Differential diagnosis of acute HBsAg positive hepatitis using IgM anti-HBc by a rapid, fully automated microparticle enzyme immunoassay

Differentiation of acute and chronic hepatitis B in IgM anti-HBc positive patients

AIM: To identify the factors that differentiate acute hepatitis B (AHB) from chronic hepatitis B with acute exacerbation (CHB-AE).

METHODS: From 2004 to 2013, a total of 82 patients (male n = 52, 63.4%; female n = 30, 36.6%) with clinical features of acute hepatitis with immunoglobulin M antibodies to the hepatitis B core antigen (IgM anti-HBc) were retrospectively enrolled and divided into two groups; AHB (n = 53) and CHB-AE (n = 29). The AHB group was defined as patients without a history of hepatitis B virus (HBV) infection before the episode and with loss of hepatitis B surface antigen within 6 mo after onset of acute hepatitis. Biochemical and virological profiles and the sample/cutoff (S/CO) ratio of IgM anti-HBc were compared to determine the differential diagnostic factors.

RESULTS: The multivariate analysis demonstrated that, the S/CO ratio of IgM anti-HBc and HBV DNA levels were meaningful factors. The S/CO ratio of IgM anti-HBc was significantly higher in the AHB group, while the HBV DNA level was significantly higher in the CHB-AE group. The optimal cutoff values of IgM anti-HBc and HBV DNA levels for differentiating the two conditions were 8 S/CO ratio and 5.5 log₁₀ IU/mL, respectively. The sensitivity and specificity were 96.2% and 89.7% for the S/CO ratio of IgM anti-HBc and 81.1% and 72.4% for HBV DNA levels, respectively. The area under receiver operating characteristic curves of both the S/CO ratio of IgM anti-HBc and HBV DNA levels were not significantly different (0.933 vs 0.844, P = 0.105). When combining IgM anti-HBc and HBV DNA, the diagnostic power significantly improved compared to HBV DNA alone (P = 0.0056). The combination of these factors yielded a sensitivity and specificity of 98.1% and 86.2%, respectively.

CONCLUSION: The combination of the S/CO ratio of IgM anti-HBc and HBV DNA levels was a useful tool for differentiating AHB from CHB-AE in patients with positive IgM anti-HBc.

Re-appraisal of old and new diagnostic tools in the current management of chronic hepatitis B

Hepatitis B virus (HBV) is a very complex and intricate DNA structure associated with a particular genomic organization and replication cycle. However, many years of investigations allowed clarification of the real HBV natural history, through a deeper knowledge of the behavior of HBV antigens and viral structures. Several of the old diagnostic tools, such as HBV surface antigen (HBsAg) and HBV e antigen (HBeAg) determinations, gained prominence now, since the variation of both HBsAg and HBeAg plasma levels was shown to predict treatment response. In addition, the availability of more sensitive methods, such as HBV DNA detection by real-time PCR, has improved the current knowledge of the relationships between HBV replication levels and the natural history of the disease. It is now well established that some HBV genotypes are associated with a better response to treatment with pegylated interferon. Despite the widely accepted value of liver biopsy as a staging tool, transient elastography is being increasingly acknowledged as a non-invasive method to assess liver stiffness, chiefly for detection of advanced fibrosis. Current international guidelines for the management of chronic hepatitis B have provided several accurate biochemical and serological criteria for selecting patients for treatment, allowing a higher number of cases to be enrolled into antiviral therapy. This review describes the different serological markers used for the study of HBV and their clinical significance. It also deals with methods used for detection of genotypes and HBV DNA, emphasizing the effectiveness of such determinations for both patient selection and chronic hepatitis B therapy/monitoring.

Acute exacerbation of chronic hepatitis B: the dilemma of differentiation from acute viral hepatitis B

Exacerbations of chronic hepatitis B are common in endemic countries. Acute exacerbation of chronic hepatitis B virus (CHB-AE) causing derangement of liver functions may be seen in a flare of HBV in immune clearance phase or as a reactivation of HBV in patients with inactive or resolved HBV infection. While reactivation of HBV is usually seen in HBsAg positive patients, it is being increasingly recognized in patients with apparently resolved HBV infection who do not have HBsAg in serum but have IgG antibody to core antigen (anti-HBc) in the serum, especially so in patients on chemotherapy, immunosuppressive therapy or undergoing hematopoietic stem cell transplantation. In an icteric patient who is HBsAg positive, it may be difficult to differentiate CHB-AE from acute viral hepatitis B (AVH-B). Both may have similar clinical presentation and even IgM anti-HBc, the traditional diagnostic marker of AVH-B, may also appear at the time of exacerbation of CHB. The differentiation between CHB-AE and AVH-B is important not only for prognostication but also because management strategies are different. Most cases of AVH-B will resolve on their own, HBsAg clearance is achieved spontaneously in 90-95% of adults and treatment is rarely indicated except in the few with severe/fulminant disease. In contrast, in CHB-AE, the onset of jaundice may lead to decompensation of liver disease and treatment is warranted. The mechanisms of acute exacerbation and the differentiating features between AVH-B and CHB-AE are reviewed.

Review of hepatitis B surveillance in China: improving information to frame future directions in prevention and control

BACKGROUND

As the WHO verified that China reached the target of 1% prevalence of chronic hepatitis B infection among children targeted by universal hepatitis B immunization of newborns, the country considered new options for hepatitis B prevention and control. We reviewed hepatitis B surveillance in the broader context of viral hepatitis surveillance to propose recommendations to improve the system.

METHODS

We described surveillance for viral hepatitis in China with a specific focus on hepatitis B. We assessed critical attributes of the system, including data quality, predictive positive value and usefulness.

RESULTS

While remarkable progress in hepatitis B immunization of infants and children has likely almost eliminated transmission in younger age groups, reported rates of hepatitis B increased steadily in China between 1990 and 2008, probably because of a failure to distinguish acute from chronic infections. Elements that prevented a clearer separation between acute and chronic cases included (1) missed opportunity to report cases accurately among clinicians, (2) low availability and use of tests to detect IgM against the hepatitis B core antigen (IgM anti-HBc) and (3) lack of systems to sort, manage and analyze surveillance data.

CONCLUSIONS

To improve hepatitis B surveillance, China may consider (1) training clinicians to diagnose acute cases and to use IgM anti-HBc to confirm them, (2) improving access and use of validated IgM anti-HBc tests and (3) developing data management and analysis techniques that sort out acute from chronic cases.

Significance of liver histology in HBsAg-positive, IgM anti-HBc-negative acute hepatitis B virus-related hepatitis

AIMS

The natural course of HBsAg-positive, IgM anti-HBc-negative acute hepatitis B virus (HBV)-related hepatitis is unclear. The aim of this study was to evaluate the prognostic significance of histological features and hepatic expression of HBV antigens in such patients.

METHODS AND RESULTS

Fifty patients with HBsAg-positive, IgM anti-HBc-negative acute hepatitis B who underwent liver biopsy during the acute hepatitis episode were studied [HBeAg seroconversion (n = 16), persistently positive for HBeAg (n = 9), and persistently negative for HBeAg (n = 25)]. Twenty-six cases had features of typical acute hepatitis only (group A), and 24 cases had changes suggesting pre-existing chronic hepatitis (group B). HBcAg and/or HBsAg immunoreactivity was detected less frequently in group A than in group B (31% versus 79%, P = 0.01). HBsAg clearance was observed in 24% of patients, almost exclusively in cases with HBeAg seroconversion. HBsAg loss was significantly more frequent in group A than in group B (52% versus 0%, P < 0.001), and in cases without rather than with immunohistochemical expression of HBV antigens (55% versus 0%, P < 0.001). In group A, HBsAg clearance was observed in 80%, 54% and 0% of patients with mild, moderate or severe acute hepatitis, respectively (P < 0.034).

CONCLUSIONS

Histological information is very important for the prognosis of HBsAg-positive, IgM anti-HBc-negative acute hepatitis B. HBeAg seroconversion with underlying typical acute hepatitis changes of mild to moderate severity without hepatic expression of HBV antigens strongly predicts subsequent HBsAg loss.

Core mutations in patients with acute episodes of chronic HBV infection are associated with the emergence of new immune recognition sites and the development of high IgM anti-HBc index values

Acute exacerbations in HBeAg negative patients with chronic hepatitis B virus (HBV) infection are invariably associated with concurrent increases in the index of IgM class antibodies against the core protein (anti-HBc) of the virus. This study aimed to investigate whether this was related to the clearance of variants from the quasispecies pool and the appearance of new ones, with aminoacid substitutions in well recognized B-cell epitopes. In this study, 5 HBeAg negative patients (A to E) with 13 sequential serum samples (A1-A2, B1-B2-B3, C1-C2, D1-D2-D3, E1-E2-E3) were investigated after amplification of the entire core encoding region followed by cloning/sequencing studies. The sequences at different time points were compared with those from a single HBeAg positive patient with no apparent acute exacerbations. The results from sequence comparison showed that virus variants emerged in all (A2, B3, C2, D3, E2, and E3) but two (B2 and D2) subsequent sera with amino-acid substitutions affecting B-cell epitopes. It is concluded that the rise in the values of IgM anti-HBc may be attributed to the alteration of the antigenic epitopes leading to new antibody production in the majority of the cases. However, it appears that increases in IgM anti-HBc indexes in a few cases may relate to other possible mechanisms which are discussed.

Clinical, biochemical, immunological and virological profiles of, and differential diagnosis between, patients with acute hepatitis B and chronic hepatitis B with acute flare

BACKGROUND AND AIM

In areas with high or intermediate endemicity for chronic hepatitis B virus (HBV) infection, it is difficult to distinguish acute hepatitis B (AHB) from chronic hepatitis B with an acute flare (CHB-AF) in patients whose prior history of HBV infection has been unknown. The present study aimed to screen laboratory parameters other than immunoglobulin M antibody to hepatitis B core antigen (IgM anti-HBc) to discriminate between the two conditions.

METHODS

A retrospective and prospective study was conducted in patients first presenting clinically as HBV-related acute hepatitis to sort out acute self-limited hepatitis B (ASL-HB). Then, clinical and laboratory profiles were compared between patients with ASL-HB and CHB-AF. Parameters closely associated with ASL-HB were chosen to evaluate sensitivity, specificity, accuracy, positive predictive values and negative predictive values for diagnosing AHB.

RESULTS

There were significant differences between patients with ASL-HB and CHB-AF in relation to clinical and laboratory aspects, with many outstanding differences in levels of serum HBV-DNA, hepatitis B e antigen (HBeAg) and alpha-fetoprotein (AFP) as well as IgM anti-HBc. In particular, there was a greater difference between the two groups in low levels of HBeAg (ratio of the optical density of the sample to the cut-off value [S/CO] <20) than in negativity for HBeAg (42.7% and 13.5% vs 49.3% and 45.9%). 1:10 000 IgM anti-HBc had a sensitivity and specificity of 96.2% and 93.1%, respectively, for predicting ASL-HB. Combining it with AFP, HBeAg or HBV-DNA could improve diagnostic power. A combination of IgM anti-HBc, HBV-DNA and HBeAg had a predictive value of 98.9% and a negative predictive value of 100.0%, similar to that of a combination of IgM anti-HBc and HBV-DNA. Adding AFP to the combinations of IgM anti-HBc and HBV-DNA or HBeAg could further heighten the positive predictive value. The positive predictive value and negative predictive value of the combination of IgM anti-HBc, HBV-DNA and AFP were both 100.0%.

CONCLUSIONS

(i) There are significant differences with respect to clinical, biochemical, immunological and virological aspects between ASL-HB and CHB-AF. (ii) Of several diagnostic combinations, IgM anti-HBc jointing HBV-DNA is most effective and most practicable in distinguishing ASL-HB from CHB-AF. (iii) A low HBeAg level is more useful than negative HBeAg in differential diagnosis between ASL-HB and CHB-AF. (iv) In those patients with a high level of IgM anti-HBc, serum AFP level >10x upper reference limit could rule out a probability of ASL-HB.

Performance characteristics of microparticle enzyme and chemiluminescence immunoassays for measurement of anti-HBc immunoglobulin M in sera of patients with HBeAg-negative chronic hepatitis B virus infection

The IMx, AxSym, and Architect immunoglobulin M anti-HBc assay systems for detecting hepatitis B virus e antigen-negative chronic hepatitis B virus infection were compared. Despite good intra- and interassay coefficients of variation, significantly different values and low correlation (overestimation by AxSym and underestimation by Architect) were observed. Association and cutoff values for distinguishing patients with viral replication should be established for all methods.

Higher cut-off index value of immunoglobulin M antibody to hepatitis B core antigen in Taiwanese patients with hepatitis B

BACKGROUND

The cut-off index value of immunoglobulin M (IgM) antibody to hepatitis B core antigen (anti-HBc; AxSYM CORE-M, Abbott) for diagnosing acute hepatitis B is 1.2. A high false-positive rate of IgM anti-HBc was observed in acute flare-ups of chronic hepatitis B in Taiwanese patients. Thus the purpose of the present paper was to study the optimal index value of IgM anti-HBc in Taiwanese subjects.

METHODS

The peak index values of 42 IgM anti-HBc-positive patients were collected. There were 20 acute hepatitis B patients and 22 patients with chronic hepatitis B with acute flare. The biochemical, virological, and serological data were obtained.

RESULTS

There were significant differences in mean age (36 vs 47 years, P = 0.01), serum alanine aminotransferase level (2042 U/L vs 1193 U/L, P = 0.02) and peak index value of IgM anti-HBc (2.9 vs 1.5, P < 0.01) between patients with acute hepatitis B and those with acute flare of chronic hepatitis B. Eleven (50%) of 22 patients with chronic hepatitis B with acute flare had index value of >1.2. The optimal cut-off index value to differentiate acute hepatitis B from chronic hepatitis B with acute flare was 2.4-2.5, with a sensitivity of 90% and specificity of 90%.

CONCLUSIONS

The cut-off index value of IgM anti-HBc to differentiate acute hepatitis B from chronic hepatitis B with acute flare among Taiwanese patients should be set at 2.4-2.5 instead of 0.8-1.2.

HBV superinfection in hepatitis C virus chronic carriers, viral interaction, and clinical course

We enrolled 44 patients with hepatitis B virus (HBV) acute infection, 21 anti-hepatitis C virus (HCV)-positive for at least 1 year (case BC group), 20 anti-HCV-negative (control B group), and 3 with HBV/HCV acute concurrent infection. For each case BC, a subject with chronic HCV infection alone was selected (control C group). At the first observation, 85.7% of patients in case BC group and 85% of those in control B group were HBV-DNA-positive (polymerase chain reaction [PCR]), with a similar trend towards a decrease and negativization in about 20 days; in the case BC group, seroconversion to antibody to hepatitis B e antigen (anti-HBe) was more rapid. HCV-RNA (PCR) was undetectable in all case BC patients but 1, who shortly became negative, whereas 85.7% of subjects in control C group were positive (P <.001). Severe acute hepatitis was more frequent in the case BC group than in the control B group (28.6% vs. 0%, P <.05). Of the 14 patients in the case BC group and of the 16 in the control B group followed up for more than 6 months, 1 in the first and 1 in the second group became hepatitis B surface angiten (HBsAg) chronic carriers. Of the 13 patients in case BC group who recovered, 1 cleared both anti-HCV and HCV-RNA, 6 became HCV-RNA-positive, and 6 remained HCV-RNA-negative. In patients with HBV/HCV acute concurrent infection, HBV-DNA became undetectable in 15 days, and HCV-RNA and anti-HCV became positive at days 30 and 45, respectively; these patients developed HCV-RNA-positive chronic hepatitis. In conclusion, HBV superinfection in chronic HCV carriers has a severe clinical course and strongly and persistently depresses HCV.

Diagnosis and management of pre-core mutant chronic hepatitis B

Chronic hepatitis due to pre-core hepatitis B virus (HBV) mutants presents as hepatitis B e antigen (HBeAg)-negative chronic hepatitis B (CHB). HBeAg-negative CHB represents a late phase in the natural course of chronic HBV infection that develops after HBeAg loss and seroconversion to anti-HBe. It is usually associated with pre-core stop codon mutation at nucleotide 1896 (mainly selected in non-A HBV genotypes), but also with other pre-core changes or with mutations in the basic core promoter region (mainly in HBV genotype A). In chronic HBV infections, pre-core mutants can be detected both in patients with HBeAg-negative CHB and in inactive hepatitis B surface antigen (HBsAg) carriers. The diagnosis of HBeAg-negative CHB is based on HBsAg positivity, HBeAg negativity, and mainly on increased alanine aminotransferase (ALT) and serum HBV-DNA levels and exclusion of other causes of liver disease. The differential diagnosis between patients with CHB and inactive HBsAg carriers can be made only by close follow-up of aminotransferase activity and viraemia levels, although the cut-off level of serum HBV DNA has not been definitely determined. IgM anti-HBc levels have also been suggested as an index that increases the diagnostic accuracy for transient hepatitis flares, while liver biopsy confirms the diagnosis and evaluates the severity of the liver disease. Interferon-alpha (IFN-alpha) and lamivudine are the two drugs that have been tried, mainly in the management of HBeAg-negative CHB. A 12-month course of IFN-alpha achieves sustained biochemical remission in about 20% of patients, which has been associated with improvement in the long-term outcome of this subset. A 12-month course of lamivudine is rather ineffective, maintaining remission in less than 15% of patients after cessation of therapy. Long-term lamivudine is associated with progressively increasing rate of virological and subsequent biochemical breakthroughs due to YMDD mutants, with approximately 30% of patients remaining in remission in the third year of therapy. Several other antiviral agents are currently being evaluated in this setting with combined regimens being the most reasonable step for the near future.