Occult hepatitis B in high-risk patients needs more attention.

I read with interest the recently published article by Ramezani et al. [1] in your journal. The issue is important but all the aspects and clinical importance of the study are not clear. According to an international workshop on occult hepatitis B virus infection (OBI) in 2008 [2], OBI is defined as the presence of HBV DNA in the liver (with detectable or undetectable HBV DNA in the serum) of individual patients who test negative for hepatitis B surface antigens (HBsAg) which are detected by highly sensitive tests [3,4]. The authors mentioned that they performed HBV DNA PCR in all anti HBcAb positive cases; however, we know that about 20% of occult hepatitis B (OHB) sera are negative for all serological markers of HBV infection except HBV DNA [3]. This data suggests that Ramezani et al. have probably underestimated the real issue in the high-risk group. Additionally, another potential problem arises when applying OHB instead of the OBI without established infectivity [3]. Hemodialysis patients are at higher risk of acquiring HBV infection [5] and there are some reports of finding HBV DNA from PBMC of HBsAg-negative hemodialysis patients [6,7]. If Ramezani et al. had conducted their investigation in all hemodialysis patients and in PBMC, the prevalence of OHB would have been greater than that reported in their study. However, I agree with their results indicating higher rates of co-infection in HIV/HCV patients than in hemodialysis patients or blood donors. These results show that, during recent years, blood screening has improved [8]. References 1. Ramezani A, Banifazl M, Eslamifar A, Aghakhani A (2010) Serological pattern of anti-HBc alone infers occult hepatitis B virus infection in high-risk individuals in Iran J Infect Dev Ctries 4: 658-661. 2. Raimondo G, Allain JP, Brunetto MR, Buendia MA, Chen DS, Colombo M, Craxì A, Donato F, Ferrari C, Gaeta GB, Gerlich WH, Levrero M, Locarnini S, Michalak T, Mondelli MU, Pawlotsky JM, Pollicino T, Prati D, Puoti M, Samuel D, Shouval D, Smedile A, Squadrito G, Trépo C, Villa E, Will H, Zanetti AR, Zoulim F (2008) Statements from the Taormina expert meeting on occult hepatitis B virus infection. J Hepatol 49: 652-657. 3. Hollinger FB and Sood G (2010) Occult hepatitis B virus infection: a covert operation. J Viral Hepat 17: 1-15. 4. Raimondo G, Navarra G, Mondello S, Costantino L, Colloredo G, Cucinotta E, Di Vita G, Scisca C, Squadrito G, Pollicino T (2008) Occult hepatitis B virus in liver tissue of individuals without hepatic disease. J Hepatol 48: 743-746. 5. Mahdavimazdeh M, Hosseini-Moghaddam SM, Alavian SM, Yahyazadeh H (2009) Hepatitis B Infection in Hemodialysis Patients in Tehran Province, Iran. Hepat Mon 9: 206-210. 6. Hollinger FB, Habibollahi P, Daneshmand A, Alavian SM (2010) Occult Hepatitis B Infection in Chronic Hemodialysis Patients: Current Cocepts and Strategy. Hepat Mon 10: 199-204. 7. Cabrerizo M, Bartolome J, De Sequera P, Caramelo C, Carreno V (1997) Hepatitis B virus DNA in serum and blood cells of hepatitis B surface antigen-negative hemodialysis patients and staff. J Am Soc Nephrol 8: 14431447. 8. Mansour-Ghanaei F, Sadeghi A, Mashhour MY, Joukar F, Besharati S, Roshan ZA, Khosh-Sorur M (2009) Prevalence of Hepatitis B and C Infection in Hemodialysis Patients of Rasht (Center of Guilan Province, Northern Part of Iran). Hepat Mon 9: 45-49.