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Bacterial vaginosis, HIV serostatus and T-cell subset distribution in a cohort of East African commercial sex workers: retrospective analysis

Schellenberg, John J.a; Card, Catherine M.a; Ball, T. Blakea,c,d; Mungai, Jane Njeric; Irungu, Erastusc; Kimani, Joshuac; Jaoko, Walterc; Wachihi, Charlesc; Fowke, Keith R.a,b,d; Plummer, Francis A.a,c,d

doi: 10.1097/QAD.0b013e32834ed7f0
Epidemiology and Social: Concise Communications

Objective: Although bacterial vaginosis is a known correlate of HIV infection, no previous studies have investigated whether women defined as HIV-exposed seronegative (HESN) are less likely to have bacterial vaginosis. Little is known about the effects of bacterial vaginosis on systemic immune activation associated with HIV+ serostatus.

Design: Cohort-based retrospective analysis of bacterial vaginosis in relation to HESN status, HIV+ serostatus and peripheral T-helper cells, with cross-sectional analysis of bacterial vaginosis in relation to peripheral T-regulatory cells (Tregs).

Methods: Bacterial vaginosis diagnosis by Gram stain and determination of systemic CD4+ and CD8+ T-helper cell frequency by flow cytometry for 3504 vaginal samples from 988 commercial sex workers over 4 years. Treg phenotyping by FoxP3 staining and multiparameter flow cytometry in peripheral blood of 97 women at a single time-point.

Results: No differences in bacterial vaginosis diagnosis were observed between HESN and other HIV-negative (HIV-N) controls; however, HIV+ women were more likely to be diagnosed with bacterial vaginosis compared to all HIV-negative women (HESN/HIV-N combined). HIV+ women with bacterial vaginosis had significantly higher CD4+/CD8+ T-helper cell counts and a lower CD4/CD8 ratio, as well as fewer Tregs as a proportion of total T-helper cells, compared to bacterial vaginosis-negative women. The number of bacterial vaginosis diagnoses in this cohort has decreased significantly over time.

Conclusion: Bacterial vaginosis is associated with HIV serostatus and shifts in distribution of T-cell subsets. A concomitant reduction in bacterial vaginosis and HIV infections over time suggests that the elucidation of bacterial vaginosis–HIV interactions will be critical to further understanding of HIV pathogenesis and prevention in this high-risk group.

aDepartment of Medical Microbiology

bDepartment of Community Health Sciences, Faculty of Medicine, University of Manitoba, Winnipeg, Canada

cDepartment of Medical Microbiology, University of Nairobi, Nairobi, Kenya

dNational Microbiology Laboratory, Canadian Science Centre for Human and Animal Health, Winnepeg, Canada.

Correspondence to John J. Schellenberg, Department of Microbiology, 412 Buller Bldg., University of Manitoba, R3T 2N2, Canada. Tel: +1 204 784 8074; fax: +1 204 789 2018; e-mail: schellej@cc.umanitoba.ca

Received 3 June, 2011

Revised 21 October, 2011

Accepted 3 November, 2011

© 2012 Lippincott Williams & Wilkins, Inc.