Hepatitis E virus (HEV)
infection is known to run a self-limiting course. Sporadic cases of acute
hepatitis due to
infection with HEV genotype 3, present in pig populations, are increasingly recognized. Zoonotic transmission seems infrequent. The entity of unexplained
chronic hepatitis after
liver transplantation has been recognized. Detection of HEV in 2
liver transplant recipients triggered a review of these cases. Freeze-stored sera were available for retrospective analysis. HEV
antibodies were determined. For virus detection and identification, a fragment of the gene encoding the major
capsid protein (open reading frame 2) was amplified by reverse-transcription polymerase chain reaction and sequenced to identify the genotype. Two months after
liver transplantation, case A developed unexplained
chronic hepatitis, which developed into
cirrhosis. Retransplantation followed 7 years later, after which
chronic hepatitis recurred. In retrospect, HEV
RNA was present in serum 3 weeks after the first
transplantation and remained present afterwards. HEV
RNA was also present in retransplant liver tissue. HEV
antibodies appeared late after retransplantation. Case B developed unexplained
chronic hepatitis 7 years after
transplantation. Retransplantation was needed 5 years later, after which no signs of
hepatitis recurred. In retrospect, the period of
chronic hepatitis up to the retransplantation coincided with HEV
RNA in serum. In case B,
antibodies developed, the viral load was much lower than in case A, and the virus seemed to be cleared after retransplantation. Genotyping in both cases revealed 2 unique strains of genotype 3. In conclusion, chronic HEV
infection may develop in immunosuppressed patients, who may then serve as long-term carriers of the virus. We hypothesize that HEV may be the cause of
chronic hepatitis in
liver transplant recipients.