Objectives

To describe the humoral immune feature of patients with coronavirus disease 2019 (COVID-19).

Methods

The levels of total immunoglobulins (IgG, IgM, IgA, and IgE), complement (C3, C4) results were retrospectively analyzed in COVID-19 patients. Univariable and multivariable logistic regression were performed to explore the risk factors associated with the in-hospital death.

Result

A total of 236 patients were enrolled in this study, of which 169 were transferred to another institution or discharged (survival group) and 67 died in hospital (non-survival group). Compared with survivors, the levels of IgA and IgE in non-survivors increased significantly, and level of complement C3 decreased. Non-survivors also showed higher incidence of chest tightness, breath shortness and dyspnoea; higher levels of inflammatory indicators, leukocytes and neutrophils; and low levels of lymphocyte subsets. Multivariable regression showed increasing odds of in-hospital death associated with older age (HR: 1.099; 95%CI: 1.057–1.143; p < 0.0001), d-dimer greater (HR: 1.294; 95%CI: 1.138–1.473; p < 0.0001) and decreased complement C3 level (HR: 0.073; 95%CI: 0.007–0.722; p = 0.025) on admission. Finally, in survival COVID-19 patients whose humoral immunity was re-examined, C3 levels tended to increase, while in non-survivors it decreased.

Conclusion

Low level of complement C3 may be an alert to the admitted COVID-19 patients with additional management. Inhibition of the complement pathway might be an effective therapeutic to COVID-19 patients.

中文翻译：

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一项回顾性队列研究显示，补体C3水平降低与COVID-19患者预后不良相关

目标

描述2019年冠状病毒病患者的体液免疫功能（COVID-19）。

方法

回顾性分析了COVID-19患者的总免疫球蛋白（IgG，IgM，IgA和IgE），补体（C3，C4）水平。进行单变量和多变量logistic回归以探讨与院内死亡相关的危险因素。

结果

本研究共纳入236名患者，其中169例被转移到另一家机构或出院（生存组），其中67例在医院死亡（非生存组）。与幸存者相比，非幸存者中IgA和IgE的水平显着增加，补体C3的水平下降。非幸存者还表现出较高的胸闷，呼吸急促和呼吸困难的发生率。炎症指标，白细胞和中性粒细胞水平较高；和低水平的淋巴细胞亚群。多变量回归显示与老年相关的院内死亡几率增加（HR：1.099; 95％CI：1.057–1.143; p  <0.0001），d-二聚体更大（HR：1.294; 95％CI：1.138–1.473; p  <0.0001）和补体C3水平降低（HR：0.073； 95％CI：0.007–0.722；p  = 0.025）。最后，在重新检查了体液免疫的存活COVID-19患者中，C3水平倾向于升高，而在非存活者中C3水平则降低。

结论

补体C3含量低可能是对入院的COVID-19患者进行了额外管理的警报。补体途径的抑制可能对COVID-19患者有效。