Figure 6.

Activation of STAT4 is correlated with increased disease activity. Isolated mononuclear cells from the peripheral blood from SLE patients or healthy controls were rested in 10% complete DMEM solution overnight, then stimulated by IL-12 of IFN-β. (A) Representative gating strategy to identify memory T cells or Tfh-like cells. (B) Intracellular IL-21 and IFN-γ staining in Tfh-like cells from an SLE patient. (C) Representative flow histogram of pSTAT4 from cells stimulated with either IFN-β (top) or IL-12 (bottom), graphs summarizing the ratio of MFI of stimulated pSTAT4 in Tfh-like (left), memory T (middle) or activated CXCR5^- cells (right) to their unstimulated pSTAT4 MFI for each individual sample. (D) Linear regression analysis of the pSTAT4/unstimulated ratio in SLE patients compared to their disease activity measured by SLEDAI. Data are representative of 27 SLE and 19 HC, *p < 0.05 by Mann-Whitney. Error bars represent SEM. Pearson R =0.182, P=0.033