Viral load, antibody titers and recombinant open reading frame 2 protein-induced Th1/Th2 cytokines and cellular immune responses in self-limiting and fulminant hepatitis E

Abstract

Objectives: Hepatitis E virus (HEV) is the predominant cause of water-borne epidemics, sporadic acute viral hepatitis (AVH) in adults and fulminant hepatic failure (FHF) among pregnant women and other adults in India. This preliminary study was designed to examine the association of viral load and certain host immune responses with uneventful recovery or progression to FHF. Methods: Viral load, anti-HEV antibody titers, rORF2p-induced Th1/Th2 cytokines levels and cellular immune responses were assessed in 47 patients with self-limiting hepatitis E and 14 FHF-E cases. The controls included 16 anti-HEV-IgM and IgG-negative healthy individuals. Results: In AVH category, the viral load was 2.4×10⁴±1.92×10⁴ copies/ml while except for one, all FHF patients were negative for HEV RNA; anti-HEV-IgM and IgG titers were higher in the FHF group. Lymphocyte proliferative response to rORF2p was comparable in both groups. As compared to AVH, significantly higher levels of both Th1 (IFN-γ, IL-2 and TNF-α) and Th2 (IL-10) cytokines were recorded in FHF patients. Analysis of sequential samples differentiated FHF recovered and fatal patients with respect to IFN-γ and IL-12. Conclusion: The results document increased Th1/Th2 responses and anti-HEV titers in FHF patients that warrant indepth immunological studies.