Probes for HIV

While combined antiretroviral therapy (cART) can result in undetectable plasma viral loads, it does not eradicate HIV infection. Furthermore, HIV-infected individuals while on cART remain at an increased risk of developing serious co-morbidities, such as cancer, neurological disease, and atherosclerosis, suggesting that during cART, tissue-based HIV may contribute to such pathologies.We obtained DNA and RNA env, nef and pol sequences using single genome sequencing from post mortem tissues of three HIV+/cART+ individuals with undetectable viral load and metastatic cancer at death, and performed time-scaled Bayesian evolutionary analyses. We used a sensitive in situ hybridization technique to visualize HIV gag-pol mRNA transcripts in cerebellum and lymph node tissues from one patient.Tissue-associated virus evolved at a similar rate in cART+ and cART- patients. Phylogenetic trees were characterized by two distinct features: 1) branching patterns consistent with constant viral evolution and dispersal amongst tissues; and 2) very recently derived clades containing both DNA and RNA sequences from multiple tissues. Cancer diagnoses were temporally associated with diversification of viral lineages. Rapid expansion of virus near death corresponded to wide-spread metastasis. HIV RNA+ cells clustered in cerebellum tissue but were dispersed in lymph node tissue, mirroring the evolutionary patterns observed for that patient. Activated, infiltrating macrophages were associated with HIV-expressing cells.Our data provide evidence that tissues serve as a sanctuary for wild-type HIV during cART and suggest the importance of macrophages as an alternative reservoir and mechanism of virus spread.

IMPORTANCE:

Combined anti-retroviral therapy (cART) reduces plasma HIV to undetectable levels; however, removal of cART results in plasma HIV rebound, thus highlighting its inability to entirely rid the body of infection. Additionally, HIV-infected individuals on cART remain at high risk of serious diseases, which suggests a contribution from residual HIV. Here, we isolated and sequenced HIV from post mortem tissues from three HIV+/cART+ individuals who died with metastatic cancer and had no detectable plasma viral load. Using high-resolution evolutionary analyses, we found that tissue-based HIV continues to replicate, evolve and migrate among tissues during cART. Furthermore, cancer onset and metastasis coincided with increased HIV diversity, suggesting a linked mechanism. HIV-expressing cells were associated with tissue macrophages, a target of HIV infection. Our results suggest the importance of tissues, and macrophages in particular, as a target for novel anti-HIV therapies.