Abdul Rahman Siti Nurul Fazlin, Hamzah Hairul Aini, Mustafa Mahmud Mohammed Imad A, Mat Harun Noraihan
Microbiology Unit, Department of Basic Medical Sciences, Kulliyyah of Medicine, International Islamic University Malaysia, Pahang, Malaysia.
Molecular and Biochemistry Unit, Department of Basic Medical Sciences, Kulliyyah of Medicine, International Islamic University Malaysia, Pahang, Malaysia.
Malays J Med Sci. 2024 Apr;31(2):30-42. doi: 10.21315/mjms2024.31.2.4. Epub 2024 Apr 23.
In occult hepatitis C virus infection (OCI), hepatitis C virus ribonucleic acid (HCV RNA) is detectable in peripheral blood mononuclear cells (PBMCs) but is not evident in serum or plasma. Understanding of OCI in patients with seronegative anti-HCV antibodies is limited.
In this study, six HCV isolates from haemodialysis (HD) patients with seronegative OCI were identified by molecular assays and phylogenetic analysis. The virus infectivity was assessed ex vivo using a primary naïve PBMC culture system. HCV isolates obtained from the PBMCs of 10 patients with chronic HCV infection (CCI) were characterised concurrently and used as positive controls in the cell culture.
Sequence analysis of the 5' untranslated region (UTR) and non-structural 5B (NS5B) region revealed that HCV genotype 3 was the most prevalent virus type in both the OCI and CCI groups. One of the occult HCV isolates was identified as a mixed type. The mean viral load (log RNA copies/106 cells) in the PBMC samples of the OCI group (M = 3.4, SD = 0.7) was lower than that of the CCI group (M = 4.6, SD = 1.7). Upon culture, de novo OCI-HCV replicates were detected in five out of six naïve PBMC cultures. Analysis of the replicates showed a single guanine addition in the domain III of 5'-UTR but the overall molecular structure was retained.
Seronegative OCI is an active form of infection that replicates at a low level in PBMCs. Seronegative OCI may share the same route of transmission as CCI. The retained viral competency may have an implication for its persistence.
在隐匿性丙型肝炎病毒感染（OCI）中，丙型肝炎病毒核糖核酸（HCV RNA）在外周血单个核细胞（PBMC）中可检测到，但在血清或血浆中不明显。对血清抗-HCV抗体阴性患者的OCI了解有限。
在本研究中，通过分子检测和系统发育分析，从血清学阴性的OCI血液透析（HD）患者中鉴定出6株HCV分离株。使用原代未致敏PBMC培养系统在体外评估病毒感染性。同时对从10例慢性HCV感染（CCI）患者的PBMC中获得的HCV分离株进行特征分析，并用作细胞培养中的阳性对照。
对5'非翻译区（UTR）和非结构5B（NS5B）区的序列分析表明，HCV基因型3是OCI组和CCI组中最常见的病毒类型。其中一株隐匿性HCV分离株被鉴定为混合型。OCI组PBMC样本中的平均病毒载量（log RNA拷贝数/106个细胞）（M = 3.4，标准差 = 0.7）低于CCI组（M = 4.6，标准差 = 1.7）。培养后，在6个未致敏PBMC培养物中的5个中检测到新生的OCI-HCV复制体。对复制体的分析显示，5'-UTR的结构域III中有一个鸟嘌呤添加，但整体分子结构得以保留。
血清学阴性的OCI是一种活跃的感染形式，在PBMC中低水平复制。血清学阴性的OCI可能与CCI具有相同的传播途径。保留的病毒活性可能与其持续性有关。
