AGT and viral infectious disease: Rajaiya et al. revealed that during viral infection, Hsp27 proves essential for p38 MAPK-mediated proinflammatory cytokine expression in host cells [50,51], and the activation of PDGFR β signaling facilitates viral entry during influenza infection [41], which may also apply during COVID-19 infections in the presence of comorbidities related to Ang II elevation.