Non-A, non-B hepatitis-like nuclear particles in nonparenchymal cells of the liver

Nuclear particles, morphologically similar to those seen in hepatocytes during non-A, non-B (NANB) hepatitis, were detected in several types of nonparenchymal cells in 10 human liver-biopsy specimens, including cases of hepatitis A and B and nonviral hepatic disease. They were also found in nonparenchymal cells of the liver in two of four normal chimpanzees and in two of four chimpanzees during experimental NANB viral hepatitis. In nonparenchymal cells the particles formed loose-to-intermediate aggregates, similar to those first described in hepatocytes during NANB hepatitis. Tightly packed aggregates, the predominant pattern in hepatocytes, were generally missing. The high prevalence of morphologically identical particles in various liver diseases and their presence in healthy livers, both in hepatocytes and in nonparenchymal cells not presumed to support the growth of hepatitis viruses, speak against their specificity for NANB hepatitis viruses. It is proposed that the particles represent a newly recognized and widespread cellular feature, of as yet unknown function.