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Open Access Research article

Characterising B cell numbers and memory B cells in HIV infected and uninfected Malawian adults

Herbert Longwe12, Stephen Gordon2, Rose Malamba1 and Neil French34*

Author Affiliations

1 Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi

2 Liverpool School of Tropical Medicine, University of Liverpool, Liverpool, UK

3 Department of Medicine, College of Medicine, University of Malawi, Blantyre, Malawi

4 Wellcome Trust/LEPRA Karonga Prevention Study, London School of Hygiene and Tropical Medicine, Chilumba, Malawi

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BMC Infectious Diseases 2010, 10:280  doi:10.1186/1471-2334-10-280

Published: 22 September 2010

Abstract

Background

Untreated human immunodeficiency virus (HIV) disease disrupts B cell populations causing reduced memory and reduced naïve resting B cells leading to increases in specific co-infections and impaired responses to vaccines. To what extent antiretroviral treatment reverses these changes in an African population is uncertain.

Methods

A cross-sectional study was performed. We recruited HIV-uninfected and HIV-infected Malawian adults both on and off antiretroviral therapy attending the Queen Elizabeth Central hospital in Malawi. Using flow cytometry, we enumerated B cells and characterized memory B cells and compared these measurements by the different recruitment groups.

Results

Overall 64 participants were recruited - 20 HIV uninfected (HIV-), 30 HIV infected ART naïve (HIV+N) and 14 HIV-infected ART treated (HIV+T). ART treatment had been taken for a median of 33 months (Range 12-60 months). Compared to HIV- the HIV+N adults had low absolute number of naïve resting B cells (111 vs. 180 cells/μl p = 0.008); reduced memory B cells (27 vs. 51 cells/μl p = 0.0008). The HIV+T adults had B-cell numbers similar to HIV- except for memory B cells that remained significantly lower (30 vs. 51 cells/μl p = 0.02). In the HIV+N group we did not find an association between CD4 count and B cell numbers.

Conclusions

HIV infected Malawian adults have abnormal B-cell numbers. Individuals treated with ART show a return to normal in B-cell numbers but a persistent deficit in the memory subset is noted. This has important implications for long term susceptibility to co-infections and should be evaluated further in a larger cohort study.