engelska delen av wikipedia är mera informativ än svenska...
While CCR5 has multiple variants in its coding region, the deletion of a 32-bp segment results in a nonfunctional receptor, thus preventing HIV R5 entry; two copies of this allele provide strong protection against HIV infection.[10] This allele is found in 5-14% of Europeans but is rare in Africans and Asians.[11] Multiple studies of HIV-infected persons have shown that presence of one copy of this allele delays progression to the condition of AIDS by about 2 years. CCR5-Δ32 decreases the number of CCR5 proteins on the outside of the CD4 cell, which can have a large effect on the HIV disease progression rates. It is possible that a person with the CCR5-Δ32 receptor allele will not be infected with HIV R5 strains.