Semin Liver Dis 2019; 39(02): 249-260
DOI: 10.1055/s-0039-1678728
Review Article
Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Current Knowledge of Occult Hepatitis B Infection and Clinical Implications

Terry Cheuk-Fung Yip
1  Institute of Digestive Disease, The Chinese University of Hong Kong, Hong Kong SAR, People's Republic of China
2  Department of Medicine and Therapeutics, The Chinese University of Hong Kong; Hong Kong SAR, People's Republic of China
,
Grace Lai-Hung Wong
1  Institute of Digestive Disease, The Chinese University of Hong Kong, Hong Kong SAR, People's Republic of China
2  Department of Medicine and Therapeutics, The Chinese University of Hong Kong; Hong Kong SAR, People's Republic of China
3  State Key Laboratory of Digestive Disease, The Chinese University of Hong Kong; Hong Kong SAR, People's Republic of China
› Author Affiliations
Financial SupportThis work was partly supported by the Direct Grant of The Chinese University of Hong Kong (Reference no: 4054345).
Further Information

Publication History

Publication Date:
25 March 2019 (eFirst)

Abstract

Occult hepatitis B infection (OBI) is a status of undetectable serum hepatitis B surface antigen (HBsAg) yet detectable serum and/or intrahepatic hepatitis B virus (HBV) DNA. Mutations in the preS1, preS2, and S regions of the HBsAg gene may result in undetectable HBsAg. OBI may either result from a self-limiting acute hepatitis, or in patients with chronic hepatitis B who achieved HBsAg seroclearance, which refers to the loss of detectability of serum HBsAg with or without antibody to HBsAg (anti-HBs) in chronic hepatitis B (CHB) patients. HBsAg seroclearance contributes to a significant proportion of population in seropositive OBI. Both spontaneous and antiviral treatment-induced HBsAg seroclearance rarely happens; yet both types of HBsAg seroclearance are durable. CHB patients who achieve HBsAg seroclearance generally have a favorable clinical course. There is still a low yet definite risk of HCC occurrence, particularly in male CHB patients who achieve HBsAg seroclearance after being 50 years old. Clinical implications of OBI include occurrence of cirrhosis and HCC, liver transplantation, blood products transfusion, hemodialysis, and so on. A potentially life-threatening condition would be OBI reactivation in patients during immunosuppression therapy, especially in the setting of intensified immunosuppression including in onco-hematological patients (those receiving hematopoietic stem cell transplantation and treated with the anti-CD20 monoclonal antibody [e.g., rituximab]). With more new insights into these two conditions, CHB patients who achieved HBsAg seroclearance generally have benign clinical course and good prognosis. Sensitive assay for serum HBV DNA should be considered to establish the presence of OBI in the clinical settings mentioned earlier, which will affect the management plan.

Authorship Statement

Terry Yip and Grace Wong were responsible for the interpretation of data, the drafting, and critical revision of the manuscript for important intellectual content.


Financial Support

This work was partly supported by the Direct Grant of The Chinese University of Hong Kong (Reference no: 4054345).