Surupa Basu,
11, Dr Biresh Guha Street, Kolkata, West Bengal, India.
E-mail: basusurupa@gmail.com
Introduction: Interleukin-6 (IL-6) is a proinflammatory cytokine released during the cytokine storm of sepsis and Coronavirus Disease-2019 (COVID-19). IL-6 has been extensively used as a biomarker in Severe Acute Respiratory Syndrome Corona Virus 2 (SARS-CoV-2) and in the emerging novel paediatric disease called Paediatric Inflammatory Multisystem Syndrometemporarily associated with SARS-CoV-2 (PIMS-TS) or Multisystem Inflammatory Syndrome in Children (MIS-C). Additionally, IL-6 measurement is necessary to decide for several cytokine-blocking and cytokine-removal therapies and to determine treatment adequacy.
Aim: Evaluation of the performance of IL-6 in COVID-19, PIMSTS/MIS-C and in CytoSorb cytokine removal therapy in sepsis as a versatile biomarker in clinical chemistry laboratory.
Materials and Methods: The study was an exploratory descriptive study carried out between March 2019 and February 2021 for a period of 24 months. IL-6 (pg/mL) was measured on Roche e411 immunoassay platform using Electrochemiluminiscence Assays (ECLIA) in 15 adult patients. Biological reference interval of the parameter was <7 pg/mL.
Results: The results showed that IL-6 was increased significantly in non survivors compared to survivors with COVID-19 (p-value=0.0043). IL-6 levels (normal <7 pg/mL) were highly elevated in children with PIMS-TS {median 75.9 pg/mL (IQR: 47.3-223.4)} reflecting the intense inflammatory state of the novel paediatric condition. All PIMS-TS cases (n=13) survived. IL-6 levels were increased post CytoSorb therapy in sepsis patients who did not survive and declined in survivors. IL-6 serially measured during treatment helped to monitor therapeutic adequacy in prolonged sepsis case.
Conclusion: The various applications of automated IL-6 testing in the clinical chemistry laboratory reflects the versatility of the trending biomarker.
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