Hepatitis E virus as an etiology of acute exacerbation of previously unrecognized asymptomatic patients with hepatitis B virus-related chronic liver disease

Background and Aim: Hepatitis E virus (HEV) has recently been implicated in episodes of acute decompensation in patients having underlying chronic liver disease (CLD) of varying etiology. However, HEV as a cause of acute exacerbation of previously asymptomatic and unrecognized hepatitis B virus (HBV)-infected patients is less well described. The aim of the present study was to investigate the etiology of acute exacerbation of previously asymptomatic and unrecognized HBV-infected patients and to evaluate the relative role of HEV. We also investigated the effect of superinfection on the clinical spectrum of underlying HBV infection. Methods: Forty-three patients presented with the following were retrospectively analyzed: (i) clinical features suggestive of acute hepatitis; (ii) with hepatitis B surface antigen (HBsAg) (+); (iii) IgM hepatitis B core antibody (IgM anti-HBc) (-); (iv) no previous history of liver disease; (v) no features suggestive of CLD at presentation; (vi) HBsAg remaining (+) for at least 12 months on follow up; and (vii) having a follow-up biopsy during the convalescent phase showing evidence of chronic hepatitis B. Results: Of the 43 patients, 21 were hepatitis e antigen (HBeAg) (+) (Gr.1) and 22 HBeAg (-) (Gr.2) at presentation. In Gr.1, only two (9.5%) had superinfection (both with hepatitis A virus), whereas in Gr.2, 11 (50%) had superinfection (27.3% hepatitis E, 13.6% hepatitis A and 9.1% both) (P = 0.007). In Gr.1, the remaining 19 (90.5%) patients had spontaneous exacerbation (immune clearance with spontaneous seroconversion) whereas in Gr.2, the remaining 11 (50%) had spontaneous exacerbation (due to reactivation). Overall, HEV superinfection contributed to 20% of acute exacerbation episodes and, in particular, 36% of episodes in initially HBeAg (-) patients. Time to alanine aminotransferase normalization was longer in patients with superinfection (n = 13) as compared to spontaneous exacerbation (n = 30) (median [range] 36 [8-48] vs 16 [6-36] weeks, P = 0.001). During convalescence, there was no significant difference between histological activity index score (median [range] 8 [4-11] vs 8 [4-16] weeks, P = 0.629) and fibrosis scores (median [range] 3.5 [1-4] vs 2 [1-4] weeks, P = 0.099] on liver biopsy after recovery among patients with acute exacerbation due to superinfection and spontaneous exacerbation. Conclusions: Acute exacerbations in HBeAg (+) patients are most often due to spontaneous viral activation, while in HBeAg (-) patients, superinfection with non-B hepatitis viruses and spontaneous viral activation are equally common. HEV is an important cause of acute exacerbation in previously asymptomatic and unrecognized patients with HBV-related CLD.