This study investigated the molecular mechanisms of immune responses in Kawasaki disease (KD) and COVID-19 using single-cell RNA sequencing (scRNA-seq) of peripheral blood mononuclear cells (PBMCs). The scRNA-seq analysis revealed differences in immune cell composition and gene expression between KD and COVID-19 patients. While both KD and COVID-19 showed elevated CD14+ monocytes, the activation of adaptive immunity differed between the two diseases. Monocytes in COVID-19 showed adhesion to both endothelial and alveolar epithelial cells, highlighting shared phenotypes. In vitro experiments validated the scRNA-seq findings, showing that SELL+/CCR1+/XAF1+ CD14 monocytes enhanced endothelial cell adhesion and damage.

Xiaoliang Liu, Tingting Luo, Zhenxin Fan, Jiawen Li, Yue Zhang, Guoyan Lu, Mingyi Lv, Sha Lin, Ziwen Cai, Jinbao Zhang, Kaiyu Zhou, Junling Guo, Yimin Hua, Yaoyao Zhang, Yifei Li