Electron microscopic studies of viral pancreatitis in coxsackie B4 virus infected mice.

Using a high titer culture of Coxsackie B₄ virus, cytonecrosis consistent with picornaviral infection and cytopathic changes indicative of viral pancreatitis were produced in the pancreas of newborn mice. Virocytonecrosis was manifested within acinocytes by formation of characteristic membrane-vesicle complexes, dilatation of rough endoplasmic reticulum, margination of nuclear chromatin, pyknosis of nuclei, and acute inflammation. Viral pancreatitis was characterized by formation of cytosegresomes, fibroid bodies, and sloughed damaged acinar cytoplasm apparent in autophagic vacuoles of macrophages. Immature leucocytic cells were closely aligned to the wall of acinar ducts. Beta cell damage was also observed. Of significance was the observation of aggregates of Coxsackie B₄ virus particles in various pancreatic cells of 11 of the 23 mice studied. These aggregates appeared in the typical crystalline form with cubic and hexagonal lattice configurations and as viral particles circularly arranged into eight-sided and ten-sided “rosettes.” These findings strongly support the concept that viruses are etiologic agents in pancreatitis and diabetes mellitus.