Hepatitis E virus (HEV) is the major cause of several outbreaks of waterborne hepatitis in tropical and subtropical countries and of sporadic cases of viral hepatitis in endemic and industrialised countries. Generally, HEV causes an acute self-limiting hepatitis. The clinical course is characterised by transient viraemia and transaminasaemia followed by a full hepatic recovery. Recent studies describe prolonged and chronic HEV infections in some immunosuppressed patients after solid organ transplantation. Here, an indigenous acute limited hepatitis E in a patient with Philadelphia chromosome-positive acute lymphoblastic leukaemia prior to allogeneic stem cell transplantation is reported. Fourteen weeks after stem cell transplantation, reappearance of HEV viraemia was observed, with increasing viral load and modestly elevated serum transaminases. Sequence analysis of the viral RNAs revealed a reactivation of endogenous HEV genotype 3, indicating viral persistence after recovery from acute hepatitis E.
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Hepatitis E virus (HEV) is the sole member of the genus Hepevirus in the family Hepeviridae and is grouped into four genotypes.1 While genotypes 1 and 2 have only been isolated from human hosts, genotypes 3 and 4 have also been found in animals, especially domestic and wild pigs. Sporadic and epidemic outbreaks in developing countries are mainly caused by genotype 1 and 2 strains, whereas 3 and 4 are considered as causative agents of sporadic indigenous cases in industrialised countries.2–4 Recently an increasing number of reports have described hepatitis E as a viral zoonosis.5 6 The clinical presentation of hepatitis E is characterised by an acute self-limiting course, but a chronic HEV infection may develop from an acute infection in immunosuppressed patients.7
Acute lymphoblastic leukaemia (ALL) is a rare neoplasia with an incidence in adults of between 0.7 and 1.8/100 000.8 Treatment is based on complex high dose chemotherapeutic regimens and central nervous system irradiation. In ∼25% of all patients a translocation between chromosomes 9 and 22, called Philadelphia chromosome, leads to the expression of the highly oncogenic p190bcr-abl fusion protein. These patients carry an elevated risk of relapse and are thus preferentially treated with early allogeneic stem cell transplantation.9
Here we report on a German Ph+ ALL patient who had an acute HEV infection prior to stem cell transplantation (SCT), cleared the infection but reactivated the endogenous virus 3.5 months post-SCT.
In April 2007 a 30-year-old male architect was diagnosed with Ph+ ALL and was treated until May 2007 with several cycles of chemotherapy. Treatment was well tolerated and by the completion of the first cycle of induction chemotherapy the patient had already achieved a complete haematological remission. Due to chemotherapy-induced cytopenia the patient received 18 transfusions of erythrocytes, 10 of platelets and four fresh frozen plasma products. Consequently, an allogeneic SCT from a matched unrelated donor was planned in the absence of a suitable sibling. In early August 2007 after completion of chemotherapy but prior to SCT, the patient stayed in the vicinity of a cattle farm in Southern Germany. He did not ingest any meat originating from this source, and no other travel activity was reported. However, in this period, he ingested pork imported from Spain.
Upon admission to our transplant unit 2 weeks later in August 2007, abdominal ultrasound was unremarkable except for mild splenomegaly (260 ml). The liver was normal in size and structure. Bone marrow and peripheral blood analysis confirmed a complete haematological remission. Pathological values were obtained for alanine aminotransferase (ALT) 1529 U/l (normal: <45), aspartate aminotransferase (AST) 934 U/l (normal: <50), alkaline phosphatase (AP) 167 U/l (normal: 40–129), γ-glutamyltransferase (γGT) 308 U/l (normal: <55) and lactate dehydrogenase (LDH) 601 U/l (normal: <248). Total bilirubin, immunoglobulins and plasma electrophoresis were within the normal range. The baseline immune status detected by flow cytometry was normal, with a CD4/CD8 ratio of 0.93 which was at the lower normal range. The relative CD3 count was in the upper normal range (85%). Standard diagnostics performed prior to SCT showed markers of past herpes simplex virus, varizella zoster virus, cytomegalovirus and Epstein–Barr virus infections. Vaccine-derived immunity to hepatitis A virus (HAV) and hepatitis B virus (HBV), and no evidence for HIV and hepatitis C virus (HCV) infection were also seen. Further virological investigation revealed the presence of HEV RNA in plasma and stool detected by real-time PCR,11 and anti-HEV immunoglobulin M (IgM)/IgG (detected by recomWell ELISA and confirmed by recomBlot; both Mikrogen, Martinsried, Germany). Follow-up samples remained HEV RNA positive in blood and/or stool specimens until day −34 (fig 1). A transcutaneous liver biopsy performed on day −57 showed preserved liver architecture with mild fibrosis of some portal tracts without septa or overt cirrhosis (fig 2A). A mild scattered inflammation was noted in the portal tracts and necroinflammatory foci in the parenchyma without massive or confluent necroses. The histopathological findings and the presence of HEV RNA in liver tissue were compatible with viral hepatitis. The marked mesenchymal iron overload was consistent with repeated blood transfusions.
Physical examination at diagnosis of HEV infection was normal apart from minimal treatment-induced weakness. Non-specific viral symptoms that may be detectable (>10%), including anorexia, abdominal pain, nausea, fever, vomiting, myalgia, pruritis or weight loss, were absent in our patient.10 Importantly, no jaundice or hepatosplenomegaly were observed. Furthermore, no alcohol or drug consumption was reported.
Three weeks after infection, the HEV IgM decreased below the detection limit and remained continuously negative, whereas the HEV IgG remained positive (fig 1).
The SCT was rescheduled until the transaminases returned to normal. The myeloablative conditioning regimen for allogeneic SCT was started 54 days after the diagnosis of HEV infection, and consisted of total body irradiation (12 Gy), etoposide (60 mg/kg) and ATG (antithymocyte globulin; 3×20 mg/kg). Stem cells (4.7×106 CD34+ cells) were given from a matched unrelated donor. Prophylaxis of graft-versus-host disease (GvHD) consisted of ciclosporin A and methotrexate. Post-transplant bone marrow analysis showed a mixed chimerism on day +28 (50% recipient) with a complete remission. No GvHD was observed.
Three months after SCT and in the presence of immunosuppression, HEV viraemia reappeared with an increasing viral load of from 103 to 108 copies/ml in serum samples. The sequence analysis based on a 242 bp fragment of open reading frame 1 (ORF1) revealed subtype 3c both prior to and after SCT. The identity of both was confirmed by additional comparative sequence analysis of two fragments within ORF2.12 The reappearance of HEV RNA was followed by slightly elevated liver enzymes (fig 1). Up to 8 months after HEV reactivation, no humoral response was detected.
At the time of HEV reappearance a bone marrow analysis revealed a complex karyotype indicating relapse of ALL (fig 1). Consequently, ciclosporin A was discontinued and DLI (donor lymphocyte infusion) was performed. Nonetheless, despite DLI, the patient relapsed shortly thereafter with 80% blast cells in the bone marrow and meningeosis leukaemica. Antileukaemic treatment consisted of repeated cycles of methotrexate, cytarabine and dexamethasone intrathecally, and systemic treatment (rituximab, cytarabine and idarubicine). On day +281 after the first SCT a second transplantation from an alternative donor was performed (fig 1). Following this procedure the patient presented with a moderate increase of ALT. A follow-up biopsy at day +333 showed no change of the liver architecture and no evidence of cirrhosis. The portal inflammation had decreased necroinflammatory foci and iron overload was still present (fig 2).
In order to identify the potential source of infection we retrospectively analysed samples of blood products (n = 26) given between May and July 2007 and of both allografts. All these samples were negative for HEV RNA (detection limit 103 copies/ml).
The patient described here experienced an acute limited hepatitis prior to allogeneic SCT due to infection with an HEV genotype 3, subtype 3c. Seroconversion, non-detectability of viral RNA and a decrease of liver enzymes within 3 weeks after acute hepatitis were in agreement with the typical course of infection.
Based on the detection of the HEV 3c strain and no reported travel to HEV endemic areas, an autochthonous HEV infection is most likely. Due to negative HEV RNA results in 26/26 of the retained samples, a possible transmission route via blood products or transplanted stem cells could not be proven (data not shown). Conversely, an alternative origin of infection such as ingestion of contaminated pork cannot be fully excluded.
The recurrence of HEV viraemia 3 months after SCT is surprising and suggests an incomplete virus elimination by the immune system or, less likely, a re-infection. To assess the likelihood of a reactivation or a possible re-infection, two different genomic regions within ORF212 were analysed for both patient-derived sequences, obtained before and after SCT. The sequence identity of >99% strongly suggests the reactivation of endogenous HEV. The rare possibility of a re-infection through the first allograft was excluded by a negative PCR test of donor-derived samples (data not shown). The reactivation of HEV associated with transient elevation of transaminases may be explained either by the immunosuppressive treatment or by the haematological relapse shortly thereafter. One may speculate on the persistence of virus in hepatocytes or other tissues.
In contrast to this case, Kamar et al7 reported 8/14 immunosuppressed patients with HEV infection following solid organ transplantation. In these patients, the acute infection progressed to a chronic active infection characterised by serum HEV RNA positivity within a mean of 14 months after the acute phase, elevated liver enzymes followed by seroconversion and histological features of chronic hepatitis. Another persistent HEV infection was observed during chemotherapy in a patient with T cell lymphoma.13 In this case, long-term HEV RNA persistence without antibody response to HEV was seen during a follow-up of 6 months.
Risk factors eventually contributing to chronic infection that were identified by Kamar et al,7 including a white cell blood count in the lower normal range, decreased CD2+, CD3+ and CD4+ counts, and thrombocytopenia, were absent in our patient. The recent observations of chronic HEV infection in patients following solid organ transplantation7 14 15 and the possible reactivation of persisting HEV as described here contribute to the general understanding of HEV infection.
Monitoring for HEV antibodies and liver enzymes of blood donations would not eliminate the risk of transmission.16 Screening for HEV RNA in the donations, however, seems to be an appropriate tool to avoid a parenteral transmission and should be considered in the treatment of immunosuppressed patients.
The authors thank Sigrid Kersten for excellent technical assistance, and Wolfram Gerlich, Miriam Greenfield and Martin Raftery for critically reading the manuscript.
Competing interests: None.
Patient consent: Obtained.
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