Examination of single-cell data from bronchoalveolar lavage fluid (BALF) samples (18) confirmed an increase in IFNG expression in T and NK cells in patients with COVID-19 relative to healthy control tissue, along with increased expression of CXCL9, CXCL10, CXCL11, and BAFF in myeloid cells and neutrophils (Figure 5A). Here, CXCL9 is linked to COVID-19.