The Battle Between Influenza and the Innate Immune Response in the Human Respiratory Tract

Nicholls, John M

Even after the discovery of the influenza virus there was not much interest from a pathological point of view on how the virus led to death. During the H2N2 and H3N2 pandemics of the 12 1950s and 1960s, limited autopsy and biopsy pathology indicated that bronchitis was the more common presentation and that a primary viral pneumonia was mainly seen in young patients, often with pre-existing disease such as mitral stenosis [5, 6] . Vaccination and intensive care with artificial ventilation was not readily available, so the overall picture was that of younger patients (possibly without prior virus exposure) succumbing to a fatal viral pneumonia within a number of days, with older subjects only developing bronchitis. Even with the advent of immunohistochemistry to identify viral antigen in biopsy and autopsy tissue, only a necrotizing bronchitis was seen and antigen was not normally present in the alveoli [7] .