摘要
:背景及目的：隐匿性HBV感染目前公认存在的一种临床状况，其特征为表面抗原的检测阴性，但血浆中或是肝脏中可以检测到HBV DNA。检出率的高低与表面抗原及HBV DNA的相关检测敏感性有关。本文中我们旨在研究在应用免疫预防后仍出现乙肝病毒感染的高危儿童中，隐匿性乙型肝炎病毒感染的发生率。
:Occult hepatitis B virus (HBV) infection is a well-recognized clinical entity characterized by the detection of HBV DNA in serum and/or liver in the absence of detectable hepatitis B surface antigen (HBsAg). The frequency of the diagnosis depends on the relative sensitivity of both HBsAg and HBV DNA assays. We aimed at determining the prevalence of occult HBV infection in a high risk group of children who developed HBV infection despite immunoprophylaxis.
:方法：使用实时－PCR的方法对母亲为表面抗原阳性的，接受了
免疫球蛋白及乙肝疫苗接种的75名婴儿的血清进行HBV DNA检测，随后，这些样本再次使用可一种敏感的，标准化的，包括所有ＨＢＶ基因的独立的引物的PCR方法进行检测，并且通过直接测序法进行分析。
:The sera of 75 children born to HBsAg-positive mothers previously immunized by HBIG and prophylaxic vaccine regimen were assayed for HBV DNA by real-time PCR. Subsequently, the samples were tested using a sensitive standard PCR, with an independent set of primers for all HBV genes, and analyzed by direct sequencing.
:结果：HBV DNA在21/75(28%)的儿童中可以被检出，并且其数值变化范围在77～9240拷贝/ml，这部分个体中乙肝表面抗体检测均为阳性，其中5例(24%)乙肝核心抗体阳性，单独的抗核心抗体阳性者没有被发现。8例(38%)并没有携带任何突变，剩余13例（62%）感染者在已知的与功能性和（或）免疫表位活性相关的区域至少存在着一个突变，有10例存在着G145R突变。
:HBV DNA was detected in 21/75 (28%) children, and ranged between 77 and 9240 copies/ml. All were positive for anti-HBs. Five (24%) children were found to be positive for anti-HBc, while anti-HBc-only positive individuals were not observed. Eight isolates (38%) did not carry any mutation. Thirteen infected children (62%) had at least one mutation in regions known to be involved in functional and/or immune epitope activity. Ten had G145R mutations.
:结论：隐匿性乙型肝炎病毒感染在母亲为表面抗原阳性，接受免疫预防的儿童中较为常见，表面抗原阴性者不足以完全除外HBV DNA的存在，这些发现强调HBV的高流行区，考虑隐匿性乙型肝炎感染的存在是很有必要的。
:HBV occult infection seems to be relatively frequent in immunized children born to HBsAg-positive mothers. HBsAg negativity is not sufficient to completely exclude HBV DNA presence. These findings emphasize the importance of considering occult HBV infection in hypo-endemic areas.
