Recent reports highlight a new clinical syndrome in children related to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)¹—multisystem inflammatory syndrome in children (MIS-C)—which comprises multiorgan dysfunction and systemic inflammation^{2,3,4,5,6,7,8,9,10,11,12,13}. We performed peripheral leukocyte phenotyping in 25 children with MIS-C, in the acute (n = 23; worst illness within 72 h of admission), resolution (n = 14; clinical improvement) and convalescent (n = 10; first outpatient visit) phases of the illness and used samples from seven age-matched healthy controls for comparisons. Among the MIS-C cohort, 17 (68%) children were SARS-CoV-2 seropositive, suggesting previous SARS-CoV-2 infections^14,15, and these children had more severe disease. In the acute phase of MIS-C, we observed high levels of interleukin-1β (IL-1β), IL-6, IL-8, IL-10, IL-17, interferon-γ and differential T and B cell subset lymphopenia. High CD64 expression on neutrophils and monocytes, and high HLA-DR expression on γδ and CD4⁺CCR7⁺ T cells in the acute phase, suggested that these immune cell populations were activated. Antigen-presenting cells had low HLA-DR and CD86 expression, potentially indicative of impaired antigen presentation. These features normalized over the resolution and convalescence phases. Overall, MIS-C presents as an immunopathogenic illness¹ and appears distinct from Kawasaki disease.

最近的报告强调了一种与严重急性呼吸综合征冠状病毒 2 (SARS-CoV-2) ¹相关的儿童新临床综合征 - 儿童多系统炎症综合征 (MIS-C) - 包括多器官功能障碍和全身炎症^{2,3,4, 5,6,7,8,9,10,11,12,13} 。我们对 25 名 MIS-C 儿童进行了外周血白细胞表型分析，包括急性期（ n = 23；入院 72 小时内病情最严重）、缓解期（ n = 14；临床改善）和恢复期（ n = 10；首次门诊就诊）疾病的各个阶段，并使用七名年龄匹配的健康对照者的样本进行比较。在 MIS-C 队列中，17 名 (68%) 儿童的 SARS-CoV-2 血清反应呈阳性，表明以前曾感染过 SARS-CoV-2 ^14,15 ，而且这些儿童的病情更为严重。在 MIS-C 的急性期，我们观察到高水平的白介素-1β (IL-1β)、IL-6、IL-8、IL-10、IL-17、干扰素-γ 以及差异性 T 和 B 细胞亚群淋巴细胞减少。急性期中性粒细胞和单核细胞上 CD64 高表达，γδ 和 CD4 ⁺ CCR7 ⁺ T 细胞上 HLA-DR 高表达，表明这些免疫细胞群被激活。抗原呈递细胞的 HLA-DR 和 CD86 表达较低，可能表明抗原呈递受损。这些特征在缓解和恢复阶段正常化。总体而言，MIS-C 表现为一种免疫致病性疾病¹ ，并且与川崎病不同。