CD19 and COVID-19: Figure 1B exemplifies for CD14+ monocytes a hierarchical clustering that suggests increases of phosphorylated p38, ERK1/2, JNK, STAT3, STAT5 and CREB in COVID-19 patients. However, when analyzing individual signaling pathways in more detail, variances among groups turned out to be very high and obscured potential differences between patients and controls (Table S1). Likewise, cluster analyses of phosphorylated signaling molecules in CD19+, CD3+ or CD11b+ cells did not reveal any COVID-19 specific activation of the respective pathways (Figure 1B, Tables S2–S4).