There is very little knowledge about the immune responses, particularly cellular immunity to coronavirus disease 2019 (COVID‐19). The main objective of this study was to evaluate the frequency of T helper (Th) cell subtypes, including Th1, Th17, and Treg cells, in moderate‐to‐severe and critical COVID‐19 patients compared to healthy controls. Twenty‐nine moderate‐to‐severe and 13 critical patients confirmed for COVID‐19, and 15 healthy subjects were included in this study. Interferon‐γ (IFN‐γ)‐producing Th1 and interleukin‐17A‐producing Th17 and Treg cells in peripheral blood were measured with flow cytometry. The frequency of Th1 and Th17 was significantly decreased in critical patients compared to healthy subjects (aMD: −2.76 and − 2.34) and moderate‐to‐severe patients (aMD: −1.89 and − 1.89), respectively (p < 0.05). Differences were not significant between moderate‐to‐severe patients and healthy subjects for both Th1 (p = 0.358) and Th17 (p = 0.535), respectively. In contrast, significant difference was not observed between study subjects regarding the frequency of Treg cells. Patients with critical COVID‐19 had a markedly lower Th1/Treg and Th17/Treg ratios compared with the controls and moderate‐to‐severe cases. Our study showed a dysregulated balance of Th1 and Th17 cells and its relation to the severity of COVID‐19.

中文翻译：

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辅助 T 17 和辅助 T 1 细胞频率降低及其与 2019 年严重冠状病毒病的关联

关于免疫反应，特别是针对 2019 年冠状病毒病 (COVID-19) 的细胞免疫，人们知之甚少。本研究的主要目的是评估中度至重度和危重 COVID-19 患者与健康对照者中 T 辅助 (Th) 细胞亚型（包括 Th1、Th17 和 Treg 细胞）的频率。本研究纳入了 29 名中度至重度确诊患者和 13 名危重患者，以及 15 名健康受试者。采用流式细胞术测量外周血中产生干扰素-γ (IFN-γ) 的 Th1 细胞和产生白细胞介素-17A 的 Th17 和 Treg 细胞。与健康受试者（aMD：-2.76和-2.34）和中重度患者（aMD：-1.89和-1.89）相比，危重患者的Th1和Th17频率分别显着降低（p <0.05）。中度至重度患者和健康受试者之间的 Th1 (p = 0.358) 和 Th17 (p = 0.535) 差异均不显着。相比之下，研究对象之间 Treg 细胞的频率没有观察到显着差异。与对照组和中重度病例相比，重症 COVID-19 患者的 Th1/Treg 和 Th17/Treg 比率显着降低。我们的研究表明 Th1 和 Th17 细胞的平衡失调及其与 COVID-19 严重程度的关系。