Sara Gianella Weibel

Dr. Sara Gianella Weibel


Research Focus & Metrics

Academic Career Length

21Years (2006-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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24 February 2020 in Journal of Clinical Investigation
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Journal Article
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ACAntoine Chaillon
Antoine Chaillon
SWSara Gianella Weibel
Sara Gianella Weibel
SDSimon Dellicour
Simon Dellicour
SRStephen Rawlings
Stephen Rawlings
TSTimothy E. Schlub
Timothy E. Schlub
DSDavey M. Smith
Davey M. Smith
BACKGROUND. Understanding HIV dynamics across the human body is important for cure efforts. This goal has been hampered by technical difficulties and the challenge of obtaining fresh tissues. METHODS. This observational study evaluated 6 individuals with HIV (n = 4 with viral suppression using antiretroviral [ART] therapy; n = 2 with rebound viremia after stopping ART), who provided serial blood samples before death and their bodies for rapid autopsy. HIV reservoirs were characterized by digital droplet PCR, single-genome amplification, and sequencing of full-length (FL) envelope HIV. Phylogeographic methods were used to reconstruct HIV spread, and generalized linear models were tested for viral factors associated with dispersal. RESULTS. Across participants, HIV DNA levels varied from approximately 0 to 659 copies/106 cells (IQR: 22.9–126.5). A total of 605 intact FL env sequences were recovered in antemortem blood cells and across 28 tissues (IQR: 5–9). Sequence analysis showed (a) the emergence of large, identical, intact HIV RNA populations in blood after cessation of therapy, which repopulated tissues throughout the body; (b) that multiple sites acted as hubs for HIV dissemination but that blood and lymphoid tissues were the main source; (c) that viral exchanges occurred within brain areas and across the blood-brain barrier; and (d) that migration was associated with low HIV divergence between sites and greater diversity at the recipient site. CONCLUSION. HIV reservoirs persisted in all deep tissues, and blood was the main source of dispersal. This may explain why eliminating HIV susceptibility in circulating T cells via bone marrow transplants allowed some individuals with HIV to experience therapy-free remission, even though deeper tissue reservoirs were not targeted. TRIAL REGISTRATION. Not applicable. FUNDING. NIH grants P01 AI31385, P30 AI036214, AI131971-01, AI120009AI036214, HD094646, AI027763, AI134295, and AI68636.

13 September 2016 in The Journal of Infectious Diseases
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SWSara Gianella Weibel
Sara Gianella Weibel
SLScott Letendre
Scott Letendre
Human immunodeficiency virus (HIV)–infected adults who take stable antiretroviral therapy (ART) are at risk for early onset of age-related diseases. This is likely due to a complex interaction between traditional risk factors, HIV infection itself, and other factors, such as underlying immune dysfunction and persistent inflammation. HIV disrupts the balance between the host and coinfecting microbes, worsening control of these potential pathogens. For example, HIV-infected adults are more likely than the general population to have subclinical bursts of cytomegalovirus (CMV) replication at mucosal sites. Production of antigens can activate the immune system and stimulate HIV replication, and it could contribute to the pathogenesis of adverse outcomes of aging, like cardiovascular disease and neurocognitive impairment. Further investigation of the relationships between CMV, immune dysfunction, and unsuccessful aging during chronic HIV infection is warranted.

26 January 2016 in Current HIV/AIDS Reports
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Journal Article
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MFMichael L. Freeman
Michael L. Freeman
MLMichael M. Lederman
Michael M. Lederman
SWSara Gianella Weibel
Sara Gianella Weibel

6 March 2015 in The Journal of Infectious Diseases
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Journal Article
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SWSara Gianella Weibel
Sara Gianella Weibel
Marta MassanellaMarta Massanella
Marta Massanella
JWJoel O. Wertheim
Joel O. Wertheim
DSDavey M. Smith
Davey M. Smith
Both human immunodeficiency virus (HIV) and human herpesvirus (HHV) infections persist lifelong, and almost all individuals infected with HIV are also infected with ≥1 HHV. These coinfections are not independent processes or benign. In this review, we discuss how HHVs, and cytomegalovirus in particular, interact with concurrent HIV infection, and we describe the next steps necessary to understand and address these connections.

15 August 2011 in Journal of Virology
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Journal Article
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SWSara Gianella Weibel
Sara Gianella Weibel
WDWayne Delport
Wayne Delport
MPMary E. Pacold
Mary E. Pacold
JYJason A. Young
Jason A. Young
JCJun Yong Choi
Jun Yong Choi
DSDavey M. Smith
Davey M. Smith
Reports of a high frequency of the transmission of minority viral populations with drug-resistant mutations (DRM) are inconsistent with evidence that HIV-1 infections usually arise from mono- or oligoclonal transmission. We performed ultradeep sequencing (UDS) of partial HIV-1 gag, pol, and env genes from 32 recently infected individuals. We then evaluated overall and per-site diversity levels, selective pressure, sequence reproducibility, and presence of DRM and accessory mutations (AM). To differentiate biologically meaningful mutations from those caused by methodological errors, we obtained multinomial confidence intervals (CI) for the proportion of DRM at each site and fitted a binomial mixture model to determine background error rates for each sample. We then examined the association between detected minority DRM and the virologic failure of first-line antiretroviral therapy (ART). Similar to other studies, we observed increased detection of DRM at low frequencies (average, 0.56%; 95% CI, 0.43 to 0.69; expected UDS error, 0.21 ± 0.08% mutations/site). For 8 duplicate runs, there was variability in the proportions of minority DRM. There was no indication of increased diversity or selection at DRM sites compared to other sites and no association between minority DRM and AM. There was no correlation between detected minority DRM and clinical failure of first-line ART. It is unlikely that minority viral variants harboring DRM are transmitted and maintained in the recipient host. The majority of low-frequency DRM detected using UDS are likely errors inherent to UDS methodology or a consequence of error-prone HIV-1 replication.

17 April 2013 in Clinical Infectious Diseases
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Journal Article
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SWSara Gianella Weibel
Sara Gianella Weibel
DSDavey M. Smith
Davey M. Smith
MVMilenka V. Vargas
Milenka V. Vargas
SLSusan J. Little
Susan J. Little
DRDouglas D. Richman
Douglas D. Richman
SMSheldon R. Morris
Sheldon R. Morris
Background. Current antiretroviral therapy (ART) suppresses human immunodeficiency virus (HIV) in blood to undetectable levels in most infected individuals; however, some men shed HIV in semen despite suppressed levels in blood. Methods. This study included 114 chronically HIV type 1–infected men who have sex with men, who were receiving ART with blood plasma HIV <500 copies/mL. Asymptomatic participants were screened for bacterial sexually transmitted infections (STIs) and nonspecific genital inflammation. Levels of HIV and 7 human herpesviruses were measured by real-time polymerase chain reaction in seminal plasma. Predictors of HIV seminal shedding were determined for the entire cohort, and on the subset of 100 subjects with blood plasma HIV <50 copies/mL. Results. Eleven subjects (9.6%) had detectable levels of seminal HIV (median, 2.1 log10 copies/mL), and 72 (63.2%) had at least 1 herpesvirus detected in their seminal plasma. Detectable levels of seminal HIV were present more often in persons with plasma HIV between 50 and 500 copies/mL compared to those 4 log10 DNA copies/mL; FDR-adjusted P = .08), and presence of Epstein-Barr virus (FDR-adjusted P = .06) in semen to be associated with detectable seminal HIV levels. In a subanalysis of 100 subjects with blood plasma HIV <50 copies/mL, high levels of CMV in semen was the only significant predictor for seminal HIV shedding. Conclusions. Low-level HIV replication in blood and high-level seminal CMV shedding, but not presence of asymptomatic STIs, is associated with seminal shedding of HIV in men receiving ART, conferring a potential risk for HIV transmission.