Pneumonia can result whenever these defense mechanisms are impaired or the resistance of the host is lowered: Defects in innate immunity and immunodeficiency Cell-mediated immune defects Exogenous aspects of lifestyle interfere cigarette smoke, alcohol --From the nasopharynx all the way into the alveolar airspaces Pulmonary infections in the form of pneumonia are responsible for one-sixth of all deaths in the usa11 Defects in innate immunity and immunodeficiency Cell-mediated immune defects Exogenous aspects of lifestyle interfere: cigarette smoke, alcohol --From the nasopharynx all the way into the alveolar airspaces Pulmonary infections in the form of pneumonia are responsible for one-sixth of all deaths in the USA. Pneumonia can result whenever these defense mechanisms are impaired or the resistance of the host is lowered: