KIR2DL3 and viral infectious disease: Among the 8 core genes present across 3 pairwise comparisons, 4 genes encoded for KIRs (KIR2DL1, KIR2DL3, KIR2DL5A, and KIR3DL2), which may implicate that the KIRs, with their crucial roles in virus infection, were under such tight regulations that their expression levels were able to reflect specific patterns of particular virus-host interactions.