In a more progressive stage of the disease, the continued injury of alveolar epithelial cells caused by interactions between the airway epithelium and activated immune cells is followed by an overproduction of IL-33, promoting lung inflammation through the production of many innate pro-inflammatory cytokines, such as IL-1 β, IL-6, TNF-α, IL-12 and IL-23 in several target cells, causing the most severe forms of COVID-19 [40]. Here, IL6 is linked to COVID-19.