ENPP2 and COVID-19: Increased ENPP2 expression was also detected in all lung DCs (Figure 5E), while comparative analysis (Venn diagrams Figure 5F) highlighted two genes upregulated in ENPP2+ COVID-19 DCs, transmembrane protein 176B (TMEM176B) and CD1a, that have been both proposed as DC differentiation and/or maturation markers [39,40,41,42,43], suggesting that ENPP2 expression may modulate DC homeostasis.