Novel approach for detection of hepatitis E virus infection in German blood donors

Abstract

The risk of transfusion-transmitted hepatitis E virus (HEV) infections by contaminated blood products remains unknown. In the present study, we evaluated and compared different nucleic acid amplification technique (NAT) methods for the detection of HEV in blood components. Minipools of a total of 16,125 individual blood donors were screened for the presence of HEV RNA using the highly sensitive RealStar HEV RT-PCR kit, revealing a minimum detection limit of 4.66 IU/ml. Thirteen donors were HEV RNA positive (0.08%), and of these donors, only three already showed reactive IgM antibody titers. The detected HEV strains all belonged to genotype 3 and were most closely related to German HEV strains from wild boars and pigs as well as from human hepatitis E cases. Furthermore, HEV RNA and HEV-specific IgM and IgG titers were determined in 136 blood donors with elevated alanine aminotransferase (ALT) levels and in 200 donors without pathological findings. HEV RNA was not detectable, but 8.08% (elevated ALT) and 0.5% (nonelevated ALT) of donors showed reactive HEV IgM titers. The overall seroprevalence rate of HEV IgG amounted to 5.94% (elevated ALT, 5.88%; nonelevated ALT, 6.0%). The clinical relevance of transfusion-associated hepatitis E infection still requires further investigation. However, in connection with raising concerns regarding blood safety, our NAT method provides a sensitive possibility for HEV testing.

Fig 1

Phylogenetic relationship of HEV sequences derived from 13 donors together with human, pig, and wild boar genotype 3 HEV strains. The sequences were selected based on a sequence similarity search using the BLASTn search facility. The tree was constructed with a 246-nucleotide fragment of the HEV ORF1 using a neighbor-joining method implemented in the MegAlign module of the DNASTAR software package (Lasergene, Madison, WI). The donor sequences are boldface, and HEV subtype reference strains are italicized. For the selected nondonor sequences, the host of the virus (Sw, swine; Hu, human; Wb, wild boar), country of detection (DE, Germany; NL, The Netherlands), time of detection (year), and the GenBank accession number are indicated. The wild boar strain WbGER27 is indicated by an asterisk. posCTRL, sequence of the PCR-positive control. Grouping of the sequences into clusters is shown on the right. The tree is scaled for nucleotide substitutions (×100), and bootstrap values of >75% are shown on the branches.