CD4 and COVID-19: Despite the number of differentially outflowing signals increasing with COVID-19 severity, the number of inferred signal inflows decreased from 37 to 32 (loss of AXL, CD4, F2RL1, ITGAX and ITGB2, TNFRSF12A and TNFRSF14; gain of CAP1) to 25 (loss of CD27, CXCR3, FPR1, IL-6R and IL-6ST, LTBR, NCL, NRP2 and PLXNA2, SDC1, TNFRSF13B, TNFRSF17 and TNFRSF25; gain of AXL, CD4, F2RL1 and TNFRSF14).