A study on so-called novel inclusion body in human hepatocyte

The so-called novel inclusion body (NIB) is an intrahepatocytic structure which is frequently observed in human cirrhotic liver. It resembles very much to, but definitely differs from Hepatitis B surface antigen (HBsAg) morphologically. The age distribution of liver cirrhosis cases positive for NIB is similar to that positive for HBsAg, except for an existence of a time lag in mean age. One of the best staining methods to demonstrate NIB, for example, is to exhibit it as a reddish body stained by Luna, with a contrast of HBsAg counterstained purple in color by aldehyde fuchsin after thiosulfation. Electron microscopy of the liver obtained from a patient, negative for both HBsAg and Hepatitis B e antigen (HBeAg) but positive for Hepatitis B core antibody (HBcAb) and Hepatitis B surface antigen antibody (HBsAb) clinically, revealed some unfamiliar, tubular and cisternal arrays showing a network pattern and ring-shaped structure at the site exactly corresponding to NIB localization. These are considered to have been induced from the endoplasmic reticulum by an unknown agent, for which non A non B hepatitis virus (NANBV) is rationally postulated as one of the possibilities. A close relation between NIB and NANBV is highly suspected because of much similarities in histology, histochemistry, age distribution, and electron microscopy. The true nature of NANBV should be rescrutinized, especially in relation with Hepatitis B virus infection, since NIB is quite often observed also in cirrhotic liver positive for HBsAg.