BIOLOGICAL BASIS OF THE HLA-B8, DR3-ASSOCIATED PROGRESSION OF ACQUIRED-IMMUNE-DEFICIENCY-SYNDROME

The factors influencing the evolution of human immunodeficiency virus (HN) infection are not fully known, but the host genotype undoubtedly plays a role in determining the outcome of the disease by affecting th e immune response to HIV. The role of the host human leukocyte antigen (HLA) genotype in the regulation of susceptibility to HIV infection a nd expression has been studied extensively in different major risk gro ups. Certain HLA alleles and haplotypes, being associated with aberran t immune responses independently from HIV infection, have been reporte d to facilitate the rapid progression of disorders related to HIV infe ction. Particularly, the association of rapid acquired immunodeficienc y syndrome (AIDS) progression with genes from the HLA-B8,DR3 haplotype has been reported by different research groups. It is well known that this haplotype is associated in all Caucasian populations with a wide variety of diseases with autoimmune features and in healthy subjects with a number of immune system dysfunctions, as a reduced production o f T helper (Th)1 type cytokine. HIV infection may act on this genetic background triggering immunopathogenetic mechanisms leading to AIDS wi th a dominant Th2 profile as a common feature.