HIV controllers are those rare people: they have high levels of HIV but do not develop AIDS, and they do not need to take medication. There are more than 300 of these genetic variations, which affect how the person's immune system recognizes HIV-infected cells through so-called HLA proteins, which display fragments of the virus on the cell's surface.

Approximately one in every 300 people infected with HIV is an HIV controller. Researchers hope that by understanding how these controllers suppress the virus's replication process, they may uncover new clues to developing a vaccine or other treatments.

Florencia Pereyra and a large research team conducted a genome-wide association analysis of patients participating in the International HIV Controller Study. A genome-wide association study compares the genomes of different individuals to look for differences between one person and another that are associated with disease or other traits.

The researchers compared HIV controllers with HIV progression among people of European, African-American, and Hispanic descent. They found more than 300 variants with genome-wide significance. All of these variants are located in a region of chromosome 6, where the HLA genes are located. They then analyzed the potency of individual amino acids located within the HLA protein, and they found six individually significant residues, five of which lined the grooves of the peptide that binds to viral particles.

Although more research must be done to understand exactly how these differences contribute to HIV control, these findings suggest that the process begins with viral peptide antigens binding to HLA proteins , and this binding then affects the activation of T cells that can recognize and destroy infected cells.