Elimination of hepatitis delta virus infection after loss of hepatitis B surface antigen in patients with chronic delta hepatitis

HBV/HDV Co-Infection: Epidemiological and Clinical Changes, Recent Knowledge and Future Challenges

Several investigations have been published on Hepatitis Delta Virus (HDV) infection in recent years, from which we have drawn the salient data to provide readers with useful information to improve their knowledge on the subject. HDV genotypes 5–8 have been recently imported to Western countries from central Africa, whose clinical relevance deserves further investigation. Ongoing HDV replication has been identified as an independent predictor of progression to cirrhosis and HCC for patients with HDV chronic hepatitis (HDV-CH). Long-term treatments of HDV-CH with standard or pegylated interferon alfa (peg-IFN-α) have all been unsatisfactory, leading to a sustained virological response (SVR) only in 20–30% of patients treated, faced with a poor tolerability and frequent serious adverse reactions; the addition of HBV nucleo(s)tide analogues to peg-IFN- α did not improve the rate of SVR. The improved knowledge of the HDV life cycle has allowed the development of direct acting agents towards key-points of the HDV life cycle, namely bulevirtide, lonafarnib and nucleic acid polymers. Preliminary data have shown that these drugs are more effective than interferon-based therapies, but adverse reactions are also common, which however seem toned down in combination therapy with other antivirals.

Hepatitis D in Children

Hepatitis D virus (HDV) is an uncommon, defective, single-stranded circular RNA virus that is dependent on the hepatitis B virus' surface antigen envelope proteins for transmission. It is highly pathogenic and associated with high rates of progression to cirrhosis and associated complications. HDV continues to ravage endemic parts of Asia and Europe, and its prevalence in the United States, although low, has not decreased in frequency, despite universal hepatitis B virus vaccination, because of lack of testing and underrecognition. There are few reports on the prevalence and characteristics of HDV infection in the pediatric population. We present 2 patients with HDV infection at our institution; both were from eastern Europe and were treated with pegylated interferon-α. The present standard of care treatment for HDV yields suboptimal results, but insights into the virology of hepatitis D are stimulating the search for novel therapeutic approaches, particularly the development of prenylation inhibitors and viral entry inhibitors.

Interferon alpha-2b therapy in chronic hepatitis delta

BACKGROUND

Approximately 5% of hepatitis B virus (HBV) carriers are coinfected with hepatitis D virus (HDV). HBV/HDV coinfection is a major cause of cirrhosis and end stage liver disease in chronic HBsAg carriers. The only approved therapy for chronic hepatitis delta is interferon alpha (IFN α) in either pegylated or conventional forms. Although higher doses and longer durations of IFN α therapy in HBV/HDV coinfected patients are currently applied, yet treatment response is low.

OBJECTIVES

We aimed to determine the efficacy of IFN α-2b therapy in patients with HBV/HDV coinfection.

PATIENTS AND METHODS

In this cross sectional study, 20 HBsAg carriers with positive Anti-HDVAb and RT-PCR for HDV RNA were recruited and treated for three year duration with 5 million units (MU) of IFN α-2b, three times weekly or one year with 5 MU of IFN α-2b daily. Sustained virological response (SVR) was defined as a negative qualitative HDV RT-PCR, 6 months after treatment cessation.

RESULTS

Overall, 3 (15%) subjects achieved SVR, 10 cases (50%) relapsed after treatment cessation and 7 (35%) patients did not clear HDV during the treatment.

CONCLUSIONS

HDV coinfection with HBV had very low response rate to high doses and long durations of IFN α-2b therapy.

Infections of the Liver

The portal vein carries blood from the gastrointestinal tract to the liver and in so doing carries microbes as well. The liver may therefore be involved in infections with a myriad number of microbial organisms. While some of these infections most commonly occur in the immunocompromised host, others affect the immune competence. Hepatic infections may be primary in nature or secondary, as part of systemic or contagious disease. The purpose of this chapter is to provide a brief overview of the various infections of the liver in the pediatric patient.

Interferon alpha for chronic hepatitis D

BACKGROUND

Hepatitis D virus is a small defective RNA virus that requires the presence of hepatitis B virus infection to infect a person. Hepatitis D is a difficult-to-treat infection. Several clinical trials have been published on the efficacy of interferon alpha for hepatitis D virus (HDV) infection. However, there are few randomised trials evaluating the effects of interferon alpha, and it is difficult to judge any benefit of this intervention from the individual trials.

OBJECTIVES

To evaluate the beneficial and harmful effects of interferon alpha for patients with chronic hepatitis D.

SEARCH METHODS

We identified relevant for the review randomised clinical trials by electronic searches in the Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, and Science Citation Index Expanded until May 2011. We also checked the bibliographic references of identified randomised trials, textbooks, and review articles in order to find randomised trials not identified by the electronic searches.

SELECTION CRITERIA

Randomised clinical trials evaluating interferon alpha versus placebo or no intervention for patients with chronic hepatitis D infection.

DATA COLLECTION AND ANALYSIS

Two authors assessed the trials and extracted data on mortality, virologic, biochemical, and histological response as well as adverse events at end of treatment and six months or more after completing treatment. The analyses were performed using the intention-to-treat principle including all randomised participants irrespective of follow-up. Drop-outs, withdrawals, and non-compliance were considered as treatment failures. Data were analysed with fixed- and random-effects models. Reported results were based on fixed-effect model except in cases where statistical significance varied between the two models.

MAIN RESULTS

Six randomised trials fulfilled the inclusion criteria. Two hundred and one randomised participants (male = 174) were included. The risk of bias in all the included trials was high. Five trials compared interferon alpha with no treatment in the control group. One of these trials had two treatment arms with a higher dose and lower dose of interferon alpha and a no-treatment control group. We analysed both treatment regimens as a single group in a primary analysis and as separate groups in the subgroup analysis of different interferon dosages. The sixth trial compared only a higher dose of interferon alpha with a lower dose.Meta-analysis of five trials comparing interferon alpha with no-treatment control group included 169 participants. There were seven drop-outs in the treatment group and nine in the control group. One patient out of 92 (1.1%) died in the interferon alpha group compared with zero out of 77 (0.0%) in the no-intervention control group (risk ratio (RR)) 3.00; 95% confidence interval (CI) 0.14 to 66.5). Interferon alpha led to failure of end of treatment virological response in 62/92 (67.4%) of the patients compared with 71/77 (92.2%) in the untreated controls (RR 0.76, 95% CI 0.66 to 0.87, P = 0.0001 by fixed-effect model and RR 0.71, 95% CI 0.43 to 1.16, P = 0.17 by random-effects model). Failure of normalisation of alanine aminotransferase (ALT) at the end of treatment was seen in 60/92 (65.2%) patients treated with interferon alpha versus 76/77 (98.7%) in the control group (RR 0.69, 95% CI 0.59 to 0.80, P < 0.00001). Sustained virological response was not achieved in 76/92 (82.6%) of patients on interferon compared with 73/77 (94.8%) of controls (RR 0.89, 95% CI 0.80 to 0.98, P = 0.02). Serum alanine aminotransferase was abnormal in 81/92 (88.0%) treated with interferon alpha patients at six months post-treatment follow-up compared with 76/77 (98.7%) in controls (RR 0.92, 95% CI 0.84 to 0.99, P = 0.04). There was no significant histological improvement in 67/92 (72.8%) patients treated with interferon alpha compared with 65/77 (84.4%) in controls (RR 0.86, 95% CI 0.74 to 1.00, P = 0.06).Two trials comparing a higher dose of interferon alpha with the lower dose showed no significant difference in sustained virological response (76.7% compared with 90.0%) (RR 0.85, 95% CI 0.68 to 1.07, P = 0.16). Adverse events such as flu-like symptoms, asthenia, weight loss, alopecia, thrombocytopenia, and leukopenia were reported in all these trials and the adverse events were related to interferon alpha. These were common and sometimes severe. One patient in the treatment group was reported to have died by suicide towards the end of the study period.

AUTHORS' CONCLUSIONS

Interferon alpha does not seem to cure hepatitis D in most patients. The agent seems effective in suppressing viral and liver disease activity in some patients, but this improvement is not sustained in the majority of patients. We cannot exclude overestimation of benefits and underestimation of harms due to high risk of bias (systematic errors) and high risk play of chance (random errors). Therefore, more randomised trials with large sample sizes and less risk of bias are needed before interferon can be recommended or refuted.

A 28-year study of the course of hepatitis Delta infection: a risk factor for cirrhosis and hepatocellular carcinoma

BACKGROUND & AIMS

Chronic infection with hepatitis Delta virus (HDV) is a risk factor for cirrhosis and hepatocellular carcinoma (HCC); predictors of disease outcome are, however, poorly defined. We tracked the course of HDV infection in 299 patients over a mean period of 233 months.

METHODS

We analyzed data from patients who had been HDV positive for at least 6 months (230 males; mean age, 30 years) admitted from 1978 to 2006 to Maggiore Hospital, Milan. HDV infection was defined by the presence of HDV antigen in liver tissue or serum HDV RNA in anti-HDV/hepatitis B surface antigen seropositive patients. At enrollment, 7 patients had acute hepatitis, 101 had mild-moderate chronic hepatitis, 76 had severe chronic hepatitis, and 104 had histologic or clinical cirrhosis. Ninety patients were treated with interferon, 62 with corticosteroids, and 12 with nucleoside analogues; 135 received no therapy.

RESULTS

Over a mean period of 233 months, 82 patients developed cirrhosis. Among the 186 total patients with cirrhosis, 46 developed HCC, 43 ascites, 44 jaundice, and 1 encephalopathy. Female sex, alcohol abuse, and HDV replication were associated with liver decompensation; HBV replication and interferon were associated with HCC development. By the end of the study, 186 patients were still alive, 63 had died, and 29 had received liver transplants. The main cause of death was liver failure (n = 37, 59%); HDV replication was the only independent predictor of mortality.

CONCLUSIONS

Persistent HDV replication leads to cirrhosis and HCC at annual rates of 4% and 2.8%, respectively, and is the only predictor of liver-related mortality.

Quantitative Analysis of Hepatitis D Virus RNA and Hepatitis B Surface Antigen Serum Levels in Chronic Delta Hepatitis Improves Treatment Monitoring

Background/aims

Treatment of chronic delta hepatitis is long and difficult and better monitoring is needed.

Methods

In this study, hepatitis delta virus (HDV) RNA, hepatitis B surface antigen (HBsAg) and hepatitis B virus (HBV) DNA were retrospectively quantified in 53 patients with hepatitis B e antigen (HBeAg)-negative chronic hepatitis delta. Twenty-one had received 28 courses of 3–5 MU interferon-α2b (IFN-α2b) thrice weekly for a median of 12.6 months (interquartile range [IQR]: 7.3–31.6), five had received eight courses of 100 mg lamivudine (LAM) daily for 23.6 months (IQR: 8.4–61.5) and 27 were untreated. The controls were 54 untreated, randomly selected, HBeAg-negative chronic hepatitis B patients without delta infection. Quantification of serum HDV RNA, HBsAg and HBV DNA were performed at baseline, during and at the end of treatment and end of follow up.

Results

Untreated patients had significantly higher median HBsAg levels than controls (5,872 vs 3,501 IU/ml; P=0.046), but lower median HBV DNA levels (2.933 vs 6.459 log10 copies/ml; P<0.001). Median baseline HDV RNA (6.374 log10 copies/ml) was similar in IFN-α2b-treated, LAM-treated and untreated patients. At the end of treatment, IFN-α2b significantly suppressed in paired measurements HDV RNA ( P=0.012) and HBsAg ( P=0.043), but LAM was inefficient. In IFN-α2b-treated patients, HDV RNA became undetectable in five patients within a median of 30 months (IQR: 8–90), followed by a slower decrease in HBsAg.

Conclusions

In untreated chronic delta hepatitis, suppressed HBV replication is associated with significantly increased HBsAg serum levels. IFN-α2b significantly suppresses both HDV RNA and HBsAg, but LAM has no effect. Long-term IFN-α2b treatment (IQR: 1.5–5.0 years) appears necessary for undetectable serum HDV RNA and further treatment is required for HBsAg loss. Monitoring of HDV RNA and HBsAg serum levels in patients with chronic delta hepatitis provides insight during treatment.

Pegylated interferon alpha-2b as monotherapy or in combination with ribavirin in chronic hepatitis delta

Therapy of chronic hepatitis delta with standard interferon therapy has met with limited efficacy. This study was designed to examine the efficacy and safety of peginterferon with or without ribavirin. Thirty-eight serum hepatitis B surface antigen- and HDV RNA-positive patients with alanine aminotransferase (ALT) more than 1.5 times the upper normal limit received peginterferon alpha-2b (1.5 microg/kg) alone as monotherapy (n=16) or in combination with ribavirin (n=22), for 48 weeks. Thereafter, all the patients were maintained on peginterferon for 24 weeks and followed for 24 weeks off therapy. The primary end point studied was the virological and biochemical response at the end of follow-up. HDV RNA was determined by single or nested polymerase chain reaction assays. Twenty-seven patients (71%), 11 receiving monotherapy and 16 receiving the combination treatment, completed the follow-up. At the end of treatment, a virological response was observed in 3 of the patients treated with peginterferon (19%) and in 2 of the patients treated with combination therapy (9%), and a biochemical response was observed in 6 (37.5%) and 9 patients (41%), respectively. In nonresponders, ALT diminished from a mean of 174+/-53 to 86+/-41 IU/L. At the end of follow-up, serum HDV RNA was negative in 8 patients (21%), and a biochemical response was detected in 10 patients (26%). Treatment was discontinued in 25% of the patients, and dosing was modified in 58%. In conclusion, a prolonged course of peginterferon alpha-2b resulted in clearance of serum HDV RNA and ALT normalization in a fifth of patients with chronic hepatitis D, while ribavirin had no effect on the viral clearance rate. Overall tolerance of therapy was poor.

Treatment of hepatitis D

Delta virus related chronic hepatitis is difficult to treat. The response to alpha-interferon (IFN), which still represents the only therapy for chronic hepatitis D, varies widely and occurs at different times from the beginning of treatment. The rate of response is proportional to the dose of IFN, with 9 million units (MU) three times a week being more effective than 3 MU thrice weekly. Sustained responses are unusual and are accompanied by the clearance of serum hepatitis B virus surface antigen (HBsAg), seroconversion to anti-HBs and improvement of liver histology. Although disease of a short-standing may respond better to therapy, clear predictors of response are still unidentified. Besides IFN, other therapeutic approaches such as immunosuppressive drugs, acyclovir, ribavirin and thymosin, have been unhelpful. Available evidence does not support the use of deoxynucleotide analogues. Famciclovir has no effect on disease activity and hepatitis D virus (HDV)-RNA levels. Twelve- or 24-month lamivudine treatment does not significantly affect biochemical, virological or histological parameters. Pegylated-IFN could represent a reasonable therapeutic option in the long-term treatment required for chronic hepatitis D. Antisense oligonucleotides and prenylation inhibitors hold promise as therapeutic agents of the future. Liver transplantation provides a valid option for end-stage HDV liver disease; the risk of re-infection is lower for HDV than for HBV under long-term administration of hyperimmune serum against HBsAg. Molecularly tailored drugs capable of interfering with crucial viral replicative processes of HDV appear to be the best prospect in the treatment of hepatitis D.

Short- and long-term effects of treatment of chronic hepatitis B and delta virus by IFN

Chronic hepatitis B virus (HBV) infection is a common infectious disease in the world. Two percent of the patients with chronic HBV infection will develop cirrhosis each year, and will die prematurely from cirrhosis or hepatocellular carcinoma. So far interferon alfa and lamivudine are the only effective drugs. Interferon alfa can be used at the dosage of 9-10 million units thrice a week for 4-6 months either intramuscularly or subcutaneously for standard treatment. Interferon provides sustained response in 1/3 of the patients when HBe Ag is (+). Response rate to interferon therapy in HBe Ag(-) patients was similar to that reported in HBe Ag(+) ones. However the responses were not sustained in many patients, serum HBV-DNA reappear in most after stopping the treatment. Extension of therapy to 1 year may be needed in patients who are unresponsive to therapy and having HBV-DNA levels <10 pg/ml and ALT >100 IU. Establishment of unresponsiveness in early phases of the therapy is important and careful follow up of serum HBe Ag may be helpful. Interferon alfa treatment of chronic HDV infection may result in temporary normalization of ALT values. Disappearance of HBV-DNA and HBs Ag from the serum upon completion of therapy dictates sustained response in chronic HDV infection. The long term effect of interferon with respect to virological and histopathological responses is poor in HDV infection and longer periods of therapy in higher doses may be beneficial.

Update on chronic viral hepatitis

Many recent and significant advances in the field of chronic viral hepatitis, including therapy, suggest that an update on chronic hepatitis is timely. Chronic hepatitis B virus infection remains a significant worldwide cause of liver cirrhosis and hepatocellular carcinoma, despite the wide availability of a long established and effective vaccine. Transmission occurs via perinatal, sexual, and parenteral routes (particularly intravenous drug abuse and although blood products still carry a risk, this is now extremely low in Western countries). Only a minority of infected adult cases develop chronic hepatitis but in children under 1 year, 90% develop chronic hepatitis. The clinical spectrum of chronic liver injury ranges from mild inflammation to end stage liver cirrhosis. Interferon alfa has been the mainstay of treatment for patients with active disease but nucleoside analogues (lamivudine and adefovir) are now available with similar efficacy. Patients with end stage liver disease and hepatocellular carcinoma can be offered transplantation but infection in the graft is commonplace. The combination of hepatitis B immunoglobulin and newer antiviral drugs reduce the incidence and severity of graft infection significantly. The hepatitis C virus epidemic of the latter half of the 20th century now affects more than 1% of populations worldwide. This RNA virus is spread parenterally and is becoming the leading indication for liver transplantation. The majority of patients develop chronic hepatitis, which may be progressive, evolving to significant liver disease (cirrhosis or hepatocellular carcinoma) in about 20% cases after decades. Treatment with the combination of interferon alfa and ribavirin is successful in up to 40% cases. Liver transplantation is a therapeutic option for some but graft infection is universal and often complicated by progressive liver fibrosis. A vaccine remains a remote prospect so that prevention is crucial. Hepatitis D virus infection occurs on a background of hepatitis B virus infection and can also cause liver damage. The response to antiviral therapy is poor. The newer "hepatitis" viruses G and TT do not cause significant liver injury.

Lamivudine-high dose interferon combination therapy for chronic hepatitis B patients co-infected with the hepatitis D virus

Currently, the best option for patients with hepatitis delta is interferon alpha therapy for at least one year. To evaluate the effect of the combination lamivudine-high-dose interferon alpha therapy, we first treated eight patients with chronic hepatitis delta infection with lamivudine for at least 24 weeks; then lamivudine was combined with a high dose of interferon alpha followed by a regular dose (9 MU tiw). Follow-up was 12 weeks. Virological, biochemical and histological features were evaluated for response to therapy. At baseline, all patients were HBsAg positive in serum and HDV RNA-(PCR)positive in plasma; HBV DNA was undetectable with the Digene Hybrid Capture assay (limit of detection 1.5 x 10(6) geq ml-(1)) in all cases. Transaminases were elevated in all patients; median ALT 68 (range 48-143) IU l(1). Seven of eight patients completed the course; one patient with a pre-existing sickle cell trait was withdrawn from the trial due to the development of a nephrotic syndrome. The HBsAg-concentration in serum decreased in two out of seven patients (29%). However, there was no significant decrease in the HBsAg-concentration in serum during treatment (median 3654 PEU l(-1) (range 548-7,684) to 5300 PEU l(-1) (range 168-19,639)). The drop of HDV RNA in plasma from baseline during treatment was not significant. Decrease of HDV RNA was observed in three out of seven patients (43%) (median 10(5) geq ml(-1); range 10(3)-10(6) to median 10(3) geq ml(-1); range 10(2)-10(7)). Serum ALT did not change as reflected by a median of 68 IU l(-1) (range 48-143) at start of therapy to 63 IU l(-1) (range 20-171) at the end of therapy. At the end of treatment transaminases had normalised in one patient and decreased in three other patients (improvement in 57%). However, three of these four patients showed a rebound after withdrawal of therapy. The Histology Activity Index (HAI) indicated a drop from a median score of 7 (range 5-9) at baseline to 5 (range 3-8) at the end of treatment, but an increase in fibrosis from a median grade of 2 (range 1-3) at baseline to 3 (range 1-4) at the end of treatment was observed. In conclusion, this study does not yield support for the combination of an HBV suppressor and 16 weeks of high-dose interferon for therapy aimed at eradicating the hepatitis delta virus.

Resolution of chronic delta hepatitis after 12 years of interferon alfa therapy

Chronic delta hepatitis is an uncommon but severe form of chronic viral hepatitis for which there is currently no satisfactory therapy. A patient with chronic delta hepatitis was treated with interferon alfa, 5 million units daily for 12 years. Serial serum samples were tested for routine liver tests and selected samples for quantitative levels of hepatitis B surface antigen (HBsAg) and hepatitis delta virus RNA. Liver biopsies were performed before, during, and after an initial 1-year course of therapy and again after 3 and 10 years of continuous therapy. With initiation of interferon therapy, serum aminotransferase levels decreased to normal range, became abnormal again when the dose was reduced, and increased to pretreatment levels when therapy was stopped. With reinstitution and prolonged therapy, aminotransferase levels became persistently normal; after several years, both hepatitis delta virus RNA and serum HBsAg became undetectable. Liver biopsy, which initially revealed cirrhosis, showed gradual improvement in inflammatory and fibrosis scores and, after 10 years, no abnormalities or fibrosis. Therapy was stopped, and the patient remained free of evidence of infection. In conclusion, long-term therapy with interferon alfa in high doses led to resolution of chronic delta hepatitis, disappearance of hepatitis delta and B virus markers, and improvement in fibrosis.

Lamivudine for chronic delta hepatitis

Chronic delta hepatitis is a severe form of chronic liver disease caused by hepatitis delta virus (HDV) infection superimposed on chronic hepatitis B or the hepatitis B surface antigen (HBsAg) carrier state. Therapy of delta hepatitis is currently unsatisfactory. We have evaluated lamivudine (3-thiacytidine), an oral nucleoside analogue with marked effects against hepatitis B, as therapy in 5 patients with chronic hepatitis D. Five men, ages 38 to 65 years, were treated. All had HBsAg, antibody to HDV, and HDV RNA in serum, as well as persistent elevations in alanine aminotransferase (ALT) levels and liver histology showing severe chronic hepatitis with fibrosis or cirrhosis. Lamivudine was given in a dose of 100 mg orally daily for 12 months. Patients were monitored carefully and tested for HBsAg, HBV-DNA and HDV-RNA levels serially during the year of treatment and for 6 months thereafter. Liver biopsies were performed before therapy and repeated after 1 year. Serum levels of HBV DNA fell rapidly in all 5 patients, becoming undetectable even by polymerase chain reaction (PCR) in 4. However, all 5 patients remained HBsAg- and HDV-RNA-positive, and serum ALT levels and liver histology did not improve. All patients tolerated therapy well. When lamivudine was stopped, HBV-DNA levels returned to pretreatment values without a change in disease activity. Lamivudine is a potent inhibitor of HBV-DNA replication, but does not improve disease activity or lower HDV-RNA levels in patients with chronic delta hepatitis.

Hepatitis viruses A, B, C, D, E and G: implications for dental personnel

BACKGROUND

This article provides dental personnel with a brief overview of the different types of viral hepatitis, including their epidemiology, clinical features, prevention and treatment. It also explores the ramifications of these diseases for the practice of dentistry. DESCRIPTION OF THE CONDITION: Viral hepatitis is an inflammation of the liver caused by one of at least six distinct viruses. The hepatitis A and E viruses, or HAV and HEV, are enterically transmitted viruses that produce acute disease only. The hepatitis B, C and D viruses, or HBV, HCV and HDV, are most efficiently transmitted by infected blood, but also can be transmitted by exposure to other infectious bodily fluids. These three viruses can cause acute or chronic hepatitis. People with chronic viral hepatitis can develop chronic liver disease, cirrhosis and hepatocellular carcinoma. The hepatitis G virus was recently identified, and its ability to cause clinically significant acute or chronic hepatitis is unknown.

CONCLUSIONS

Dental health care workers, or DHCWs, should be concerned primarily with HBV, HCV and HDV, as occupational exposure to these pathogens places them at risk of developing acute or chronic infections. Vaccines and immune globulins are available and effective in protecting against infections with HAV, HBV and HDV, but not HCV.

CLINICAL IMPLICATIONS

DHCWs should become knowledgeable about viral hepatitis. They should be vaccinated against hepatitis B. Adherence to infection control measures will help prevent occupational transmission of all bloodborne pathogens, including hepatitis viruses.

Review: hepatitis delta

The causative agent of hepatitis delta virus (HDV) is the most unusual of all causative agents for all hepatitis viruses. Current knowledge of the molecular biology of HDV strengthens its proposed classification within the satellites, a family of subviral agents, some of which are pathogens of higher plants. Hepatitis delta virus is the only virus in the satellite family known to infect animal species, with hepatitis D having affected more than 10 million people worldwide who are also infected with its helper virus, HBV. Recently, the world map for hepatitis D appears somewhat modified, with decreasing HDV prevalence in certain areas and some new foci of HDV endemicity. Despite changing HDV prevalence, hepatitis. D, particularly the chronic form, is still an important health problem worldwide in terms of morbidity and mortality (mainly due to chronic liver disease, including hepatocellular carcinoma). Molecular studies have greatly advanced our understanding of the life cycle of HDV and of the function of its proteins. The new molecular information is of clinical relevance, with implications for the pathogenesis of liver damage, the diagnosis of HDV infection, for the natural course of the disease and, potentially, for therapy. Sensitive assays for HDV-RNA by polymerase chain reaction and sequencing techniques have clarified the patterns of HDV transmission and have confirmed the existence of unusual clinical forms of the virus and their relationship to replicative levels and genotypes of HDV. Prevention and treatment of hepatitis D are still in their infancy. However, liver transplantation for delta cirrhosis has proven far more successful than in any other viral form of cirrhosis, with few reinfections of the grafted liver, and has given important information on HDV biology and the pathogenesis of liver damage.

Suppression of hepatitis C virus (HCV) replication by hepatitis D virus (HDV) in HIV-infected hemophiliacs with chronic hepatitis B and C

Most hemophiliacs who are coinfected with human immunodeficiency virus (HIV) and hepatitis C virus (HCV) have high serum levels of HCV RNA. To study the impact of multiple hepatitis virus infections, we evaluated all eight chronic carriers of hepatitis B surface antigen (HBsAg) from a previously studied cohort of 99 hemophiliacs with chronic HIV and HCV infections. Stored serum or plasma samples were tested for antibody to hepatitis D virus (anti-HDV) by ELISA; qualitatively for HCV RNA, HBV DNA, and HDV RNA by the polymerase chain reaction (PCR); and quantitively for HIV RNA, HCV RNA, and hepatitis B virus (HBV) DNA by a quantitative branched DNA signal amplification assay. HCV RNA was detected in only one of five patients with HDV infections on a cross-sectional study, and this individual had low levels (< 3.5 x 10(5) genome eq/ml) of HCV RNA. In contrast, all three without HDV infections had high levels (> 1.5 x 10(7) genome eq/ml) of HCV RNA. HIV RNA was present in all eight patients. There was no correlation between the level of HIV RNA and the presence of hepatitis viruses. Three of the eight patients (38%) died of liver failure and another has hypersplenism with hypoprothrombinemia. We conclude that HDV infection appears to suppress HCV replication and that liver failure is common in adult HIV-infected hemophiliacs with chronic HCV and HBV infections. These findings have implications for the therapy of HCV-infected hemophiliacs who are HBsAg positive.