CCR2 and HIV infectious disease: Curiously, an in vitro study has shown that both wild-type CCR2 and the mutated (V64I) version of the receptor were equally permissive for HIV infection regardless of viral tropism, were expressed at similar levels on the cell surface and were equally effective acting as viral co-receptors and as chemokine receptors, suggesting that this variation probably has neither a protective nor a deleterious effect in the course of HIV infection [35].