IL15 and HIV infectious disease: Indeed, flow cytometry analysis of CCR5 expression in CD4+ T cells stimulated with IL-15 or IL-2 revealed that IL-15 slightly increased both the percentage of CCR5+ cells as well as CCR5 MFI (Fig. 5H to J), suggesting that IL-15 may also favor HIV infection by increasing CCR5 expression in CD4+ T cells.