CARS2 and influenza: For example, we found that influenza infection increased various biomarkers of oxidative (nitrative) stress, which include 8-hydroxy-2ʹ-deoxyguanosine (8-OHdG) (Fig. 1i and Supplementary Fig. 2i), GSSG/GSH ratio (GSSG/GSH) (Fig. 1j), 3-nitrotyrosine (3-NT) formation in Cars2+/− mice after infection (Supplementary Fig. 2e).