GP130 production and activity in primary lymphocytes and monocytes from patients. (A–E) GP130 levels, as evaluated by flow cytometry, in primary CD56^bright and CD56^dim NK cell subsets (A), naive and memory B cells (B), naive and memory CD8⁺ T cells (C), naive and memory CD4⁺ T cells (D), and monocytes (E). The graphs show the MFI of GP130, as measured by flow cytometry, in eight controls (C) and six patients (P2–P7). Representative data for GP130 expression in naive B cells (B) and monocytes (E) from P2 and a healthy control are shown, together with data for the isotypic control. (A–E)t tests were used for all comparisons. (F) PBMCs from P6 (red lines) and a control (black lines) were stimulated for 15 min with IL-6, IL-6/IL-6Rα, IL-27, or IFN-α or left unstimulated, and the phosphorylation of STAT3 (pY705) and STAT1 (pY701) was then evaluated in the indicated subsets. (G) Purified monocytes from P5 (red lines) and a control (black lines) were stimulated for 15 min with IL-6, IL-6/IL-6Rα, IL-27, or IFN-α or left unstimulated, and the phosphorylation of STAT3 (pY705) and STAT1 (pY701) was then evaluated. ns, not significant.