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Immune activation and increased IL-21R expression are associated with the loss of memory B cells during HIV-1 infection.

Authors: Ruffin, N  Lantto, R  Pensieroso, S  Sammicheli, S  Hejdeman, B  Rethi, B  Chiodi, F 
Citation: Ruffin N, etal., J Intern Med. 2012 Apr 24. doi: 10.1111/j.1365-2796.2012.02550.x.
Pubmed: (View Article at PubMed) PMID:22530560
DOI: Full-text: DOI:10.1111/j.1365-2796.2012.02550.x

Abstract. Ruffin N, Lantto R, Pensieroso S, Sammicheli S, Hejdeman B, Rethi B, Chiodi F (Karolinska Institutet, Stockholm; and South Hospital, Stockholm, Sweden). Immune activation and increased IL-21R expression are associated with the loss of memory B cells during HIV-1 infection. J Intern Med 2012; doi: 10.1111/j.1365-2796.2012.02550.x Objectives. Microbial translocation and chronic immune activation were previously shown to be associated with impairment of T cell functions and disease progression during infection with human immunodeficiency virus type-1 (HIV-1); however, their impact on B cell function and number remains unknown. By measuring markers of immune activation and molecules involved in apoptosis regulation, we have evaluated the association between microbial translocation and loss of memory B cells in HIV-1-infected patients. Methods. Markers of activation [the interleukin-21 receptor (IL-21R) and CD38] and apoptosis (Bim, Bcl-2 and annexin V) were measured in B cell subpopulations by multicolour flow cytometry. Levels of soluble CD14 (sCD14) and lipopolysaccharide (LPS), measures of microbial translocation, were determined in plasma. Purified B cells were also exposed in vitro to Toll-like receptor (TLR) ligands. Results. IL-21R expression was higher in cells from HIV-1-infected patients, compared with control subjects, with the highest levels in nontreated patients. An inverse correlation was observed between IL-21R expression and percentages of circulating resting memory (RM) B cells. IL-21R-positive memory B cells were also more susceptible to spontaneous apoptosis and displayed lower levels of Bcl-2. It is interesting that the levels of sCD14, which are increased during HIV-1 infection, were correlated with decreased percentages of RM B cells and high IL-21R expression. In the plasma of HIV-1-infected individuals, a correlation was found between sCD14 and LPS levels. TLR activation of B cells in vitro resulted in IL-21R up-regulation. Conclusions. Microbial translocation and the associated immune activation during HIV-1 infection may lead to high expression levels of the IL-21R activation marker in RM B cells, a feature associated with increased apoptosis and a reduced number of these cells in the circulation.

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CRRD Object Information
CRRD ID: 6892924
Created: 2012-08-16
Species: All species
Last Modified: 2012-08-16
Status: ACTIVE



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RGD is funded by grant HL64541 from the National Heart, Lung, and Blood Institute on behalf of the NIH.