Liver histology and immunohistochemical findings in asymptomatic Indians with incidental detection of hepatitis B virus infection.

Background and Objectives: The relationship be­ tween hepatocyte expression of hepatitis B virus (HBV) antigens, liver histology and viral replication in asymptomatic subjects with incidental detection of hepatitis B surface antigen (HBsAg) remains un­ clear. We evaluated the histological activity index (HAI) and hepatocyte expression of viral antigens with replicative status in asymptomatic chronic HBV infection. Methods: Asymptomatic subjects with in­ cidental detection of HBsAg and ALT levels less than twice the upper limit of normal were grouped as follows: Group A – negative for HBeAg and HBV DNA (no HBV replication); B – HBeAg negative, HBV DNA positive (low HBV replication or pre-core mutant); C – positive HBeAg and HBV DNA (high viral replication). Liver biopsies were assessed for HAI (Ishak’s scor­ ing system). These were also subjected to immuno­ histochemistry for expression of HBsAg and hepati­ tis B core antigen (HBcAg); distribution, staining pattern and quantitative measurement of antigen ex­ pression were assessed. Results: Median HAI was similar in the three groups (1.0, 2.0 and 2.0 in groups A, B and C, respectively). All subjects in Group C showed discrete cytoplasmic expression of HBsAg, whereas the other two groups showed heterogeneity in distribution and pattern of HBsAg staining. Quanti­ tative measurement of cytoplasmic HBsAg revealed similar results in the three groups. Core antigen (nuclear) was detected in 4 of 5 subjects in Group C and none of those in Groups A and B. Ground-glass hepatocytes were seen in 20 and orcein-positive cells in 26 cases. HBsAg was detected by immunohis­ tochemistry in 37 biopsies. Conclusions: Among asymptomatic subjects with chronic HBV infection, those with high rate of viral replication had discrete cytoplasmic HBsAg expression and nuclear expres­ sion of core antigen; these findings were uncommon in subjects with low or no viral replication. [Indian J Gastroenterol 2006;25:128-131]