Indeed, individuals homozygous for the mutated gene allele who have been exposed to HIV or are at high risk of HIV infection have not developed AIDS. Furthermore, individuals heterozygous for the mutated allele may have some protection and may develop the disease more slowly. In one study of 1955 people, scientists found no individuals who were infected and homozygous for the mutated allele. The allele seems to be more common in Caucasian populations than in African American populations.
Treatment for AIDS involving CKR5 looks promising, as research indicates that people live perfectly well without CKR5. Therapy involving chemokines seems more risky, as unnatural levels of these chemicals can cause severe immune system complications. On the other hand, treatments that block or disable CKR5 may prove to be successful.
"New AIDS Study Reveals Startling Immunity Data" by Gina Kolata, New York Times, September 27, 1996.