Clinical manifestations of COVID-19 caused by the novel coronavirus SARS-CoV-2 are associated with age. While children are largely spared from severe respiratory disease, they can present with a SARS-CoV-2-associated multisystem inflammatory syndrome (MIS-C) similar to Kawasaki's disease. Here, we show distinct antibody (Ab) responses in children with MIS-C compared to adults with severe COVID-19 causing acute respiratory distress syndrome (ARDS), and those who recovered from mild disease. There was a reduced breadth and specificity of anti-SARS-CoV-2-specific antibodies in MIS-C patients compared to the COVID patient groups; MIS-C predominantly generated IgG Abs specific for the Spike (S) protein but not for the nucleocapsid (N) protein, while both COVID-19 cohorts had anti-S IgG, IgM and IgA Abs, as well as anti-N IgG Abs. Moreover, MIS-C patients had reduced neutralizing activity compared to COVID-19 cohorts, indicating a reduced protective serological response. These results suggest a distinct infection course and immune response in children and adults who develop severe disease, with implications for optimizing treatments based on symptom and age.

中文翻译：

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与成人COVID-19相比，MIS-C儿童对SARS-CoV2的抗体反应明显。

新型冠状病毒SARS-CoV-2引起的COVID-19的临床表现与年龄有关。虽然儿童在很大程度上免于遭受严重的呼吸道疾病的困扰，但他们可能会出现与川崎病类似的SARS-CoV-2相关性多系统炎性综合征（MIS-C）。在这里，我们显示与严重COVID-19导致成人急性呼吸窘迫综合征（ARDS）的成年人以及从轻度疾病中恢复的成年人相比，MIS-C儿童的抗体（Ab）反应不同。与COVID患者组相比，MIS-C患者中抗SARS-CoV-2特异性抗体的广度和特异性降低。MIS-C主要产生对Spike（S）蛋白具有特异性的IgG Abs，但对核衣壳（N）蛋白没有特异性，而COVID-19人群均具有抗S IgG，IgM和IgA Abs以及抗N IgG Abs 。此外，与COVID-19队列相比，MIS-C患者的中和活性降低，表明保护性血清学反应降低。这些结果表明，在患有严重疾病的儿童和成人中，感染过程和免疫反应不同，这可能会根据症状和年龄优化治疗方法。