PTPRC and COVID-19: By virtue of CyTOF, we differentiated CD45+ PBMCs into 31 clusters using metal-labeled antibodies (Supplementary Table 2) against 18 immune cell surface markers and observed obvious differences in the composition of CD45+ PBMC populations in HDs and COVID-19 patients under different clinical conditions (Fig. 1a–c and Supplementary Fig. 1b).