Compared to control cases, and in line with above mentioned phenotypic differences (Figures 1–3) and the results of the pathway enrichment analysis (Figure 5), there was a downregulation of multiple genes related to T-cell function and differentiation (LCP2, CD3E, LEF1, CD6, MAL, TCL1A, TYROBP, CD84, CD5), particularly related to CD4 cells (IL16, CD4), macrophage function (LYZ, SIGLEC1), genes encoding for immunoglobulin receptors (FCER2, PIGR) and transcription factors (ETS1, EGR1, FOS) in COVID-19. The gene discussed is FOS; the disease is COVID-19.