Ameratunga Rohan, Woon See-Tarn, Steele Richard, Lehnert Klaus, Leung Euphemia, Brooks Anna E S
Department of Virology and Immunology, Auckland City Hospital, Auckland, New Zealand
Department of Clinical Immunology, Auckland City Hospital, Auckland, New Zealand.
J Clin Pathol. 2022 Dec;75(12):793-797. doi: 10.1136/jcp-2022-208305. Epub 2022 Oct 10.
After almost 3 years of intense study, the immunological basis of COVID-19 is better understood. Patients who suffer severe disease have a chaotic, destructive immune response. Many patients with severe COVID-19 produce high titres of non-neutralising antibodies, which are unable to sterilise the infection. In contrast, there is increasing evidence that a rapid, balanced cellular immune response is required to eliminate the virus and mitigate disease severity. In the longer term, memory T cell responses, following infection or vaccination, play a critical role in protection against SARS-CoV-2.Given the pivotal role of cellular immunity in the response to COVID-19, diagnostic T cell assays for SARS-CoV-2 may be of particular value for immunodeficient patients. A diagnostic SARS-CoV-2 T cell assay would be of utility for immunocompromised patients who are unable to produce antibodies or have passively acquired antibodies from subcutaneous or intravenous immunoglobulin (SCIG/IVIG) replacement. In many antibody-deficient patients, cellular responses are preserved. SARS-CoV-2 T cell assays may identify breakthrough infections if reverse transcriptase quantitative PCR (RT-qPCR) or rapid antigen tests (RATs) are not undertaken during the window of viral shedding. In addition to utility in patients with immunodeficiency, memory T cell responses could also identify chronically symptomatic patients with long COVID-19 who were infected early in the pandemic. These individuals may have been infected before the availability of reliable RT-qPCR and RAT tests and their antibodies may have waned. T cell responses to SARS-CoV-2 have greater durability than antibodies and can also distinguish patients with infection from vaccinated individuals.
经过近3年的深入研究，人们对新型冠状病毒肺炎（COVID-19）的免疫基础有了更好的理解。患有严重疾病的患者会出现混乱、破坏性的免疫反应。许多重症COVID-19患者会产生高滴度的非中和抗体，这些抗体无法清除感染。相比之下，越来越多的证据表明，需要快速、平衡的细胞免疫反应来清除病毒并减轻疾病严重程度。从长远来看，感染或接种疫苗后的记忆T细胞反应在预防严重急性呼吸综合征冠状病毒2（SARS-CoV-2）方面起着关键作用。鉴于细胞免疫在应对COVID-19中的关键作用，针对SARS-CoV-2的诊断性T细胞检测对于免疫缺陷患者可能具有特别的价值。一种诊断性SARS-CoV-2 T细胞检测对于无法产生抗体或已从皮下或静脉注射免疫球蛋白（SCIG/IVIG）替代治疗中被动获得抗体的免疫功能低下患者将很有用。在许多抗体缺乏的患者中，细胞反应仍然存在。如果在病毒脱落窗口期未进行逆转录酶定量聚合酶链反应（RT-qPCR）或快速抗原检测（RAT），SARS-CoV-2 T细胞检测可能会识别出突破性感染。除了对免疫缺陷患者有用外，记忆T细胞反应还可以识别在疫情早期感染的患有长期COVID-19的慢性症状患者。这些人可能在可靠的RT-qPCR和RAT检测可用之前就已感染，并且他们的抗体可能已经减弱。对SARS-CoV-2的T细胞反应比抗体具有更强的持久性，还可以区分感染患者和接种疫苗的个体。
