%0 Journal Article
%T Transplacental Transfer of Hepatitis B Neutralizing Antibody during Pregnancy in an Animal Model: Implications for Newborn and Maternal Health
%A Li Ma
%A Malgorzata G. Norton
%A Iftekhar Mahmood
%A Zhong Zhao
%A Lilin Zhong
%A Pei Zhang
%A Evi B. Struble
%J Hepatitis Research and Treatment
%D 2014
%I Hindawi Publishing Corporation
%R 10.1155/2014/159206
%X Despite the success of postexposure prophylaxis (PEP) of the newborn in preventing mother-to-child transmission of hepatitis B virus), in non-US clinical trials, administering hepatitis B immune globulin (HBIG) to mothers at the end of pregnancy (in addition to passive-active PEP of the newborn) only partially improved outcomes. That is, a significant percentage of newborns became infected during their first year of life. We used a relevant animal model for human IgG transplacental transfer to study dose, time and subclass dependence of HBV neutralizing antibody (nAb) maternal, and fetal levels at the end of pregnancy. Pregnant guinea pigs received 50 or 100ˋIU/kg HBIGIV 2每5 days before delivery. Human total IgG, IgG subclasses, and nAb in mothers and their litters were measured. In vitro analyses of guinea pig Fc neonatal receptor binding to HBIGIV, as well as to all human IgG subclasses, were also performed. Our study showed that nAb transferred transplacentally from the pregnant guinea pigs to their litters; no transfer occurred during parturition. The amount of the transferred nAb was dose and time dependent. Thus, selection of an efficacious dose in the clinic is important: microdosing may be underdosing, particularly in cases of high viraemia. 1. Introduction Chronic hepatitis B is a serious viral disease, associated with a high risk for developing liver cirrhosis and hepatocellular carcinoma [1每3]. Worldwide, two billion people have been infected with the virus and about 600,000 people die every year due to the consequences of hepatitis B [4]. HBV is endemic in China and other parts of Asia where 8每10% of the adult population is chronically infected, often since birth. Because 90% of infants infected at birth develop chronic HBV infection and 25% of those die prematurely from cirrhosis or liver cancer [5, 6], failure to prevent infection following perinatal exposure to HBV carries a heavy burden to the individual, family, and society at large. Passive-active postexposure prophylaxis (PEP) with HBIG and hepatitis B vaccine is 85每95% effective in preventing vertical transmission of HBV compared to 70每95% prevention rate for the vaccine alone [6, 7]. Despite PEP, 3每13% of infants born to infected mothers acquire HBV [8]. The risk is particularly high for children born to mothers with a high viral load [9, 10]. Although pregnancy, especially the peripartum period, has been associated with an increase in hepatitis B viral load [11], maternal use of antiviral drugs, such as nucleoside analogs, as an adjunct to PEP of the newborn has not shown
%U http://www.hindawi.com/journals/heprt/2014/159206/