Influence of HLA-C Expression Level on HIV Control

Thwarting HIV Multiple genome-wide association studies have revealed that human leukocyte antigen (HLA) genes of the major histocompatibility complex locus have the strongest impact on HIV. In particular, a single-nucleotide polymorphism 35 base pairs upstream of HLA-C shows significant association with viral load and protection against HIV. How HLA-C mediates these effects is unknown. Apps et al. (p. 87 ) now demonstrate that increasing surface expression of HLA-C is associated with reduced viral load and reduced rate of progression to low CD4 + T cell counts in African and European Americans. High HLA-C expression likely promoted improved HIV control through a more effective cytotoxic CD8 + T cell response. In contrast to HIV infection, high HLA-C expression was associated with a higher risk of the inflammatory bowel disease, Crohn's disease.