Abstract

Persisting inflammation has been discovered in lungs and other parenchymatous organs of some COVID-19 convalescents. Calprotectin, neutrophil extracellular traps (NETs), syndecan-1 and neopterin are general key inflammatory markers, and systemically enhanced levels of them may remain after the COVID-19 infection. These inflammatory markers were therefore measured in serum samples of 129 COVID-19 convalescent and 27 healthy blood donors or employees at Oslo Blood bank, Norway. Also antibodies against SARS-CoV-2 nucleocapsid antigen were measured, and timing of sampling and severity of infection noted. Whereas neopterin and NETs values remained low and those for syndecan-1 were not raised to statistically significant level, concentrations for calprotectin, as measured by a novel mixed monoclonal assay, were significantly increased in the convalescents. Antibodies against SARS-CoV-2 nucleocapsid antigen were elevated, but did not correlate with levels of inflammatory markers. Difference between the groups in only one biomarker makes evaluation of ongoing or residual inflammation in the convalescents difficult. If there is a low-grade inflammation, it would in that case involve neutrophils.

摘要

在一些 COVID-19 康复者的肺部和其他实质器官中发现了持续性炎症。钙卫蛋白、中性粒细胞胞外陷阱 (NETs)、syndecan-1 和新蝶呤是一般的关键炎症标志物，在 COVID-19 感染后它们的全身增强水平可能仍然存在。因此，在挪威奥斯陆血库的 129 名 COVID-19 康复者和 27 名健康献血者或员工的血清样本中测量了这些炎症标志物。还测量了针对 SARS-CoV-2 核衣壳抗原的抗体，并记录了采样时间和感染严重程度。虽然新蝶呤和 NETs 值仍然很低，而 syndecan-1 的值没有提高到统计学上显着的水平，但通过一种新型混合单克隆测定法测量的钙卫蛋白浓度，在康复者中显着增加。针对 SARS-CoV-2 核衣壳抗原的抗体升高，但与炎症标志物水平无关。仅一种生物标志物的组间差异使得评估恢复期的持续或残留炎症变得困难。如果存在低度炎症，则在这种情况下会涉及中性粒细胞。