Acute non-A, non-B, non-C hepatitis differences and similarities between hepatitis E virus infection and autoimmune hepatitis, with phylogenetic analysis of hepatitis E virus in humans and wild boars

Abstract

Background Hepatitis E virus (HEV) infection incidence is increasing in Europe, accounting for the majority of acute hepatitis cases. We investigated the prevalence and clinical characteristics of acute hepatitis E (AHE) in patients with acute non-A/B/C hepatitis from central Greece, their differences from acute autoimmune hepatitis (AIH) patients and the molecular similarity of human strains to local HEV strains in wild boars. Methods Sera from 20 patients with non-A/B/C acute hepatitis (2015-2017) were tested prospectively for anti-HEV IgM, IgG antibodies and HEV-RNA. Sera from patients diagnosed with acute AIH (2000-2015; n=56) were tested retrospectively. Liver tissue samples from 40 wild boars were tested for HEV-RNA. Positive wild boar and patients’ samples were sequenced and phylogenetically analyzed. Results Twelve of the 76 (16%) patients were diagnosed with AHE: HEV-RNA 11.5x104 (38.7-39.7x106) IU/mL; 11/20 (55%) acute non-A/B/C hepatitis and 1/56 (2%) AIH patients. Patients with AHE were older than those without, predominately men, with higher alanine aminotransferase but lower IgG levels (P=0.005 and P=0.002, respectively), and had high titers of smooth muscle antibodies. Liver biopsies, performed in 6/12 patients with HEV infection, revealed histology compatible with AIH. HEV strains from both patients and wild boars belonged to genotype 3. Conclusions Approximately one sixth of patients with acute non-A/B/C hepatitis had autochthonous HEV infection with AIH features. Therefore, a careful workup to exclude HEV should be carried out in all acute hepatitis cases before a definite diagnosis of AIH is established. Wild boars seem to be an important reservoir of HEV in Greece. © 2022 Hellenic Society of Gastroenterology.