Abstract
In patients with chronic liver disease (CLD), hepatitis E virus (HEV) may lead to decompensation and death. We tested 438 CLD patients (71.0% male; age 23–84 years) for HEV-IgG antibodies. Reactive samples were tested for HEV-IgM antibodies using ELISA. IgM positive samples were tested for HEV RNA using RT-PCR. HEV-IgG antibodies were found in 15.1% of patients, whereas 4.5% of IgG positive patients had detectable IgM antibodies. Not a single patient tested HEV RNA positive. Seroprevalence increased with age, from 9.7% (<45 years) to 17.4% (>60 years, p = 0.368). There was no difference in HEV-IgG seropositivity related to gender, level of education, geographic region, area of residence, liver disease, or hepatocellular carcinoma presence. Previous exposure to HEV was detected in 15.1% of patients, corresponding with the data from other endemic European regions. Despite the high local exposure, we did not find any evidence of acute or chronic hepatitis E among CLD patients.
In recent decades, the hepatitis E virus (HEV) has emerged as a significant cause of hepatitis in Europe. The clinical spectrum of HEV infection ranges from asymptomatic or acute cases to chronic hepatitis in immunocompromised patients. In patients with chronic liver disease (CLD), HEV may lead to decompensation and death (Blasco-Perrin et al. 2015). HEV seroprevalence in CLD patients in Europe varies from 3.1 in north Germany (Pischke et al. 2010) to 41.4% in southwest France (Blasco-Perrin et al. 2015). However, commercially available serologic tests vary in their performances; therefore, the data should be interpreted with caution. Given high liver transplantation (LT) rates in Croatia, 27.35–32.2 per million population (2014–2019) (International Registry in Organ Donation and Transplantation 2020), we analyzed the HEV burden in potential LT candidates—CLD patients. From 2016 to 2018, 438 CLD patients (71.0% male; median age 60, range 23–84 years) with alcohol-related (ALD), viral, autoimmune, nonalcoholic fatty liver disease, were tested for HEV-IgG antibodies in a single center in Croatia. IgG reactive samples were further tested for HEV-IgM antibodies using enzyme-linked immunosorbent assay (Euroimmun, Lübeck, Germany). IgM positive samples were tested for HEV RNA using RT-PCR. The study was approved by the Institutional Review Board.
HEV-IgG antibodies were found in 15.1% of patients, whereas 4.5% of IgG positive patients had detectable IgM antibodies. Not a single patient tested HEV RNA positive. Seroprevalence increased with age, from 9.7% (<45 years) to 17.4% (>60 years), but it was not statistically significant (p = 0.368). There was no difference in HEV-IgG seropositivity related to gender, level of education, geographic region, area of residence, liver disease, and presence of hepatocellular carcinoma (HCC) (Table 1).
Hepatitis E IgG Seroprevalence Among Patients with Chronic Liver Diseases
HBV, hepatitis B virus; HCV, hepatitis C virus; HEV, hepatitis E virus, NAFLD, non-alcoholic fatty liver disease.
HEV-IgG seropositivity in CLD patients is higher than in other population groups in Croatia; intravenous drug users (6.1%), patients with war-related post-traumatic stress disorder (8.6%), alcohol abusers (8.9%) (Vilibic-Cavlek et al. 2016) and in patients with acute non-A-C hepatitis (10.7%) (Ðaković Rode et al. 2014), implicating potential HEV impact on the CLD development. It has been hypothesized that HEV may promote chronic inflammation and cellular pathways disturbances and that in association with hepatitis B/C and/or alcohol may even be a cofactor in HCC occurrence (Colson et al. 2019).
It is well established that HEV-IgG seroprevalence increases with age due to cumulative exposure to the virus through different routes of transmission (Dalton et al. 2011, European Association for the Study of the Liver 2018). This increase was also evident in our cohort, even though it has not reached a statistical significance. In contrast to previous studies, HEV-IgG seroprevalence rates were not higher in men (Dalton et al. 2011) and did not differ between various liver diseases (Dalton et al. 2011, Pischke et al. 2014, Blasco-Perrin et al. 2015). As more severe forms of infection in ALD patients are reported, some authors suggested that due to excess mortality, usually lower HEV-IgG rates in ALD patients (Dalton et al. 2011, Blasco-Perrin et al. 2015), actually represent a “culled” population. In contrast, patients with autoimmune hepatitis have higher HEV-IgG prevalence, for the reasons that still had to be determined (Pischke et al. 2014). Finally, in the same region, HEV-IgG rates in liver transplant recipients (24.5%) (Mrzljak et al. 2019) are higher, suggesting that transplant-related events convey an additional HEV burden (European Association for the Study of the Liver 2018). Given high prevalence rate, HEV testing should be routinely considered in pretransplant evaluation.
In conclusion, the HEV burden in CLD patients in Croatia is high. Previous exposure to HEV was detected in 15.1% of patients, corresponding with the data from other endemic regions in Europe. Despite the high local exposure, we did not find any evidence of acute or chronic hepatitis E among CLD patients.
Footnotes
Acknowledgments
We thank Josipa Nosil and Nada Vujatovic for their excellent technical support.
Author Disclosure Statement
No conflicting financial interests exist.
Funding Information
This study was supported by the “Zaklada Adris” Grant for the project “Hepatitis E virus infection before and after solid-solid organ transplantation in Croatia,” Transplant Centre, Merkur University Hospital Merkur (to A.M.).