Nasal macrophages had several differentially expressed (DE) genes in patients with COVID-19 versus patients with LRTD that mirrored alveolar macrophage responses (SPP1, LGALS1 and TMSB10), including IFN-γ response genes (HLA-DPB1, HLA-DQA1 and C1QB) (Fig. 5c). This evidence concerns the gene HLA-DPB1 and COVID-19.