HBsAg Loss/Seroconversion is uncommon in Low replicative chronic HBV infection patients. The purpose of this study is to investigate the ability of peginterferon alpha to achieve HBsAg loss/seroconversion therapy in Low replicative chronic HBV infection patients with Low Level HBsAg.

Low replicative chronic HBV infection patients with low Level HBsAg were enrolled in the out-patient department of 3rd Affiliated Hospital of Sun Yat-sen University. All of them were HBsAg positive and anti-HBs negative for more than 6 months with HBV DNA<2000 IU/mL and HBsAg levels ≤1000 IU/mL. All patients did not have other liver diseases and contraindications for interferon therapy.

After giving informed consent, patients were treated with weekly subcutaneous injections of alfa-2a 180 micrograms/week or peginterferon alfa-2b 80 micrograms/week. The use of other immune suppressive or regulatory drugs and other antiviral drugs was prohibited during the course of the study.

In this study, treatment endpoint was HBsAg loss(<0.05 IU/mL) and anti-HBs positive(>10 milli-International unit(mIU)/mL) defined as seroconversion. Depending on the decline of HBsAg level, treatment was either continued for a prolonged period (no more than 96 weeks) until the endpoint was achieved, or terminated in case of nonresponse. Treatment was proceeded if HBsAg level continued to decline until HBsAg seroconversion was achieved and the anti-HBs level was above 200 mIU/ml. If the patients were not willing to extend treatment, the therapy was ended at the time of HBsAg loss, or stopped without further decline of HBsAg levels.

Inclusion Criteria:

1. Hepatitis B surface antigen (HBsAg) positive and <1000 IU/mL.
2. Hepatitis B surface antibody (HBsAb) negative.
3. Hepatitis B e antigen (HBeAg) negative.
4. Hepatitis B virus DNA <2000 IU/mL.
5. Absence of previous antiviral therapy.

Exclusion Criteria:

1. Patients with active alcohol and/or drugs consumption.
2. Patients with liver cirrhosis, Hepatocellular Carcinoma or other malignancies.
3. Patients with other factors causing liver diseases.
4. Pregnant and lactating women.
5. Patients with concomitant HIV infection or congenital immune deficiency diseases.
6. Patients with diabetes, autoimmune diseases.
7. Patients with important organ dysfunctions.
8. Patients with mental illness.
9. Patients who receive antineoplastic or immunomodulatory therapy in the past 12 months.
10. Patients who can't come back to clinic for follow-up on schedule.