Pathology of influenza hepatitis in susceptible and genetically resistant mice.

Mice resistant (homozygous or heterozygous for the gene Mx) and mice susceptible to the lethal effect of influenza viruses were inoculated intraperitoneally and intraportally with a hepatotropic variant of influenza A virus. Disease evolution was followed histologically and by immunofluorescence. In susceptible animals, rapidly spreading foci of hepatocyte necrosis with little inflammatory infiltration was observed. Death occurred on the 3rd day, when the entire liver was involved. In resistant animals foci became detectable later, and were fewer and smaller. They were infiltrated by cells morphologically resembling liver macrophages (Kupffer cells), and they regressed from the 4th day after infection. Barriers to virus spread appeared to be present at all stages of the disease.