Abbott Laboratories, Infectious Diseases Research, Diagnostics Division, 100 Abbott Park Road, Abbott Park, IL 60064, USA.
Laboratori de Seguretat Transfusional BST, Banc de Sang I Teixits Passeig Taulat, 08005 Barcelona, Spain.
Viruses. 2021 Oct 13;13(10):2053. doi: 10.3390/v13102053.
Gaps remain in the detection of nucleic acid test (NAT) yield and occult hepatitis B virus (HBV) infection (OBI) by current HBV surface antigen (HBsAg) assays. The lack of detection may be due to HBsAg levels below current assay detection limits, mutations affecting HBsAg assays or HBsAg levels, or the masking of HBsAg by antibody to HBsAg (anti-HBs). In this study, we evaluate the incremental detection of NAT yield and OBI from five diverse geographic areas by an improved sensitivity HBsAg assay and characterize the samples relative to the viral load, anti-HBs status, and PreS1-S2-S mutations. Included is a comparison population with HBV DNA levels comparable to OBI, but with readily detectable HBsAg (High Surface-Low DNA, HSLD).
A total of 347 samples collected from the USA, South Africa, Spain, Cameroon, Vietnam, and Cote D'Ivoire representing NAT yield (HBsAg(-), antibody to HBV core antigen (anti-HBc)(-), HBV DNA(+), N = 131), OBI (HBsAg(-), anti-HBc(+), HBV DNA(+), N = 188), and HSLD (HBsAg(+), anti-HBc(+), HBV DNA(+), N = 28) were tested with ARCHITECT HBsAg NEXT (HBsAgNx) (sensitivity 0.005 IU/mL). The sequencing of the PreS1-S2-S genes from a subset of 177 samples was performed to determine the genotype and assess amino acid variability, particularly in anti-HBs(+) samples.
HBsAgNx detected 44/131 (33.6%) NAT yield and 42/188 (22.3%) OBI samples. Mean HBV DNA levels for NAT yield and OBI samples were lower in HBsAgNx(-) (50.3 and 25.9 IU/mL) than in HBsAgNx(+) samples (384.1 and 139.5 IU/mL). Anti-HBs ≥ 10 mIU/mL was present in 28.6% HBsAgNx(+) and 45.2% HBsAgNx(-) OBI, and in 3.6% HSLD samples. The genotypes were A1, A2, B, C, D, E, F, and H. There was no significant difference between HBsAgNx(-) and HBsAgNx(+) in the proportion of samples harboring substitutions or in the mean number of substitutions per sample in PreS1, PreS2, or S for the NAT yield or OBI ( range: 0.1231 to >0.9999). A total of 21/27 (77.8%) of HBsAgNx(+) OBI carried S escape mutations, insertions, or stop codons. HSLD had more PreS1 and fewer S substitutions compared to both HBsAgNx(-) and HBsAgNx(+) OBI. Mutations/deletions associated with impaired HBsAg secretion were observed in the OBI group.
HBsAgNx provides the improved detection of NAT yield and OBI samples. Samples that remain undetected by HBsAgNx have exceptionally low HBsAg levels below the assay detection limit, likely due to low viremia or the suppression of HBsAg expression by host and viral factors.
当前的乙型肝炎表面抗原（HBsAg）检测方法仍然存在核酸检测（NAT）产量和隐匿性乙型肝炎病毒（HBV）感染（OBI）的检测差距。这种检测可能是由于 HBsAg 水平低于当前检测限、影响 HBsAg 检测的突变或 HBsAg 水平，或 HBsAg 被乙型肝炎表面抗体（抗-HBs）所掩盖。在这项研究中，我们评估了通过改进的高灵敏度 HBsAg 检测方法从五个不同地理区域中增加 NAT 产量和 OBI 的检测，并且对样本进行了与病毒载量、抗-HBs 状态和 PreS1-S2-S 突变相关的特征描述。包括一个与 OBI 相比 HBV DNA 水平相当但 HBsAg 可检测（高表面低 DNA，HSLD）的比较人群。
总共收集了 347 个来自美国、南非、西班牙、喀麦隆、越南和科特迪瓦的样本，代表了 NAT 产量（HBsAg(-)，乙型肝炎核心抗原抗体（抗-HBc)(-)，HBV DNA(+)，N = 131）、OBI（HBsAg(-)，抗-HBc(+)，HBV DNA(+)，N = 188）和 HSLD（HBsAg(+)，抗-HBc(+)，HBV DNA(+)，N = 28）。用 ARCHITECT HBsAg NEXT（HBsAgNx）（检测下限为 0.005 IU/mL）检测了其中的 177 个样本的 PreS1-S2-S 基因的测序，以确定基因型并评估氨基酸的变异性，特别是在抗-HBs(+)样本中。
HBsAgNx 检测到 44/131（33.6%）NAT 产量和 42/188（22.3%）OBI 样本。NAT 产量和 OBI 样本中 HBsAgNx(-)的 HBV DNA 水平较低（分别为 50.3 和 25.9 IU/mL），而 HBsAgNx(+)的 HBV DNA 水平较高（分别为 384.1 和 139.5 IU/mL）。28.6%的 HBsAgNx(+)和 45.2%的 HBsAgNx(-) OBI 样本以及 3.6%的 HSLD 样本中抗-HBs 水平≥10 mIU/mL。基因型为 A1、A2、B、C、D、E、F 和 H。HBsAgNx(-)和 HBsAgNx(+)的样本中，PreS1、PreS2 或 S 中携带替换或每个样本中平均替换数的比例没有显著差异（范围：0.1231 至>0.9999）。在 HBsAgNx(+) OBI 样本中，21/27（77.8%）携带 S 逃逸突变、插入或终止密码子。与 HBsAgNx(-)和 HBsAgNx(+) OBI 相比，HSLD 样本具有更多的 PreS1 和更少的 S 替换。在 OBI 组中观察到与 HBsAg 分泌受损相关的突变/缺失。
HBsAgNx 提供了 NAT 产量和 OBI 样本的改进检测。未被 HBsAgNx 检测到的样本 HBsAg 水平极低，低于检测限，可能是由于病毒血症极低或宿主和病毒因素抑制 HBsAg 表达。
