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

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.Overall 64 participants were recruited - 20 HIV uninfected (HIV-), 30 HIV infected ART na？ve (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 na？ve 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.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.Untreated HIV infection leads to disruption of the immune system leading to an increased risk of many infections and in particular pneumococcal disease [1,2]. A classic feature of HIV-disease progression is the consistent destruction of lymph nodes (LN) contributing to the progressive loss of the CD4 T-cells and degeneration of germinal centres. In addition there is massive and progressive destruction of B cells as a consequence of LN destruction and by a direct effect of HIV leading to apoptosis of B cells [3,4]. This decline in the B cell numbers is a major factor rendering HIV-infected individuals incapable of mounting an effective functional antibody response to pneumococcal polysaccharides [5]In addit