Commentary: Role of Tocilizumab in Hospitalized COVID-19 Patients: A Pragmatic Guide for Clinicians

Abstract

COVID-19 caused by severe acute respiratory syndromecoronavirus 2(SARS-CoV2) has resulted in many deaths worldwide. The pathophysiology of COVID-19 involves an initial mild viremic phase, followed by a pulmonary phase and then hyperinflammatory phase1. The hyperinflammatory phase involves a dysregulated immune response and is associated with ‘hypercytokinemia’. A recent review by Datta et al.2 suggested that several cytokines and chemokines may be involved in COVID-19 such as IL-1β, IL-2, IL-6, IL-7, IL-8, IL-17, IL-18, IL-33, GM-CSF, monocyte chemoattractant protein-1 (MCP-1), interferon-γ, inducible protein 10 (IP-10), macrophage inflammatory protein-1α (MIP-1α), tumor necrosis factor-α (TNF-α) and transforming growth factor-β (TGF-β). IL-6 plays a central role by promoting proliferation of myeloid precursor cells, growth and activation of leucocytes and synthesis of C reactive proteins. It also causes suppression of T-lymphocytes, dendritic cells, and macrophages, resulting in decreased ability of the immune system to clear SARS-CoV2. Our publication further elaborates on the efficacy of specific IL-6 inhibitors such as tocilizumab in COVID-19 patients based on recent randomized controlled trials (RCTs) and pragmatic guidelines for its use.