The human leukocyte antigens are genetically inherited proteins present on the surface of the cells of the immune system. Cells of the immune system recognize antigens only when presented to them next to an MHC self-molecule. Three main types of HLA Class I namely, HLA-A, HLA-B and HLA-C they are expressed by most human cells. Class I HLAs are involved in discriminating and presenting antigens to T-lymphocytes. T-lymphocytes kill the cell presenting it. T-lymphocytes destroy cells infected together with viruses, including HIV. Developing a vaccine for HIV may be aided by a complete understanding of those rare cases in which some HIV-infected individuals control replication of the virus. Most of these elite controllers express the histocompatibility alleles HLA-B57 or HLA-B27, these alleles remain the most robust associations with low concentrations of plasma virus.