Loss of Ddx3x in the myeloid compartment leads to increased susceptibility to IAV infection and tissue damage.A, survival analysis of WT (n = 10), LysMCre (n = 10), Ddx3xfl/fl (n = 8), or Ddx3xfl/flLysMCre (n = 10) mice to influenza A virus PR8 (IAV–PR8) infection (50 PFU). ∗p = 0.0137 (Mantel–Cox test). B, quantification of viral load in the infected lungs of Ddx3xfl/fl (n = 9) and Ddx3xfl/flLysMCre (n = 5) mice on day 5 after infection by determining the number of plaque-forming units (PFU). ∗p = 0.0279 (unpaired two-sided t test). C, immunohistochemistry (IHC) analysis of the infected lungs with the IAV NP antibody showing viral spread in the lungs on day 5 after infection. D, high-magnification images of the lungs showing increased viral load and spread and tissue damage (black arrows). DDX3X, DEAD-box helicase 3 X-linked; IAV, influenza A virus; NP, nucleoprotein; PR8, Puerto Rico/8/34.