Considering genetic profiles in functional studies of immune responsiveness to HIV-1

Over the last two decades HIV-1 has spread worldwide and has now surpassed malaria as the leading cause of infectious disease mortality in adults (http://www.who.int/infectious-disease-report/pages/ch1text.html). The clinical course and outcome of HIV-1 infection are highly variable among individuals. Most individuals infected with HIV develop AIDS within 10 years. However about 1-5% remain relatively healthy for 15 years or more (long-term nonprogressors), while others progress to AIDS within the first 2-3 years after infection (rapid progressors). A small number of individuals are resistant to infection, while some individuals appear to eliminate the virus. Factors that influence susceptibility to infection and rate of disease progression are a combination of viral, host, and environmental determinants. With few exceptions, genetic resistance to infectious diseases is likely to involve a complex array of host genetic effects involving variants that have very subtle, but significant consequences on gene expression or protein function. We have gained considerable insight into the genetic effects on HIV-1 disease, yet we likely have uncovered only a fraction of the total picture. The greater our knowledge of various effects on HIV disease, the more likely we will be able to predict disease outcome on an individual-by-individual basis. While this may seem obvious, there is no standard practice of taking into account the genetic profile (i.e. genotypes at loci known to associate with rate of AIDS progression) of subjects used in functional studies of immune responsiveness to HIV-1. Here, we propose an approach for assessing overall genetic risk on an individual basis, and suggest that this information be considered when selecting comparison groups in studies of immune responses to HIV and/or in the interpretation of data derived from such studies.