HIV causes a chronic infection characterized by depletion of
CD4+ T lymphocytes and development of opportunistic infections.
Despite drugs that inhibit viral spread, HIV has been difficult to cure because
of uncharacterized reservoirs of infected cells that are resistant to highly
active antiretroviral therapy and the immune response. Here we used
CD34+ cells from infected people as well as in
vitro studies of wild type HIV to demonstrate infection and killing
of CD34+ multipotent hematopoietic progenitor cells (HPCs). In some
HPCs, we detected latent infection that stably persisted in cell culture until
viral gene expression was activated by differentiation factors. A novel reporter
HIV that directly detects latently infected cells in vitro
confirmed the presence of distinct populations of active and latently infected
HPCs. These findings have important implications for understanding HIV bone
marrow pathology and the mechanisms by which HIV causes persistent
infection.
TDF/emtricitabine is an effective and safe therapy for preventing HIV transmission. Increasing prescription of TDF/emtricitabine for patients at risk of acquiring HIV has the potential to reduce new HIV infections.
Endogenous fungal endophthalmitis, involving only the chorioretinal structures or extending to involve the vitreous (vitritis), is a sight-threatening infection requiring early appropriate therapy. Endophthalmitis is a relatively frequent complication of candidemia and less commonly occurs in patients who have invasive aspergillosis. Because the eye is a protected compartment, penetration of systemically administered antifungal agents is highly variable. In the posterior segment of the eye, amphotericin B (AmB) achieves very poor concentrations, but fluconazole concentrations are high. Among newer antifungal agents, voriconazole shows the most promise, because therapeutic concentrations for most Candida and Aspergillus species are achieved in the vitreous, and its antifungal activity is broad. In contrast, neither posaconazole nor the 3 echinocandins achieve adequate therapeutic concentrations in the vitreous. For sight-threatening macular involvement and vitritis, intravitreal injection of either AmB or voriconazole is helpful to achieve high local antifungal activity as quickly as possible. We review the available evidence regarding the most appropriate use of antifungal agents for endogenous fungal endophthalmitis, with the emphasis on treatment of infections due to Candida species.
SUMMARY
HIV infection is characterized by gradual immune system collapse and hematopoietic dysfunction. We recently showed that HIV enters multipotent hematopoietic progenitor cells and establishes both active cytotoxic and latent infections that can be reactivated by myeloid differentiation. However, whether these multipotent progenitors include long-lived hematopoietic stem cells (HSCs) that could establish viral reservoirs for the life of the infected person remains unknown. Here we provide direct evidence that HIV targets long-lived HSCs and show that infected HSCs yield stable, multilineage engraftment in a xenograft model. Furthermore, we establish that the capacity to use the chemokine receptor CXCR4 for entry determines whether a virus will enter multipotent versus differentiated progenitor cells. Because HSCs live for the lifespan of the infected person and are crucial for hematopoietic health, these data may explain the poor prognosis associated with CXCR4-tropic HIV infection and suggest HSCs as long-lived cellular reservoirs of latent HIV.
Background
HIV-infected individuals have a higher incidence of head and neck cancer.
Methods
Case series of 94 HIV-infected head and neck cancer patients (HIV-HNC) at six tertiary care referral centers in the US between 1991–2011. Clinical and risk factor data were abstracted from the medical record. Risk factors for survival were analyzed using Cox proportional hazard models. Human papillomavirus (HPV) and p16 testing was performed in 46 tumors. Findings were compared with SEER HNC (US-HNC) data.
Results
This study represents the largest HIV-HNC series reported to date. HIV-HNC cases were more likely than US-HNC to be male (91% vs. 68%), younger (median 50 vs. 62 years), non-White (49% vs.18%), and current smokers (61% vs. 18%). Median HIV-HNC survival was not appreciably lower than US-HNC survival (63 vs. 61 months). At diagnosis, most cases were currently on HAART (77%), but had detectable HIV viremia (99%) and median CD4 was 300 cells/μL (IQR=167–500). HPV was detected in 30% of HIV-HNC and 64% of HIV-oropharyngeal cases. Median survival was significantly lower among those with CD4 counts ≤200 than >200 cells/μL at diagnosis (16.1 vs. 72.8 months, p<0.001). In multivariate analysis, poorer survival was associated with CD4 <100 cells/μL (aHR=3.09, 95%CI=1.15–8.30), larynx/hypopharynx site (aHR=3.54, 95%CI=1.34–9.35), and current tobacco use (aHR=2.54, 95%CI=0.96–6.76).
Conclusion
Risk factors for the development of HNC in patients with HIV infection are similar to the general population, including both HPV-related and tobacco/alcohol-related HNC.
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