The Role of Inflammatory Cytokines (Interleukin-1 and Interleukin-6) as a Potential Biomarker in the Different Stages of COVID-19 (Mild, Severe, and Critical)

Abstract

Cytokine storm refers to the overproduction of immune and inflammatory cells and their proteins (cytokines) [interleukin (IL)-1 and IL-6] causing acute respiratory distress syndrome in COVID-19. COVID-19 causes inflammatory reactions, and patients with COVID-19 had categorized as mild, severe, and critical after reviewing previous studies. Then, it is crucial to find immune-inflammatory indicators that might predict the disorder severity and the prognosis primarily for guiding medical therapy in the face of this unexpectedly developing unique infectious disease. Higher levels of IL-6 and IL-1 levels might be seen in patients with COVID-19 at each stage. In addition, IL-1-induced IL-6 assists in the synthesis of liver C-reactive protein (CRP) in acute phase responses. Recent studies suggested that IL-6 levels are an independent predictor of COVID-19 illness because they were significantly higher in patients with severe than with mild COVID-19 symptoms. Anakinra and tocilizumab (TCZ) are beneficial in lowing mortality in COVID-19 patients; however, information on their safety and efficacy is scarce. The aim of this study was to investigate the role of inflammatory cytokines (IL-1 and IL-6) as potential biomarkers in the different stages (mild, severe, and critical) of COVID-19. A systematic search during the years 2021-2022 using the keywords SARS-CoV-2, COVID-19, IL-6, IL-1, CRP, mild stage, severe stage, critical stage, cytokine storm, tocilizumab, and anakinra was performed in PubMed and Google Scholar databases. This study reviews studies that have investigated the role of high levels of these cytokines in the severity of the disease in patients with COVID-19 and the inhibitory function of TCZ and anakinra in preventing mechanical ventilation and patient mortality. According to the result, studies suggest that decreased innate immune response against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in association with the production of inflammatory cytokines is the determining and driving function of COVID-19.

Keywords: COVID-19; CRP cytokine storm; IL-1; IL-6; SARS-CoV-2; anakinra; tocilizumab.