[Genetics in the study of HIV infection]

Thirty years after the discovery of the human immunodeficiency virus (HIV) as the cause of acquired immunodeficiency syndrome (AIDS), no effective vaccines are available and there is no cure for the disease. The susceptibility to HIV infection shows a considerable degree of individual heterogeneity, which may be largely due to the genetic variability of the host. In an effort to find the host factors required for viral replication, to identify the crucial pathogenetic pathways, and reveal the full armament of host defenses, there has been a shift from candidate-gene studies to unbiased genomewide genetic and functional studies. Nevertheless, the number of established genetic factors involved in the susceptibility to diseases caused by HIV infection remains small, explaining only 15-20% of the observed heterogeneity, most of which is attributable to polymorphisms of human leukocyte antigens (HLA). Genetic studies, however, have allowed to clarify which genetic variations underlie the adverse response to some antiretroviral drugs (such as HLA-B*5701 in the treatment with abacavir) or the occurrence of renal complications as the disease progresses. The results of these studies already have a possible impact on healthcare practice.