Hepatitis E virus (HEV)
infection is increasingly recognized as a cause of acute
hepatitis in the industrialized world. We aimed to determine the frequency of acute HEV
infection in cases of suspected
drug-induced liver injury (DILI), mainly a diagnosis of exclusion. To this aim,
formalin-fixed
paraffin-embedded (FFPE) liver tissues of all cases routinely processed in our institute during a 2 1/2 years period in which DILI was among the differential diagnoses (157 liver biopsies, 1 liver explant) were subjected to semi-nested RT-PCR for the detection of HEV
RNA. Histopathology was re-evaluated on all cases tested positive. HEV
RNA was detectable in 3 of 158 cases (2%) tested, comprising autochthonic as well as
travel-related infections with genotypes 1, 3, and 4 each found once, respectively. Histopathologic findings comprised one case with subtotal hepatic
necrosis and two cases of acute (cholestatic)
hepatitis not distinguishable from acute
hepatitis of other etiology. Thus, the overall frequency of acute HEV
infection as determined by detection of HEV
RNA in liver tissue is substantially increased in patients with suspected DILI compared to the healthy population, emphasizing the need to actively look for HEV
infection in cases of suspected DILI. Molecular testing for HEV
RNA in routinely processed FFPE liver tissues can be applied to cases with undetermined HEV status.