Division of Clinical Immunology and Infectious Diseases, Department of Medicine, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy.
Division of Otorhinolaryngology, Department of Surgery, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy.
Front Immunol. 2021 Nov 10;12:748881. doi: 10.3389/fimmu.2021.748881. eCollection 2021.
Olfactory and taste disorders (OTD) are commonly found as presenting symptoms of SARS-CoV-2 infection in patients with clinically mild COVID-19. Virus-specific T cells are thought to play an important role in the clearance of SARS-CoV-2; therefore the study of T cell specific immune responses in patients with mild symptoms may help to understand their possible role in protection from severe disease. We evaluated SARS-CoV-2-specific T cell responses to four different peptide megapools covering all SARS-CoV-2 proteins during the acute phase of the disease in 33 individuals with mild or no other symptom beside OTD and in 22 age-matched patients with severe infection. A control group of 15 outpatients with OTD and consistently negative nasopharyngeal SARS-CoV-2 RNA swabs and virus-specific IgG serology was included in the study. Increased frequencies of virus-specific CD4 and CD8 T cells were found in SARS-CoV-2 positive patients with OTD compared with those with severe COVID-19 and with SARS-CoV-2 negative OTD individuals. Moreover, enhanced CD4 and CD8 T-cell activation induced by SARS-CoV-2 peptides was associated with higher interferon (IFN)γ production. Increased frequencies of Spike (S1/S2)-specific CD4 T cells showing enhanced IFNγ secretion and granzyme B content were associated with serum spike-specific IgG in the OTD group. In conclusion, patients with SARS-CoV-2 induced OTD develop highly functional virus-specific CD4 and CD8 T cells during the symptomatic phase of the disease, suggesting that robust and coordinated T-cell responses provide protection against extension of COVID-19 to the lower respiratory tract.
嗅觉和味觉障碍（OTD）是 COVID-19 患者中临床轻症 SARS-CoV-2 感染的常见表现症状。病毒特异性 T 细胞被认为在清除 SARS-CoV-2 中发挥重要作用；因此，研究轻症患者的 T 细胞特异性免疫反应有助于了解它们在预防重症疾病方面的可能作用。我们评估了 33 例仅出现 OTD 症状和 22 例年龄匹配的重症感染患者在疾病急性期对涵盖 SARS-CoV-2 所有蛋白的四个不同多肽混合库的 SARS-CoV-2 特异性 T 细胞反应。研究纳入了 15 例 OTD 门诊患者作为对照组，这些患者的鼻咽 SARS-CoV-2 RNA 拭子持续为阴性且具有病毒特异性 IgG 血清学。与重症 COVID-19 患者和 SARS-CoV-2 阴性 OTD 患者相比，出现 OTD 的 SARS-CoV-2 阳性患者中病毒特异性 CD4 和 CD8 T 细胞的频率增加。此外，SARS-CoV-2 肽诱导的 CD4 和 CD8 T 细胞激活增强与较高的干扰素（IFN）γ产生相关。在 OTD 组中，S 蛋白（S1/S2）特异性 CD4 T 细胞的频率增加，这些细胞表现出增强的 IFNγ 分泌和颗粒酶 B 含量，与血清刺突特异性 IgG 相关。总之，SARS-CoV-2 引起 OTD 的患者在疾病的症状期会产生高度功能性的病毒特异性 CD4 和 CD8 T 细胞，这表明强大而协调的 T 细胞反应可防止 COVID-19 向下呼吸道扩散。
