IFNG and COVID-19: For instance, infection of human iPSCs-derived BECs with SARS-CoV-2 did not affect barrier properties but upregulated IFN-γ signaling, and these results were consistent with histopathological studies showing upregulated IFN-γ pathway in COVID-19 human neurovascular unit.23 Finally, BBB can selectively transport several proinflammatory cytokines from the peripheral circulation into the brain parenchyma and promote secondary BBB injury.37 In the future, a systematic comparison of molecular responses between BECs exposed to COVID-19 and control plasma may resolve this issue.