HBsAg sero conversion

[bram44]

Thought of sharing a latest post from medscape (by a doctor) :

http://www.medscape.com/viewarticle/708522



Question
Can the HBsAg test become negative after treatment in an otherwise healthy HBsAg-positive patient?

  Response from Paul Martin, MD, FACP
Professor of Medicine and Chief, Division of Hepatology, Center for Liver Disease, University of Miami School of Medicine, Miami, Florida

Hepatitis B surface antigen (HBsAg) seropositivity indicates the presence of hepatitis B viral (HBV) infection (acute or chronic). The disappearance of HBsAg from serum with development of the corresponding antibody, anti-HBs, indicates conventional resolution of infection. The likelihood of spontaneous HBsAg seroconversion during acute HBV infection varies according to patient age and immune competence. Up to 97% of healthy adults with acute HBV will clear the infection. In contrast, HBsAg seroconversion in chronically infected patients is a relatively uncommon event, with an incidence of only 0.8%-2% per annum.[1] Chronically infected whitepatients who typically acquired HBV infection in adulthood[1] have a higher rate of spontaneous HBsAg loss than Asian patients with presumed vertical acquisition of HBV.[2]

Antiviral studies generally used intermediate markers of treatment response; early research used hepatitis B e antigen (eAg) loss, seroconversion, and biochemical and histologic improvement to document response to treatment. More recently, serum HBV DNA suppression has been used as a marker of response, because initially HBsAg loss was not typically observed in antiviral studies. However, with longer follow-up it became apparent that HBsAg loss was frequent in eAg seroconverters, and these patients had a diminished risk for hepatic morbidity compared with patients who had failed to clear eAg.

Clearance of HBsAg has been perceived to be a specific benefit of interferon therapy for chronic HBV infection because HBsAg clearance was not initially recognized with oral therapy. Greater experience with oral therapy has made it apparent that HBsAg seroconversion can be induced by drugs other than interferon. In recent reports, 5% of entecavir-treated patients and 6% of tenofovir-treated patients seroconverted and cleared HBsAg.[3,4] In an analysis of the entecavir-treated patients who lost HBsAg, white race and infection with HBV genotypes A and D, which are not typically present in Asian patients, were key predictors of HBsAg seroconversion. For patients on treatment, predictors of ultimate HBsAg loss were eAg loss and development of anti-HBe antibody at week 24 of treatment. These data indicate that HBsAg seroconversion can be a benefit of oral as well as interferon-based therapy. It remains to be determined whether this outcome will be achieved in most patients treated with newer regimens and also whether therapy can accelerate HBsAg loss in patients with the eAg-negative form of chronic HBV.

[April63]

Thank you for the info.

[zellyf]

Thanks, Bram!