CCR5 and HIV infectious disease: Reasoning that CCR5 expression might be indirectly induced by HIV infection, we evaluated CCR5 expression on thymocyte subpopulations after HIV inoculation and found, at day 42 but not day 21, statistically significant increases in the percentage of CCR5-expressing ITTP [to 6.4±1.5% (P = 0.017) for Ba-L and to 3.2±0.2% for 81A (P = 0.001) versus a mean of 1.3±0.2% for mock-infected implants] (Figure 1D and E).