The Egyptian Journal of Haematology

: 2015  |  Volume : 40  |  Issue : 3  |  Page : 143--147

Prevalence and significance of hepatitis B core antibodies among hepatitis B surface antigen-negative Egyptian polytransfused adult patients

Tamer A Elbedewy1, Nashwa M Noreldin1, Sarah A Hamam2,  
1 Department of Internal Medicine, Faculty of Medicine, Tanta University, Tanta, Egypt
2 Department of Clinical Pathology, Faculty of Medicine, Tanta University, Tanta, Egypt

Correspondence Address:
Tamer A Elbedewy
Department of Internal Medicine, Faculty of Medicine, Tanta University, 31527 Tanta


Background/aims Blood transfusion is a well-established line of therapy associated with risk of infection transmission. Occult hepatitis B virus (HBV) infection is defined as the presence of HBV-DNA in the serum and/or the liver in the absence of hepatitis B surface antigen (HBsAg). Combined screening of HBsAg and hepatitis B core antibody (anti-HBc) can virtually eradicate blood-transmitted HBV. The aim of this study was to evaluate the presence of anti-HBc among Egyptian polytransfused adult patients and to determine the presence or absence of HBV-DNA in the serum samples of HBsAg-negative, anti-HBc-positive polytransfused adult patients using the polymerized chain reaction (PCR) method to assess the magnitude of occult HBV infection in these patients. Patients and methods This cross-sectional study included 79 polytransfused patients negative for HBsAg, HBsAb, and anti-hepatitis C virus. Patients were investigated for anti-HBc and samples of anti-HBc-positive patients were tested for HBV-DNA using real-time PCR. Results Among the 79 HBsAg-negative sera, anti-HBc was detected in 12 of 79 (15.19%) cases. All anti-HBc-positive sera were anti-HBs-negative. HBV-DNA was detected in five of 12 (41.67%) cases. Occult HBV infection was present in 6.33% of patients. Conclusion The overall prevalence of occult HBV in adult Egyptian polytransfused patients on regular blood transfusion is 6.33%.

How to cite this article:
Elbedewy TA, Noreldin NM, Hamam SA. Prevalence and significance of hepatitis B core antibodies among hepatitis B surface antigen-negative Egyptian polytransfused adult patients.Egypt J Haematol 2015;40:143-147

How to cite this URL:
Elbedewy TA, Noreldin NM, Hamam SA. Prevalence and significance of hepatitis B core antibodies among hepatitis B surface antigen-negative Egyptian polytransfused adult patients. Egypt J Haematol [serial online] 2015 [cited 2022 Jan 24 ];40:143-147
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Transfusion of blood and blood products is an important therapy for many patients; however, it still carries a small risk for transmission of infection [1] . Hepatitis B virus (HBV) transmission through blood transfusion is more common compared with hepatitis C virus (HCV) transmission [2],[3] . Transfusion of blood contaminated with hepatitis B surface antigen (HBsAg) is usually followed by post-transfusion infection [4] .

Occult HBV infection is defined as the presence of HBV-DNA in serum and/or liver tissue in the absence of HBsAg [5] . Occult HBV can cause the transmission of the infection through organ transplantation or blood transfusion, with reactivation of HBV when an immunosuppressive status occurs [6] . Occult HBV is related to low level of HBV infection, and may also be due to infection with HBV variants or mutants [7] . Occult HBV can aggravate chronic liver damage and fibrosis, can cause progression of cirrhosis, can lead to development of hepatocellular carcinoma, and can also lower the virology response in HCV infection [8],[9],[10] .

Hepatitis B core antibody (anti-HBc) is the most sensitive marker of previous HBV infection [11] . Blood that is free of HBsAg but has high-titer (anti-HBc) in the absence of antibodies against HBsAg (anti-HBs) can also transmit HBV infection [4] . Combined HBsAg and anti-HBc screening can virtually eliminate blood-transmitted HBV, with the rare exception of donations during the early phase of the window period when all serological markers are still negative [12] .

The aim of this study was to evaluate the presence of anti-HBc among Egyptian polytransfused adult patients and to determine the presence or absence of HBV-DNA in the serum samples from HBsAg-negative, anti-HBc-positive polytransfused adult patients using the PCR method to assess the magnitude of occult HBV infection in these patients.

 Patients and methods

This cross-sectional study included 79 polytransfused patients on regular blood transfusion. Patients of this study were selected from among the outpatients and inpatients of the Hematology Unit, Internal Medicine Department, Faculty of Medicine, Tanta University, from June 2013 to October 2014. All participants included were negative for HBsAg, HBsAb, and antibody for hepatitis C (anti-HCV). This study was conducted in accordance with the guidelines of the declaration of Helsinki and its subsequent amendments. Participation in the study was voluntary and informed written consent was obtained from the patients before the study.

Full history taking was carried out, including frequency of blood transfusion, past surgical procedures, intravenous drug abuse, jaundice, fever-related hospitalization, schistosomiasis, and HBV vaccination. Careful clinical examination was performed for all patients before enrollment into the study.

Exclusion criteria were as follows: intravenous drugs abusers, a history of promiscuous sexual relationships, homosexuals, patients with recent jaundice, recent hospitalization for fever, pregnancy, recent delivery less than 12 weeks ago, close contact with a patient suffering from hepatitis in the last 6 months, acute or chronic HBV infection as marked by positive HBsAg, patients with AIDS, those with end-stage renal disease on hemodialysis, or those receiving immune suppressive medications (for any chronic disease).

Serological assays

A volume of 10 mm of blood was collected from each patient in a sterile, capped tube. Thereafter, the blood was centrifuged and stored at -80°C until it was needed for testing. All serum samples were tested for serum alanine transaminase (ALT) (upper normal limit, 42 IU/l) and aspartate transaminase (AST) (upper normal limit, 37 IU/l) using chemistry auto analyzer (Synchron CX5; Beckman Instrument Inc., Scientific Instrument Division, Fullerton, California, USA). Hepatitis B markers (anti-HBc, HBsAg, and HBsAb) were detected using electrochemiluminescence immunoassay (Elecsys) (Roche Diagnostics Limited, Rotkreuz, Switzerland, Anti-HCV was detected using a standard third generation ELISA test (Murex anti-HCV, version 4.0) (Murex Biotech S.A. (PTY) Ltd, Kyalami, Republic of South Africa). All procedures were performed according to the manufacturers' instructions.

Detection of HBV-DNA and HCV-RNA [13]

Following serological tests, DNA was extracted from the serum samples of anti-HBc-positive patients. Samples from each patient were tested for HBV-DNA using highly sensitive and specific real-time PCR. HBV-DNA was extracted from 850 μl of plasma using the Cobas AmpliPrep instrument (Roche Diagnostics Limited, Rotkreuz Switzerland, The Cobas TaqMan 48 analyzer was used for automated real-time PCR amplification and detection of PCR products. HBV-DNA levels were expressed in IU/ml. The HBV detection limit was 12 IU/ml.

Evaluation of serum samples for patients with anti-HBc for HCV-RNA was carried out using real-time PCR. The HCV detection limit was 15 IU/ml.

Statistical analysis

The collected data were tabulated and analyzed using SPSS version 17 software (SPSS Inc., Chicago, Illinois, USA). Categorical data were presented as number and percentages, whereas quantitative data were expressed as mean and standard deviation. Comparison of continuous data between the two groups was made using the Mann-Whitney U-test. Fisher's exact test was used for comparison between categorical data. The accepted level of significance in this work was 0.05 (P < 0.05 was considered significant).


This study included 79 polytransfused patients on regular blood transfusion, of whom 58 were male (73.42%) and 21 were female (26.58%); their ages ranged from 18 to 31 years (mean 23.66 ± 3.438 years). As regards the diagnosis, there were 52 thalassemic patients (65.82%), 10 hemophilic patients (12.66%), nine sickle cell anemia patients (11.39%), and eight patients (10.13%) with other diagnosis. None of the patients had received HBV vaccination before. Fifty-five patients (69.62%) had undergone splenectomy before. Twelve patients (15.19%) had a history of schistosomiasis with oral treatment only. Among the 79 HBsAg-negative patients, anti-HBc was detected in 12 patients (15.19%). All anti-HBc-positive patients were anti-HBs-negative. HBV-DNA was detected in five out of those 12 anti-HBc-positive patients (41.67%) (6.33% of all patients) ([Table 1]). None of the patients with occult HBV infection had anti-HCV or HCV-RNA.{Table 1}

Frequencies of anti-HBc-positive and HBV-DNA-positive in different categories of the studied group are shown in [Table 2].{Table 2}

Comparison between patients with positive anti-HBc and patients with negative anti-HBc is shown in [Table 3], and comparison between patients with positive HBV-DNA and patients with negative HBV-DNA in anti-HBc-positive patients is shown in [Table 4].{Table 3}{Table 4}


HBV infection is a major health problem and about two billion people are currently infected despite effective vaccination. There are 350 million carriers of HBV worldwide, and about one million die annually from HBV-related liver disease [14] . The prevalence of HBV infection varies in different parts of the world, ranging from less than 1 to 15%. In the Middle East, the carrier rate is 2-8% [15] . Anti-HBc is the first antibody produced after HBV infection, and it is the only detectable marker in the window period. Isolated anti-HBc refers to the presence of anti-HBc in the serum without HBsAg or HBsAb. Isolated anti-HBc may be due to resolved HBV infection in which HBsAb had declined to an undetectable level, testing during the window period or chronic infection, in which HBsAg cannot be detected due to protein mutation, makes it undetectable by certain diagnostic assays [16],[17] .

The risk of HBV infection through blood transfusion has been reduced with the introduction of HBsAg screening in blood donors [18] . Recent studies cannot judge HBV infection based only on the presence or absence of HBsAg and HBsAb [19] . It is possible that, donors with occult HBV infection, who lack detectable HBsAg, might have HBV infection that is only indicated by anti-HBc and HBV-DNA [20] . Donation by such individuals is a potential source of HBV transmission to the recipients [21] . All blood donors with occult HBV infection may not transmit the disease to recipients. Factors such as viral load in the blood component and immune status of the patient may play a role in aborting viral transmission [22] .

In Egypt, testing for the presence of HBsAg is the initial diagnostic examination used to determine HBV infection. Anti-HBc is not used as a screening test to determine previous exposure to the HBV. In our study, among the 79 HBsAg-negative patients, anti-HBc was detected in 12 patients (15.19%). All anti-HBc-positive patients were anti-HBs-negative. HBV-DNA was detected in five out of those 12 anti-HBc-positive patients (41.67%) (6.33% of all patients). This prevalence rate of occult hepatitis B is higher compared with that in nonendemic countries such as Germany (1.59%), Italy (4.96%), and Brazil (0.85%) [23],[24],[25] . These differences in the occult HBV prevalence may also be attributed to race and ethnicity, geographical area, and the HBV subtypes.

Our study showed that 17.31% of thalassemia patients had positive anti-HBc and 5.77% had positive HBV-DNA. Although there are several publications on HBV infection prevalence in thalassemia patients, there are only four studies on the prevalence of the occult HBV infection among thalassemic patients. Singh et al. [26] from India reported that occult HBV had high prevalence among thalassemia patients, with a prevalence of 31.4%. Arababadi et al. [27] studied 60 Iranian thalassemia patients and no occult HBV cases were detected. Shaker et al. [28] reported that 26 out of 80 (32.5%) Egyptian patients who were negative for HBsAg were positive for HBV-DNA as detected with PCR. Of the 26 HBV-DNA-positive patients, 24 patients (representing 30% of the whole study group) were positive for anti-HBc. Sabat et al. [29] conducted their study in 174 thalassemia patients in India. The prevalence of anti-HBc was found to be 21.8%. Anti-HBc was found to be the only marker in six patients (3.45%). Anti-HBc was 12, 26.8, and 71.4% in patients who received less than 40, 40-80, and greater than 80 units of transfusions, respectively. HBV-DNA was detected in 50% (3/6) of participants having anti-HBc as the only marker (occult HBV infection).

Our study showed that 20% of hemophilic patients had positive anti-HBc and 10% had positive HBV-DNA. However, globally, there are few reports on occult HBV prevalence among patients with hemophilia. Toyoda et al. [30] reported that occult HBV prevalence among Japanese hemophilia patients was 51.2%. In contrast, another study by Windyga et al. [31] on 115 patients with hemophilia demonstrated that none of the evaluated patients had been infected with occult HBV. Borhany et al. [32] reported another rate of occult HBV prevalence among hemophilic patients in Pakistan was 1.73%.

Moreover, our study showed that 11.11% of sickle cell disease patients had positive anti-HBc and 11.11% had positive HBV-DNA, but, according to our knowledge, no other similar studies to compare with could be found.

Occult HBV incidence in Egypt had many different figures, ranging from 0 to 62.5% in different studies [28],[33],[34],[35],[36],[37],[38],[39],[40] . The discrepancy in the reported incidence of occult HBV between several studies, including our study, could be due to several factors. One could be the differences in sensitivity of the methods used for detection of the virus genome (nested PCR vs. quantitative real-time PCR) [41] . Other factors may also be attributed to the number and the diagnosis of the studied groups.

Our study is not without limitations. We investigated patients with multiple disease categories; however, we believe that this might not affect our results, as our main concern was to study polytransfused patients regardless of their etiology of transfusion. Moreover, our study lacked examination of liver biopsy to certify that patients with anti-HBc and negative HBV-DNA had no occult HBV. Indeed, we found it unethical to expose the patient to this aggressive technique without direct benefit to them.


The overall prevalence of occult HBV in adult polytransfused patients on regular blood transfusion is 6.33%. All patients with prolonged blood transfusion and had positive anti-HBc, should be screened for probable occult HBV infection. Routine anti-HBc screening is recommended for all blood transfusion donors and recipients.

 Acknowledgements and authors' contributions

Tamer A. Elbedewy: concept, design, definition of intellectual content, data acquisition, data analysis, statistical analysis and manuscript preparation. Tamer A. Elbedewy, Nashwa M. Noreldin, Sarah A. Hamam: literature search, manuscript review and manuscript editing. Tamer A. Elbedewy, Nashwa M. Noreldin: clinical studies. Sarah A. Hamam: experimental studies.

Conflicts of interest

There are no conflicts of interest.


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