Histopathological findings in the nasal mucosa of COVID-19 patients: (A,B)—lymphocytic inflammation in the lamina propria, regardless of the absence ((A), HE ob. 10×) or presence ((B), HE ob. 20×) of squamous metaplasia; (C,D)—squamous metaplasia accompanied by a viral cytopathic effect in the hyperplastic basal layer (arrows) (HE ob. 20×); (E)—multinucleated giant cells (white arrows), prominent eosinophilic nuclear inclusion (black arrows) with cytomegaly, and some cells in induced necrobiosis (*) with nuclear lysis (HE ob. 40×); (F)—similar effect in alveolar macrophages in COVID-19 pneumonia (personal collection) (HE ob. 40×).