Serum immunoglobulin M antibody to hepatitis D as a surrogate marker of hepatitis D in interferon-treated patients and in patients who underwent liver transplantation

The Forgotten Virus, Hepatitis D: A Review of Epidemiology, Diagnosis, and Current Treatment Strategies

Hepatitis D virus (HDV) is an RNA subvirus that infects patients with co-existing hepatitis B virus (HBV) infections. HDV burden is estimated to be approximately 15-20 million people worldwide. Despite HDV severity, screening for HDV remains inadequate. HDV screening would benefit from a revamped approach that automatically reflexes testing when individuals are diagnosed with HBV if HBsAg-positive, to total anti-HDV, and then to quantitative HDV-RNA polymerase chain reaction (PCR) rather than only testing those at high risk sequentially. There are no current treatments in the United States that are Food and Drug Administration (FDA)-approved for the treatment of HDV; however, bulevirtide (BLV) is approved in the European Union conditionally and is under review with the United States FDA. Current treatment strategies in many countries are centered on the use of pegylated-interferon-alfa-2a (PEG-IFNa-2a). There are other therapies in development globally that have shown promise, including BLV, pegylated-interferon-lambda (PEG-IFN-lambda), and lonafarnib (LNF). LNF has shown substantial response in the LOWR trials. BLV is a well-tolerated drug, but it is not finite therapy and has shown significant on-treatment responses in the MYR clinical trials, and the FDA cited concerns with the manufacturing and patient preparation of the drug that have delayed approval. The PDUFA date for BLV in the United States is mid-2024. Current studies with both BLV and LNF are limited in providing sustained virological response (SVR); future trials will need to demonstrate more substantial SVR with possible triple combination trials as options.

Immunology of hepatitis D virus infection: General concepts and present evidence

Infection with the hepatitis D virus induces the most severe form of chronic viral hepatitis, affecting over 12 million people worldwide. Chronic HDV infection leads to rapid development of liver cirrhosis and hepatocellular carcinoma in ~70% of patients within 15 years of infection. Recent evidence suggests that an interplay of different components of the immune system are contributing to viral control and may even be implicated in liver disease pathogenesis. This review will describe general concepts of antiviral immune response and elicit the present evidence concerning the interplay of the hepatitis D virus with the immune system.

Epidemiology, Natural History, and Treatment of Hepatitis Delta Virus Infection in HIV/Hepatitis B Virus Coinfection

PURPOSE OF REVIEW

Limited data exist on the prevalence, determinants, and outcomes of hepatitis delta virus (HDV) infection among HIV/hepatitis B virus (HBV)-coinfected persons. This review provides current evidence on the epidemiology, natural history, and treatment of HDV infection in patients with HIV/HBV coinfection and highlights future research needs.

RECENT FINDINGS

Cross-sectional studies in Europe, Africa, South America, and Asia show that the prevalence of HDV among HIV/HBV-coinfected patients ranges from 1.2 to 25%. No studies have evaluated the prevalence of HDV infection among HIV/HBV-coinfected patients in the USA. HDV infection increases the risk of hepatic decompensation and hepatocellular carcinoma among HIV/HBV-coinfected patients. HDV treatment remains limited to pegylated interferon-alpha, which results in sustained virologic response in fewer than 25%. Data on the epidemiology, natural history, and treatment of HDV among HIV/HBV-coinfected persons remain limited. More research is needed to address these knowledge gaps in order to better manage HDV coinfection in HIV/HBV-coinfected patients.

Laboratory Diagnosis and Monitoring of Viral Hepatitis

Many microbes, toxins, autoimmune diseases, and neoplastic diseases may cause liver inflammation; however, 5 viruses whose main pathogenesis is liver disease are referred to as hepatitis A, B, C, D, and E viruses. These viruses cause a significant burden of global illness. With the exception of hepatitis A virus, all may cause chronic infection potentially leading to cirrhosis and hepatocellular carcinoma. Excellent serologic and nucleic acid detection methods are available for determining the precise cause and, in some cases, the duration of infection. Diagnostics are critical for identifying individuals needing treatment and for monitoring the treatment success.

A new dual-targeting real-time RT-PCR assay for hepatitis D virus RNA detection

In this study, a real-time reverse transcription-polymerase chain reaction (real time RT-PCR) assay targeting 2 genetic segments was established to detect HDV RNA. Utilizing the World Health Organization International Standard for Hepatitis D Virus RNA, the lower limit of detection was 575 IU/mL, and the linearity of quantification ranged from 575,000 IU/mL to 575 IU/mL. 384 HBsAg-positive samples collected from China were tested by this method and HDV antibody detection. Eleven samples were positive for anti-HDV IgG which may persist after HDV resolution, 6 samples were HDV RNA positive, and 5 samples were positive for anti-HDV IgM. This assay showed more sensitivity than the detection of anti-HDV IgM. These data demonstrate that the real-time RT-PCR assay for HDV RNA could be implemented in the clinical detection of HDV infection in chronic HBV-infected patients in China.

The serological markers of acute infection with hepatitis A, B, C, D, E and G viruses revisited

Viral hepatitis is a liver infection caused by one of the six hepatitis viruses: hepatitis A, B, C, D, E, and G virus (HAV to HEV and HGV). These agents differ in their biological, immunological, pathological and epidemiological characteristics. They cause infections that, when symptomatic, lead to clinical manifestations and laboratory findings that are not specific to a particular virus, often making differential diagnosis difficult, especially when no knowledge is available regarding the patient's medical history or the epidemiological background. A number of acute-phase serological markers, such as anti-HAV, anti-HBc, anti-HDV and anti-HEV IgM antibodies, are able to provide a clear indication of an infection caused by HAV, HBV, HDV or HEV. Anti-HCV antibodies and HGV/RNA are used for the diagnosis of HCV and HGV infections. The importance of each of these markers will be reviewed, and different factors that can interfere with the diagnosis of acute infections caused by these viruses will be described.

Anti-HDV IgM as a marker of disease activity in hepatitis delta

Background

Hepatitis delta frequently leads to liver cirrhosis and hepatic decompensation. As treatment options are limited, there is a need for biomarkers to determine disease activity and to predict the risk of disease progression. We hypothesized that anti-HDV IgM could represent such a marker.

Methods

Samples of 120 HDV-infected patients recruited in an international multicenter treatment trial (HIDIT-2) were studied. Anti-HDV IgM testing was performed using ETI-DELTA-IGMK-2-assay (DiaSorin). In addition, fifty cytokines, chemokines and angiogenetic factors were measured using multiplex technology (Bio-Plex System). A second independent cohort of 78 patients was studied for the development of liver-related clinical endpoints (decompensation, HCC, liver transplantation or death; median follow up of 3.0 years, range 0.6–12).

Results

Anti-HDV IgM serum levels were negative in 18 (15%), low (OD<0.5) in 76 (63%), and high in 26 (22%) patients of the HIDIT-2 cohort. Anti-HDV IgM were significantly associated with histological inflammatory (p<0.01) and biochemical disease activity (ALT, AST p<0.01). HDV replication was independent from anti-HDV IgM, however, low HBV-DNA levels were observed in groups with higher anti-HDV IgM levels (p<0.01). While high IP-10 (CXCL10) levels were seen in greater groups of anti-HDV IgM levels, various other antiviral cytokines were negatively associated with anti-HDV IgM. Associations between anti-HDV IgM and ALT, AST, HBV-DNA were confirmed in the independent cohort. Clinical endpoints occurred in 26 anti-HDV IgM positive patients (39%) but in only one anti-HDV IgM negative individual (9%; p = 0.05).

Conclusions

Serum anti-HDV IgM is a robust, easy-to-apply and relatively cheap marker to determine disease activity in hepatitis delta which has prognostic implications. High anti-HDV IgM levels may indicate an activated interferon system but exhausted antiviral immunity.

Epidemiology and diagnosis of hepatitis D virus

The distribution of hepatitis D virus (HDV) is worldwide but not uniform. Current estimates suggest that 15–20 million people have exposure to HDV. Traditionally, areas of high prevalence are the Mediterranean basin, the Middle East, central Africa, the Amazonian basin and parts of Asia. As a consequence of vaccination against HBV and other prophylactic measures, the prevalence of HDV declined in Italy, Spain, Turkey and Taiwan. This downward trend stopped in the 1990s; a new location for HDV epidemics arose in western Europe, due to migration from endemic areas. HDV appeared in new geographic regions, posing a serious health threat in underdeveloped countries. Testing for anti-HVD antibodies in serum is the initial step in diagnosing HDV infection, but unravelling HDV RNA is essential to identify active replication.

Anti-HDV immunoglobulin M testing in hepatitis delta revisited: correlations with disease activity and response to pegylated interferon-α2a treatment

BACKGROUND

The role of anti-HDV immunoglobulin M (IgM) testing in patients receiving pegylated interferon-α therapy for hepatitis delta is unknown. We performed anti-HDV IgM testing in a well defined cohort of HDV-infected patients who were treated with pegylated interferon-α2a plus adefovir, or either drug alone.

METHODS

Sera from 33 HDV-RNA-positive patients from the international HIDIT-1 trial were available for anti-HDV IgM testing (ETI-DELTA-IGMK-2 assay, DiaSorin, Saluggia, Italy) before therapy, at treatment weeks 24 and 48, and at 24 weeks after the end of treatment.

RESULTS

Anti-HDV IgM tested positive in 31 out of the 33 patients (94%) prior to treatment. HDV IgM levels correlated with histological inflammatory activity (r=0.51, P<0.01) and were higher in patients with alanine aminotransferase and γ-glutamyl transpeptidase levels above the median (P<0.05). Quantitative anti-HDV IgM values declined in patients responding to antiviral therapy, however anti-HDV IgM remained positive after treatment in the majority of virological responders.

CONCLUSIONS

We suggest that anti-HDV IgM testing might give additional useful information to determine disease activity in hepatitis delta and to predict treatment response to antiviral therapy with type I interferons. However, determination of anti-HDV IgM can not substitute HDV RNA testing, which remains the primary virological marker for response to therapy.

Hepatitis delta virus infection: open issues

Hepatitis delta virus (HDV) consists of a circular single-stranded RNA genome which assembles two viral proteins and acquires a lipid envelope in which the hepatitis B surface antigens (HBsAg) are embedded. HDV does not encode its own polymerase, but exploits a cellular enzyme for its replication. A better understanding of the mechanisms of HDV replication mechanism would provide new insights for antiviral strategies. Based on genomic variability, eight major genotypes of HDV have been identified, which differ as much as 40% in the nucleotide sequence. The cloning of HDV-RNA has provided genetic probes for the measurement of HDV-RNA in serum and liver; the sensitivity of HDV-RNA detection improved significantly when the reverse transcriptase-polymerase chain reaction (PCR) technique was introduced. As no commercial test is standardized for viral load detection, home-made assays have been developed in the different referral centers, which may not be comparable. Quantification of HDV in serum by real-time PCR has been recently proposed in the management of chronically infected patients. No specific inhibitors of HDV are available at present and, in spite of the crucial relationship between HDV and HBV, drugs that block HBV have only a theoretical but no sound effect on HDV replication.

Treatment of chronic hepatitis B: recommendations from an Italian workshop

The changing scenario of hepatitis B virus therapy has encouraged the organisation of a workshop, endorsed by three Italian scientific societies, aimed at defining the current recommendations for hepatitis B virus treatment. Liver histology and stage of disease remain fundamental for treatment decisions; interferon and nucleoside/nucleotide analogues-based therapy represent different strategies for different phases of the hepatitis B virus disease. The recommendations defined: new and lower cut-off of hepatitis B virus-DNA for eligibility to therapy according to disease stage, how to optimise the use of nucleoside/nucleotide analogues and to individualise the monitoring of response and what to do with treatment failures. Specific recommendations have also been given for cirrhosis patients, those immune suppressed and co-infected with HIV and other hepatitis viruses.

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.

Histologic findings in recurrent HBV

1. The histopathologic presentation of hepatitis B (HB) infection in liver allografts is generally similar to that seen in the nonallografts. 2. An atypical pattern of recurrent HB, i.e., fibrosing cholestatic hepatitis (FCH) occurs in a small number of patients. These patients present with a severe cholestatic syndrome, which may clinically resemble acute or chronic rejection. 3. There are several other possible causes of acute and chronic hepatitis in liver allografts that may need to be considered. 4. Hepatitis B virus (HBV) infection in the liver allograft can easily be confirmed by performing immunohistochemical stains for hepatitis B surface antigen (HBsAg) and hepatitis B core antigen (HBcAg). The expression pattern of these HBV antigens varies and is sometimes helpful in determining whether the liver injury is mainly from the HBV or from other causes in coexistence with the HBV infection. 5. Histological grading of the necroinflammatory activity and staging of the fibrosis should only be applied when the changes are related to the recurrent HB. 6. The pathology of liver transplantation is complex; therefore, clinical correlations remain extremely important in arriving at the final and correct diagnosis.

Immunology of HDV infection

Hepatitis delta virus (HDV) infection may occur as coinfection with hepatitis B virus (HBV) or as superinfection of a chronically HBV-infected patient. A strong antibody response is mounted, which persists for many years; however, it is not able to modulate the course of infection. In most cases the superinfection takes a chronic course. In patients with inactive disease (HDV PCR negative) an oligospecific T-helper cell immune response and a cytotoxic T-cell response were found, which were absent in patients with persistent viremia. The role of the cellular immune response in liver injury during acute infection has not been investigated. Vaccination strategies tested in the woodchuck model induced specific B- and T-cell responses but failed to protect from HDV infection.

Natural Course and Treatment of Hepatitis D Virus Infection

Hepatitis D virus (HDV) is a subviral satellite with hepatitis B virus (HBV) as its natural helper virus. After entry into hepatocytes, it utilizes host cellular enzymes to replicate by a double-rolling-circle mechanism. HDV is most often transmitted by contact with contaminated blood and body fluid, similar to HBV infection. Approximately 5% of the global HBV carriers are coinfected with HDV, leading to a total of 10-15 million HDV carriers worldwide. HDV infection can occur concurrently with HBV infection (coinfection) or in a patient with established HBV infection (superinfection). The pathogenesis of HDV remains controversial. A decline in the prevalence of both acute and chronic hepatitis D (CHD) has been observed worldwide. At present, therapy for chronic HDV infection is by the use of interferon-alpha. Compared to chronic hepatitis B or C, CHD treatment requires a higher dosage and a longer duration of treatment, and post-treatment relapses are common. In order to prevent the progression of CHD and its related morbidity and mortality, more effective treatments are needed.

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.

[Hepatitis D]

The hepatitis D virus (HDV), also called delta virus, is a small circular RNA virus. The HDV is dependent on the hepatitis B virus (HBV) and can cause infection in normal individuals with hepatitis B or yet, superinfect chronic HBV carriers. Three genotypes have already been cloned and sequenced. Infection with HDV has a worldwide distribution and a high HDV endemicity has been documented in the western Amazon region, in Brazil. It has been estimated that 18 million people are infected with this virus amongst the 350 million carriers of the HBV around the world. The HDV transmission and risk factors for infection are similar to those for HBV infection. The diagnosis is based on the immunohistological identification of HDAg in the liver and detection of IgM and IgG anti-HD in serum using RIA or EIA. The clinical course of hepatitis D is variable. Fulminant disease occurs more commonly in hepatitis B and D than in other forms of acute viral hepatitis. Chronic HDV infection is usually associated with severe histological changes in the liver and with a rapidly progressive course, that can lead to cirrhosis, liver failure and death. Treatment of chronic hepatitis D is currently unsatisfactory and interferon alpha is the only agent found to have some effect on the course of chronic hepatitis. Orthotopic liver transplantation is indicated for terminal cases of cirrhosis. Prophylaxis for HDV infection is possible by vaccination against the hepatitis B virus.

Clearance of hepatitis B surface antigen in chronic carriers of hepatitis delta antibodies

BACKGROUND/AIMS

We evaluated the rate of seroclearance of the hepatitis B surface antigen (HBsAg) and its clinical significance in patients with chronic hepatitis delta virus (HDV).

METHODS

Antibody to HDV was tested in HBsAg-positive subjects admitted to our Hospital from 1991 to 1995. In 1997, a biochemical and virologic study was performed in the surviving anti-HD-positive patients who had not undergone transplantation. As a control, a cohort of 106 HBsAg-positive, anti-HD-negative patients was studied.

RESULTS

One hundred and forty-one subjects were originally positive for anti-HD. After 4 years of follow-up, six of the 60 patients who underwent re-evaluation (10%) had cleared the HBsAg: three of the six patients had minimal changes at the initial liver histology and normal ALT, whereas in the remaining three patients with chronic active hepatitis ALT normalized during the observation. Anti-HD persisted in five of the six patients. Only one patient had raised anti-HBs. In contrast, three of 106 HBsAg carriers without HDV infection (2.8%) cleared the HBsAg within the same time and seroconverted to anti-HBs (p=0.002).

CONCLUSION

HBsAg clearance is increased over the years in HDV patients compared to ordinary HBsAg carriers, and is often associated with improvement of HDV disease without seroconversion to anti-HBs.