Publications

Highly potent broadly neutralizing human monoclonal antibodies hold promise for HIV prophylaxis and treatment. We used the SCID-hu Thy/Liv and BLT humanized mouse models to study the efficacy of these antibodies, primarily PG16, against HIV-1 clades A, B, and C. PG16 targets a conserved epitope in the V1/V2 region of gp120 common to 70-80% of HIV-1 isolates from multiple clades and has extremely potent in vitro activity against HIVJR-CSF. PG16 was highly efficacious in SCID-hu mice as a single intraperitoneal administration the day before inoculation of R5-tropic HIV directly into their Thy/Liv implants and demonstrated even greater efficacy if PG16 administration was continued after Thy/Liv implant HIV inoculation. However, PG16 as monotherapy had no activity in humanized mice with established R5-tropic HIV infection. These results provide evidence of tissue penetration of the antibodies, which could aid in their ability to prevent infection if virus crosses the mucosal barrier.

OBJECTIVE

To determine whether earlier initiation of antiretroviral therapy (ART) is associated with better economic outcomes.

DESIGN

Prospective cohort study of HIV-positive patients on ART in rural Uganda.

METHODS

Patients initiating ART at a regional referral clinic in Uganda were enrolled in the Uganda AIDS Rural Treatment Outcomes study starting in 2005. Data on labor force participation and asset ownership were collected on a yearly basis, and CD4 cell counts were collected at pre-ART baseline. We fitted multivariable regression models to assess whether economic outcomes at baseline and in the 6 years following ART initiation varied by baseline CD4 cell count.

RESULTS

Five hundred and five individuals, followed up to 6 years, formed the estimation sample. Participants initiating ART at CD4 cell count at least 200 cells/μl were 13 percentage points more likely to be working at baseline (P < 0.01, 95% confidence interval 0.06-0.21) than those initiating below this threshold. Those in the latter group achieved similar labor force participation rates within 1 year of initiating ART (P < 0.01 on the time indicators). Both groups had similar asset scores at baseline and demonstrated similar increases in asset scores over the 6 years of follow-up.

CONCLUSION

ART helps participants initiating therapy at CD4 cell count below 200 cells/μl rejoin the labor force, though the findings for participants initiating with higher CD4 cell counts suggests that pretreatment declines in labor supply may be prevented altogether with earlier therapy. Baseline similarities in asset scores for those with early and advanced disease suggest that mechanisms other than morbidity may help drive the relationship between HIV infection and economic outcomes.

A low CD4/CD8 ratio in elderly HIV-uninfected adults is associated with increased morbidity and mortality. A subset of HIV-infected adults receiving effective antiretroviral therapy (ART) fails to normalize this ratio, even after they achieve normal CD4+ T cell counts. The immunologic and clinical characteristics of this clinical phenotype remain undefined. Using data from four distinct clinical cohorts and three clinical trials, we show that a low CD4/CD8 ratio in HIV-infected adults during otherwise effective ART (after CD4 count recovery above 500 cells/mm3) is associated with a number of immunological abnormalities, including a skewed T cell phenotype from naïve toward terminally differentiated CD8+ T cells, higher levels of CD8+ T cell activation (HLADR+CD38+) and senescence (CD28- and CD57+CD28-), and higher kynurenine/tryptophan ratio. Changes in the peripheral CD4/CD8 ratio are also reflective of changes in gut mucosa, but not in lymph nodes. In a longitudinal study, individuals who initiated ART within six months of infection had greater CD4/CD8 ratio increase compared to later initiators (>2 years). After controlling for age, gender, ART duration, nadir and CD4 count, the CD4/CD8 ratio predicted increased risk of morbidity and mortality. Hence, a persistently low CD4/CD8 ratio during otherwise effective ART is associated with increased innate and adaptive immune activation, an immunosenescent phenotype, and higher risk of morbidity/mortality. This ratio may prove useful in monitoring response to ART and could identify a unique subset of individuals needed of novel therapeutic interventions.