Infection With Mutated HIV May Offer Survival Advantage

Individuals infected with a mutated strain of HIV, transmitted from a person possessing the HLA gene sequences that have allowed them to control the virus, may also have a survival advantage even if they do not possess the same gene sequences, AIDS researchers from South Africa report in the open-access online journal PLoS Pathogens.

Dr. Carolyn Williamson, of the University of Cape Town, South Africa, and colleagues looked for HIV genetic mutations in 21 newly infected women from Durban, South Africa.

These women were negative for HLA-B*57 and HLA-B*5801 - versions of the human leukocyte antigen (HLA) gene that are associated with slower HIV replication and often long-term non-progressor status in HIV-infected individuals.

Examination of Gag sequences from these HLA-B*57/5801-negative women showed that two polymorphisms -- A146X and T242N - were associated with lower viral loads and higher CD4+ counts up to 1 year after infection.

"These lower viral initial loads and higher CD4+ counts at the onset of infection may slow disease progression in these individuals," the researchers note.

"As both polymorphisms have been previously identified as HLA-B*57/5801 immune evasion mutations, we propose that they are probably genetic footprints of prior virus passage through HLA-B*57/5801 positive individuals," add the investigators.

They also note that while HLA imprinting of circulating HIV sequences is an established phenomenon, their finding that such imprinting might enable better control of virus replication following transmission to HLA mismatched recipients is "entirely novel."

PLoS Pathogens 2008.