Immunohistochemistry for core and surface antigens in chronic hepatitis

Hepatitis B virus infection constitutes a significant proportion of patients presenting with chronic hepatitis. Chronic hepatitis is said to be due to HBV if HBsAg is demonstrated in the serum with or without replication as determined by the presence of HBeAg in the serum. Immunohistochemical staining for HBsAg and HBcAg in liver tissue has been reported to improve the detection rate of HBV.

To study positivity of immunohistochemical staining of liver tissue for HBsAg and HBcAg in patients of chronic hepatitis and correlate it with histological activity index.

One hundred consecutive patients of chronic hepatitis were selected for this study. Histological scoring of liver biopsies was done using Knodell's numerical scoring system. Immunohistochemical staining was done by the Indirect immunoperoxidase technique using goat polyclonal anti-HBsAg and rabbit polyclonal anti-HBsAg. ELISA was used to detect HBsAg in the serum.

Serum HBsAg was positive in only 40 patients whereas tissue HBsAg was positive in 48 patients. Thirteen of these forty-eight tissue positive HBsAg patients also showed HBcAg on immunohistochemical staining of liver tissue. Patients with higher grades of histological activity index (HAI) score had higher values of serum bilirubin and prothrombin time as compared to the patients with a low HAI score. Significantly higher levels of serum transaminases (AST/ALT) were observed in patients who were positive for both HBsAg and HBcAg when compared with patients positive for HBsAg or HBsAg negative patients. A mixed pattern (diffuse/focal cytoplasmic and membranous) of surface antigen expression was seen in 83.3% patients, whereas expression of core antigen was predominantly nuclear (77%). There was no significant correlation between the pattern of antigen expression and HAI score.