Histological and immunohistochemical features in fatal acute fulminant hepatitis E

Background: Hepatitis E is being increasingly recognized as an emerging infection in developed countries. Data on histological findings and nature of inflammatory cell infiltrate in liver in this disease are quite sparse. Aims: This study was planned to study the histological features and the type of inflammatory infiltrate in liver biopsies of patients with acute fulminant hepatitis E. Materials and Methods: We retrieved postmortem liver biopsies of 11 Indian patients with fulminant hepatitis E, and compared these with biopsies from seven patients with fulminant hepatitis B. Results: Biopsies from acute fulminant hepatitis E showed varying degrees of hepatocyte necrosis, mixed portal and lobular inflammation, accompanied by bile ductular proliferation, lymphocytic cholangitis, Kupffer cell prominence, cholestasis, apoptotic bodies, pseudo-rosette formation, steatosis, and presence of plasma cells in portal tracts. Interface hepatitis was more frequent in acute hepatitis B than in acute hepatitis E (100% vs 20%; P<0.05). These findings differ from those reported in cases with autochthonous hepatitis E in Europe. On immunohistochemistry, lymphocyte infiltrate consisted predominantly of CD3(+) T cells in both hepatitis E and hepatitis B; these cells contained a predominant cytotoxic (CD8(+)) cell subpopulation in 81.8% of cases with hepatitis E and in 50% of cases with hepatitis B. Conclusion: Our findings suggest that histological changes in HEV infection may vary with geographical location because of prevalent HEV genotypes, and that CD8(+) lymphocytes play a role in HEV-induced liver injury.