The expression of representative ISGs, selected based on the transcriptome profile of the HBV-HDV–infected cells (Table 1 and Table 2), IFN-induced protein 44-like (IFI44L), IFN-induced transmembrane protein 1 (IFITM1), and radical S-adenosyl methionine domain containing 2 (RSAD2), were all significantly upregulated upon HDV superinfection, and their expression remained at a high level throughout the infection (Figure 3C). The gene discussed is IFITM1; the disease is infection.