The infection of alveolar epithelial cells and endothelial cells with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) triggers an inflammatory response at the blood–gas barrier, inducing the release of IL-1β, interleukin-6 (IL-6), and tumor necrosis factor-α (TGF-α), leading to the disintegration and thickening of the blood–gas barrier [33]. The gene discussed is TNF; the disease is infection.