Fig. 2

Toll-like receptor 7 (TLR7)-induced interferon- α (IFN-α) production by plasmacytoid dendritic cells (pDCs) increased and was positively correlated with disease activity in systemic lupus erythematosus (SLE). Peripheral blood mononuclear cells (PBMCs) were stimulated with imiquimod and cytokine-producing pDCs were analyzed by flow cytometry in healthy controls (HC) and patients with SLE with inactive or active disease. a The proportions of pDCs producing IFN-α, TNF-α, or both IFN-α and TNF-α are shown. Each symbol represents the value of one individual. The box plot indicates the first and third quartiles and the middle line indicates the median. Whiskers indicate the minimum and maximum. *p < 0.05, **p < 0.01, ****p < 0.001 (Kruskal-Wallis test followed by Dunn’s multiple comparisons test). b The correlation of the frequency of imiquimod-induced INF-α-producing pDCs with SLE activity (SLE Disease Activity Index 2000 (SLEDAI)) score was examined using Spearman correlation. Each symbol represents the value of one individual. c Frequencies of imiquimod-induced IFN-α-producing pDCs were compared between patients with glomerulonephritis (GN) or other manifestations, in all patients (left) or in patients with active disease (right))