Fig. 5

a Gating strategy used to quantify interleukin-21 (IL-21) production capacity after lentiviral transduction. Transduced cells were gated as green fluorescent protein (eGFP) + and within this population CD4+CD45RO+ T cells were selected and the percentages of IL-21+ cells were measured. Panel shows healthy controls (HCs) and systemic lupus erythematosus (SLE) patients transduced with either GFP alone or GFP + microRNA-155 (miR-155) (both n = 5). No CD45RO– populations were observed after the transduction and subsequent incubation. b Percentages of IL-21 CD4+CD45RO+ and CD8+CD45RO+ T cells from SLE patients and HCs transduced with either miR-155 or GFP alone. CD4+ T cells transduced with miR-155 from both SLE patients and HCs showed a significant increase in IL-21 production compared to GFP controls. *p < 0.05, **p < 0.01. c Ratio of IL-21 (miR-155/eGFP) expression upon miR-155 transduction. CD4+CD45RO+ T cells from SLE patients had significantly higher IL-21 upregulation compared with HCs (ratios 1.47 vs. 1.09, respectively; p < 0.05). CD8+CD45RO+ T cells are low level producers of IL-21 and were included as controls. No significant difference in upregulation of IL-21 production between SLE patients and HCs was seen in CD8+CD45RO+ T cells. *p < 0.05. SSC side-scatter