CD8A and COVID-19: A recent study using single-cell RNA sequencing (scRNA-seq) of bronchoalveolar lavage fluid (BALF) samples revealed that BALFs from patients with severe symptoms had more proinflammatory monocyte-derived macrophages, higher levels of inflammatory cytokines (IL8, IL6, and IL1B), and less clonally expanded CD8+ T cells than that from the moderate cases, suggesting that cytokine storm is associated with severity of COVID-19 (Liao et al., 2020).