The understanding of the factors associated with HIV-1 acquisition and
disease progression has been significantly advanced in the past few y
ears. These factors can be broadly defined as intrinsic or acquired an
d are operative at the levels of disease acquisition and progression o
r both. Much recent attention has focused on the identification of all
elic variants at specific genetic loci that alter either susceptibilit
y to infection or the natural history of disease progression. In addit
ion, a more detailed understanding of the immunologic responses to HIV
-1 and factors that perturb these responses has greatly enhanced our u
nderstanding of the immunologic control of HIV-1 and the roles of cofa
ctors in HIV-1 acquisition and disease progression.