Hyperactivation of the host immune system during infection by SARS-CoV-2 is the leading cause of death in COVID-19 patients. It is also evident that patients who develop mild/moderate symptoms and successfully recover display functional and well-regulated immune response. Whereas a delayed initial interferon response is associated with severe disease outcome and can be the tipping point towards immunopathological deterioration, often preceding death in COVID-19 patients. Further, adaptive immune response during COVID-19 is heterogeneous and poorly understood. At the same time, some studies suggest activated T and B cell response in severe and critically ill patients and the presence of SARS-CoV2-specific antibodies. Thus, understanding this problem and the underlying molecular pathways implicated in host immune function/dysfunction is imperative to devise effective therapeutic interventions. In this comprehensive review, we discuss the emerging immunopathological determinants and the mechanism of virus evasion by the host cell immune system. Using the knowledge gained from previous respiratory viruses and the emerging clinical and molecular findings on SARS-CoV-2, we have tried to provide a holistic understanding of the host innate and adaptive immune response that may determine disease outcome. Considering the critical role of the adaptive immune system during the viral clearance, we have presented the molecular insights of the plausible mechanisms involved in impaired T cell function/dysfunction during various stages of COVID-19.

SARS-CoV-2 感染期间宿主免疫系统的过度激活是 COVID-19 患者死亡的主要原因。同样明显的是，出现轻度/中度症状并成功康复的患者表现出功能性且调节良好的免疫反应。然而，延迟的初始干扰素反应与严重的疾病结果相关，并且可能是免疫病理学恶化的转折点，通常在 COVID-19 患者死亡之前。此外，COVID-19 期间的适应性免疫反应是异质的且知之甚少。与此同时，一些研究表明重症和危重症患者的 T 细胞和 B 细胞反应被激活，并且存在 SARS-CoV2 特异性抗体。因此，了解这个问题以及与宿主免疫功能/功能障碍有关的潜在分子途径对于设计有效的治疗干预措施至关重要。在这篇综合综述中，我们讨论了新出现的免疫病理学决定因素以及宿主细胞免疫系统逃避病毒的机制。利用从以前的呼吸道病毒中获得的知识以及 SARS-CoV-2 的新临床和分子发现，我们试图全面了解可能决定疾病结果的宿主先天性和适应性免疫反应。考虑到适应性免疫系统在病毒清除过程中的关键作用，我们提出了有关 COVID-19 各个阶段 T 细胞功能受损/功能障碍的可能机制的分子见解。