IL6 and COVID-19: Hypoxic respiratory failure in patients with COVID-19 is associated with evidence of systemic inflammation, including release of pro-inflammatory cytokines, such as interleukin (IL)-1, IL-6, and tumour necrosis factor α, and elevated concentrations of D-dimer, ferritin, and C-reactive protein (CRP).3, 4 The host immune response is thought to play a key role in driving an acute inflammatory pneumonic process with diffuse alveolar damage, myeloid cell infiltrates, and microvascular thrombosis.5