Moreover, the fourth group included 25 CDs involved in many cellular functions, such as viral infection (IFITM1), interferon-gamma receptor signaling (IFITM1, IFNGR1), growth factor/cytokine receptors (TNFSF10, ADAM10, TFRC, FAS, CD109, IL13RA2, IL3RA, LIFR, DPP4), immune checkpoint receptors (PDCD1LG2), complement signaling (CD55, CD46), and hematopoiesis and stem cells [CD34, EVI2B, and KIT (104)] (Figure 3C). The gene discussed is DPP4; the disease is viral infectious disease.