Hepat Mon. 2011;11(2):128-129 Journal home page: www.HepatMon.ir KOWSAR Occult hepatitis B infection in chronic hemodialysis patients: Comparison of results and concepts Amitis Ramezani 1, Mohammad Banifazl 2, Arezoo Aghakhani 1* 1 Clinical Research Department, Pasteur Institute of Iran, Tehran, IR Iran 2 Iranian Society for Support Patients with Infectious Diseases, Tehran, IR Iran A R T I C L E I N F O Article Type: Letter to Editor Article history: Received: 14 Sep 2010 Revised: 19 Sep 2010 Accepted: 21 Dec 2010 Keywords: Occult hepatitia B infection Hemodialysis Dear Editor, We greatly enjoyed reading the excellent review by Hol- linger and colleagues on occult hepatitis B infection in chronic hemodialysis (HD) patients (1). As Hollinger et al. mentioned in their review, few studies have shown the prevalence of occult hepatitis B virus (HBV) infection in HD patients. Due to the parenteral transmission of HBV, HD pa- tients are at high risk of acquiring this virus because they need frequent blood transfusions and undergo medical procedures that accompany bleeding (2). The prevalence of occult HBV infection in these patients is between 0 to 58% (3-5). The different frequencies of occult HBV infection in HD patients may be due to variation in the prevalence of HBV infection among countries, sensitivity of molecular tech- niques, and the size and virological features of the study groups. In one study, we determined the rate of occult HBV infection in Iranian HD patients with isolated hepatitis B core antibody (anti-HBc) (6). Of 289 patients enrolled in this study, 18 subjects had isolated anti-HBc and HBV-DNA was de- tected in 50% of patients who had isolated anti-HBc. Plasma HBV-DNA load was less than 50 IU/ml in each patient. Our in- vestigation showed that occult HBV infection was common in HD patients with isolated anti-HBc regardless of age, sex, aminotransferases levels, or length of time on dialysis (6). Our data is in agreement with the results of hollinger et al. * Corresponding author at: Arezoo Aghakhani, Clinical Research Department, Pas- teur Institute of Iran, No 69, Pasteur Ave., Tehran, IR Iran. Tel: +98-2166465147, Fax: +98-2166465147. E-mail address: aaghakhani@pasteur.ac.ir, araghakhani@hotmail.com c 2011 Kowsar M.P.Co. All rights reserved. Please cite this paper as: Ramezani A, Banifazl M, Aghakhani A. Occult hepatitis B infection in chronic hemodialysis patients: Comparison of results and concepts. Hepat Mon. 2011;11(2):128-129. c 2011 Kowsar M.P.Co. All rights reserved. (1) and suggests a relatively high prevalence of occult HBV infection in hemodialysis patients. Our study showed that detection of isolated anti-HBc could reflect unrecognized occult HBV infection in HD patients which is in concordance with the conclusions of Hollinger et al. The majority of these infections were associated with low viral loads (6). In anoth- er study, we determined the genotype and surface gene mu- tations of HBV in HD patients with occult HBV infection. All HBV isolates belonged to genotype D. The most important mutations were the insertion of a single nucleotide, prema- ture stop codons at Leu15, and Gly10 and S207N mutations. No “a” determinant mutations were found. Our study sug- gested that “a” regionmutations do not play a major role in HBsAg detection (7). This review provides important infor- mation about the current concepts and strategy in occult HBV infection in chronic HD patients. Our study is limited in that we report no data on liver histopathology or outcome measurements; these should be investigated in the future. References 1. Hollinger FB, Habibollahi P, Daneshmand A, Alavian SM. Occult Hepa- titis B Infection in Chronic Hemodialysis Patients: Current Concepts and Strategy. Hepat Mon. 2010; 10(3):199-204. 2. Eslamifar A, Hamkar R, Ramezani A, Ahmadi F, Gachkar L, Jalilvand S, et al. Hepatitis G virus exposure in dialysis staff. Ther Apher Dial. 2007; 11(5):370-4. 3. Minuk GY, Sun DF, Greenberg R, Zhang M, Hawkins K, Uhanova J, et al. Occult hepatitis B virus infection in a North American adult hemodi- alysis patient population. Hepatology. 2004; 40(5):1072-7. 4. Cabrerizo M, Bartolome J, Caramelo C, Barril G, Carreno V. Molecu- lar analysis of hepatitis B virus DNA in serum and peripheral blood mononuclear cells from hepatitis B surface antigen-negative cases. Hepatology. 2000; 32(1):116-23. 5. Fabrizi F, Messa PG, Lunghi G, Aucella F, Bisegna S, Mangano S, et al.