CCL3 and idiopathic pulmonary fibrosis: Among immune cells, alveolar macrophages (Mph) CCL3+ showed heterogeneity in their association with COVID-19 (FDR = 0.010), whereas proliferating alveolar macrophages exhibited heterogeneous associations with IFA, IPF, and PAH (FDRIFA = 0.020, FDRIPF = 0.047, FDRPAH = 0.034, Figure 1).