Safety and Efficacy of Tocilizumab in critically ill patients with COVID-19: An Observational study

Abstract

he current coronavirus disease 2019 (COVID-19) outbreak is a worldwide emergency, as its rapid spread and high mortality rate has caused severe disruptions. The number of people infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV 2), the causative agent of COVID-19, is rapidly increasing worldwide. Patients with COVID-19 can develop pneumonia, (Zhu et al., 2019; Huang et al., 2020). Severe symptoms of acute respiratory distress syndrome (ARDS), and multiple organ failure (Haung et al., 2020; Wang et al., 2020). Increasing evidence shows that immune patterns are closely associated with disease progression of patients infected with viruses. A decrease in peripheral T cell subsets is a unique characteristic in patients with severe acute respiratory syndrome (SARS) (Li et al., 2004). In recovered patients, a rapid restoration of peripheral T cell subsets is detected; thus, peripheral T cell number can serve as an accurate diagnostic tool for SARS (Li et al., 2004). A similar phenomenon was also reported in another study, where the immune system was found impaired during SARS (Cui et al., 2003). In another study, natural killer (NK) cell number was found decreased in patients with Ebola compared with healthy donors (Cimini et al., 2017). Proinflammatory cytokines were elevated after Ebola virus disease symptom onset, whereas recovered patients showed low cytokine levels (Reynard et al., 2019). With the unraveling of the relationship between immune responses and COVID-19, immune characteristics are now being recognized as potential biomarkers for disease progression as well as potential therapeutic targets for COVID-19. In this review, we summarize the immune characteristics of COVID-19 and discuss the potential mechanisms of SARS-CoV-2-induced immune changes, their effect on disease out.