Seroconversion of hepatitis B virus surface antigen in chronic hepatitis B child treated with entecavir

Abstract

Sir, Hepatitis B virus (HBV) infection in children possesses a higher rate of progression to chronic hepatitis, however, a consensus guideline for treatment has not been established so far.[1,2] Entecavir as carbocyclic analog with inhibition of HBV replication[3] is shown encouraging effects in control of chronic HBV infection.[3] In the present article, we present seroconversion of hepatitis B virus surface antigen (HBsAg) by entecavir administrated in a young child with chronic hepatitis B. A 4-year-old girl was presented in a history of chronic HBV infection for 2 years. The perinatal history indicated that her mother was a HBV carrier, and grandmother died of cirrhosis due to chronic hepatitis B. The patient was vaginally born, and was immunized with hepatitis B vaccine and high-titter immunoglobulin against HBV at birth. During past 2 years, the patient had been administrated with Chinese herbal medicines. Because of unsatisfying theroputic effect, the patient was then transferred to our department. On admission, abdominal computed tomography (CT) scan demonstrated a normal size of the liver, but the spleen was enlarged in size. The laboratory tests showed that alanine aminotransferase (ALT) 92 U/L, aspartate transaminase (AST) 96 U/L, γ-glutamyl transpeptadase (GGT) 8 U/L, HBsAg positive, HBeAg positive, anti-HBV core antibody positive, and HBV DNA level 2.703 × 107 copies/mL. The autoimmune antibodies were absent, and serum markers for hepatitis A virus, hepatitis C virus, hepatitis E virus, cytomegalovirus, and Epstein Bar virus were negative. The patient was diagnosed with chronic hepatitis B with positive HBsAg. After informed consent was obtained from her parents, the patient was started with oral administration of entecavir at dose of 0.16 mg once a day. During administration of entecavir, the patient was regularly monitored by tests of liver function, HBsAg and HBV DNA level, and hematologic system. Tests showed that ALT was declined 2 weeks after entecavir administrator, and was normalized 4 weeks after treatment. The level of HBV DNA decreased in 2 weeks, and negative 24 weeks after entecavir administration. Interestingly, we noticed that HBeAg seroconversion was started 12 weeks after the treatment, and HBsAg became negative 48 weeks after treatment, followed by HBsAg seroconversion 72 weeks after treatment. Entecavir was terminated at 192nd week when liver function and HBV DNA were back to normal. Entecavir was tolerated well in this little patient, and nephrotoxicity or myopathy were not noticed during the treatment. The patient has so far been followed-up for a period of 96 weeks since the termination of entecavir. The patient has positive anti-HBs, anti-HBe, anti-HBc, and normal liver function [Table 1]. The girl is well and in healthy condition now. Table 1 Variations of laboratory tests before and after treatment of entecavir The ultimate goal of antiviral treatment in chronic HBV infection is to eradicate replicating HBV. HBV requires HBsAg to propagate infection and cause disease. Entecavir is a nucleoside analog with therapeutic effect on chronic HBV,[4–7] and has been shown to decrease HBsAg in animal research.[8] Although potential effects of entecavir on chronic HBV infection were reported in some other studies,[3,4–6] those studies had no involved lowering of HBsAg or HBsAg seroconversion. The satisfied outcome observed in our little girl patient using entecavir might be the first case, specifically lowering HBsAg or HBsAg seroconversion, in the reported literatures. Large sample are, however, needed to evaluate entecavir in term of clinical efficacy in children with chronic HBV.