Department of Infectious Diseases, Peking University Hepatology Institute, Peking University People's Hospital, No. 11, Xizhimen South Street, Xicheng District, Beijing, 100044, People's Republic of China.
Peking University Hepatology Institute, Peking University People's Hospital, No. 11, Xizhimen South Street, Xicheng District, Beijing, 100044, People's Republic of China.
Virol J. 2023 May 26;20(1):101. doi: 10.1186/s12985-023-02067-2.
Influenza A viruses have undergone rapid evolution with virulent; however, complete and comprehensive data on gene evolution and amino acid variation of HA and NA in immunosuppressed patients was few. In this study, we analysed molecular epidemiology and evolution of influenza A viruses in immunosuppressed population, and immunocompetent population were used as controls.
Full sequences of HA and NA of A(H1N1)pdm09 and A(H3N2) were acquired through reverse transcription-polymerase chain reaction (RT-PCR). HA and NA genes were sequenced using the Sanger method and phylogenetically analysed using ClustalW 2.10 and MEGA software version 11.0.
During the 2018-2020 influenza seasons, 54 immunosuppressed and 46 immunocompetent inpatients screened positive for influenza A viruses by using the quantitative real-time PCR (qRT-PCR) were enrolled. 27 immunosuppressed and 23 immunocompetent nasal swab or bronchoalveolar lavage fluid samples were randomly selected and sequenced using the Sanger method. A(H1N1)pdm09 were detected in 15 samples and the remaining 35 samples were A(H3N2) positive. By analyzing the HA and NA gene sequences of these virus strains, we found that all A(H1N1)pdm09 viruses shared high similarities to each other and the HA and NA genes of these viruses exclusively belonged to subclade 6B.1A.1. Some NA genes of A(H3N2) viruses were not in the same clade as those of A/Singapore/INFIMH-16-0019/2016 and A/Kansas/14/2017, which may have led to A(H3N2) being the dominant strain in the 2019-2020 influenza season. Both A(H1N1)pdm09 and A(H3N2) viruses showed similar evolutionary lineages patterns of HA and NA between immunosuppressed and immunocompetent patients. Compared with the vaccine strains, there were no statistically significant of HA and NA genes and amino acid sequences of influenza A viruses in immunosuppressed and immunocompetent patients. However, the oseltamivir resistance substitution of NA-H275Y and R292K have been observed in immunosuppressed patients.
A(H1N1)pdm09 and A(H3N2) viruses showed similar evolutionary lineages patterns of HA and NA between immunosuppressed and immunocompetent patients. Both immunocompetent and immunosuppressed patients have some key substitutions, which should be of note monitored, especially those with potential to affect the viral antigen.
甲型流感病毒发生了快速进化，变得具有毒性；然而，关于免疫抑制患者的 HA 和 NA 的基因进化和氨基酸变异的完整且全面的数据却很少。在这项研究中，我们分析了免疫抑制人群和免疫功能正常人群中甲型流感病毒的分子流行病学和进化情况，免疫功能正常人群被用作对照。
通过逆转录-聚合酶链反应（RT-PCR）获得 A(H1N1)pdm09 和 A(H3N2)的 HA 和 NA 的全长序列。使用 Sanger 法对 HA 和 NA 基因进行测序，并使用 ClustalW 2.10 和 MEGA 软件版本 11.0 进行系统发育分析。
在 2018-2020 年流感季节，通过定量实时 PCR（qRT-PCR）筛选出 54 例免疫抑制住院患者和 46 例免疫功能正常住院患者的甲型流感病毒呈阳性。随机选择 27 例免疫抑制和 23 例免疫功能正常的鼻拭子或支气管肺泡灌洗液样本，使用 Sanger 法进行测序。检测到 15 份 A(H1N1)pdm09 样本，其余 35 份为 A(H3N2)阳性。通过分析这些病毒株的 HA 和 NA 基因序列，我们发现所有 A(H1N1)pdm09 病毒彼此之间具有高度相似性，并且这些病毒的 HA 和 NA 基因仅属于 6B.1A.1 亚群。一些 A(H3N2)病毒的 NA 基因与 A/Singapore/INFIMH-16-0019/2016 和 A/Kansas/14/2017 的 NA 基因不在同一进化枝中，这可能导致 A(H3N2)成为 2019-2020 年流感季节的优势株。A(H1N1)pdm09 和 A(H3N2)病毒在免疫抑制和免疫功能正常患者中的 HA 和 NA 进化谱系模式相似。与疫苗株相比，免疫抑制和免疫功能正常患者的甲型流感病毒的 HA 和 NA 基因及其氨基酸序列均无统计学意义上的显著差异。然而，在免疫抑制患者中观察到了 NA-H275Y 和 R292K 的奥司他韦耐药替代。
A(H1N1)pdm09 和 A(H3N2)病毒在免疫抑制和免疫功能正常患者中的 HA 和 NA 进化谱系模式相似。免疫功能正常和免疫抑制患者都有一些关键的替代，这应该值得注意和监测，特别是那些可能影响病毒抗原的替代。
