High HLA Gene Expression May Slow AIDS Progression
Genotyping study shows HIV-infected subjects with genetic variant also better control viral loads
MONDAY, Nov. 23 (HealthDay News) -- High HLA-C expression on cell surfaces in individuals infected with HIV appears to slow progression to full-blown AIDS, while better controlling plasma viral loads, according to a study published online Nov. 22 in Nature Genetics.
Rasmi Thomas, Ph.D., of SAIC-Frederick Inc. in Maryland, and colleagues genotyped 1,698 HIV patients of European descent for a genetic variant 35 kb upstream of the HLA-C gene (−35C/T), which had been previously associated with HLA-C mRNA expression level and steady plasma HIV RNA levels. Disease progression analysis was conducted using subjects for whom seroconversion dates were known and viral load data over time were available. The researchers also tested cell surface HLA-C expression in normal subjects.
The researchers found that subjects with high-expressing HLA-C alleles progressed to AIDS more slowly, and controlled viremia better, than subjects with low-expressing HLA-C alleles.
"These data strongly implicate high HLA-C expression levels in more effective control of HIV-1, potentially through better antigen presentation to cytotoxic T lymphocytes or recognition and killing of infected cells by natural killer cells," the authors write.