CD4 and HIV-1 infection: In the setting of preferentially loss of unmodified CD4+ T cells due to HIV-induced cell death, expansion of CD4+ T cells expressing an inhibitor able to mediate a survival advantage could result in a repopulation of the immune system by cells resistant to HIV-1 infection, as was observed in the HIV-1-infected patient who underwent a bone marrow transplant with hematopoietic cells deficient in CCR5 [21].