HIV-1 Infection in Persons Homozygous for CCR5-Δ32 Allele: The Next Case and the Review

CC-chemokine receptor 5 serves as the coreceptor for the HIV-1 R5 strains, which are responsible for the majority of HIV transmissions. A deletion of 32 nucleotides in the gene encoding this receptor (termed CCR5-Delta 32) leads to the suppression of CC-chemokine receptor 5 presentation at the cell surface, thus impeding process of HIV entry into the cell. Individuals homozygous for the CCR5-Delta 32 allele are resistant to infection with HIV-1 R5 strains, and are extremely rare among HIV-1-infected individuals. We have described a person homozygous for CCR5-Delta 32, who was infected with subtype B HIV-1. Based on examination of proviral V3 sequences obtained from the first clinical blood sample within less than five months after seroconversion, the CXC-chemokine receptor 4-using strains (X4 or R5/X4) were detected. Data on HIV-1-infected patients homozygous for the CCR5-Delta 32 allele, course of HIV-1 infection in these cases, and the infecting viral strains from current and all former reports on HIV-1 infection in CCR5-Delta 32 homozygotes were gathered and compared. Identification of HIV-1-infected persons homozygous for CCR5-Delta 32 supports the evidence that the lack of functional CC-chemokine receptor 5 at the cell surface does not confer absolute protection against HIV-1 infection, which should be considered when designing future HIV pre-exposure prophylaxis schemes based on CC-chemokine receptor 5 blocking drugs.