Maxwell Finland lecture: the influenza viruses and the human respiratory tract.

This paper has reviewed evidence concerning the changes brought about in the structure and function of the lower airways by influenza virus infections. Disposal of inhaled bacteria is believed to be hindered by the mechanical damage to the epithelium of the respiratory tract caused by the virus infection, and phagocytosis is inhibited as well. Alteration in the ventilation, particularly of the peripheral small airways, which has been found in previously healthy persons during and after influenza, may add to the obstruction of the airways in those with chronic bronchitis and emphysema during influenza and may be important in the genesis of these disorders. The immunological defense of the respiratory tract against the influenza viruses has been discussed briefly with reference to the best available means of enhancing this defense, particularly in individuals with chronic pulmonary disease.