As CXCR3 is predominantly expressed on memory T cells, subpopulation analysis revealed increased percentage of peripheral CXCR3+ CD8 but no CD4 TEM cells (Figure 3) in acute RSV infection, indicating that augmented antiviral type-1 CTL response is necessary to balance type-2 microenviroment and restrain viral infection [34]. This evidence concerns the gene CD8A and viral infectious disease.