Serological markers in fulminant hepatitis B

Mapping Neutralizing and Immunodominant Sites on the SARS-CoV-2 Spike Receptor-Binding Domain by Structure-Guided High-Resolution Serology

Analysis of the specificity and kinetics of neutralizing antibodies (nAbs) elicited by SARS-CoV-2 infection is crucial for understanding immune protection and identifying targets for vaccine design. In a cohort of 647 SARS-CoV-2-infected subjects, we found that both the magnitude of Ab responses to SARS-CoV-2 spike (S) and nucleoprotein and nAb titers correlate with clinical scores. The receptor-binding domain (RBD) is immunodominant and the target of 90% of the neutralizing activity present in SARS-CoV-2 immune sera. Whereas overall RBD-specific serum IgG titers waned with a half-life of 49 days, nAb titers and avidity increased over time for some individuals, consistent with affinity maturation. We structurally defined an RBD antigenic map and serologically quantified serum Abs specific for distinct RBD epitopes leading to the identification of two major receptor-binding motif antigenic sites. Our results explain the immunodominance of the receptor-binding motif and will guide the design of COVID-19 vaccines and therapeutics.

Distinct disease features in chimpanzees infected with a precore HBV mutant associated with acute liver failure in humans

Transmission to chimpanzees of a precore hepatitis B virus (HBV) mutant implicated in acute liver failure (ALF) in humans did not cause ALF nor the classic form of acute hepatitis B (AHB) seen upon infection with the wild-type HBV strain, but rather a severe AHB with distinct disease features. Here, we investigated the viral and host immunity factors responsible for the unusual severity of AHB associated with the precore HBV mutant in chimpanzees. Archived serial serum and liver specimens from two chimpanzees inoculated with a precore HBV mutant implicated in ALF and two chimpanzees inoculated with wild-type HBV were studied. We used phage-display library and next-generation sequencing (NGS) technologies to characterize the liver antibody response. The results obtained in severe AHB were compared with those in classic AHB and HBV-associated ALF in humans. Severe AHB was characterized by: (i) the highest alanine aminotransferase (ALT) peaks ever seen in HBV transmission studies with a significantly shorter incubation period, compared to classic AHB; (ii) earlier HBsAg clearance and anti-HBs seroconversion with transient or undetectable hepatitis B e antigen (HBeAg); (iii) limited inflammatory reaction relative to hepatocellular damage at the ALT peak with B-cell infiltration, albeit less extensive than in ALF; (iv) detection of intrahepatic germline antibodies against hepatitis B core antigen (HBcAg) by phage-display libraries in the earliest disease phase, as seen in ALF; (v) lack of intrahepatic IgM anti-HBcAg Fab, as seen in classic AHB, but at variance with ALF; and (vi) higher proportion of antibodies in germline configuration detected by NGS in the intrahepatic antibody repertoire compared to classic AHB, but lower than in ALF. This study identifies distinct outcome-specific features associated with severe AHB caused by a precore HBV mutant in chimpanzees, which bear closer resemblance to HBV ALF than to classic AHB. Our data suggest that precore HBV mutants carry an inherently higher pathogenicity that, in addition to specific host factors, may play a critical role in determining the severity of acute HBV disease.

Role of humoral immunity against hepatitis B virus core antigen in the pathogenesis of acute liver failure

Hepatitis B virus (HBV)-associated acute liver failure (ALF) is a dramatic clinical syndrome leading to death or liver transplantation in 80% of cases. Due to the extremely rapid clinical course, the difficulties in obtaining liver specimens, and the lack of an animal model, the pathogenesis of ALF remains largely unknown. Here, we performed a comprehensive genetic and functional characterization of the virus and the host in liver tissue from HBV-associated ALF and compared the results with those of classic acute hepatitis B in chimpanzees. In contrast with acute hepatitis B, HBV strains detected in ALF livers displayed highly mutated HBV core antigen (HBcAg), associated with increased HBcAg expression ex vivo, which was independent of viral replication levels. Combined gene and miRNA expression profiling revealed a dominant B cell disease signature, with extensive intrahepatic production of IgM and IgG in germline configuration exclusively targeting HBcAg with subnanomolar affinities, and complement deposition. Thus, HBV ALF appears to be an anomalous T cell-independent, HBV core-driven B cell disease, which results from the rare and unfortunate encounter between a host with an unusual B cell response and an infecting virus with a highly mutated core antigen.

Immune mediated liver failure

Liver failure is a clinical syndrome of various etiologies, manifesting as jaundice, encephalopathy, coagulopathy and circulatory dysfunction, which result in subsequent multiorgan failure. Clinically, liver failure is classified into four categories: acute, subacute, acute-on-chronic and chronic liver failure. Massive hepatocyte death is considered to be the core event in the development of liver failure, which occurs when the extent of hepatocyte death is beyond the liver regenerative capacity. Direct damage and immune-mediated liver injury are two major factors involved in this process. Increasing evidence has suggested the essential role of immune-mediated liver injury in the pathogenesis of liver failure. Here, we review the evolved concepts concerning the mechanisms of immune-mediated liver injury in liver failure from human and animal studies. Both innate and adaptive immunity, especially the interaction of various immune cells and molecules as well as death receptor signaling system are discussed. In addition, we highlight the concept of "immune coagulation", which has been shown to be related to the disease progression and liver injury exacerbation in HBV related acute-on-chronic liver failure.

Management of severe acute to fulminant hepatitis B: to treat or not to treat or when to treat?

Despite a decline in cases of acute hepatitis B and the low hepatitis B virus (HBV) chronicity rates in adults, still some patients progress to HBV-related fulminant liver failure. In this review, we discuss treatment options that may prevent the progression of severe acute hepatitis B to fulminant liver failure and death. In severe acute HBV with prolonged prothrombin time and increased bilirubin, interferon failed to be effective while antiviral treatment, particularly with lamivudine, appears to improve survival (mean survival almost 80%). Outcome without antiviral therapy has remained considerably poor, whereas there is no convincing evidence of amelioration of HBV-targeted immunity. Of note, most patients who died or required transplantation despite lamivudine therapy, were started on lamivudine at advanced stages compared with those survived. This suggests that prompt and timely antiviral therapy is crucial. Owing to the abovementioned results the design of randomized placebo-control trials in the setting of severe acute hepatitis B seems unethical. On the contrary, the design of multicentre double-blind randomized trials to compare the efficacy between lamivudine and entecavir or even tenofovir in acute severe HBV cases is ideally needed, but these studies appear to be very difficult to perform considering that these cases are not frequent and therefore, it is almost impossible to have two arms adequately numerous and homogenous for statistical evaluation. Thus, in the absence of solid evidence based data, the hepatologists could treat their patients with severe acute hepatitis B with lamivudine or the most potent antivirals entecavir or tenofovir.

Fatal fulminant primary hepatitis B virus infections with G1896A precore viral mutants in southeastern France

Fulminant hepatitis has been shown to occur in about 1% of acute hepatitis B virus (HBV) infections, and its mortality rate is nearly 70%. Specific HBV genotypic features have been pointed out in fulminant acute hepatitis B worldwide, but these associations remain controversial. We describe all four primary HBV infections diagnosed in 2008 in our institution in Marseille, southeastern France, including two fatal cases. HBV genotypes were D or E. Precore G1896A HBV mutants were detected in both fatal fulminant primary HBV infections. Hepatitis B surface antigen and hepatitis B e antigen (HBeAg) were negative in two and three cases, respectively, despite HBV DNA detection. Primary HBV infection remains a cause of death in France. The impact of the precore G1896A mutation on the severity of AHB deserves to be assessed in larger studies in this country.

B cell gene signature with massive intrahepatic production of antibodies to hepatitis B core antigen in hepatitis B virus-associated acute liver failure

Hepatitis B virus (HBV)-associated acute liver failure (ALF) is a dramatic clinical syndrome due to a sudden loss of hepatic cells leading to multiorgan failure. The mechanisms whereby HBV induces ALF are unknown. Here, we show that liver tissue collected at the time of liver transplantation in two patients with HBV-associated ALF is characterized by an overwhelming B cell response apparently centered in the liver with massive accumulation of plasma cells secreting IgG and IgM, accompanied by complement deposition. We demonstrate that the molecular target of these antibodies is the hepatitis B core antigen (HBcAg); that these anti-bodies display a restricted variable heavy chain (V(H)) repertoire and lack somatic mutations; and that these two unrelated individuals with ALF use an identical predominant V(H) gene with unmutated variable domain (IGHV1-3) for both IgG and IgM anti-HBc antibodies, indicating that HBcAg is the target of a germline human V(H) gene. These data suggest that humoral immunity may exert a primary role in the pathogenesis of HBV-associated ALF.

Failure to incriminate hepatitis B, hepatitis C, and hepatitis E viruses in the aetiology of fulminant non-A non-B hepatitis

Sporadic non-A, non-B hepatitis is the most common indication for liver transplantation in patients presenting with fulminant and subacute liver failure. This study used serological, histological, and molecular biological techniques to examine specimens from 23 consecutive patients transplanted for sporadic non-A, non-B hepatitis. No evidence was found of hepatitis C virus, hepatitis E virus, or 'cryptic' hepatitis B virus infection.

Immunostaining for membrane attack complex of complement is related to cell necrosis in fulminant and acute hepatitis

BACKGROUND/AIMS

Complement activation is one of the mechanisms involved in inflammatory lesions. Initiation of the complement terminal pathway at a cell surface leads to the formation of a cytolytic membrane attack complex. Our study assess whether a membrane attack complex-associated mechanism is involved in liver cell necrosis of fulminant and subfulminant hepatitis.

METHODS

Immunostaining for membrane attack complex was compared with immunostaining for cytokeratin and complement inhibitory proteins such as membrane cofactor protein, decay-accelerating factor, and homologous restriction factor in 15 patients with fulminant hepatitis and 5 patients with nonfulminant acute hepatitis.

RESULTS

In all patients, hepatocytes surrounding necrotic areas, but not those at a distance, were stained for membrane attack complex, whereas the opposite staining pattern for membrane cofactor protein was observed. In controls, no hepatocyte staining for membrane attack complex was observed, whereas membrane cofactor protein, but not decay-accelerating factor or homologous restriction factor, was detected on hepatocytes.

CONCLUSIONS

Complement activation by antibody-dependent or non-antibody-dependent mechanisms might be involved in the pathogenesis of either fulminant or acute hepatitis. Modulation of membrane cofactor protein expression on hepatocytes might contribute to the sensitivity of hepatocytes to membrane attack complex and subsequent cell lysis.

Acute liver failure due to lymphoma. A diagnostic concern when considering liver transplantation

Lymphomatous involvement of the liver may present as acute liver failure but is an absolute contraindication for liver transplantation. Therefore it is imperative to diagnose such patients since survival in this group is poor and recurrence is high. We describe two patients with acute liver failure referred for liver transplantation whose diagnostic testing revealed hepatic lymphoma. These cases underscore the importance of considering lymphoma in the differential diagnosis of acute liver failure prior to liver transplant.

Nucleotide sequence analysis of the precore region in patients with fulminant hepatitis B in the United States

BACKGROUND

A precore defective hepatitis B virus (HBV) mutant unable to produce hepatitis B e antigen (HBeAg) has been associated with fulminant hepatitis B. We have studied the etiologic contribution of precore mutants among North American patients with this disorder.

METHODS

We studied 39 patients with fulminant hepatitis B. The precore and proximal core regions of HBV from 37 of 39 patients were sequenced.

RESULTS

Four patients (10.8%) harbored nonsense mutants likely to produce an HBeAg negative HBV infection; two such mutants had a G to A substitution at position 1896, one lost the precore initiation codon, and one harbored a stop codon immediately downstream of the precore initiation codon. Recovered sequences from seven additional patients displayed silent or missense mutations in these regions. All delta coinfected patients harbored known wild type strains of HBV. A significantly poorer survival was associated with antibody to HBe positivity and presence of nucleotide substitutions in the precore/core region.

CONCLUSIONS

The prevalence of precore mutations in 37 patients from the United States was lower than reported elsewhere; only two patients were found to have the G to A transition mutation in the precore region at position 1896. We conclude that HBeAg negative HBV mutants do not play a predominant etiologic role among North American patients with fulminant hepatitis B.

Acute delta hepatitis without hepatitis B surface antigen detectable in the blood

The case is described of a 42-year-old man suffering from acute delta hepatitis without hepatitis B surface antigen (HBsAg) being detectable in his blood. Tests on the patient's blood were negative for anti-HBcIgM and HBeAg but positive for anti-HBs, anti-HBe, HDAg and anti-DIgM. It is well known that the delta antigen-antibody system is detectable only in HBsAg carriers except rarely in persons recently recovered from acute hepatitis B virus (HBV) and delta infection. We report one of the rare cases in which the circulating HBsAg as well as anti-HBcIgM and HBeAg were not found in the patient's serum, thus indicating the absence of recent infection with HBV.

Liver transplantation and hepatitis viruses

Considerations regarding liver transplantation in viral-hepatitis-related acute liver failure and end-stage chronic liver disease are discussed. Parameters of prognosis and indications for transplantation are presented. Differences according to the causative agent are noted, in particular regarding the danger of reinfection. The role of immunoprophylaxis is addressed as is the question of additional antiviral (interferon) treatment.

Prognostic significance of pre-S2 antigen and antibody in fulminant hepatitis B. Evidence for heterogeneous serological responses

Serial sera were collected prospectively and from early on in the clinical course of ten patients with fulminant hepatitis B. These were analysed for HBV DNA (dot-blot technique), HBsAg, HBeAg, pre-S2-Ag and their respective antibodies. Two patterns emerged in nine of the patients. The first and well-recognised pattern of rapid clearance of antigens and appearance of antibodies was seen in four patients, all of whom survived. The second pattern seen in five patients was one of persistence of HBsAg and pre-S2 antigen and failure to detect antibodies but only one patient survived. The first pattern may reflect a more rapid cessation of virus replication and this may favour liver cell regeneration and recovery. In contrast, the second pattern may indicate continuing virus replication and liver cell damage which could contribute to the high mortality in some patients with fulminant hepatitis B.

Intensive liver care and management of acute hepatic failure

In describing acute liver failure, the term fulminant hepatic failure (FHF) is used to denote patients with the most rapid progression, normally defined as the onset of encephalopathy within eight weeks of the onset of symptoms. For patients with a slower onset of encephalopathy, ranging from eight weeks to six months after the onset of symptoms, late-onset hepatic failure is the term used to reflect the overlap in clinical features with some patients with FHF. The importance of accurately determining the type of acute liver failure results from increasing evidence of an inverse relationship between the tempo of disease progression and the chances of recovery. Prognosis is also dependent on the underlying etiology. Principles of management are as follows: (1) an accurate recognition of the tempo of the hepatic failure--fulminant, late onset, acute on chronic--and the establishment of a likely etiology; (2) early detection and treatment of complications, particularly metabolic acidosis (early), renal failure, cerebral edema, and infection (late); (3) optimization of conditions for regeneration by maintenance of a near normal metabolic milieu (with removal of toxins by various methods of artificial liver support if necessary); and (4) early consideration of an orthotopic liver transplant for those patients in the poor prognosis group. Variations in the natural history and clinical features of acute liver failure (ALF) have led to a number of different classifications and subgroupings. Knowledge of these is important in relation to the assessment of prognosis and is even more important now that transplantation is a therapeutic option.(ABSTRACT TRUNCATED AT 250 WORDS)

Fulminant hepatic failure

These discussions are selected from the weekly staff conferences in the Department of Medicine, University of California, San Francisco. Taken from transcriptions, they are prepared by Drs Homer A. Boushey, Professor of Medicine, and David G. Warnock, Associate Professor of Medicine, under the direction of Dr Lloyd H. Smith, Jr, Professor of Medicine and Associate Dean in the School of Medicine. Requests for reprints should be sent to the Department of Medicine, University of California, San Francisco, School of Medicine, San Francisco, CA 94143.

Does tumor necrosis factor play a role in the pathogenesis of fulminant hepatitis?

Fulminant hepatitis is associated with an 80% mortality rate. Surviving patients do not develop chronic liver disease. Failure to produce adequate amounts of interferon and to achieve an antiviral state seem to be the basic defects in this condition. Tumor necrosis factor (TNF) has been shown to be induced by viruses. By rapid lysis of virus infected cells, it also prevents optimal viral replication thus reducing the viral yield and the infection rate and extent. On the other hand, it has growth promoting characteristics. We postulate that TNF has a dual role in fulminant hepatitis: (a) It acts as an antiviral agent by eliminating virus infected cells thus reducing viral yields and limiting spread of infection; (b) it may be the signal for hepatocyte regeneration. Only those patients, in whom the regeneration rate exceeds lysis of infected hepatocyte by TNF, survive.

Dual color fluorescence analysis of peripheral T cell subsets in hepatitis B virus-induced liver disease

By using dual color fluorescence analysis, peripheral T cells can be divided into four different subsets, Leu-2a+15+, Leu-2a+15-, Leu-3a+8+ and Leu-3a+8- cells. The ratio of these T cell subsets in hepatitis B virus-induced hepatitis patients was studied and compared with that of controls. No significant difference was found in acute hepatitis and chronic hepatitis, but an elevation of Leu-2a+15- (29.5 +/- 2.8% vs. 18.8 +/- 4.1%, p less than 0.05) as well as a reduction of Leu-2a+15+ cells (3.2 +/- 0.7% vs. 10.4 +/- 3.2%, p less than 0.05) were found in fulminant hepatitis patients. In addition, serial studies of two fulminant hepatitis patients revealed that the imbalance of these two Leu-2a cells was only found in the acute phase, but not in the recovery phase. These results indicate that the imbalance of these two Leu-2a cells is associated with the clinical status of patients with fulminant hepatitis.

Hepatitis B serology--help in interpretation

This review discusses the serologic markers of hepatitis B virus (HBV) infection. Interpretation of various serologic profiles is provided, and the importance of maternal screening for interruption of perinatal transmission of HBV infection is stressed.

Virological markers and antibody responses in fulminant viral hepatitis

Clinical profiles, serological markers, and antibody responses to antigens of hepatitis B virus (HBV) were studied in patients with fulminant viral hepatitis. Whereas hepatitis A and B were found to be uncommon causes (6.9% and 12.2%, respectively), non-A, non-B (NANB) hepatitis was found to be the most common cause of fulminant hepatitis (80.9%). As against this, the incidence of hepatitis B and NANB hepatitis was very similar in nonfulminant acute viral hepatitis in adults (41.2% and 51.9%, respectively). Pregnancy with labour was an important precipitating factor for development of fulminant hepatitis of the NANB type only; 32% of fulminant NANB hepatitis patients were pregnant women and 22.6% had a history of labour preceding hepatic coma. Only 0.8% of nonfulminant NANB hepatitis cases were pregnant women. Another major precipitating factor for the development of the fulminant form of NANB hepatitis was concomitant chronic HBV carrier state. A total of 38.6% of fulminant NANB hepatitis patients were HBV carriers, whereas only 19.2% of nonfulminant acute NANB hepatitis cases were HBV carriers. Sera of 32 chronic HBV carriers with fulminant NANB hepatitis and 10 cases of fulminant hepatitis B were tested for delta antibody, and all were nonreactive. The antibody responses of the fulminant hepatitis B patients to the antigens of HBV were found to be greater compared to those of patients with nonfulminant acute hepatitis B. Antibody responses of chronic HBV carriers with fulminant NANB hepatitis to antigens of HBV were found to be depressed in comparison with those of chronic asymptomatic carriers.

An enzyme-linked immunosorbent assay (ELISA) for the detection of IgG and IgM anti-idiotypes directed against anti-HBs molecules

A simple and specific enzyme-linked immunosorbent assay (ELISA) has been developed to detect circulating IgG and IgM anti-idiotypic antibodies directed against anti-HBs molecules using 96-well polyvinyl microtitre plates as the solid phase and HRPO-labelled goat anti-HBs as conjugate. Anti-idiotype reactions were observed in the supernatant portion after precipitation of immune complexes from sera with polyethylene glycol 6000 (PEG). Both IgG and IgM with anti-idiotype activity were detected concurrently in HBsAg-positive sera from HBV-infected patients and asymptomatic HBV carriers. Anti-idiotype activity was absent in HBsAg-negative sera from healthy persons, and in patients with non-A, non-B hepatitis and viral hepatitis A. However, such antibodies could be demonstrated in the sera of two out of eight HBsAg vaccine recipients negative for anti-HBs but in none of 11 recipients positive for anti-HBs after receiving a booster immunising dose of HBsAg vaccine. Those sera showing positive anti-idiotype reactions were free from rheumatoid factor and HBsAg/IgM or HBsAg/IgG complex activity. An analysis of anti-idiotype positive sera for anti-HBs, HBeAg and HBV-specific DNA-polymerase activity demonstrated these markers in 20%, 30% and 60% of cases, respectively. The presence of anti-idiotypic antibodies was presumed to permit a more active multiplication of hepatitis B virus.

Fulminant hepatitis B in successive female sexual partners of two anti-HBe-positive males

In two separate families, consecutive, unrelated female sexual partners of a symptom-free, male, HBsAg-positive carrier died of fulminant hepatitis B. Although one man was HBeAg positive on the first occasion, both men were considered of low infectivity, being anti-HBe positive, negative for serum DNA polymerase activity, and negative for serum hepatitis B virus (HBV) DNA when their second partners presented with fulminant hepatitis B. By means of molecular hybridisation techniques, both men were found to have HBV DNA (3.2 kb) in seminal fluid, sputum, saliva, peripheral blood leucocytes, and liver.

Search for hepatitis B virus DNA in sera from patients with acute type B or non-A, non-B hepatitis

One hundred and three single sera from adults hospitalized with acute type B (78) or non-A, non-B (25) hepatitis were tested for the presence of hepatitis B virus DNA (HBV DNA). All sera from patients with type B hepatitis were IgM anti-HBc-positive. These patients were classified as benign (47) or fulminant (31) hepatitis. The 25 acute non-A, non-B patients were also classified as benign (21) or fulminant (4) hepatitis and were negative for serologic markers of past HBV infection. Serum HBV DNA was detected with similar frequency in benign (38.5%) and fulminant (FH, 34.6%) HBsAg-positive cases. HBV DNA was not detected in either the 26 acute HBsAg-negative hepatitis B cases who were positive for anti-HBc and anti-HBs or the 25 acute non-A, non-B hepatitis cases. The absence of HBV DNA in 43.8% of benign hepatitis B patients who were positive for HBsAg and HBeAg could possibly be attributed to either low level replication of HBV that was not detectable by the [32P]HBV DNA probe or to a period of delayed clearance of free HBeAg following cessation of HBV replication. Emergence of anti-HBs in the presence of HBsAg did not always correspond to clearance of HBV in fulminant type B cases. However, in acute type B hepatitis, irrespectively of severity, disappearance of HBsAg and appearance of anti-HBs was accompanied by reduction of HBV replication to undetectable levels.

Acute delta hepatitis without circulating HBsAg

Infection with the delta agent can only occur in the context of coexistent hepatitis B virus infection. We describe a patient in whom the clinical features of acute delta hepatitis developed when seroconversion from hepatitis B surface antigen to antibody had already occurred and diagnosis of recent acute hepatitis B was based on high titre IgM antibody to hepatitis B core antigen. We discuss the significance of such a serological profile, not previously described.