Laboratory of Molecular Virology, Polyclinic Tor Vergata Foundation, Rome, Italy.
Department of Infectious, Parasitic and Immunomediated Diseases, National Institute of Health, Rome, Italy.
Intervirology. 2017;60(4):165-170. doi: 10.1159/000486593. Epub 2018 Feb 2.
The cytomegalovirus (CMV) UL55 gene encodes for a glycoprotein implicated in virus pathogenesis. Based on UL55 polymorphism, CMV has been divided into 4 genotypes. Previous studies investigated the possible role of genotypes in the clinical outcome of infection in different categories of patients; however, few data are available, particularly in the transplant setting and Italian case records.
Phylogenetic analysis through a maximum likelihood tree was used to evaluate the prevalence and distribution of CMV genotypes in whole blood specimens from 47 transplant patients and investigate the relation with demographic and clinical features.
Overall, 40.4% of patients were classified as single genotype (12.8% gB1, 23.4% gB2, 4.2% gB3); mixed genotypes were detected in 59.6%. Genotype 4 was detected only in mixed cases. In comparison to single genotypes, mixed genotypes were more frequently associated with a higher duration of DNA viremia and higher peak viral load.
Mixed infections seem to be prevalent in Italian transplant patients; it is likely that mixed infections are more difficult to control by immunological response in comparison to single genotype infections. In this context, the genetic profile of infecting viruses and relation to clinical outcome should be investigated, also taking into account the CMV-specific cellular immune response.
巨细胞病毒 (CMV) 的 UL55 基因编码一种糖蛋白，与病毒发病机制有关。根据 UL55 多态性，CMV 分为 4 种基因型。先前的研究调查了基因型在不同类别患者感染临床结果中的可能作用；然而，数据很少，特别是在移植环境和意大利病例记录中。
通过最大似然树进行系统发育分析，评估了来自 47 名移植患者全血标本中 CMV 基因型的流行情况和分布，并调查了其与人口统计学和临床特征的关系。
总体而言，40.4%的患者被归类为单一基因型（12.8% gB1、23.4% gB2、4.2% gB3）；混合基因型占 59.6%。基因型 4仅在混合病例中检测到。与单一基因型相比，混合基因型与较长时间的 DNA 病毒血症和较高的病毒载量峰值更相关。
混合感染在意大利移植患者中似乎很常见；与单一基因型感染相比，混合感染更难以通过免疫反应控制。在这种情况下，应调查感染病毒的遗传特征及其与临床结果的关系，同时也要考虑 CMV 特异性细胞免疫反应。
