SPP1 and COVID-19: These findings are consistent with our previous analyses where nonalveolar macrophages expressing CMKLR1 in COVID-19 lungs also expressed FOLR2-Mφ features like LYVE1 and F13A1 (16) (Fig. 1D) and how CMKLR1 expression was observed highest among FOLR2+ and SPP1+ interstitial macrophage in patients with cystic fibrosis (16).