Re: Is there a human population which resist toward the HIV???

Dear Damien:

Yes, you are correct, there are some people who appear to be naturally more resistant to HIV. These people lack CCR5, which is one of the coreceptors for the HIV virion (CD4 being the receptor and CXCR4 being the other coreceptor). Estimates of up to 20% of Caucasians may be CCR5-deficient in at least one copy of the gene (we all have two), potentially making them more reistant to the virus. People who are heterozygous for the CCR5 mutation (known as CCR5-delta32)and are HIV infected progressed more slowly to AIDS in a Spanish study of IV drug users. Because of this doubly positive effect - resistance to the virus and a slowing of progression to AIDS - some companies are investigating means of blocking CCR5 to prevent the virus from entering cells. This is only being considered because people who lack CCR5 do not have any overt problems with their health. Lacking CCR5, however, will not render one completely immune to HIV, as another coreceptor exists (CXCR4) and is perfectly functional for generating a productive infection. In other words, even if you are Caucasian you should be careful.

As well as people deficient in CCR5, there are also people who are infected with HIV but do not progress to AIDS (so-called long-term non-progressors). These people are also being actively studied to determine the cause of their resistance to disease, if not infection.

I hope this answers your question!

Ingrid Dodge
Mad Scientist

References:

Alvarez V, Lopez-Larrea C, Coto E. Mutational analysis of the CCR5 and CXCR4 genes (HIV-1 coreceptors) in resistance to HIV-1 infection and AIDS development among IV drug users. Human Genetics (1998) 102(4): 483-486.

Dean M, Jacobson LP, McFarlane G et al. Reduced risk of AIDS lymphoma in individuals heterozygous for the CCR5-delta32 mutation. Cancer Research (1999) 59: 3561-3564.

Yudin NS, Sergey VV, Potapova TA et al. Distribution of CCR5-delta32 gene deletion across the Russian part of Eurasia. Human Genetics (1998) 102(6): 695- 698.