Fig 2.

Enhanced IFN and proapoptotic signaling associated with loss-of-function SOCS1 variants. Patient 2 was on corticosteroids (CSs) for 2 months at the time of sampling for the assays shown. A, Schematic of the interaction between SOCS1 and the JAKs. B, Quantification of phospho-STAT1 expression in CD14⁺ monocytes from healthy controls and patients before and after treatment with IFN-β (25 ng/mL) or IFN-γ (25 ng/mL) for 20 minutes. Histograms are representative of 2 independent experiments; the isotype control was comparable between controls and patients. Plotted data are combined from 2 independent experiments, each with 4 controls and 2 patients. C, Expression of the IFN-stimulated gene CD64 compared with CD32, which is independent of IFN signaling, on CD14⁺ monocytes from healthy controls and patients. The flow cytometry histogram (left) is representative of 2 experiments, which were pooled for quantification (right). The MFI for each sample was normalized to the average expression of healthy controls. Gray shading indicates the 25% to 75% quartiles of control values. D. Quantitative PCR analysis of 2 additional IFN-stimulated genes, IFI44 and ISG15, compared with TNF, which is IFN-independent, in PBMCs from controls and patients. Fold expression for each sample was normalized to the average expression of healthy controls. Gray shading indicates the 25% to 75% quartiles of control values. Data are combined from 2 independent experiments. E and F, Heat-map of type I and type II ISGs (Fig 2, E) as well as proapoptotic vs antiapoptotic genes (Fig 2, F) in 4 controls and patients. MFI, Mean fluorescence intensity.