Re-emerging interest in hepatitis delta: New insights into the dynamic interplay between HBV and HDV
Authors: Heiner Wedemeyer
Journal: Journal of Hepatology (2010)

Quantitative longitudinal evaluations of hepatitis delta virus RNA and hepatitis B virus DNA shows a dynamic, complex replicative profile in chronic hepatitis B and DJournal of HepatologyVol. 52Issue 5PreviewThis study presents a real-time reverse-transcription PCR (rt-RT-PCR) assay for hepatitis delta virus (HDV) RNA quantification, designed to clarify the interplay between HDV and hepatitis B virus (HBV) in chronic infection. Full-Text PDF Delta hepatitis is still a major global health problem affecting 15–20 million individuals world-wide [1Rizzetto M. Hepatitis D: thirty years after.J Hepatol. 2009; 50: 1043-1050Abstract Full Text Full Text PDF PubMed Scopus (183) Google Scholar, 2Wedemeyer H. Manns M.P. Epidemiology, pathogenesis and management of hepatitis D: update and challenges ahead.Nat Rev Gastroenterol Hepatol. 2010; 7: 31-40Crossref PubMed Scopus (291) Google Scholar]. The implementation of vaccine programs against hepatitis B was initially associated with a decline in hepatitis D virus (HDV) infections in Southern Europe during the 1980s and 1990s [3Farci P. Delta hepatitis: an update.J Hepatol. 2003; 39: S212-S219Abstract Full Text Full Text PDF PubMed Google Scholar, 4Degertekin H. Yalcin K. Yakut M. Yurdaydin C. Seropositivity for delta hepatitis in patients with chronic hepatitis B and liver cirrhosis in Turkey: a meta-analysis.Liver Int. 2008; 28: 494-498Crossref PubMed Scopus (85) Google Scholar]. However, several studies published over the last few years have shown that the prevalence of hepatitis delta remains rather high in Europe – in particular in immigrant populations. Between 8% and 12% of HBsAg-positive individuals tested anti-HDV positive in France [[5]Le Gal F. Marcellin P. Deny P. Reply to "Wedemeyer et al., Hepatitis D – Not a vanishing disease".Hepatology. 2007; 45: 1332-1333Crossref Scopus (32) Google Scholar], Germany [6Wedemeyer H. Heidrich B. Manns M.P. Hepatitis D virus infection – not a vanishing disease in Europe!.Hepatology. 2007; 45: 1331-1332Crossref PubMed Scopus (145) Google Scholar, 7Erhardt A. Knuth R. Sagir A. Kirschberg O. Heintges T. Haussinger D. Socioepidemiological data on hepatitis delta in a German university clinic–increase in patients from Eastern Europe and the former Soviet Union.Z Gastroenterol. 2003; 41: 523-526Crossref PubMed Scopus (29) Google Scholar], Italy [8Gaeta G.B. Stroffolini T. Smedile A. Niro G. Mele A. Hepatitis delta in Europe: vanishing or refreshing?.Hepatology. 2007; 46: 1312-1313Crossref PubMed Scopus (52) Google Scholar, 9Mele A. Mariano A. Tosti M.E. Stroffolini T. Pizzuti R. Gallo G. et al.Acute hepatitis delta virus infection in Italy: incidence and risk factors after the introduction of the universal anti-hepatitis B vaccination campaign.Clin Infect Dis. 2007; 44: e17-e24Crossref PubMed Scopus (50) Google Scholar, 10Sagnelli E. Stroffolini T. Mele A. Imparato M. Almasio P.L. Chronic hepatitis B in Italy: new features of an old disease – approaching the universal prevalence of hepatitis B e antigen-negative cases and the eradication of hepatitis D infection.Clin Infect Dis. 2008; 46: 110-113Crossref PubMed Scopus (54) Google Scholar], the United Kingdom [[11]Cross T.J. Rizzi P. Horner M. Jolly A. Hussain M.J. Smith H.M. et al.The increasing prevalence of hepatitis delta virus (HDV) infection in South London.J Med Virol. 2008; 80: 277-282Crossref PubMed Scopus (149) Google Scholar], and Turkey [[4]Degertekin H. Yalcin K. Yakut M. Yurdaydin C. Seropositivity for delta hepatitis in patients with chronic hepatitis B and liver cirrhosis in Turkey: a meta-analysis.Liver Int. 2008; 28: 494-498Crossref PubMed Scopus (85) Google Scholar]. A common feature of all these studies was that the majority of HDV-infected individuals were born in highly endemic areas such as Eastern Turkey, Central Asia, or Africa. HDV is also prevalent in South America, in particular in the Amazonian region of Western Brazil [[12]Parana R. Kay A. Molinet F. Viana S. Silva L.K. Salcedo J.M. et al.HDV genotypes in the Western Brazilian Amazon region: a preliminary report.Am J Trop Med Hyg. 2006; 75: 475-479PubMed Google Scholar], and the Western pacific population [[13]Dimitrakakis M. Gust I. HDV infection in the Western Pacific region.Prog Clin Biol Res. 1991; 364: 89-96PubMed Google Scholar]. Hepatitis D has been considered as the most severe form of viral hepatitis in humans. As compared to mono-infection with the hepatitis B virus (HBV), HBV–HDV coinfection is associated with an accelerated course of fibrosis progression, earlier hepatic decompensation of cirrhosis, and an increased risk for the develop-ment of hepatocellular carcinoma [1Rizzetto M. Hepatitis D: thirty years after.J Hepatol. 2009; 50: 1043-1050Abstract Full Text Full Text PDF PubMed Scopus (183) Google Scholar, 2Wedemeyer H. Manns M.P. Epidemiology, pathogenesis and management of hepatitis D: update and challenges ahead.Nat Rev Gastroenterol Hepatol. 2010; 7: 31-40Crossref PubMed Scopus (291) Google Scholar]. In a 28-year long-term follow-up study from Italy, earlier findings were confirmed as one quarter of patients with hepatitis D developed hepatocellular carcinoma, and liver failure was the cause of death for nearly 60% of the patients [[14]Romeo R. Del N.E. Rumi M. Russo A. Sangiovanni A. de F.R. et al.A 28-year study of the course of hepatitis Delta infection: a risk factor for cirrhosis and hepatocellular carcinoma.Gastroenterology. 2009; 136: 1629-1638Abstract Full Text Full Text PDF PubMed Scopus (238) Google Scholar], which is in line with a recent preliminary report from Germany [[15]Calle Serrano B. Heidrich B. Jaroszewicz J. Deterding K. Raupach R. Cornberg M. et al.Long-term outcome of hepatitis delta: a 14-year single center experience.Hepatology. 2009; 50: A773-A774Google Scholar]. Despite continuous interest in the epidemiology and clinical outcome of hepatitis delta, our knowledge on the pathophysiology of liver disease in HDV infection is still rather limited. Several cross-sectional studies showed that different patterns of viral dominances can be observed in patients with hepatitis delta and that HDV infection is frequently associated with suppressed HBV replication. About 70–90% of HDV-infected patients are HBeAg negative and HDV seems also to suppress hepatitis C virus (HCV) replication in triple infected individuals [16Jardi R. Rodriguez F. Buti M. Costa X. Cotrina M. Galimany R. et al.Role of hepatitis B, C, and D viruses in dual and triple infection: influence of viral genotypes and hepatitis B precore and basal core promoter mutations on viral replicative interference.Hepatology. 2001; 34: 404-410Crossref PubMed Scopus (204) Google Scholar, 17Sagnelli E. Coppola N. Scolastico C. Filippini P. Santantonio T. Stroffolini T. et al.Virologic and clinical expressions of reciprocal inhibitory effect of hepatitis B, C, and delta viruses in patients with chronic hepatitis.Hepatology. 2000; 32: 1106-1110Crossref PubMed Scopus (200) Google Scholar, 18Heidrich B. Deterding K. Tillmann H.L. Raupach R. Manns M.P. Wedemeyer H. Virological and clinical characteristics of delta hepatitis in Central Europe.J Viral Hepat. 2009; 16: 883-894Crossref PubMed Scopus (84) Google Scholar]. However and importantly, very few studies did investigate virological patterns over time and determined virological markers longitudinally for several years. In this context the paper by Maria Buti's group from Barcelona, published in the current issue of the Journal of Hepatology, is of major interest [[19]Schaper M. Rodriguez-Frias F. Jardi R. Tabernero D. Homs M. Ruiz G. et al.Quantitative longitudinal evaluation of hepatitis delta virus RNA and hepatitis B virus DNA shows a dynamic complex replicative profile in chronic hepatitis B and D.J Hepatol. 2010; 52: 658-664Abstract Full Text Full Text PDF PubMed Scopus (134) Google Scholar]. In a retrospective-prospective approach, the authors studied samples of HDV-infected patients over a period of 4–8 years and determined quantitative levels of HBV DNA, HDV RNA, and HBsAg. Importantly, and in contrast to conclusions drawn from previous cross-sectional approaches, the authors demonstrate a high frequency of fluctuating activity of either one or even both viruses (Fig. 1). Thus, HDV cannot necessarily be considered as the "dominant" virus based on a single determination. The authors conclude that the role of HBV replication for the pathogenesis of liver disease in hepatitis D should not be underestimated. Schaper et al. first developed a quantitative real-time PCR assay for HDV RNA. Until recently, few studies quantitated HDV RNA in patients with hepatitis delta [[20]Le G.F. Gordien E. Affolabi D. Hanslik T. Alloui C. Deny P. et al.Quantification of hepatitis delta virus RNA in serum by consensus real-time PCR indicates different patterns of virological response to interferon therapy in chronically infected patients.J Clin Microbiol. 2005; 43: 2363-2369Crossref PubMed Scopus (0) Google Scholar]. A possible advantage of the assay developed by Schaper et al. is that genomic HDV RNA from an HDV-infected patient was used as a standard instead of a cloned cDNA. Thus, the reverse transcription step was appropriately assessed in this study. Unfortunately, a WHO standard for HDV RNA is still missing which however would be highly desirable as it is difficult to compare quantitative HDV RNA results between different laboratories at present. HDV RNA levels are not associated with grading or staging of liver disease [[21]Zachou K. Yurdaydin C. Drebber U. Dalekos G.N. Erhardt A. Cakaloglu Y. et al.Quantitative HBsAg and HDV-RNA levels in chronic delta hepatitis.Liver Int. 2009; : 15PubMed Google Scholar]. Nevertheless, HDV RNA quantification may become more important as viral declines during antiviral treatment are associated with long-term virological responses, and thus, treatment duration could be individualized based on HDV RNA kinetics [22Erhardt A. Gerlich W. Starke C. Wend U. Donner A. Sagir A. et al.Treatment of chronic hepatitis delta with pegylated interferon-alpha2b.Liver Int. 2006; 26: 805-810Crossref PubMed Scopus (127) Google Scholar, 23Castelnau C. Le Gal F. Ripault M.P. Gordien E. Martinot-Peignoux M. Boyer N. et al.Efficacy of peginterferon alpha-2b in chronic hepatitis delta: relevance of quantitative RT-PCR for follow-up.Hepatology. 2006; 44: 728-735Crossref PubMed Scopus (218) Google Scholar, 24Yurdaydin C. Bozkaya H. Onder F.O. Senturk H. Karaaslan H. Akdogan M. et al.Treatment of chronic delta hepatitis with lamivudine vs lamivudine + interferon vs interferon.J Viral Hepat. 2008; 15: 314-321Crossref PubMed Scopus (113) Google Scholar]. The genetic variability of HDV has also to be considered when developing new assays for HDV RNA quantification. At least eight different HDV genotypes have been identified [25Radjef N. Gordien E. Ivaniushina V. Gault E. Anais P. Drugan T. et al.Molecular phylogenetic analyses indicate a wide and ancient radiation of African hepatitis delta virus, suggesting a deltavirus genus of at least seven major clades.J Virol. 2004; 78: 2537-2544Crossref PubMed Scopus (189) Google Scholar, 26Makuwa M. Caron M. Souquiere S. Malonga-Mouelet G. Mahe A. Kazanji M. Prevalence and genetic diversity of hepatitis B and delta viruses in pregnant women in Gabon: molecular evidence that hepatitis delta virus clade 8 originates from and is endemic in central Africa.J Clin Microbiol. 2008; 46: 754-756Crossref PubMed Scopus (62) Google Scholar] and assays have rarely been standardized for all the different variants. However, the HDV genotype was no issue in the study by Schaper et al. as all subjects were infected with HDV genotype 1 which could have been expected for European hepatitis D patients [[2]Wedemeyer H. Manns M.P. Epidemiology, pathogenesis and management of hepatitis D: update and challenges ahead.Nat Rev Gastroenterol Hepatol. 2010; 7: 31-40Crossref PubMed Scopus (291) Google Scholar]. HDV is considered as the dominant virus in HBV–HDV coinfection or HBV–HCV–HDV triple infection. Analysing quantitative data for HDV RNA, Schaper and colleagues identified HDV as predominant in about half of the patients only. Thus, HDV may not generally suppress HBV. Recently, molecular mechanisms have been proposed to explain how HDV proteins could interfere with HBV replication. Both the small HDV p24 protein as well as the large HDV p27 protein may repress the HBV enhancers pIIE1 and pIIE2 and thereby inhibit HBV replication [[27]Williams V. Brichler S. Radjef N. Lebon P. Goffard A. Hober D. et al.Hepatitis delta virus proteins repress hepatitis B virus enhancers and activate the alpha/beta interferon-inducible MxA gene.J Gen Virol. 2009; 90: 2759-2767Crossref PubMed Scopus (80) Google Scholar]. However, still up to 30% of hepatitis delta patients are HBeAg positive and also the present data from Barcelona describe several patients with high HBV DNA levels of >105 copies/ml despite HDV coinfection [[19]Schaper M. Rodriguez-Frias F. Jardi R. Tabernero D. Homs M. Ruiz G. et al.Quantitative longitudinal evaluation of hepatitis delta virus RNA and hepatitis B virus DNA shows a dynamic complex replicative profile in chronic hepatitis B and D.J Hepatol. 2010; 52: 658-664Abstract Full Text Full Text PDF PubMed Scopus (134) Google Scholar]. Moreover, any potential suppressive effect of one virus above the other was not fixed as several patients showed fluctuating patterns over time. Notably note, HBV DNA levels did only change if also HDV RNA levels fluctuated. However, both alternating and parallel HBV DNA and HDV RNA profiles were observed, thus making a general dominant direct HBV DNA suppression by HDV unlikely. Overall, these data are also in line with one Italian study that analyzed patients with HBV–HCV coinfection over time including some individuals who were also anti-HDV positive [[28]Raimondo G. Brunetto M.R. Pontisso P. Smedile A. Maina A.M. Saitta C. et al.Longitudinal evaluation reveals a complex spectrum of virological profiles in hepatitis B virus/hepatitis C virus-coinfected patients.Hepatology. 2006; 43: 100-107Crossref PubMed Scopus (182) Google Scholar]. Nevertheless, both studies included in the end a rather limited number of patients for the various subgroups. It is therefore too early to draw finite conclusions and more studies are needed to define the meaning different virological profiles and dynamics for the long-term outcome of the patients. For example, it will be important to determine if specific fluctuation patterns are associated with an increased risk to develop clinical endpoints, and to define which patients most urgently require antiviral treatment. Schaper et al. also studied quantitative HBsAg levels over time. HBsAg levels do significantly differ between different phases of HBV infection [[29]Jaroszewicz J. Calle Serrano B. Wursthorn K. Deterding K. Schlue J. Raupach R. et al.Hepatitis B surface antigen levels in the natural history of hepatitis B virus infection: an European perspective.J Hepatol. 2010; 52: 514-522Abstract Full Text Full Text PDF PubMed Scopus (342) Google Scholar], and are usually high in hepatitis delta despite suppressed HBV DNA [[18]Heidrich B. Deterding K. Tillmann H.L. Raupach R. Manns M.P. Wedemeyer H. Virological and clinical characteristics of delta hepatitis in Central Europe.J Viral Hepat. 2009; 16: 883-894Crossref PubMed Scopus (84) Google Scholar]. HBsAg levels correlated with HDV RNA levels in various cross-sectional studies [21Zachou K. Yurdaydin C. Drebber U. Dalekos G.N. Erhardt A. Cakaloglu Y. et al.Quantitative HBsAg and HDV-RNA levels in chronic delta hepatitis.Liver Int. 2009; : 15PubMed Google Scholar, 30Sheldon J. Ramos B. Toro C. Rios P. Martinez-Alarcon J. Bottecchia M. et al.Does treatment of hepatitis B virus (HBV) infection reduce hepatitis delta virus (HDV) replication in HIV–HBV–HDV-coinfected patients?.Antivir Ther. 2008; 13: 97-102PubMed Google Scholar, 31Shih H.H. Jeng K.S. Syu W.J. Huang Y.H. Su C.W. Peng W.L. et al.Hepatitis B surface antigen levels and sequences of natural hepatitis B virus variants influence the assembly and secretion of hepatitis D virus.J Virol. 2008; 82: 2250-2264Crossref PubMed Scopus (49) Google Scholar]. However, longitudinal testing of both parameters in the present study did not reveal parallel fluctuations of HDV RNA and HBsAg in all cases. One has to consider that HBsAg production and HBV DNA replication are disconnected in later phases of infection, which could be due, in part, to integration of HBV into the host genome; potentially providing a separate template for HBsAg production or cytokine dependent modification of viral replication pathways [[32]Thompson A. Locarnini S. Visvanathan K. The natural history and the staging of chronic hepatitis B: time for reevaluation of the virus–host relationship based on molecular virology and immunopathogenesis considerations?.Gastroenterology. 2007; 133: 1031-1035Abstract Full Text Full Text PDF PubMed Scopus (18) Google Scholar]. All these factors could also play a role in HBV–HDV coinfection, and thus, short-term changes in HDV RNA viremia may not necessarily parallel with changes in HBsAg levels. What are the main clinical consequences of the study by Schaper et al. for the management and treatment of hepatitis delta patients? (i) Most importantly hepatitis delta has to be considered as a highly dynamic disease which is for example in contrast to chronic hepatitis C. Treatment decisions should not be based on single determinations of virological parameters, and patients should be advised to consult their doctors on regular basis, e.g. every 3–6 months. (ii) The role of HBV for disease progression in delta hepatitis should not be underestimated. Thus, although nucleoside and nucleotide analogues currently approved for the treatment of HBV infection are not effective against HDV [[33]Niro G.A. Rosina F. Rizzetto M. Treatment of hepatitis D.J Viral Hepat. 2005; 12: 2-9Crossref PubMed Scopus (108) Google Scholar], treatment of HBV infection should not be forgotten in hepatitis delta if indicated according to current guidelines [[34]European Association for the Study of the Liver. EASL clinical practice guidelines: management of chronic hepatitis B. J Hepatol 2009;50:227–42.Google Scholar]. However, HBV resistance should be avoided as treatment-induced HBV polymerase variants may also confer changes in the structure of the HBsAg, as the open reading frames for HBV polymerase and HBsAg overlap. There is some evidence that the lamivudine-induced sW196S HBsAg variant inhibits secretion of HDV particles [35Vietheer P.T. Netter H.J. Sozzi T. Bartholomeusz A. Failure of the lamivudine-resistant rtM204I hepatitis B virus mutants to efficiently support hepatitis delta virus secretion.J Virol. 2005; 79: 6570-6573Crossref PubMed Scopus (34) Google Scholar, 36Blanchet M. Sureau C. Analysis of the cytosolic domains of the hepatitis B virus envelope proteins for their function in viral particle assembly and infectivity.J Virol. 2006; 80: 11935-11945Crossref PubMed Scopus (54) Google Scholar] with yet unknown clinical consequences. (iii) Treatment options for patients with hepatitis delta need to be improved as this complex disease is associated with significant morbidity and mortality. Currently, only interferon alpha is effective against HDV and, as treatment can be complicated in advanced disease, early treatment might be considered. However and most importantly, the study by Schaper et al. can only represent the starting point of investigating the complex nature of virological patterns in hepatitis delta in more detail. Combined efforts by various centers are needed to define distinct clinical courses which may require more aggressive treatment interventions and monitoring strategies. We have just started to understand the complex biology of this very interesting virus – more than 30 years after its discovery!