Collectively, these data indicate that the reduced phagocytosis by the recruited neutrophils, the reduced number of AM, a reduction in heme oxygenase-1 level, and an impairment in the production of both pro-inflammatory and anti-inflammatory cytokines, as well as a compromise in signaling pathways, may contribute to a defective immunosurveillance resulting in an increased susceptibility to respiratory infection in old age. The gene discussed is HMOX1; the disease is respiratory tract infectious disorder.