A new method of concentrating hepatitis B virus (HBV) DNA and HBV surface antigen: an application of the method to the detection of occult HBV infection

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A new method of concentrating hepatitis B virus (HBV) DNA and HBV surface

antigen: an application of the method to the detection of occult HBV infection

Authors: Satoh, K.1; Iwata-Takakura, A.1; Yoshikawa, A.1; Gotanda, Y.1; Tanaka,

T.2; Yamaguchi, T.3; Mizoguchi, H.1

Source: Vox Sanguinis, Volume 95, Number 3, October 2008 , pp. 174-180(7)

Publisher: Blackwell Publishing

Abstract:

Background 

The risk of post-transfusion hepatitis B virus (HBV) infection has been reduced

after the implementation of HBV nucleic acid amplification technology (NAT).

However, the problem of HBV DNA-positive and HBV surface antigen

(HBsAg)-negative occult HBV infections remains to be solved. This is in part due

to the HBV DNA load being too low to detect these occult HBV infections using

mini-pool NAT. In Japan, the assay for the antibody against the HBV core antigen

(anti-HBc) has not completely excluded occult HBV infection. To solve this

problem, we have developed a new method of concentrating HBV DNA and HBsAg

simultaneously to increase the sensitivity of detection tests. Methods 

Virus concentration is achieved by the enhancement of the agglutination of

viruses using poly-L-lysine in the presence of a bivalent metal.

Poly-L-lysine-coated magnetic beads are used to shorten the time of each step of

the concentration procedure. Seventy-seven anti-HBc-positive and HBsAg-negative

donations were examined. HBsAg and anti-HBc were tested by enzyme immunoassay

(EIA) (AxSYM; Abbott) and haemagglutination inhibition test (Japanese Red

Cross), respectively. Results 

HBV surface antigen and HBV DNA levels were concentrated up to four- to

sevenfold. Using this method, 35 of the 77 anti-HBc-positive and HBsAg-negative

donors were HBV DNA-positive by individual NAT and a further five donors became

HBV DNA-positive by HBV concentration. Twenty-seven of 40 occult HBV infections

became HBsAg-positive by HBsAg concentration. Conclusion 

Our new method of concentrating HBV and HBsAg increased the sensitivities of EIA

and HBV NAT, and enabled us to detect 27 of 40 occult HBV infections by HBsAg

EIA.

Keywords: anti-HBc; concentration of HBV DNA; concentration of HBsAg; occult HBV

infection; poly-L-lysine-coated magnetic beads

Document Type: Research article

DOI: 10.1111/j.1423-0410.2008.01091.x

Affiliations: 1: Japanese Red Cross Saitama Blood Center, Hidaka, Saitama, Japan

2: Tokyo Women's Medical University, International Research and Educational

Institute for Integrated Medical Sciences (IREIIMS), Kawada-cho, Shinjuku-ku,

Tokyo, Japan 3: The National Institute of Health Sciences, Division of

Biological Chemistry and Biologicals, Kamiyoga, Setagaya-ku, Tokyo, Japan