The causal connection between serum biomarkers and COVID-19 severity or pathogenicity in children is unclear. The aim of this study was to describe clinical and immunological features of children affected by COVID-19. The secondary aim was to evaluate whether these cytokines could predict severity of COVID-19. All children (aged 0−18) admitted to the Pediatric Emergency Department and tested with nasopharyngeal swab for SARS-CoV-2 were recruited and assigned to three groups: COVID-19, other infections, control group. Clinical and laboratory data of these patients, including circulating cytokine levels, were analyzed in three groups. Fever was the most frequent symptom in COVID-19 (67.3%). Neutropenia was found in the COVID-19 group (p < 0.05); no difference was observed for lymphocyte counts in the three groups. Higher levels of IL-6 and TNF-alpha were found in the COVID-19 group compared to other infections and control groups (p = 0.014 and p = 0.001, respectively). Whereas, in the COVID-19 group, no difference was observed as for the same cytokines among sub-groups of different disease severity (p = 0.7 and p = 0.8). Serum levels of IL-6 and TNF-alpha were higher in COVID-19 children than in children with other infectious diseases, but those levels did not correlate with disease severity. Clinical studies in a large pediatric population are necessary to better define the role of the immune-mediated response in SARS-CoV-2 infections in children.

中文翻译：

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儿童对 SARS-CoV-2 感染的细胞因子反应

血清生物标志物与儿童 COVID-19 严重程度或致病性之间的因果关系尚不清楚。本研究的目的是描述受 COVID-19 影响的儿童的临床和免疫学特征。次要目的是评估这些细胞因子是否可以预测 COVID-19 的严重程度。招募了所有被儿科急诊科收治并用鼻咽拭子检测 SARS-CoV-2 的儿童（0-18 岁），并被分配到三组：COVID-19、其他感染、对照组。在三组中分析了这些患者的临床和实验室数据，包括循环细胞因子水平。发烧是 COVID-19 中最常见的症状（67.3%）。在 COVID-19 组中发现中性粒细胞减少症（p< 0.05); 三组淋巴细胞计数无差异。与其他感染组和对照组相比，在 COVID-19 组中发现了更高水平的 IL-6 和 TNF-α（分别为p = 0.014 和p = 0.001）。然而，在 COVID-19 组中，在不同疾病严重程度的亚组中，相同细胞因子没有观察到差异（p = 0.7 和p = 0.8）。COVID-19 儿童的血清 IL-6 和 TNF-α 水平高于患有其他传染病的儿童，但这些水平与疾病严重程度无关。为了更好地确定免疫介导的反应在儿童 SARS-CoV-2 感染中的作用，需要在大量儿科人群中进行临床研究。