RMRP and susceptibility to pneumonia measurement: To further investigate the effects of Rmrp depletion on AM immune function, SII, and the prognosis of secondary pneumonia, we intratracheally injected mice with a macrophage‐specific adeno‐associated virus (AAV) harboring a synthetic F4/80 promoter, an Rmrp‐specific shRNA, and a cytomegalovirus promoter (Figure S23A, Supporting Information).