Figure 2.
Circulating MKs upregulate S100A8/A9 in COVID-19. (A) Volcano plot showing 1436 DEGs from scRNA-seq of MKs from severe COVID-19 vs uninfected controls. (B) Expression of S100A8 and S100A9 in MKs from scRNA-seq samples. Two-way ANOVA with Dunnett post hoc multiple comparisons test. All groups compared with uninfected controls. Adjusted P values: ∗P = .05 to .01; ∗∗P = .01 to .001; ∗∗∗P = .001 to .0001; ∗∗∗∗P < .0001. Black asterisks indicate S100A9 statistical comparisons. Red asterisks = S100A8 statistical comparisons. Severe: n = 14; mild-moderate: n = 15; early recovery (<7 days after first negative PCR test): n = 7; late recovery (>14 days after first negative PCR test): n = 5; uninfected: n = 16. (C) Flow cytometry quantification of S100A8/A9 expression in platelets vs MKs (n = 218 patients; 220 samples). Unpaired 2-tailed t test; ∗∗∗∗P < .0001. (D) Flow cytometry plots and quantification of S100A8/A9 expression in circulating MKs from uninfected controls (n = 9 donors) vs COVID-19 (n = 218 patients; 220 samples). Unpaired 2-tailed t test; ∗∗∗∗P < .0001. (E) PrimeFlow flow cytometry showing S100A8/A9 messenger RNA (mRNA) expression by S100A8/A9 protein expression in COVID-19 MKs. Quantification of S100A8/A9 mRNA expression in S100A8/A9+ MKs vs S100A8/A9− MKs (n = 3 donors). Unpaired 2-tailed t test; ∗∗∗∗P < .0001. (F) PrimeFlow flow cytometry showing IFITM3 mRNA expression by S100A8/A9 protein expression in COVID-19 MKs. Quantification of IFITM3 mRNA expression in S100A8/A9+ MKs vs S100A8/A9− MKs (n = 8 donors). Unpaired 2-tailed t test; ∗∗∗∗P < .0001. (G) Quantification of PrimeFlow IFI27 mRNA expression in S100A8/A9+ MKs vs S100A8/A9− MKs (n = 8 donors). Unpaired 2-tailed t test; ∗∗∗∗P < .0001. (H) Representative imaging flow cytometry from FACS-sorted S100A8/A9+ MKs vs S100A8/A9− MKs. (I) Histogram showing SSC-A granularity in S100A8/A9+ MKs vs S100A8/A9− MKs and quantification of SSC-A granularity in S100A8/A9+ MKs vs S100A8/A9− MKs (n = 218 patients; 220 samples). Unpaired 2-tailed t test; ∗∗∗∗P < .0001. All graphs are mean ± SEM. DEGs, differentially expressed genes.