Faculty Bibliography

Critical advances in the early diagnosis of HIV now allow for treatment opportunities during acute infection. It remains unclear whether treatment of acute HIV infection with antiretroviral therapy improves long-term clinical outcomes for the individual and current guidelines are not definitive in recommending therapy at this stage of infection. However, treatment of acute HIV infection may have short-term benefit on viral set point when compared to delayed therapy as well as reducing the risk of transmission to others. Herein we review the immunological and clinical literature to discuss whether we should treat acute HIV infection, both from the perspective of the individual HIV-infected patient and from the public health perspective. As transmission of drug-resistant HIV variants are of concern, we also review recent clinical trial data to provide recommendations for which specific antiretroviral treatment regimens should be considered for the treatment of acute HIV infection.

The lentiviral accessory protein Vpx is thought to facilitate the infection of macrophages and dendritic cells by counteracting an unidentified host restriction factor. Although human immunodeficiency virus type 1 (HIV-1) does not encode Vpx, the accessory protein can be provided to monocyte-derived macrophages (MDM) and monocyte-derived dendritic cells (MDDC) in virus-like particles, dramatically enhancing their susceptibility to HIV-1. Vpx and the related accessory protein Vpr are packaged into virions through a virus-specific interaction with the p6 carboxy-terminal domain of Gag. We localized the minimal Vpx packaging motif of simian immunodeficiency virus SIVmac(239) p6 to a 10-amino-acid motif and introduced this sequence into an infectious HIV-1 provirus. The chimeric virus packaged Vpx that was provided in trans and was substantially more infectious on MDDC and MDM than the wild-type virus. We further modified the virus by introducing the Vpx coding sequence in place of nef. The resulting virus produced Vpx and replicated efficiently in MDDC and MDM. The virus also induced a potent type I interferon response in MDDC. In a coculture system, the Vpx-containing HIV-1 was more efficiently transmitted from MDDC to T cells. These findings suggest that in vivo, Vpx may facilitate transmission of the virus from dendritic cells to T cells. In addition, the chimeric virus could be used to design dendritic cell vaccines that induce an enhanced innate immune response. This approach could also be useful in the design of lentiviral vectors that transduce these relatively resistant cells

Plasmacytoid DCs (pDCs) are innate immune cells that are specialized to produce IFN-alpha and to activate adaptive immune responses. Although IFN-alpha inhibits HIV-1 replication in vitro, the production of IFN-alpha by HIV-activated pDCs in vivo may contribute more to HIV pathogenesis than to protection. We have now shown that HIV-stimulated human pDCs allow for persistent IFN-alpha production upon repeated stimulation, express low levels of maturation molecules, and stimulate weak T cell responses. Persistent IFN-alpha production by HIV-stimulated pDCs correlated with increased levels of IRF7 and was dependent upon the autocrine IFN-alpha/beta receptor feedback loop. Because it has been shown that early endosomal trafficking of TLR9 agonists causes strong activation of the IFN-alpha pathway but weak activation of the NF-kappaB pathway, we sought to investigate whether early endosomal trafficking of HIV, a TLR7 agonist, leads to the IFN-alpha-producing phenotype we observed. We demonstrated that HIV preferentially traffics to the early endosome in human pDCs and therefore skews pDCs toward a partially matured, persistently IFN-alpha-secreting phenotype

Myeloid and plasmacytoid dendritic cells (DCs) are important mediators of both innate and adaptive immunity against pathogens such as HIV. During the course of HIV infection, blood DC numbers fall substantially. In the present study, we sought to determine how early in HIV infection the reduction occurs and whether the remaining DC subsets maintain functional capacity. We find that both myeloid DC and plasmacytoid DC levels decline very early during acute HIV in-fection. Despite the initial reduction in numbers, those DCs that remain in circulation retain their function and are able to stimulate allogeneic T-cell responses, and up-regulate maturation markers plus produce cytokines/chemokines in response to stimulation with TLR7/8 agonists. Notably, DCs from HIV-infected subjects produced significantly higher levels of cytokines/chemokines in response to stimulation with TLR7/8 agonists than DCs from uninfected controls. Further examination of gene expression profiles indicated in vivo activation, either directly or indirectly, of DCs during HIV infection. Taken together, our data demonstrate that despite the reduction in circulating DC numbers, those that remain in the blood display hyperfunctionality and implicates a possible role for DCs in promoting chronic immune activation

BACKGROUND: Cryptococcal meningitis (CM) is the proximate cause of death in 20%-30% of persons with acquired immunodeficiency syndrome in Africa. METHODS: Two prospective, observational cohorts enrolled human immunodeficiency virus (HIV)-infected, antiretroviral-naive persons with CM in Kampala, Uganda. The first cohort was enrolled in 2001-2002 (n = 92), prior to the availability of highly active antiretroviral therapy (HAART), and the second was enrolled in 2006-2007 (n = 44), when HAART was available. RESULTS: Ugandans presented with prolonged CM symptoms (median duration, 14 days; interquartile range, 7-21 days). The 14-day survival rates were 49% in 2001-2002 and 80% in 2006 (P < .001). HAART was started 35 +/- 13 days after CM diagnosis and does not explain the improved 14-day survival rate in 2006. In 2006-2007, the survival rate continued to decrease after hospitalization, with only 55% surviving to initiate HAART as an outpatient. Probable cryptococcal-related immune reconstitution inflammatory syndrome occurred in 42% of patients, with 4 deaths. At 6 months after CM diagnosis, 18 persons (41%) were alive and receiving HAART in 2007. The median cerebral spinal fluid (CSF) opening pressure was 330 mm H(2)O; 81% of patients had elevated pressure (>200 mm H(2)O). Only 5 patients consented to therapeutic lumbar puncture. There was a trend for higher mortality for pressures >250 mm H(2)O (odds ratio [OR], 2.1; 95% confidence interval [CI], 0.9-5.2; P = .09). Initial CSF WBC counts of <5 cells/mL were associated with failure of CSF sterilization (OR, 17.3; 95% CI, 3.1-94.3; P < .001), and protein levels <35 mg/dL were associated with higher mortality (OR, 2.0; 95% CI, 1.2-3.3; P = .007). CONCLUSIONS: Significant CM-associated mortality persists, despite the administration of amphotericin B and HIV therapy, because of the high mortality rate before receipt of HAART and because of immune reconstitution inflammatory syndrome-related complications after HAART initiation. Approaches to increase acceptance of therapeutic lumbar punctures are needed