CXCL10 and COVID-19: In addition to decreased cell fraction, differential expression analysis revealed the severely downregulated expression of CXCL10, which is IFN-γ-induced gene and reported to be involved in COVID-19 severity with proteomics analysis5,13, in ncMono for severe COVID-19, and cell–cell communication analysis inferred the possibility that CXCL10/CXCR3 interaction between ncMono and pDC was depleted whereas ncMono firmly received IFN-γ signal from activated T cells in severe COVID-19.