Hepatitis E Virus Infection: A General Review with a Focus on Hemodialysis and Kidney Transplant Patients

Background: Hepatitis E virus (HEV) infection is a self-limited viral disease that causes acute hepatitis epidemics in developing countries. The common route of transmission for HEV is supposedly fecal-oral. Serological evidence may be unexpectedly found in hemodialysis (HD) patients and kidney transplant recipients. Although the route of HEV transmission is not usually determined in HD subjects, this virus seems to be transmitted either directly through HD or nosocomially. In this study, we gathered the published information on HEV infection in HD patients and kidney transplant recipients. Methods: For this review, we collected the relevant articles by searching through Medline and Google Scholar from January 1980 up to September 2009. Results: Some variables including older age, low education, living in rural versus urban areas and the duration of HD seem to be risk factors for HEV infection in HD patients. Compared with non-HD subjects, HEV infection may be specifically associated with poor outcome in HD patients. Specific considerations seem to be required to prevent transmission of HEV to Received: September 13, 2009 Accepted: March 1, 2010 Published online: March 31, 2010 Nephrology American Journal of Seyed Mohammadmehdi Hosseini-Moghaddam, MD Urology and Nephrology Research Center, No. 103 Boostan 9th St., Pasdaran Ave, PO Box 1666677951 Tehran (Islamic Republic of Iran) Tel. +98 21 2256 7222, Fax +98 21 2277 0954, E-Mail h_sasan @ hotmail.com © 2010 S. Karger AG, Basel 0250–8095/10/0315–0398$26.00/0 Accessible online at: www.karger.com/ajn D ow nl oa de d by : 54 .7 0. 40 .1 1 11 /1 9/ 20 17 8 :0 1: 47 A M HEV Review with Focus on HD and Kidney Transplantation Am J Nephrol 2010;31:398–407 399 Although HEV was first classified as belonging to the Caliciviridae family, the most updated International Committee on Taxonomy of Viruses classification has grouped it as class IV positive-sense RNA virus assumed to belong to the ‘hepatitis-E-like viruses’ [6] . Phylogenetic studies have demonstrated 4 main genotypes of 1–4, and up to 24 different subtypes, so far. The clinical relevance of the subtypes is rather poorly understood. The other issue is that genotypes 1 and 2 have been found to be restricted to humans, but genotypes 3 and 4 are common in both humans and animals. Among all 4 genotypes, type 3 has been reported as the least virulent type [7] . Nonetheless, there has recently been a report of infected patients with a genotype 3 HEV by blood transfusion in Japan [8] . The common route of transmission is fecal-oral. Other probable modes of transmission in endemic areas include vertical transmission, blood transfusions, person-to-person contact and zoonotic transmission [1] . In general, the clinical significance of other than fecal-oral routes for HEV transmission still remains to be determined. Materials and Methods For this review, related articles were collected by searching through Medline from January 1980 up to September 2009. We also reviewed Google Scholar to check other manuscripts or papers in regional journals that might have not been included in Medline. The search was carried out by using several predefined combinations of the following key words and MESH terms or their equivalents: ‘hemodialysis’, ‘dialysis’, ‘renal transplantation’, ‘kidney transplantation’ in combination with ‘HEV’ or ‘hepatitis E’ and ‘hepatitis E virus’. A total of 155 related articles only in the English language were collected. Of those, 119 papers were recognized to provide minor information on HEV transmission, poor data or they were written in non-English languages. Finally, we focused on 36 manuscripts which provided data on hepatitis E in hemodialysis (HD) or renal transplantation. Additionally, we used other manuscripts for a better description of the epidemiological, diagnostic and preventive concepts. The information was retrieved by S.M.H.-M. and A.-Z. Then, the manuscripts were reviewed for data relevance by S.M.H.-M., S.M.A. and A.-Z., independently. To reach a consensus, the matter was discussed in several sessions. Although the focus of the published manuscripts was on HEV status in HD and kidney transplant patients, various clinical, epidemiological, preventive, diagnostic and therapeutic aspects were covered, too. The comparison of HEV prevalence between HD patients and the general population is provided in table 1 . By using the preliminary data, the draft of the article was prepared by A.Z. under the predetermined subtitles. Afterwards, the intermediate report was written by S.M.H.-M. in cooperation with A.-Z. and M.-M.; the final report was drafted after several sessions of reevaluating and reassessing the data. Once the preliminary data had been checked thoroughly again, the final text was composed. Then, by reviewing the final list of titles and abstracts, those eligible were selected. The eligibility criteria for inclusion were articles published in English, using any format, in a journal or the Cochrane library. The bibliographies of the collected full articles were studied to find relevant articles, too. The final decision to include the articles was reached by consensus. In addition, those studies relevant to HEV status in HD and kidney transplant patients, but prepared by other criteria for different search purposes, were excluded.