Detection of hepatitis B virus in seropositive and seronegative patients with chronic liver disease using DNA amplification by PCR

Socio-demographic characteristics of health care workers and hepatitis B virus (HBV) infection in public teaching hospitals in Khartoum State, Sudan

BACKGROUND

HBV is second to tobacco as a known human carcinogen and the 10th leading cause of death worldwide.

OBJECTIVES

To examine the socio-demographic characteristics of health care workers and hepatitis B virus in Public Teaching Hospitals in Khartoum State, Sudan, in 2004.

METHODS

It was an observational, cross sectional, facility-based study. A total of 843 subjects were selected. It was conducted through multistage cluster sampling. The clustering was based on: type of hospital (Federal or State) and degree of exposure (type of department). For the analysis, Z-test for single proportion and some non-parametric tests such as Chi-Square test were used.

RESULTS

Among the 843 subjects tested for HBV markers (Anti-HBc, HBsAg, HBsAb, and HBeAg), the prevalence of Anti-HBc, HBsAg, HBsAb, and HBeAg was found to be 57%, 6%, 37% and 9% respectively. Seroprevalence of all HBV markers was found to be statistically significant with demographic factors (P<0.05).

CONCLUSION

Infection rate, carrier rate and a profile of high infectivity rate were found to be high. The immunity rate was low. There is a significant association between HBV markers and socio-demographic characteristics. Highest rate of infection was found in State Hospitals, South and West regions, married HCWs and HCWs of age group 30-49.

Clinical significance of antibody to hepatitis B core antigen in multitransfused hemodialysis patients

BACKGROUND

In spite of the progress made in the prevention of transfusion transmitted infections over the last few years, transmission of HBV infection through transfusion of HBsAg negative blood has been documented.

OBJECTIVES

To assess the frequency and clinical significance of anti-HBc in multitransfused hemodialysis patients.

MATERIALS AND METHODS

One hundred and forty-three hemodialysis patients who had been receiving blood regularly with an average of 39.4 +/- 7.579 months on hemodialysis were enrolled in this study. HBV markers (HBsAg, anti-HBc, anti-HBs) were measured in these patients and in 100 healthy controls by the ELISA technique. The following data were obtained for all patients: socio demographic data, number of blood transfusions and some laboratory investigations.

RESULTS

In our patients, anti-HBc was positive in 9%, anti HBs in 7%, coexistant HbsAg/anti-HBc in 2.8% and anti HBc/anti HBs in 18.9%, meanwhile no patients were positive for HBsAg alone. In patients with only positive anti-HBc, the levels of anti-HBc were significantly related to abnormal results of liver function. In patients with positive anti-HBs/anti-HBc (n = 27), 18 patients had abnormal liver function, and 9 patients had normal liver function with no significant difference between them.

CONCLUSIONS

This study suggests that hepatitis B prevalence in our multitransfused hemodialysis patients is far in excess of that anticipated on the basis of HBsAg prevalence. Absence of HBsAg in the blood of hemodialyzed patients may not be sufficient to ensure lack of circulating HBV, and isolated positivity of anti-HBc may be a possible indicator of active hepatitis B infection.

Can the serological status of anti-HBc alone be considered a sentinel marker for detection of occult HBV infection?

Some individuals have "occult" infection with hepatitis B virus (HBV), defined as presence of HBV genome in the serum or liver tissue without HBV surface antigen (HBsAg) in the serum. The aim of this study was to investigate whether serum antibodies against HBV core antigen in isolation ("anti-HBc alone") are a useful marker of "occult" HBV in patients with or without hepatitis C virus (HCV) infection. "Anti-HBc alone" was detected in the sera of 119/6,544 (1.8%) asymptomatic outpatients referred to the diagnostic laboratory for routine testing for viral hepatitis, 62/607 (10.2%) drug users, and 42/195 (21.5%) patients with hepatocellular carcinoma. Using three in-house nested-PCR amplification assays to detect HBV preS-S (S), precore-core (C), and Pol viral regions, respectively, "occult" HBV sequences were found in 9 of the 223 sera (4.0%) with "anti-HBc alone." The highest prevalence of "occult" HBV sequences (5.9%) was detected in "anti-HBV alone" sera of individuals referred to the diagnostic laboratory without HCV antibodies. Direct sequencing of all PCR products confirmed the specificity of the PCR reactions and revealed the predominance of HBV genotype D. The data presented in this study suggest that detection of "anti-HBc alone" could reflect unrecognized "occult" HBV infection and that physicians should consider investigating such patients with HBV molecular tests.

Genotype, phylogenetic analysis, and transmission pattern of occult hepatitis B virus (HBV) infection in families of asymptomatic HBsAg carriers

Occult hepatitis B is defined by the presence of hepatitis B virus (HBV) DNA in the serum in absence of hepatitis B surface antigen (HBsAg). Studies were conducted to screen for occult HBV infection among family members of HBV carriers, incidentally detected positive for HBV infection with a view to assess the pattern of virus transmission among them. Nested PCR assay, employing independent sets of primers to surface and core genes, was used for detection of HBV DNA in serum samples from 28 index cases with asymptomatic HBV infection, and in serum samples from 72 HBsAg negative/anti-HBc positive family members. HBV DNA was detected in 15 HBsAg negative family members of 10 HBsAg positive index patients and was studied in detail. Direct sequencing of S gene region of 25 isolates (10 index cases and 15 contacts) and phylogenetic analysis with data base sequences revealed that genotypes A, C, and D and subtype adw2, adr, and ayw3 were present among them. Evidence of transmission from outside family sources was found in addition to intrafamilial transmission among individuals with occult infection. Mutations in the major hydrophilic loop (MHL) of the S gene region were also detected, including the 'vaccine escape' mutation G145R in three cases. Although majority of the occult infection was associated with low viral load, 3/15 (20%) cases were with higher viral load and potential infectivity. These cases are especially notable in diagnostic, blood banking, and transplantation services.

Evaluation of liver tissue by polymerase chain reaction for hepatitis B virus in patients with negative viremia

AIM: To assess the clinical significance of Hepatitis B virus (HBV) DNA localization in the liver tissue of patients with positive HBsAg and negative viremia.

METHODS: HBV virological parameters of 33 HBsAg positive chronic hepatitis patients, including seromarkers and HBV DNA amplification in both sera and liver biopsies, were evaluated.

RESULTS: Ten patients had negative viremia and positive HBV DNA in their liver biopsies. Most of them had HBeAg-negative/HBeAb-positive chronic hepatitis. Their liver biochemical and histopathological profiles were different from the viremic patients. Their disease pattern was designated as “hepatitis B in situ”.

CONCLUSION: Hepatitis B in situ is a consequential entity which can be missed in clinical practice. It is a new clinical pattern of chronic HBV infection that considers HBV in liver biopsy and adds a new indication for antiviral therapy.

Serological detection of hepatitis B viral infection by a panel of solid-phase enzyme-linked immunosorbent assays (ELISA)

Immunoassays for the detection of hepatitis B virus (HBV) in biological samples were developed. Using recombinant HBV antigens (Ags) and HBV-specific antibodies (Abs), we designed and evaluated a panel of enzyme-linked immunosorbent assays (ELISAs) detecting the main hepatitis B-related viral markers, namely HBV surface Ag (HBsAg), HBV e Ag (HBeAg), Abs to HBsAg (anti-HBs), Abs to HBV core Ag (anti-HBc) and Abs to HBeAg (anti-HBe), in blood serum. The ELISAs were validated using a panel of prescreened, by commercial tests, serum samples. In principle, HBV Ags or anti-HBV monoclonal antibodies (mAbs) were immobilised on microplate wells. Horseradish peroxidase (HRP) or biotin were used to prepare labeled Abs. Specifically for the determination of HBsAg and HBeAg, two-site sandwich immunoenzymometric assays were developed. The useful range was estimated at 20-500 ng/ml and human serum samples assayed were diluted 10- and 4-fold for HBsAg and HBeAg, respectively, with phosphate buffered saline (PBS) containing Tween 20 and gelatin. For the detection of Abs to HBs an indirect ELISA was formulated. Sera were similarly 4-fold diluted in the same buffer. Finally, competitive ELISAs were used for detecting anti-HBc and anti-HBe and sera tested were diluted 20- and 5-fold, respectively. All selected dilutions resulted in the accurate and reliable determination of HBV Ags and anti-HBV Abs. Taken altogether, these ELISAs are highly specific and equally sensitive to the circulating tests. However, their design could be very useful for research and/or preclinical studies of selected HBV-infected individuals.