A central question in HIV research has been why some human immunodeficiency virus (HIV)-positive individuals have been able to stay AIDS-free for decades, while others develop the disease relatively soon after being infected. Now a piece of this puzzle has been put in place.
Immunologists at the National Cancer Institute in Frederick, Maryland, led by Mary Carrington, PhD, have been analyzing two of the more promising genes known to be associated with the body’s defenses against HIV. These are two genes involved in regulation of the natural killer cells (NK cells) – a “primary line of defense” against viral invasions.
In genetic analysis of 1,500 HIV-positive individuals, Carrington, et al. found that these two genes (HLIA-B and KIR3DL1) occurred in a many variants and combinations within the study population, and that these differences “significantly and strongly influence both AIDS progression and plasma HIV RNA abundance in a consistent manner.”
Specifically, their data show that fewer than one-third of the study subjects with the most beneficial combination of NK cell-regulating genes had developed AIDS within 9 years after their infection with HIV, compared with half of those subjects who did not have this particular combination.
The researchers concluded that “The various epistatic effects observed here for common, distinct KIR3DL1 and HLA-B Bw4 combinations are unprecedented with regard to any pair of genetic loci in human disease, and indicate that NK cells may have a critical role in the natural history of HIV infection.”
Their report on this study - “Innate partnership of HLIA-B and KIR3DLI subtypes against HIV-1,” was published online ahead of print May 13, 2007 in the journal Nature Genetics. To read an abstract of this report in the ImmuneSupport.com library, click here.