Characterization of EBV-specific CD8⁺ T cells from SLE patients and healthy controls.

<p><b>A,</b> Representative cytofluorometric detection (left) and functional analysis (right) of CD8⁺ T cells specific for one of the lytic EBV antigens tested (BZLF1) pre (upper panel) and post (lower panel) peptide antigen stimulation of PBMCs from a healthy donor. Lytic EBV antigen-specific cells were detected with peptide/MHC tetramer and anti-CD8 antibody (red box) and simultaneously analyzed for intra-cellular IFN-γ, TNF-α, IL-2 and MIP-1β content. Cytokine/chemokine gates were positioned according to control stains of non-stimulated virus-specific T cells. <b>B,</b> EBV-specific T cells are strikingly less polyfunctional in 19 inactive (iSLE) and 27 active (aSLE) SLE patients compared to 26 controls (healthy). Pie representations of virus-specific CD8⁺ T cells represent the fraction of individual cells secreting none (0) or any (1, 2, 3 or 4) of the four cytokines IFN-γ, TNF-α, IL-2 and MIP-1β (color coded as indicated). E.g. the red pie slice indicates the proportion of cells producing four cytokines (IFN-γ, TNF-α, IL-2 and MIP-1β). <b>C,</b> Polyfunctionality index values of EBV-specific CD8⁺ T cells from inactive and active SLE patients as well as healthy controls. <i>P</i>-values monitoring differences between healthy donors and SLE patients are calculated using a non-parametric Mann-Whitney test and pie comparison statistics of the Spice software. Pie charts in B were adapted from our previous work. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0042403#pone.0042403-Larsen1" target="_blank">[11]</a>