[Pathomorphological aspects and outcome of influenza virus and Klebsiella pneumonia in the experiment].

Mice infected with K. pneumoniae against the background of prior introduction of influenza A/Hong-Kong/68 virus developed focal bronchial pneumonia with leukocytic exudate that started resolving at day 10 of the experiment. At about this time and later there appeared in the lungs spots of apparent proliferative processes characteristic of productive inflammation. These were manifested by diffuse and focal infiltration of the interstice with plasmablasts, plasmacytes, histiocytes, lymphocytes, by proliferation of the vascular endothelium epithelium, of the bronchi, bronchioles, alveolar cells that were seen to be desquamative and developing obliterating macrophagal alveolitis, focal proliferation of fibroblasts. Abnormalities in immunoregulatory mechanisms were induced by immunodepressive action of the influenza virus, early chronization of viral-bacterial pneumonia, with pneumosclerosis developing in its wake.