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Dive into the research topics where Aaron A.R. Tobian is active.

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Featured researches published by Aaron A.R. Tobian.


The Journal of Infectious Diseases | 2011

Effects of HIV-1 and Herpes Simplex Virus Type 2 Infection on Lymphocyte and Dendritic Cell Density in Adult Foreskins from Rakai, Uganda

Kristine E. Johnson; Andrew D. Redd; Thomas C. Quinn; Aleisha Collinson-Streng; Toby C. Cornish; Xiangrong Kong; Rajni Sharma; Aaron A.R. Tobian; Benjamin Tsai; Mark E. Sherman; Godfrey Kigozi; David Serwadda; Maria J. Wawer; Ronald H. Gray

BACKGROUND Male circumcision reduces human immunodeficiency virus (HIV) and herpes simplex virus type 2 (HSV-2) acquisition, and HSV-2 infection is associated with an increased risk of HIV acquisition. To assess the cellular basis for these associations, we estimated immunologic cellular densities in foreskin tissue. METHODS Immunostained CD1a(+) dendritic cell and CD4(+) and CD8(+) T cell densities were quantified in foreskin samples obtained from medical circumcision in Rakai, Uganda (35 HIV-infected, HSV-2-infected men; 5 HIV-infected, HSV-2-uninfected men; 22 HIV-uninfected, HSV-2-infected men; and 29 HIV-uninfected, HSV-2-uninfected men. RESULTS CD1A(+) dendritic cell densities did not vary by HIV or HSV-2 status. Compared with densities in HIV-uninfected, HSV-2-uninfected men (mean, 26.8 cells/mm(2)), CD4(+) T cell densities were similar in the HIV-infected, HSV-2-infected group (mean, 28.7 cells/mm(2)), were significantly decreased in the HIV-infected, HSV-2-uninfected group (mean, 11.2; P < .05), and were increased in the HIV-uninfected, HSV-2-infected group (mean, 68.7; P < .05). Dermal CD8(+) T cell densities were higher in the HIV and HSV-2-coinfected group (mean, 102.9) than in the HIV-uninfected, HSV-2-uninfected group (mean, 10.0; P < .001), the HIV-infected, HSV-2-uninfected group (mean, 27.3; P < .001), and the HIV-uninfected, HSV-2-infected group (mean, 25.3; P < .005). DISCUSSION The increased CD4(+) cellular density in the HIV-uninfected, HSV-2-infected men may help to explain why HSV-2-infected men are at increased risk of HIV acquisition. The absence of this increase in men coinfected with both HIV and HSV-2 is likely in part the result of the progressive loss of CD4(+) cells in HIV infection. Conversely, HIV and HSV-2 coinfection appears to synergistically increase CD8(+) T cell densities.


PLOS Medicine | 2009

Effects of Genital Ulcer Disease and Herpes Simplex Virus Type 2 on the Efficacy of Male Circumcision for HIV Prevention: Analyses from the Rakai Trials

Ronald H. Gray; David Serwadda; Aaron A.R. Tobian; Michael Z. Chen; Frederick Makumbi; Tara Suntoke; Godfrey Kigozi; Fred Nalugoda; Boaz Iga; Thomas C. Quinn; Lawrence H. Moulton; Oliver Laeyendecker; Steven J. Reynolds; Xiangrong Kong; Maria J. Wawer

Ron Gray and colleagues analyze data from two circumcision trials in Uganda to assess how HSV-2 status and genital ulcer disease affect the procedures ability to reduce HIV infection.


Transfusion | 2011

Allergic transfusion reactions to platelets are associated more with recipient and donor factors than with product attributes

William J. Savage; Aaron A.R. Tobian; Alice K. Fuller; Robert A. Wood; Karen E. King; Paul M. Ness

BACKGROUND: Mechanisms of allergic transfusion reactions (ATRs) are not well understood. The aim of this study was to distinguish recipient‐, donor‐, and product‐specific factors associated with ATRs.


Transfusion | 2013

Scratching the surface of allergic transfusion reactions.

William J. Savage; Aaron A.R. Tobian; Jessica H. Savage; Robert A. Wood; John T. Schroeder; Paul M. Ness

Allergic transfusion reactions (ATRs) are a spectrum of hypersensitivity reactions that are the most common adverse reaction to platelets and plasma, occurring in up to 2% of transfusions. Despite the ubiquity of these reactions, little is known about their mechanism. In a small subset of severe reactions, specific antibody has been implicated as causal, although this mechanism does not explain all ATRs. Evidence suggests that donor, product, and recipient factors are involved, and it is possible that many ATRs are multifactorial. Further understanding of the mechanisms of ATRs is necessary so that rationally designed and cost‐effective prevention measures can be developed.


Transfusion | 2011

Atopic predisposition of recipients in allergic transfusion reactions to apheresis platelets

William J. Savage; Aaron A.R. Tobian; Jessica H. Savage; Robert G. Hamilton; Paul M. Ness

BACKGROUND: The biologic mechanisms of allergic transfusion reactions (ATRs) are largely unknown. We sought to compare the atopic predisposition of platelet (PLT) recipients who experienced an ATR to nonreactive control recipients.


Transfusion | 2012

Allergic agonists in apheresis platelet products are associated with allergic transfusion reactions.

William J. Savage; Jessica H. Savage; Aaron A.R. Tobian; Chris Thoburn; Robert G. Hamilton; John T. Schroeder; Paul M. Ness

BACKGROUND: The mechanisms that underlie allergic transfusion reactions (ATRs) are not well characterized, but likely involve recipient, donor, and product factors. To assess product factors associated with ATRs, we investigated candidate mediators in apheresis platelet (PLT) products associated with ATRs and controls.


International Journal of Std & Aids | 2009

Aetiology of genital ulcer disease in female partners of male participants in a circumcision trial in Uganda

A E Brankin; Aaron A.R. Tobian; Oliver Laeyendecker; Tara Suntoke; A Kizza; B Mpoza; Godfrey Kigozi; Fred Nalugoda; B Iga; Michael Z. Chen; Ronald H. Gray; Maria J. Wawer; Thomas C. Quinn; Steven J. Reynolds

HIV acquisition is associated with herpes simplex virus type 2 (HSV-2) infection and genital ulcer disease (GUD). Three randomized control trials demonstrated that male circumcision significantly decreases HIV, HSV-2, human papillomavirus and self-reported GUD among men. GUD is also decreased among female partners of circumcised men, but it is unknown whether male circumcision status affects GUD pathogens in female partners. For the evaluation of GUD aetiology, two separate multiplex assays were performed to detect Haemophilus ducreyi, Treponema pallidum, HSV-1 and HSV-2. Of all the female GUD swabs evaluated, 67.5% had an aetiology identified, and HSV-2 was the primary pathogen detected (96.3%). However, there was no difference in the proportion of ulcers due to HSV-2 or other pathogens between female partners of circumcised men (11/15, 73.3%) compared with uncircumcised men (15/25, 60.0%, P = 0.39). The seroprevalence of HSV-2 is high in this population and therefore most of the detected HSV-2 infections represent reactivation. Since GUD is associated with HIV acquisition and one-third of GUD in this study did not have an aetiological agent identified, further research is needed to better understand the aetiology of GUD in Africa, and its relationship to circumcision and HIV infection.


PLOS ONE | 2016

Adolescent sexual and reproductive health services and implications for the provision of voluntary medical male circumcision: Results of a systematic literature review.

Michelle R. Kaufman; Marina Smelyanskaya; Lynn M. Van Lith; Elizabeth C. Mallalieu; Aliza Waxman; Karin Hatzhold; Arik V. Marcell; Susan Kasedde; Gissenge Lija; Nina. Hasen; Gertrude Ncube; Julia Samuelson; Collen Bonnecwe; Kim Seifert-Ahanda; Emmanuel Njeuhmeli; Aaron A.R. Tobian

Background Voluntary medical male circumcision (VMMC) is a critical HIV prevention tool. Since 2007, sub-Saharan African countries with the highest prevalence of HIV have been mobilizing resources to make VMMC available. While implementers initially targeted adult men, demand has been highest for boys under age 18. It is important to understand how male adolescents can best be served by quality VMMC services. Methods and Findings A systematic literature review was performed to synthesize the evidence on best practices in adolescent health service delivery specific to males in sub-Saharan Africa. PubMed, Scopus, and JSTOR databases were searched for literature published between January 1990 and March 2014. The review revealed a general absence of health services addressing the specific needs of male adolescents, resulting in knowledge gaps that could diminish the benefits of VMMC programming for this population. Articles focused specifically on VMMC contained little information on the adolescent subgroup. The review revealed barriers to and gaps in sexual and reproductive health and VMMC service provision to adolescents, including structural factors, imposed feelings of shame, endorsement of traditional gender roles, negative interactions with providers, violations of privacy, fear of pain associated with the VMMC procedure, and a desire for elements of traditional non-medical circumcision methods to be integrated into medical procedures. Factors linked to effective adolescent-focused services included the engagement of parents and the community, an adolescent-friendly service environment, and VMMC counseling messages sufficiently understood by young males. Conclusions VMMC presents an opportune time for early involvement of male adolescents in HIV prevention and sexual and reproductive health programming. However, more research is needed to determine how to align VMMC services with the unique needs of this population.


The Journal of Allergy and Clinical Immunology | 2014

Defining risk factors and presentations of allergic reactions to platelet transfusion

William J. Savage; Robert G. Hamilton; Aaron A.R. Tobian; Ginger L. Milne; Richard M. Kaufman; Jessica H. Savage; P. Dayand Borge; Paul M. Ness

From the Department of Asthma, Allergy and Respiratory Science and Randall Division of Cell and Molecular Biophysics, King’s College London; the Section for Allergy and Clinical Immunology at NHLI, Imperial College, London; and the Department of Respiratory Medicine and Allergy, Homerton University Hospital NHS Foundation Trust, London, United Kingdom. E-mail: [email protected]. *These authors have contributed equally to this work. Supported by research grants from the Wellcome Trust UK (no. 091449/Z/10/Z), Novartis UK, and Guy’s and St Thomas’ Charity. Also supported by the Department of Health via the National Institute for Health Research (NIHR) comprehensive Biomedical Research Centre award to Guy’s & St Thomas’ NHS Foundation Trust in partnership with King’s College London and King’s College Hospital NHS Foundation Trust. Disclosure of potential conflict of interest: C. Harper has received research support from Novartis. L. Ohm-Laursen has received research support from the Wellcome Trust. A. Menzies-Gow has received lecture fees and travel support from Novartis. C. J. Corrigan has received consultancy fees from Chiesi, Novartis, and Allergy Therapeutics; has received lecture fees from GlaxoSmithKline; has received payment for development of educational presentations from Henry Stewart Talks; and has received travel support from Novartis. The rest of the authors declare that they have no relevant conflicts of interest.


PLOS Pathogens | 2016

Chemokine Levels in the Penile Coronal Sulcus Correlate with HIV-1 Acquisition and Are Reduced by Male Circumcision in Rakai, Uganda

Jessica L. Prodger; Ronald H. Gray; Brett Shannon; Kamnoosh Shahabi; Xiangrong Kong; Kate Grabowski; Godfrey Kigozi; Fred Nalugoda; David Serwadda; Maria J. Wawer; Steven J. Reynolds; Cindy M. Liu; Aaron A.R. Tobian; Rupert Kaul

Individual susceptibility to HIV is heterogeneous, but the biological mechanisms explaining differences are incompletely understood. We hypothesized that penile inflammation may increase HIV susceptibility in men by recruiting permissive CD4 T cells, and that male circumcision may decrease HIV susceptibility in part by reducing genital inflammation. We used multi-array technology to measure levels of seven cytokines in coronal sulcus (penile) swabs collected longitudinally from initially uncircumcised men enrolled in a randomized trial of circumcision in Rakai, Uganda. Coronal sulcus cytokine levels were compared between men who acquired HIV and controls who remained seronegative. Cytokines were also compared within men before and after circumcision, and correlated with CD4 T cells subsets in foreskin tissue. HIV acquisition was associated with detectable coronal sulcus Interleukin-8 (IL-8 aOR 2.26, 95%CI 1.04–6.40) and Monokine Induced by γ-interferon (MIG aOR 2.72, 95%CI 1.15–8.06) at the visit prior to seroconversion, and the odds of seroconversion increased with detection of multiple cytokines. Coronal sulcus chemokine levels were not correlated with those in the vagina of a man’s female sex partner. The detection of IL-8 in swabs was significantly reduced 6 months after circumcision (PRR 0.59, 95%CI 0.44–0.87), and continued to decline for at least two years (PRR 0.29, 95%CI 0.16–0.54). Finally, prepuce IL-8 correlated with increased HIV target cell density in foreskin tissues, including highly susceptible CD4 T cells subsets, as well as with tissue neutrophil density. Together, these data suggest that penile inflammation increases HIV susceptibility and is reduced by circumcision.

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Paul M. Ness

Johns Hopkins University

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Thomas C. Quinn

National Institutes of Health

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William J. Savage

Brigham and Women's Hospital

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Eshan U. Patel

Johns Hopkins University School of Medicine

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Arik V. Marcell

Johns Hopkins University School of Medicine

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Emmanuel Njeuhmeli

United States Agency for International Development

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Jessica H. Savage

Brigham and Women's Hospital

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Robert G. Hamilton

Johns Hopkins University School of Medicine

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Steven J. Reynolds

National Institutes of Health

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