Impact of antiretroviral resistance and virological failure on HIV-1 informational entropy.

Objectives: The present study investigated the relationship between genomic variability and resistance of HIV-1 sequences in protease (PR) and reverse transcriptase (RT) regions of the pol gene. In addition, we analysed the resistance among 651 individuals presenting antiretroviral virological failure, from 2009 to 2011, in the state of São Paulo, Brazil.
Methods: The genomic variability was quantified by using informational entropy methods and the relationship between resistance and replicative fitness, as inferred by the residual viral load and CD4+ T cell count.
Results: The number of antiretroviral schemes is related to the number of resistance mutations in the HIV-1 PR (α = 0.2511, P = 0.0003, R2 = 0.8672) and the RT (α = 0.7892, P = 0.0001, R2 = 0.9141). Increased informational entropy rate is related to lower levels of HIV-1 viral loads (α = -0.0121, P = 0.0471, R2 = 0.7923), lower levels of CD4+ T cell counts (α = -0.0120, P = 0.0335, R2 = 0.8221) and a higher number of antiretroviral resistance-related mutations.
Conclusions: Less organized HIV genomes as inferred by higher levels of informational entropy relate to less competent host immune systems, lower levels of HIV replication and HIV genetic evolution as a consequence of antiretroviral resistance.